eMedicine Specialties > Pediatrics: Cardiac Disease and Critical Care Medicine > Neonatology
Neonatal SepsisAnn L Anderson-Berry, MD, Assistant Professor of Pediatrics, Joint Division of Newborn Medicine, University of Nebraska Medical Center, Creighton University School of Medicine; Medical Director, NICU Nebraska Medical CenterLinda L Bellig, MA, RN, NNP, Track Coordinator, Instructor, Neonatal Nurse Practitioner Program, Medical University of South Carolina College of Nursing. Currently, retired; Bryan L Ohning, MD, PhD, Medical Director of NICU, Medical Director of Neonatal Transport, Division of Neonatology, Children's Hospital, Greenville Hospital System, University Medical Center; GHS Professor of Clinical Pediatrics, University of South Carolina, School of Medicine; Clinical Associate Professor of Pediatrics, Medical University of South Carolina
Updated: Feb 23, 2010
Neonatal sepsis may be categorized as early or late onset. Eighty-five percent of newborns with early-onset infection present within 24 hours, 5% present at 24-48 hours, and a smaller percentage of patients present within 48-72 hours. Onset is most rapid in premature neonates. Early onset sepsis syndrome is associated with acquisition of microorganisms from the mother. Transplacental infection or an ascending infection from the cervix may be caused by organisms that colonize in the mother's genitourinary tract, with acquisition of the microbe by passage through a colonized birth canal at delivery. The microorganisms most commonly associated with early-onset infection include group B Streptococcus (GBS), Escherichia coli , coagulase-negative Staphylococcus, Haemophilus influenzae , and Listeria monocytogenes .[1 ]
Trends in the epidemiology of early onset sepsis show a decreasing incidence of GBS sepsis.[2 ]This article primarily focuses on bacterial infection and sepsis. Please see relevant eMedicine chapters for discussion of congenital infection, fungal infection, and viral infection of the newborn.
Late-onset sepsis syndrome occurs at 4-90 days of life and is acquired from the caregiving environment. Organisms that have been implicated in causing late-onset sepsis syndrome include
coagulase-negative staphylococci, Staphylococcus aureus , E coli, Klebsiella, Pseudomonas, Enterobacter, Candida, GBS, Serratia, Acinetobacter, and anaerobes. Trends in late-onset sepsis show an increase in coagulase-negative Streptococcal sepsis; most of these isolates are susceptible to first-generation cephalosporins.[2 ]The infant's skin, respiratory tract, conjunctivae, GI tract, and umbilicus may become colonized from the environment, leading to the possibility of late-onset sepsis from invasive microorganisms. Vectors for such colonization may include vascular or urinary catheters, other indwelling lines, or contact from caregivers with bacterial colonization.
Pneumonia is more common in early onset sepsis, whereas meningitis and bacteremia are more common in late-onset sepsis. Premature and ill infants have an increased susceptibility to sepsis and subtle nonspecific initial presentations; therefore, they require much vigilance so that sepsis can be effectively identified and treated.
The infectious agents associated with neonatal sepsis have changed over the past 50 years. S aureus and E coli were the most common bacterial infectious hazards for neonates during the 1950s in the United States. Over the ensuing decades, GBS replaced S aureus as the most common gram-positive organism that caused early-onset sepsis. During the 1990s, GBS and E coli continued to be associated with neonatal infection; however, coagulase-negative Staphylococcus epidermidis is now more frequently observed. Additional organisms, such as L monocytogenes, Chlamydia pneumoniae, H influenzae, Enterobacter aerogenes, and species of Bacteroides and Clostridium have also been identified in neonatal sepsis.
Meningoencephalitis and neonatal sepsis syndrome can also be caused by infection with adenovirus, enterovirus, or coxsackievirus. Additionally, sexually transmitted diseases (eg, gonorrhea, syphilis, herpes simplex virus [HSV], cytomegalovirus [CMV], hepatitis, human immunodeficiency virus [HIV], rubella, toxoplasmosis, Trichomonas vaginalis, Candida species) have all been implicated in neonatal infection.
Bacterial organisms with increased antibiotic resistance have also emerged and have further complicated the management of neonatal sepsis. The colonization patterns in nurseries and personnel are reflected in the organisms currently associated with nosocomial infection. In neonatal ICUs (NICUs), infants with lower birth weight and infants who are less mature have an increased susceptibility to these organisms.
Staphylococcus epidermidis, a coagulase-negative Staphylococcus, is increasingly seen as a cause of nosocomial or late-onset sepsis, especially in the premature infant, in whom it is considered the leading cause of late-onset infections. Its prevalence is likely related to several intrinsic properties of the organism that allow it to readily adhere to the plastic mediums found in intravascular catheters and intraventricular shunts. The bacterial capsule polysaccharide adheres well to the plastic polymers of the catheters. Also, proteins found in the organism (AtlE and SSP-1) enhance attachment to the surface of the catheter. The adherence creates a capsule between microbe and catheter, preventing C3 deposition and phagocytosis.
Biofilms are formed on indwelling catheters by the aggregation of organisms that have multiplied with the protection provided by the adherence to the catheter. Slimes are produced at the site from the extracellular material formed by the organism, which provides a barrier to the host defense, as well as antibiotic action, making coagulase-negative staphylococcal septicemia more difficult to treat. The toxins formed by this organism have also been associated with necrotizing enterocolitis.
In addition to being a cause of neonatal sepsis, the ubiquitous nature of coagulase-negative Staphylococcus as part of the normal skin flora makes it a frequent contaminant of blood and cerebrospinal fluid (CSF) cultures; therefore, a culture growing coagulase-negative Staphylococcus may represent a contaminated sample rather than true coagulase-negative staphylococcal septicemia. The clinical setting, colony counts, and presence of polymorphonuclear (PMN) cells on gram stain of the submitted specimen often help to differentiate true infection and positive culture from a false-positive or contaminated specimen.
In addition to the specific microbial factors mentioned above, numerous host factors predispose the newborn infant to sepsis. These factors are especially prominent in the premature infant and involve all levels of host defense, including cellular immunity, humoral immunity, and barrier function.
The neonatal neutrophil or polymorphonuclear (PMN) cell, which is vital for effective killing of bacteria, is deficient in chemotaxis and killing capacity. Decreased adherence to the endothelial lining of blood vessels reduces their ability to marginate and leave the intravascular space to migrate into the tissues. Once in the tissues, they may fail to degranulate in response to chemotactic factors. Also, neonatal PMNs are less deformable; therefore, they are less able to move through the extracellular matrix of tissues to reach the site of inflammation and infection. The limited ability of neonatal PMNs for phagocytosis and killing of bacteria is further impaired when the infant is clinically ill. Lastly, neutrophil reserves are easily depleted because of the diminished response of the bone marrow, especially in the premature infant.
Neonatal monocyte concentrations are at adult levels; however, macrophage chemotaxis is impaired and continues to exhibit decreased function into early childhood. The absolute numbers of macrophages are decreased in the lungs and are likely decreased in the liver and spleen, as well. The chemotactic and bacteriocidal activity and the antigen presentation by these cells are also not fully competent at birth. Cytokine production by macrophages is decreased, which may be associated with a corresponding decrease in T-cell production.
Although T cells are found in early gestation in fetal circulation and increase in number from birth to about age 6 months, these cells represent an immature population. These naive cells do not proliferate as readily as adult T cells when activated and do not effectively produce the cytokines that assist with B-cell stimulation and differentiation and granulocyte/monocyte proliferation. A delay occurs in the formation of antigen specific memory function following primary infection, and the cytotoxic function of neonatal T cells is 50-100% as effective as adult
T cells. At birth, neonates are deficient in memory T cells. As the neonate is exposed to antigenic stimuli, the number of these memory T cells increases.
Natural killer (NK) cells are found in small numbers in the peripheral blood of neonates. These cells are also functionally immature in that they produce far lower levels of interferon-gamma upon primary stimulation than do adult NK cells. This combination of findings may contribute to the severity of HSV infections in the neonatal period.
The fetus has some preformed immunoglobulin present, primarily acquired through nonspecific placental transfer from the mother. Most of this transfer occurs in late gestation, such that lower levels are found with increasing prematurity. The neonate's ability to generate immunoglobulin in response to antigenic stimulation is intact; however, the magnitude of the response is initially decreased, rapidly rising with increasing postnatal age.
The neonate is also capable of synthesizing immunoglobulin M (IgM) in utero at 10 weeks' gestation; however, IgM levels are generally low at birth, unless the infant was exposed to an infectious agent during the pregnancy, thereby stimulating increased IgM production. Immunoglobulin G (IgG) and immunoglobulin E (IgE) may be synthesized in utero. Most of the IgG is acquired from the mother during late gestation. The neonate may receive immunoglobulin A (IgA) from breastfeeding but does not secrete IgA until 2-5 weeks after birth. Response to bacterial polysaccharide antigen is diminished and remains so during the first 2 years of life.
Complement protein production can be detected as early as 6 weeks' gestation; however, the concentration of the various components of the complement system widely varies among individual neonates. Although some infants have had complement levels comparable with those in adults, deficiencies appear to be greater in the alternative pathway than in the classic pathway. The terminal cytotoxic components of the complement cascade that leads to killing of organisms, especially gram-negative bacteria, are deficient. This deficiency is more marked in preterm infants. Mature complement activity is not reached until infants are aged 6-10 months. Neonatal sera have reduced opsonic efficiency against GBS, E coli, and S pneumoniae because of decreased levels of fibronectin, a serum protein that assists with neutrophil adherence and has opsonic properties.
The physical and chemical barriers to infection in the human body are present in the newborn but are functionally deficient. Skin and mucus membranes are broken down easily in the premature infant. Neonates who are ill and/or premature are additionally at risk because of the invasive procedures that breach their physical barriers to infection. Because of the interdependence of the immune response, these individual deficiencies of the various components of immune activity in the neonate conspire to create a hazardous situation for the neonate exposed to infectious threats.
The incidence of culture-proven sepsis is approximately 2 per 1000 live births. Of the 7-13% of neonates who are evaluated for neonatal sepsis, only 3-8% have culture-proven sepsis. The early signs of sepsis in the newborn are nonspecific; therefore, many newborns undergo diagnostic studies and the initiation of treatment before the presence of sepsis has been proven. Additionally, because the American Academy of Pediatrics (AAP),[3 ]American Academy of Obstetrics and Gynecology (AAOG), and Centers for Disease Control and Prevention (CDC)[4 ]all have recommended sepsis screening and/or treatment for various risk factors related to GBS diseases, many asymptomatic neonates now undergo evaluation. Because the mortality rate of untreated sepsis can be as high as 50%, most clinicians believe that the hazard of untreated sepsis is too great to wait for confirmation based on positive culture results; therefore, most clinicians initiate treatment while awaiting culture results.
The mortality rate in neonatal sepsis may be as high as 50% for infants who are not treated. Infection is a major cause of fatality during the first month of life, contributing to 13-15% of all neonatal deaths. Neonatal meningitis, a serious morbidity of neonatal sepsis, occurs in 2-4 cases per 10,000 live births and significantly contributes to the mortality rate in neonatal sepsis; it is responsible for 4% of all neonatal deaths. In the preterm infant, inflammatory mediators associated with neonatal sepsis may contribute to brain injury and poor neurodevelopmental outcomes.
Black infants have an increased incidence of GBS disease and late-onset sepsis. This is observed even after controlling for risk factors of low birth weight and decreased maternal age.
The incidence of bacterial sepsis and meningitis, especially for gram-negative enteric bacilli, is higher in males than in females.
Premature infants have an increased incidence of sepsis. The incidence of sepsis is significantly higher in infants with very low birth weight (<1000 g), at 26 per 1000 live births, than in infants with a birth weight of 1000-2000 g, at 8-9 per 1000 live births. The risk for death or meningitis from sepsis is higher in infants with low birth weight than in full-term neonates.
The most common risk factors associated with early onset neonatal sepsis include maternal group B Streptococcus (GBS) colonization (especially if untreated during labor), premature rupture of membranes (PROM), preterm rupture of membranes, prolonged rupture of membranes, prematurity, maternal urinary tract infection, and chorioamnionitis.
Other factors associated with or predisposing to early onset neonatal sepsis include low Apgar score (<6 at 1 or 5 min), maternal fever greater than 38°C, maternal urinary tract infection, poor prenatal care, poor maternal nutrition, low socioeconomic status, recurrent abortion, maternal substance abuse, low birth weight, difficult delivery, birth asphyxia, meconium staining, and congenital anomalies.[5 ]Risk factors implicated in neonatal sepsis reflect the stress and illness of the fetus at delivery, as well as the hazardous uterine environment surrounding the fetus before delivery.
Late onset sepsis is associated with the following risk factors: prematurity, central venous catheterization (duration of >10 d), nasal cannula or continuous positive airway pressure (CPAP) use, H2 blocker/proton pump inhibitor use, and gastrointestinal tract pathology.
An awareness of the many risk factors associated with neonatal sepsis prepares the clinician for early identification and effective treatment, thereby reducing mortality and morbidity.
Maternal GBS statuso The most common etiology of neonatal bacterial sepsis is GBS. Nine serotypes
exist, and each is related to the polysaccharide capsule of the organism. Types I, II, and III are commonly associated with neonatal GBS infection. The type III strain has been shown to be most highly associated with CNS involvement in early-onset infection, whereas types I and V have been associated with early-onset disease without CNS involvement.
o The GBS organism colonizes the maternal GI tract and birth canal. Approximately 30% of women have asymptomatic GBS colonization during pregnancy. GBS is responsible for approximately 50,000 maternal infections per year in women, but only 2 neonates per 1000 live births are infected. Women with heavy GBS colonization and culture results that are chronically positive for GBS have the highest risk of perinatal transmission. Also, heavy colonization at 23-26 weeks of gestation is associated with prematurity and low birth weight. Colonization at delivery is associated with neonatal infection. Intrapartal chemoprophylaxis of women with positive culture results for GBS has been shown to decrease the transmission of the organism to the neonate during delivery.
PROM may occur in response to an untreated urinary tract infection or birth canal and is also associated with previous preterm delivery, uterine bleeding in pregnancy, and heavy cigarette smoking during pregnancy.
o Rupture of membranes without other complications for more than 24 hours prior to delivery is associated with a 1% increase in the incidence of neonatal sepsis; however, when chorioamnionitis accompanies the rupture of membranes, the incidence of neonatal infection is quadrupled.
o A recent multicenter study demonstrated that clinical chorioamnionitis and maternal colonization with GBS are the most important predictors of subsequent neonatal infection following PROM.[6 ]
o When membranes have ruptured prematurely before 37 weeks' gestation, a longer latent period precedes vaginal delivery, increasing the likelihood that the infant will be infected. The relationship between duration of membrane rupture and neonatal infection is inversely related to gestational age. Therefore, the more premature an infant, the longer the delay between rupture of membranes and delivery, and the higher the likelihood of neonatal sepsis.
o A study by Seaward et al found that more than 6 vaginal digital examinations, which may occur as part of the evaluation for PROM, were associated with neonatal infection even when considered separately from the presence of chorioamnionitis.[6 ]
Prematurity: The relationship between preterm PROM and neonatal sepsis has already been described; however, other associations between prematurity and neonatal sepsis increase the risk for premature infants.
o Preterm infants are more likely to require invasive procedures, such as umbilical catheterization and intubation.
o Prematurity is associated with infection from cytomegalovirus (CMV), herpes simplex virus (HSV), hepatitis B, toxoplasmosis, Mycobacterium tuberculosis, Campylobacter fetus, and Listeria species.
o Intrauterine growth retardation and low birth weight are also observed in CMV and toxoplasmosis infections.
o Premature infants have less immunologic ability to resist and combat infection. This leads to infection with common organisms such as coagulase-negative staphylococci an organism usually not associated with severe sepsis.
Chorioamnionitis: The relationship between chorioamnionitis and other risk variables is strong. Suspect chorioamnionitis in the presence of fetal tachycardia, uterine tenderness, purulent amniotic fluid, elevated maternal WBC count, and unexplained maternal temperature above 100.4°F (38°C).
The clinical signs of neonatal sepsis are nonspecific and are associated with characteristics of the causative organism and the body's response to the invasion. These nonspecific clinical signs of early sepsis syndrome are also associated with other neonatal diseases, such as respiratory distress syndrome (RDS), metabolic disorders, intracranial hemorrhage, and a traumatic delivery. Given the nonspecific nature of these signs, providing treatment for suspected neonatal sepsis while excluding other disease processes is prudent.
A systematic physical assessment of the infant is best performed in series and should include
observation, auscultation, and palpation in that order to obtain the most information from the examination. Changes in findings from one examination to the next provides important information about the presence and evolution of sepsis.[7 ]
Congenital pneumonia and intrauterine infection: Inflammatory lesions are observed postmortem in the lungs of infants with congenital and intrauterine pneumonia. This may not be caused by the action of the microorganisms themselves but may be caused by aspiration of amniotic fluid containing maternal leukocytes and cellular debris. Tachypnea, irregular respirations, moderate retracting, apnea, cyanosis, and grunting may be observed. Neonates with intrauterine pneumonia may also be critically ill at birth and require high levels of ventilatory support. The chest radiograph may depict bilateral consolidation or pleural effusions.
Congenital pneumonia and intrapartum infection: Neonates who are infected during the birth process may acquire pneumonia through aspiration of the microorganisms during the delivery process. The aspiration may lead to infection with pulmonary changes, infiltration, and destruction of bronchopulmonary tissue. This damage is partly due to the granulocytes' release of prostaglandins and leukotrienes. Fibrinous exudation into the alveoli leads to inhibition of pulmonary surfactant function and respiratory failure with an RDS-like presentation. Vascular congestion, hemorrhage, and necrosis may occur.
o Klebsiella species and S aureus are especially likely to generate severe lung damage, producing microabscesses and empyema.
o Early onset GBS pneumonia has a particularly fulminant course, with significant mortality in the first 48 hours of life.
o Infectious pneumonia is also characterized by pneumatoceles within the pulmonary tissue. Coughing, grunting, costal and sternal retractions, nasal flaring, tachypnea and/or irregular respiration, rales, decreased breath sounds, and cyanosis may be observed.
o Radiographic evaluation may demonstrate segmental or lobar atelectasis or a diffuse reticulogranular pattern, much like what is observed in RDS.
o Pleural effusions may be observed in advanced disease. Postnatal infection: Postnatally acquired pneumonia may occur at any age. Because these
infectious agents exist in the environment, the likely cause depends heavily on the infant's recent environment. If the infant has remained hospitalized in an NICU environment, especially with endotracheal intubation and mechanical ventilation, the organisms may include Staphylococcus or Pseudomonas species. Additionally, these hospital-acquired organisms frequently demonstrate multiple antibiotic resistances. Therefore, the choice of antibiotic agents in such cases requires knowledge of the likely causative organisms and the local antibiotic-resistance patterns.
Cardiac signs: In overwhelming sepsis, an initial early phase characterized by pulmonary hypertension, decreased cardiac output, and hypoxemia may occur. These cardiopulmonary disturbances may be due to the activity of granulocyte-derived biochemical mediators, such as hydroxyl radicals and thromboxane B2, an arachidonic acid metabolite. These biochemical agents have vasoconstrictive actions that result in pulmonary hypertension when released in pulmonary tissue. A toxin derived from the polysaccharide capsule of type III Streptococcus has also been shown to cause pulmonary hypertension. The early phase of pulmonary hypertension is followed by further
progressive decreases in cardiac output with bradycardia and systemic hypotension. The infant manifests overt shock with pallor, poor capillary perfusion, and edema. These late signs of shock are indicative of severe compromise and are highly associated with mortality.
Metabolic signs: Hypoglycemia, hyperglycemia, metabolic acidosis, and jaundice all are metabolic signs that commonly accompany neonatal sepsis syndrome. The infant has an increased glucose requirement because of sepsis. The infant may also have impaired nutrition from a diminished energy intake. Hypoglycemia accompanied by hypotension may be secondary to an inadequate response from the adrenal gland and may be associated with a low cortisol level. Metabolic acidosis is due to a conversion to anaerobic metabolism with the production of lactic acid. When infants are hypothermic or they are not kept in a neutral thermal environment, efforts to regulate body temperature can cause metabolic acidosis. Jaundice occurs in response to decreased hepatic glucuronidation caused by both hepatic dysfunction and increased erythrocyte destruction.
Neurologic signs: Meningitis is the common manifestation of infection of the CNS. It is primarily associated with GBS (36%), E coli (31%), and Listeria species (5-10%) infections, although other organisms such as S pneumoniae, S aureus, Staphylococcus epidermis, H influenzae, and species of Pseudomonas, Klebsiella, Serratia, Enterobacter, and Proteus may cause meningitis. Acute and chronic histologic features are associated with specific organisms.
o Ventriculitis Ventriculitis is the initiating event, with inflammation of the ventricular
surface. Exudative material usually appears at the choroid plexus and is external to the plexus. Then, ependymitis occurs with disruption of the ventricular lining and projections of glial tufts into the ventricular lumen. Glial bridges may develop by these tufts and cause obstruction, particularly at the aqueduct of Sylvius.
The lateral ventricles may become multiloculated, which is similar to forming abscesses. Multiloculated ventricles can isolate organisms in an area, making treatment more difficult.
Meningitis is likely to arise at the choroid plexus and extend via the ventricles through aqueducts into the subarachnoid space to affect the cerebral and cerebellar surfaces. The high glycogen content in the neonatal choroid plexus provides an excellent medium for the bacteria. When meningitis develops from ventriculitis, it complicates effective treatment because achieving adequate antibiotic levels in the cerebral ventricles is difficult.
When present, ventricular obstruction causes additional problems.o Arachnoiditis: This is the next phase and is the hallmark of meningitis. The
arachnoid is infiltrated with inflammatory cells that produce an exudate that is thick over the base of the brain and more uniform over the rest of the brain. Early in the infection, the exudate is primarily polymorphonuclear (PMN) cells, bacteria, and macrophages. Exudate is prominent around the blood vessels and extends into the brain parenchyma. In the second and third weeks of infection, the proportion of PMNs decreases; the dominant cells are histiocytes, macrophages,
and some lymphocytes and plasma cells. Exudate infiltration of cranial roots 3-8 occurs. After this period, the exudate decreases. Thick strands of collagen form, and arachnoid fibrosis occurs, which is responsible for obstruction. Hydrocephalus results. Early onset GBS meningitis is characterized by much less arachnoiditis than late-onset GBS meningitis.
o Vasculitis: This extends the inflammation of the arachnoid and ventricles to the blood vessels surrounding the brain. Occlusion of the arteries rarely occurs; however, venous involvement is more severe. Phlebitis may be accompanied with thrombosis and complete occlusion. Multiple fibrin thrombi are especially associated with hemorrhagic infarction. This vascular involvement is apparent within the first days of meningitis and becomes more prominent during the second and third weeks.
o Cerebral edema: This may occur during the acute state of meningitis. The edema may be severe enough to greatly diminish the ventricular lumen. The cause is unknown, but it is likely related to vasculitis and the increased permeability of blood vessels. It may also be related to cytotoxins of microbial origin. Herniation of edematous supratentorial structures does not generally occur in neonates because of the cranium's distensibility.
o Infarction: This is a prominent and serious feature of neonatal meningitis. It occurs in 30% of infants who die. Lesions occur because of multiple venous occlusions, which are frequently hemorrhagic. The loci of infarcts are most often in the cerebral cortex and underlying white matter but may also be subependymal within the deep white matter. Neuronal loss occurs, especially in the cerebral cortex, and periventricular leukomalacia may subsequently appear in areas of neuronal cell death.
o Laboratory findings Meningitis due to early onset neonatal sepsis usually occurs within 24-48
hours and is dominated by nonneural signs. Neurologic signs may include stupor and irritability. Overt signs of meningitis occur in only 30% of cases. Even culture-proven meningitis may not demonstrate white cell changes in the CSF. Meningitis due to late-onset disease is more likely to demonstrate neurologic signs (80-90%). Impairment of consciousness (ie, stupor with or without irritability), coma, seizures, bulging anterior fontanel, extensor rigidity, focal cerebral signs, cranial nerve signs, and nuchal rigidity occur. In the neonate, many of these physical examination findings are subtle or nonapparent.
The CSF findings in infectious neonatal meningitis are an elevated WBC count (predominately PMNs), an elevated protein level, a decreased CSF glucose concentration, and positive culture results. The decrease in CSF glucose concentration does not necessarily reflect serum hypoglycemia. Glucose concentration abnormalities are more severe in late-onset disease and with gram-negative organisms. The CSF WBC count is within the reference range in 29% of GBS meningitis infections; in gram-negative meningitis, it is within the reference range in only 4%. Reference range CSF protein and glucose concentrations are found in about 50% of patients with GBS meningitis; however, in gram-negative infections,
reference range CSF protein and glucose concentrations are found in only 15-20%.
Temperature instability is observed with neonatal sepsis and meningitis, either in response to pyrogens secreted by the bacterial organisms or from sympathetic nervous system instability. The neonate is most likely to be hypothermic. The infant may also have decreased tone, lethargy, and poor feeding. Signs of neurologic hyperactivity are more likely when late-onset meningitis occurs.
Hematologic signso The platelet count in the healthy newborn is rarely less than 100,000/µL in the
first 10 days of life. Thrombocytopenia with counts less than 100,000 may occur in neonatal sepsis in response to the cellular products of the microorganisms. These cellular products cause platelet clumping and adherence leading to platelet destruction. Thrombocytopenia may be a presenting sign and can last as long as 3 weeks; 10-60% of infants with sepsis have thrombocytopenia. Because of the appearance of newly formed platelets, mean platelet volume (MPV) and platelet distribution width (PDW) are shown to be significantly higher in neonatal sepsis after 3 days. Because of the myriad of causes of thrombocytopenia and its late appearance in neonatal sepsis, the presence of thrombocytopenia does not aid the diagnosis of neonatal sepsis.
o Although WBC counts and ratios are more sensitive for determining sepsis than platelet counts, they remain very nonspecific and have low positive predictive value. Normal WBC counts may be initially observed in as many as 50% of cases of culture-proven sepsis. Infants who are not infected may also demonstrate abnormal WBC counts related to the stress of delivery or several other factors. A differential may be of use in diagnosing sepsis. Total neutrophil count (PMNs and immature forms) is slightly more sensitive in determining sepsis than total leukocyte count (percent lymphocyte + monocyte/PMNs + bands). Abnormal neutrophil counts, taken at the time of symptom onset, are only observed in two thirds of infants; therefore, the neutrophil count does not provide adequate confirmation of sepsis. Neutropenia is observed in sepsis, maternal hypertension, severe perinatal asphyxia, and periventricular or intraventricular hemorrhage.
o Neutrophil ratios have been more useful in diagnosing or excluding neonatal sepsis; the immature-to-total (I/T) ratio is the most sensitive. All immature neutrophil forms are counted, and the maximum acceptable ratio for excluding sepsis during the first 24 hours is 0.16. In most healthy, nonseptic newborns, the ratio falls to 0.12 within 60 hours of life. The sensitivity of the I/T ratio has ranged from 60-90%, and elevations may be observed with other physiological events, limiting the positive predictive value of these ratios; therefore, when diagnosing sepsis, the elevated I/T ratio should be used in combination with other signs.
o Disseminated intravascular coagulation (DIC) can occur in infected infants. Predicting which infants will be affected at the onset of sepsis is difficult. Affected infants show abnormalities in prothrombin time (PT), partial thromboplastin time (PTT), and fibrinogen and D-dimer levels and may need blood products, including fresh frozen plasma (FFP) and cryoprecipitate, to
replace coagulation factors consumed in association with DIC. If infants show signs consistent with impaired coagulation, including gastric blood, bleeding from intravenous or laboratory puncture sites, or other bleeding, evaluating coagulation by checking these values is important.
GI signs: The intestinal tract can be colonized by organisms in utero or at delivery by swallowing infected amniotic fluid. The immunologic defenses of the intestinal tract are not mature, especially in the preterm infant. Lymphocytes proliferate in the intestines in response to mitogen stimulation; however, this proliferation is not fully effective in responding to a microorganism because antibody response and cytokine formation is immature until approximately 46 weeks. Necrotizing enterocolitis (NEC) has been associated with the presence of a number of species of bacteria in the immature intestine, and bacterial overgrowth of these organisms in the neonatal lumen is a component of the multifactorial pathophysiology of NEC.
Acidosis, Metabolic Necrotizing EnterocolitisBowel Obstruction in the Newborn OsteomyelitisCoarctation of the Aorta Pericarditis, BacterialCongenital Diaphragmatic Hernia Pulmonary Atresia With Intact Ventricular SeptumCongenital Lung Malformations Pulmonary Hypertension, Persistent-NewbornCongenital Pneumonia Pulmonary HypoplasiaHeart Failure, Congestive Pulmonary SequestrationHemolytic Disease of Newborn Respiratory Distress SyndromeHemorrhagic Disease of Newborn Single VentricleHypoglycemia Urinary Tract InfectionHypoplastic Left Heart SyndromeMeconium Aspiration SyndromeMeningitis, Bacterial
Blood, cerebrospinal fluid (CSF), and urine cultures
Aerobic and anaerobic cultures are appropriate for most of the bacterial etiologies associated with neonatal sepsis. Anaerobic cultures are especially important in neonates with abscess formation, processes with bowel involvement, massive hemolysis, and refractory pneumonia.
A Gram stain provides early identification of the gram-negative or gram-positive status of the organism for preliminary identification.
Bacterial culture results should generally reveal the organism of infection within 36-48 hours; subsequent initial identification of the organism occurs within 12-24 hours of the
growth. Single-site blood cultures are effective in isolating bacteria in the neonate with sepsis.
Urine cultures are most appropriate when investigating late-onset sepsis. Blood and CSF cultures are appropriate for early onset and late-onset sepsis. Because of the low incidence of meningitis in the newborn infant with negative blood
culture results, clinicians may elect to culture the CSF of only those infants with documented or presumed sepsis. However, recent data in large numbers of patients show a 38% rate of culture-positive meningitis in neonates with negative blood culture results and suspected sepsis. Therefore, a lumbar puncture should be part of the evaluation of an infant with suspected sepsis.
A CBC count and differential may be ordered serially to determine changes associated with the infection, such as thrombocytopenia or neutropenia, or to monitor the development of a left shift or an elevated I/T ratio. Such serial monitoring of the CBC count may be useful in aiding the differentiation of sepsis syndrome from nonspecific abnormalities due to the stress of delivery.
The platelet count in the healthy newborn is rarely less than 100,000/µL in the first 10 days of life (normal, 150,000/μ L). Thrombocytopenia with counts less than 100,000 may occur in neonatal sepsis. Mean platelet volume (MPV) and platelet distribution width (PDW) have been shown to be significantly elevated in infants with sepsis after 2-3 days of life. These measures may assist in determining the etiology of thrombocytopenia.
WBC counts and ratios may be helpful in determining sepsis, although normal WBC counts may be observed in as many as 50% of culture-proven sepsis cases. WBC counts and ratios remain very nonspecific and have low positive predictive value. Infants who are not infected may also have abnormal WBC counts related to the stress of delivery. A differential may be of use in diagnosing sepsis; however, these counts are laboratory technician–dependent. Total neutrophil count (polymorphonuclear (PMN) cells and immature forms) is slightly more sensitive in determining sepsis than total leukocyte count (percent lymphocyte + monocyte/PMNs + bands). Abnormal neutrophil counts at the time of symptom onset are only observed in two thirds of infants; therefore, neutrophil count does not provide adequate confirmation of sepsis. Neutropenia is also observed with maternal hypertension, severe perinatal asphyxia, and periventricular or intraventricular hemorrhage.
Neutrophil ratios have been more useful in diagnosing neonatal sepsis; the I/T ratio is the most sensitive. All immature neutrophil forms are counted, and the maximum acceptable ratio for excluding sepsis in the first 24 hours is 0.16. In most newborns, the ratio falls to 0.12 within 60 hours of life. The sensitivity of the I/T ratio has ranged from 60-90%, and elevations may be observed with other physiological events, limiting the positive predictive value of these ratios; therefore, when diagnosing sepsis, the elevated I/T ratio should be used in combination with other signs.
The CSF findings in infectious neonatal meningitis are an elevated WBC count (predominately PMNs), an elevated protein level, a depressed glucose level, and positive culture results. The decrease in glucose is not reflective of serum hypoglycemia. The CSF abnormalities are more severe in late onset and with gram-negative organisms. The WBC count is within the reference range in 29% of GBS meningitis infections; in gram-negative meningitis, it is within the
reference range in only 4%. Reference range protein and glucose concentrations are found in about 50% of patients with GBS meningitis; however, in gram-negative infections, reference range protein and glucose concentration are found in only 15-20%.
Levels of C-reactive protein (CRP), an acute phase protein associated with tissue injury, are elevated at some point in 50-90% of infants with systemic bacterial infections.[8 ]CRP levels rise secondary to macrophage, T-cell, and adipocyte production of interleukin-6 (IL-6). This is especially true of infections with abscesses or cellulitis of deep tissue. CRP levels usually begin to rise within 4-6 hours of onset of infection and are abnormal within 24 hours of infection, peak within 2-3 days, and remain elevated until the inflammation is resolved. The CRP level is not recommended as a sole indicator of neonatal sepsis but may be used as part of a sepsis workup or as a serial study during infection to determine response to antibiotics, duration of therapy, and/or relapse of infection.
IgM concentration in serum may be helpful in determining the presence of an intrauterine infection, especially if the infection has been present over a period of time.
Current evidence on the use of infection markers such as CD11b, CD64, interleukin-6, and interleukin-8 for evaluation of sepsis in neonates shows that they may be helpful as adjunctive markers. Serial measurements and use of combinations of tests may improve their value. However, at this time, these tests should not be used alone to determine the need for antibiotic therapy. In some cases, they may prove useful in determining when to stop antibiotic therapy.
Levels of other acute phase reactants, such as procalcitonin and serum amyloid, are often elevated with the onset of sepsis. Evidence is insufficient and the clinical laboratory availability is too limited to routinely use these levels as markers for neonatal sepsis. Their use may be in combination with other acute phase reactants, such as CRP.
Chest radiography may reveal segmental or lobar infiltrate but more commonly reveals a diffuse, fine, reticulogranular pattern, much like what is observed in respiratory distress syndrome (RDS). Pleural effusions may also be observed.
CT scanning or MRI may be needed late in the course of complex neonatal meningitis to document obstructive hydrocephalus, the site where the obstruction is occurring, and the occurrence of major infarctions or abscesses. Signs of chronic disease, such as ventricular dilation, multicystic encephalomalacia, and atrophy, may also be demonstrated on CT scanning or MRI.
Head ultrasonography in neonates with meningitis may reveal evidence of ventriculitis, abnormal parenchymal echogenicities, extracellular fluid, and chronic changes. Serially, head ultrasonography can reveal the progression of complications.
No consensus regarding the inclusion of herpes simplex virus (HSV) polymerase chain reaction (PCR) testing as part of a routine sepsis work-up in the neonate has been reached. Currently, HSV PCR is reserved for infants with CNS abnormalities, skin vesicles, CSF abnormalities, or infants not responding to antibiotics with negative cultures and clinical symptoms.[9 ]However, vesicles are not present in as many as one third of CNS HSV and disseminated HSV cases. Further research in this area is needed to provide clear practice recommendations.
Although not yet available clinically, emerging technology using PCR could help in more rapidly identifying sepsis and the causative organism compared with blood culture alone.[10 ]Rapid pathogen detection using multiplex PCR may be useful in more timely selection of targeted antibiotic therapy, at the same time limiting exposure to broad-spectrum antibiotics.[11 ]
Lumbar puncture is warranted for early and late-onset sepsis, although clinicians may be unsuccessful in obtaining sufficient or clear fluid for all the studies. Infants may be positioned on their side or sit with support. The insertion site should be between L3 and L4 in order to be below the lowest point of the spinal cord in infants. If positive culture results are demonstrated, a follow-up lumbar puncture is often performed within 24-36 hours after antibiotic therapy is initiated to document CSF sterility. If organisms are still present, modification of drug type or dosage may be required to adequately treat the meningitis. An additional lumbar puncture within 24-36 hours of the change in therapy is necessary if organisms are still present.
When neonatal sepsis is suspected, treatment should be initiated immediately because of the neonate's relative immunosuppression. Begin antibiotics as soon as diagnostic tests are performed. Additional therapies have been investigated for the treatment of neonatal sepsis; however, no substantial clinical trials have shown that these treatments are beneficial. These additional therapies include granulocyte transfusion, intravenous immune globulin (IVIG) replacement, exchange transfusion, and the use of recombinant cytokines.
In the United States and Canada, the current approach to treat early onset neonatal sepsis syndrome includes combined intravenous (IV) aminoglycoside and expanded-spectrum penicillin antibiotic therapy. This provides coverage for gram-positive organisms, especially group B Streptococcus (GBS), and gram-negative bacteria, such as E coli. The specific antibiotics to be used are chosen on the basis of maternal history and prevalent trends of organism colonization and antibiotic susceptibility in individual nurseries.
o If an infection appears to be nosocomial, antibiotic coverage should be directed at organisms implicated in hospital-acquired infections, including S aureus, S epidermis, and Pseudomonas species. Most strains of S aureus produce beta-
lactamase, which makes them resistant to penicillin G, ampicillin, carbenicillin, and ticarcillin. Vancomycin has been favored for this coverage; however, concern exists that overuse of this drug may lead to vancomycin-resistant organisms, thereby eliminating the best response to these resistant organisms. Oxacillin therapy is preferred by some clinicians because of this.
o Cephalosporins are attractive in the treatment of nosocomial infection because of their lack of dose-related toxicity and adequate serum and cerebrospinal fluid (CSF) concentration; however, resistance by gram-negative organisms has occurred with their use. Ceftriaxone displaces bilirubin from serum albumin and should be used with caution in infants with significant hyperbilirubinemia. Resistance and sensitivities for the organism isolated from cultures are used to select the most effective drug.
o Aminoglycosides and vancomycin both have the potential to produce ototoxicity and nephrotoxicity and should therefore be used with caution. The serum drug level is assessed around the third dose or at 48 hours after starting treatment to determine if levels are within the therapeutic range. The drug dosage or interval may need to be adjusted to optimize the drug serum levels. A serum level may also be warranted if the infant's clinical condition has not improved to ensure that a therapeutic level has been reached. In addition, renal function and hearing screening should be considered after completion of the therapeutic course to determine if any short- or long-range toxic effects of these drugs have occurred.
o If culture results are negative but the infant has significant risk or clinical signs for sepsis, the clinician must decide whether to provide continued treatment. Two to three days of negative culture results should provide confidence in the data; however, a small number of infants documented to have had sepsis by postmortem examination had negative culture results during their initial sepsis evaluation.
o Management is further complicated if the mother received antibiotic therapy before delivery, especially if she received the therapy within several hours of delivery. This may result in negative culture results in an infant who actually has bacteremia or sepsis. With this in mind, the need for continued therapy should be based not on a single test, but on a review of all diagnostic data, including culture results, maternal and intrapartal risk factors, CSF results, the CBC count and differential, C-reactive protein (CRP) trends, radiographs, and clinical progress. Treatment for 7-10 days may be appropriate, even if culture results remain negative at 48-72 hours.
o Infants with bacterial meningitis often require different dosages of antibiotics and longer courses of treatment. These infants may also require an antimicrobial that has better penetration of the blood-brain barrier to achieve therapeutic drug concentrations in the CSF. A follow-up lumbar puncture within 24-36 hours after antibiotic therapy has been initiated to determine if the CSF is sterile is recommended. If organisms are still present, modification of drug type or dosage is required to adequately treat the meningitis. Continue antibiotic treatment for 2 weeks after sterilization of the CSF or for a minimum of 2 weeks for gram-positive meningitis and 3 weeks for gram-negative meningitis.
o Meningitis complicated by seizures or persistent positive cultures may require extended IV antimicrobial therapy. Chloramphenicol or trimethoprim-sulfamethoxazole has been shown to be effective in the treatment of highly resistant bacterial meningitis. Trimethoprim-sulfamethoxazole should not be used if hyperbilirubinemia and kernicterus are of concern in the newborn.
Granulocyte transfusion has been shown to be suitable for infants with significant depletion of the storage neutrophil pool; however, the documentation of storage pool depletion requires a bone marrow aspiration, and the granulocyte transfusion must be administered quickly to be beneficial. The number of potential adverse effects, such as graft versus host reaction, transmission of cytomegalovirus (CMV) or hepatitis B, and pulmonary leukocyte sequestration, is considerable. Therefore, this therapy remains an experimental treatment.
IVIG infusion has been studied as a possible therapy for neonatal sepsis to provide type-specific antibodies to improve opsonization and phagocytosis of bacterial organisms and to improve complement activation and chemotaxis of neonatal neutrophils; however, difficulties with IVIG therapy for neonatal sepsis exist. The effect has been transient, clinically available IVIG solutions do not contain type-specific antibody and adverse effects associated with the infusion of any blood product can occur. Dose-related problems with this therapy decrease its usefulness in neonatal populations. At present, the data do not support the routine use of IVIG in neonatal sepsis.
Recombinant human cytokine administration to stimulate granulocyte progenitor cells has been studied as an adjunct to antibiotic therapy. These therapies have shown promise in animal models, especially for GBS sepsis, but require pretreatment or immediate treatment to demonstrate efficacy. The use of granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) has been studied in clinical trials, but their use in clinical neonatology remains experimental.
The infant with sepsis may require treatment aimed at the overwhelming systemic effects of the disease. Cardiopulmonary support and intravenous nutrition may be required during the acute phase of the illness until the infant's condition stabilizes. Monitoring of blood pressure, vital signs, hematocrit, platelets, and coagulation studies is vital. The need for blood product transfusion including packed RBCs (PRBCs), platelets, and fresh frozen plasma (FFP) is not uncommon.
If an abscess is present, surgical drainage may be necessary because intravenous antibiotic therapy cannot adequately penetrate an abscess and because antibiotic treatment alone is ineffective.
Surgical consultation for central line placement may be necessary in infants who require prolonged IV antimicrobial therapy for sepsis, if peripheral IV access can not be maintained.
If hydrocephalus associated with neonatal meningitis occurs, and progressive accumulation of CSF is present, a ventriculoperitoneal (VP) shunt may be necessary to drain off the excess fluid. The immediate complications of shunt placement are overdrainage, equipment failure, disconnection, migration of catheter, or shunt infection. Abdominal obstruction, omental cysts,
and perforation of the bladder, gallbladder, or bowel are uncommon. The VP shunt may cause long-term neurologic complications, including slit-ventricle syndrome, seizures, neuro-ophthalmological problems, and craniosynostosis; however, the outcome for children with VP shunt placement is generally good with careful follow-up.
Infectious disease consultation is useful, especially if the infant is not responding to treatment, is infected with an unusual organism, or has had a complicated clinical course.
If neonatal meningitis is identified, consultation with a pediatric neurologist may be necessary for assistance with outpatient follow-up of neurological sequelae. Inpatient consultation may be necessary if meningitis is complicated by seizures.
Consultation with a pediatric pharmacologist may be helpful for advice on the most appropriate antibiotic or dosage to use should changes prove necessary because of inadequate or toxic drug levels obtained with therapeutic monitoring.
Pediatric surgical consultation may be necessary if sepsis is complicated by abscess, if the differential diagnosis includes necrotizing enterocolitis (NEC), or if central line placement is required.
The neonate may need to be given nothing by mouth (NPO) during the first days of treatment because of gastrointestinal symptoms, feeding intolerance, or poor feeding.
Consider parenteral nutrition to ensure that the patient's intake of calories, protein, minerals, and electrolytes is adequate during this period.
Feeding may be restarted via a nasogastric tube for the infant with serious compromise.
For most infants, breast milk is the enteral diet recommended by the AAP.
The infant with temperature instability needs thermoregulatory support with a radiant warmer or incubator.
Once the infant is stable from a cardiopulmonary standpoint, parental contact is important.
Some of the antibiotics commonly used to treat neonatal sepsis syndrome include ampicillin, gentamicin, cefotaxime, vancomycin, metronidazole, erythromycin, and piperacillin. The choice of antibiotic agents should be based on the specific organisms associated with sepsis, sensitivities
of the bacterial agent, and prevalent nosocomial infection trends in the nursery. Viral infections such as herpes and fungal infections can masquerade as bacterial infections.
Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting. Neonatal doses for antibiotics may be based on several variables (eg, postmenstrual age [PMA], postnatal age, weight).
A beta-lactam antibiotic that is bacteriocidal for susceptible organisms, such as GBS, Listeria, non–penicillinase-producing Staphylococcus, some strains of H influenzae, and meningococci. Recent publications indicate ampicillin (in combination with gentamicin) is the first-line therapy for suspected sepsis in the newborn.
<29 weeks PMA and 0-28 days: 50-100 mg/kg/dose IV/IM q12h<29 weeks PMA and >28 days: 50-100 mg/kg/dose IV/IM q8h30-36 weeks PMA and 0-14 days: 50-100 mg/kg/dose IV/IM q12h30-36 weeks PMA and >14 days: 50-100 mg/kg/dose IV/IM q8h37-44 weeks PMA and 0-7 days: 50-100 mg/kg/dose IV/IM q12h37-44 weeks PMA and >7 days: 50-100 mg/kg/dose IV/IM q8h>45 weeks PMA: 50-100 mg/kg/dose IV/IM q6hHigher dosage may be used with meningitis and GBS
Aminoglycosides reduce effectiveness when coadministered; probenecid and disulfiram elevate levels; allopurinol decreases effects and has additive effects on ampicillin rash
Adjust dose in renal failure; evaluate rash and differentiate from hypersensitivity reaction
An aminoglycoside that is bacteriocidal for susceptible gram-negative organisms, such as E coli and Pseudomonas, Proteus, and Serratia species. Effective in combination with ampicillin for GBS and Enterococcus. Recent publications indicate gentamicin (in combination with ampicillin) is the first-line therapy for suspected sepsis in the newborn.
<29 weeks PMA and 0-7 days: 5 mg/kg/dose IV/IM q48h<29 weeks PMA and 8-28 days: 4 mg/kg/dose IV/IM q36h<29 weeks PMA and >29 days: 4 mg/kg/dose IV/IM q24h30-34 weeks PMA and 0-7 days: 4.5 mg/kg/dose IV/IM q36h30-34 weeks PMA and >7 days: 4 mg/kg/dose IV/IM q24h>35 weeks PMA: 4 mg/kg/dose IV/IM q24hIV dosage preferred; IM may be used if IV access is difficult
Coadministration with other aminoglycosides, cephalosporins, penicillins, indomethacin, and amphotericin B may increase nephrotoxicity; because aminoglycosides enhance effects of neuromuscular blocking agents prolonged respiratory depression may occur; coadministration with loop diuretics may increase auditory toxicity of aminoglycosides; possible irreversible hearing loss of varying degrees may occur (monitor levels regularly)
Documented hypersensitivity;a relative contraindication is severe renal disease
Neonates with renal immaturity, renal disease, auditory impairment, vestibular impairment, hypocalcemia, or who are receiving ECMO; monitoring levels is important to avoid possible renal and auditory damage (normal peaks 5-12 mcg/mL, normal troughs 0.5-1 mcg/mL)
Third-generation cephalosporin with excellent in vitro activity against GBS and E coli and other gram-negative enteric bacilli. Has good serum and CSF concentrations. Concern exists about the emergence of drug-resistant gram-negative bacteria at a more rapid rate than with traditional penicillin and aminoglycoside coverage. Ineffective against Listeria and enterococci. Use in combination with ampicillin. In most recent publications, this is not a first-line agent for neonatal sepsis because of its association with increased mortality.
<29 weeks PMA and 0-28 days: 50 mg/kg/dose IV/IM q12h<29 weeks PMA and >28 days: 50 mg/kg/dose IV/IM q8h30-36 weeks PMA and 0-14 days: 50 mg/kg/dose IV/IM q12h30-36 weeks PMA and >14 days: 50 mg/kg/dose IV/IM q8h37-44 weeks PMA and 0-7 days: 50 mg/kg/dose IV/IM q12h37-44 weeks PMA and >7 days: 50 mg/kg/dose IV/IM q8h>45 weeks PMA: 50 mg/kg/dose IV/IM q6h
Probenecid decreases renal elimination of cefotaxime and prolongs therapeutic half-life; coadministration with furosemide and aminoglycosides may increase nephrotoxicity
History of penicillin hypersensitivity, impaired renal function, or history of colitis
Bacteriocidal agent against most aerobic and anaerobic gram-positive cocci and bacilli. Especially important in the treatment of MRSA. Recommended therapy when coagulase-negative staphylococcal sepsis is suspected. Therapy with rifampin, gentamicin, or cephalothin may be required with endocarditis or CSF shunt infection by coagulase-negative staphylococcus.
<29 weeks PMA and 0-14 days: 10-15 mg/kg/dose IV/IM q18h<29 weeks PMA and >14 days: 10-15 mg/kg/dose IV/IM q12h30-36 weeks PMA and 0-14 days: 10-15 mg/kg/dose IV/IM q12h30-36 weeks PMA and >14 days: 10-15 mg/kg/dose IV/IM q8h37-44 weeks PMA and 0-7 days: 10-15 mg/kg/dose IV/IM q12h37-44 weeks PMA and >7 days: 10-15 mg/kg/dose IV/IM q8h>45 weeks PMA: 10-15 mg/kg/dose IV/IM q6hUse higher dosing range in meningitis
Concurrent ototoxic or nephrotoxic drugs (eg, aminoglycosides, loop diuretics); erythema, histaminelike flushing and anaphylactic reactions may occur when administered with anesthetic agents; effects in neuromuscular blockade may be enhanced when coadministered with nondepolarizing muscle relaxants
Documented hypersensitivity; hearing impairment
Administer over 60 min to avoid possibility of histamine reaction, which is characterized by a rash; levels greater than therapeutic trough (5-10 mg/dL) may be associated with ototoxicity; caution in renal failure or neutropenia
Antimicrobial that has shown effectiveness against anaerobic infections, especially Bacteroides fragilis meningitis, ventriculitis, and endocarditis. Also useful in treatment of infections caused by T vaginalis.
Loading dose: 15 mg/kg PO/IVMaintenance dose:<29 weeks PMA and 0-28 days: 7.5 mg/kg/dose IV/PO q48h<29 weeks PMA and >28 days: 7.5 mg/kg/dose IV/PO q24h30-36 weeks PMA and 0-14 days: 7.5 mg/kg/dose IV/PO q24h30-36 weeks PMA and >14 days: 7.5 mg/kg/dose IV/PO q12h37-44 weeks PMA and 0-7 days: 7.5 mg/kg/dose IV/PO q24h37-44 weeks PMA and >7 days: 7.5 mg/kg/dose IV/PO q12h>45 weeks PMA: 7.5 mg/kg/dose IV/PO q8h
May increase levels of phenytoin; phenobarbital and rifampin may increase metabolism of metronidazole; when administered with food, a decrease and/or delay in reaching peak levels may occur
Documented hypersensitivity; first trimester of pregnancy
Liver impairment, blood dyscrasias, CNS disease; inject with caution in patients receiving corticosteroids or patients predisposed to edema because the drug molecule contains sodium
Bactericidal antibiotic that inhibits cell wall synthesis. Used in the treatment of infections caused by penicillinase-producing staphylococci. May be used to initiate therapy when a staphylococcal infection is suspected.
25-50 mg/kg dose IVPostmenstural age/Postnatal days/Dose interval<29 weeks and 0-28 days: q12h<29 weeks and >28 days: q8h30-36 weeks and 0-14 days: q12h30-36 weeks and >14 days: q8h37-44 weeks and 0-7 days: q12h37-44 weeks and >7 days: q8h>45 weeks (all postnatal ages): q6h
Oxacillin decreases effects of contraceptives and tetracycline; administered concomitantly with disulfiram and probenecid, may increase oxacillin levels; effect of anticoagulants increase when large IV doses of oxacillin given
Caution in renal impairment
An acylampicillin with excellent activity against Pseudomonas aeruginosa. Effective against Klebsiella pneumonia, Proteus mirabilis, B fragilis, S marcescens, and many strains of Enterobacter. Administer in combination with an aminoglycoside.
<7 days and 1200-2000 g: 75 mg/kg IV/IM q12h<7 days and >2000 g: 75 mg/kg IV/IM q8h>7 days and 1200-2000 g: 75 mg/kg IV/IM q8h>7 days and >2000 g: 75 mg/kg/dose IV/IM q6h
Synergic and antagonistic interactions observed when combined with various cephalosporins; piperacillin at high concentrations may physically inactivate aminoglycosides; coadministration with aminoglycosides has synergistic effects
Dosage modification required in patients with impaired renal function
Macrolide antimicrobial agent that is primarily bacteriostatic and is active against most gram-positive bacteria, such as Neisseria species, Mycoplasma pneumoniae, Ureaplasma urealyticum, and Chlamydia trachomatis. Not well concentrated in the CSF.
<7 days and <2000 g: 5 mg/kg/dose PO/IV/IM q12h<7 days and >2000 g: 5 mg/kg/dose PO/IV/IM q8h>7 days and <1200 g: 5 mg/kg PO/IV/IM q12h>7 days and >1200 g: 10 mg/kg PO/IV/IM q8h
CYP1A2 and CYP3A4 inhibitor; coadministration may increase toxicity of theophylline, digoxin, carbamazepine, and cyclosporine; may potentiate anticoagulant effects of warfarin
Documented hypersensitivity; hepatic impairment
Monitor parenteral administration closely because of associated tissue damage; caution in liver disease; estolate formulation may cause cholestatic jaundice; GI adverse effects are common (give doses pc); discontinue use if nausea, vomiting, malaise, abdominal colic, or fever occur
A viral infection, such as HSV, may masquerade as bacterial sepsis. At the onset of the infection, treatment must be initiated promptly to effectively inhibit the replicating virus.
Used for treatment of mucosal, cutaneous, and systemic HSV-1 and HSV-2 infections.
20 mg/kg/dose IV q8h; may increase dosage interval in patients <34 weeks PMA or in patients with significant hepatic or renal failureTreatment duration for localized infections is 14 d; for disseminated disease or CNS infections, treat for 21 d
Concomitant use of probenecid or zidovudine prolongs half-life and increases CNS toxicity of acyclovir
Renal disease, dehydration, underlying neurologic disease, patients with hypoxia and hepatic or electrolyte abnormalitiesPeriodic monitoring of CBC count is indicatedFollow renal and hepatic function
Zidovudine (Retrovir, ZDV, AZT)
A thymidine analog that inhibits viral replication. Used to treat patients with HIV.
<29 weeks PMA and 0-28 days: 1.5 mg/kg/dose IV q12h or 2 mg/kg/dose PO q12h<29 weeks PMA and >28 days: 1.5 mg/kg/dose IV q8h or 2 mg/kg/dose PO q8h30-34 weeks PMA and 0-14 days: 1.5 mg/kg/dose IV q12h or 2 mg/kg/dose PO q12h30-34 weeks PMA and >14 days: 1.5 mg/kg/dose IV q8h or 2 mg/kg/dose PO q8h>35 weeks PMA: 1.5 mg/kg/dose IV q6h or 2 mg/kg/dose PO q6h
Acyclovir, ganciclovir, or coadministration with drugs that inhibit glucuronidation (eg, acetaminophen, cimetidine, indomethacin) may increase toxicity
Do not administer IM; bone marrow compromise or impaired renal function; rare severe lactic acidosis and hepatomegaly with steatosis, including fatal cases, reported
Fungal infections can masquerade as bacterial infections and/or may appear at the end of prolonged antibacterial therapy. Their mechanism of action may involve an alteration of RNA and DNA metabolism or an intracellular accumulation of peroxide that is toxic to the fungal cell.
Used to treat susceptible fungal infections, including oropharyngeal, esophageal, and vaginal candidiasis. Also used for systemic candidal infections and cryptococcal meningitis. Fungistatic activity. Synthetic oral antifungal (broad-spectrum bistriazole) that selectively inhibits fungal CYP450 and sterol C-14 alpha-demethylation, which prevents conversion of lanosterol to ergosterol, thereby disrupting cellular membranes.
Systemic infections and meningitis:Loading dose: 12 mg/kg IVMaintenance dose:<29 weeks PMA and 0-14 days: 6 mg/kg/dose IV q72h<29 weeks PMA and >14 days: 6 mg/kg/dose IV q48h30-36 weeks PMA and 0-14 days: 6 mg/kg/dose IV q48h30-36 weeks PMA and >14 days: 6 mg/kg/dose IV q24h
37-44 weeks PMA and 0-7 days: 6 mg/kg/dose IV q48h37-44 weeks PMA and >7 days: 6 mg/kg/dose IV q24h>45 weeks PMA: 6 mg/kg/dose IV q24hProphylaxis for ELBW infants in the NICU: 3 mg/kg/dose IV 2 times/wkThrush: 6 mg/kg PO on day 1, then 3 mg/kg/dose PO q24h
CYP2C19 and CYP3A4 inhibitor; levels may increase with hydrochlorothiazide; long-term coadministration of rifampin may decrease levels; may decrease phenytoin clearance; may increase concentrations of theophylline, tolbutamide, glyburide, and glipizide; may increase effects of anticoagulants; may increase cyclosporine concentrations
Perform periodic liver function and renal function tests; dosage modification required in patients with impaired renal function
Amphotericin B (Fungizone)
Used to treat severe systemic infections and meningitis caused by susceptible fungi, such as Candida and Aspergillus species, H capsulatum, and C neoformans. Polyene antibiotic produced by a strain of S nodosus; can be fungistatic or fungicidal. Binds to sterols, such as ergosterol, in fungal cell membrane, causing intracellular components to leak and subsequent fungal cell death.
0.5-1 mg/kg IV q24h infused over 2-6 h
Coadministration with other nephrotoxic drugs (eg, antineoplastic agents, aminoglycosides, vancomycin, cyclosporine) may enhance renal toxicity; antineoplastic agents may increase risk of bronchospasm and hypotension; corticosteroids, digitalis, and thiazides may potentiate hypokalemia
Decrease dose with renal impairment; determine BUN and serum creatinine levels weekly; monitor serum potassium and magnesium closely; check electrolytes, CBC, liver function studies, input and output, BP, and temperature regularly; administer slowly because cardiovascular collapse reported after rapid injection
Amphotericin B, liposomal (AmBisome)
Used to treat severe systemic infections and meningitis caused by susceptible fungi, such as Candida and Aspergillus species, H capsulatum, and C neoformans. Used in systemic fungal infections resistant to amphotericin B or in patients with renal or hepatic failure. Consists of amphotericin B within a single bilayer liposomal drug delivery system. Polyene antibiotic produced by a strain of S nodosus; can be fungistatic or fungicidal. Binds to sterols, such as ergosterol, in fungal cell membrane, causing intracellular components to leak and subsequent fungal cell death.
5-7 mg/kg/dose IV q24h infused over 2 h
Coadministration with other nephrotoxic drugs (eg, antineoplastic agents, aminoglycosides, vancomycin, cyclosporine) may enhance renal toxicity; antineoplastic agents may increase risk
of bronchospasm and hypotension; corticosteroids, digitalis, and thiazides may potentiate hypokalemia
Can lead to anemia, thrombocytopenia, hypokalemia, nausea/vomiting, fever, and chills
Further Outpatient Care
The primary care provider (PCP) should evaluate the infant with neonatal sepsis within one week of discharge from the hospital. The infant can be evaluated for superinfection and bacterial colonization associated with antibiotic therapy, especially if the therapy was prolonged. The PCP should evaluate growth and determine if the feeding regimen and activity have returned to normal.
If neonatal sepsis was associated with meningitis, prolonged hypoxia, extracorporeal membrane oxygenation (ECMO) therapy, or brain abscess formation, the infant should be observed for several years to assess their neurodevelopment and should receive appropriate early intervention services and therapies when appropriate.
The infant may require transfer to a level III perinatal center, especially if he or she requires cardiopulmonary support, parenteral nutrition, or prolonged intravenous access.
Multidisciplinary services available at larger centers may be necessary when treating an acutely compromised neonate.
The Committee on Infectious Diseases of the AAP recommends that obstetric care include a strategy to manage early-onset group B Streptococcus (GBS) disease. Treat women with GBS bacteriuria during pregnancy when it is diagnosed and during the intrapartum period. The committee also recommends that women who have previously given birth to an infant with invasive GBS disease receive antibiotic prophylaxis during labor and delivery. To minimize the
risk of early-onset GBS disease, practitioners should obtain screening vaginal and rectal cultures at 35-37 weeks' gestation for all pregnant women unless they have had GBS bacteriuria in the current pregnancy or a previous child with invasive GBS disease. The implementation of a screening protocol has led to a significant decrease in the incidence of neonatal GBS disease (see the image below).
Incidence of early onset and late-onset invasive group B Streptococcus (GBS) disease.
Graph available at http://img.medscape.com/pi/emed/ckb/pediatrics_cardiac/973235-978352-3214.gif.
Intrapartum antibiotic prophylaxis is indicated for all of the following (see the image below):
Indications for intrapartum group B Streptococcus (GBS) antibiotic prophylaxis.
Previous infant with GBS disease GBS bacteriuria in the current pregnancy Positive GBS screening culture results during the current pregnancy (unless a planned
cesarean delivery, in the absence of labor or amniotic membrane rupture, is performed) Unknown GBS status (culture not done, or results unknown) and any of the following:
o Delivery earlier than 37 weeks' gestationo Amniotic membrane rupture at 18 hours or latero Intrapartum temperature of 100.4°F or higher (>38°C)
See the image below for recommended antibiotic prophylaxis regimens.
Recommended regimens for intrapartum antimicrobial prophylaxis for perinatal group B Streptococcus (GBS) disease prevention.
Graph available at http://img.medscape.com/pi/emed/ckb/pediatrics_cardiac/973235-978352-3215.gif.
Other methods of prevention of late-onset sepsis, particularly in the preterm neonate are under investigation. Administration of lactoferrin, the major whey protein in mammalian milk, is thought to have properties that contribute to innate immune host defences.[12 ]
Infants with meningitis may acquire hydrocephalus and/or periventricular leukomalacia. They may also have complications associated with the use of aminoglycosides, such as hearing loss and/or nephrotoxicity.
With early diagnosis and treatment, term infants are not likely to experience long-term health problems associated with neonatal sepsis; however, if early signs and/or risk factors are missed, the mortality rate increases. Residual neurologic damage occurs in 15-30% of neonates with septic meningitis.
Impaired neurodevelopment in preterm infants with sepsis is a concern. Proinflammatory molecules may negatively affect brain development in this patient population. In a large study of about 6000 premature infants who weighed less than 1000 g at birth, preterm infants with sepsis who did not have meningitis had higher rates of cognitive deficits, cerebral palsy, and other neurodevelopmental disabilities when compared with infants without sepsis.[13,14 ]
For excellent patient education resources, visit eMedicine's Blood and Lymphatic System Center. Also, see eMedicine's patient education article Sepsis (Blood Infection).
Delay in diagnosis and initiation of proper treatment in neonatal sepsis may result in morbidity and mortality.
Failure to provide prophylaxis to women with group B Streptococcus (GBS) infection may create liability if the infant subsequently becomes ill.
The Joint Commission on Infant Hearing of the AAP recommends that infants who received aminoglycosides should have audiology screening before discharge. Screen these infants again at 3 months, but no later than 6 months, to determine whether damage has occurred.
Media file 1: Incidence of early onset and late-onset invasive group B Streptococcus (GBS) disease.
Graph available at http://img.medscape.com/pi/emed/ckb/pediatrics_cardiac/973235-978352-3214.gif.
Media file 2: Indications for intrapartum group B Streptococcus (GBS) antibiotic prophylaxis.
Media file 3: Recommended regimens for intrapartum antimicrobial prophylaxis for perinatal group B Streptococcus (GBS) disease prevention.
Graph available at http://img.medscape.com/pi/emed/ckb/pediatrics_cardiac/973235-978352-3215.gif.
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neonatal sepsis, neonatal infection, early onset neonatal sepsis, late-onset neonatal sepsis, early onset sepsis syndrome, late-onset sepsis syndrome, neonatal bacteremia, treatment, diagnosis
Contributor Information and Disclosures
Ann L Anderson-Berry, MD, Assistant Professor of Pediatrics, Joint Division of Newborn Medicine, University of Nebraska Medical Center, Creighton University School of Medicine; Medical Director, NICU Nebraska Medical CenterAnn L Anderson-Berry, MD is a member of the following medical societies: American Academy of Pediatrics and Nebraska Medical Association Disclosure: Nothing to disclose.
Linda L Bellig, MA, RN, NNP, Track Coordinator, Instructor, Neonatal Nurse Practitioner Program, Medical University of South Carolina College of Nursing. Currently, retiredDisclosure: Nothing to disclose.
Bryan L Ohning, MD, PhD, Medical Director of NICU, Medical Director of Neonatal Transport, Division of Neonatology, Children's Hospital, Greenville Hospital System, University Medical Center; GHS Professor of Clinical Pediatrics, University of South Carolina, School of Medicine; Clinical Associate Professor of Pediatrics, Medical University of South CarolinaBryan L Ohning, MD, PhD is a member of the following medical societies: American Academy of Pediatrics, American Thoracic Society, and South Carolina Medical Association Disclosure: Pediatrix Medical Group of SC Salary Employment; Draeger Medical, Inc. Consulting fee Consulting
Scott S MacGilvray, MD, Clinical Associate Professor, Department of Pediatrics, Division of Neonatology, The Brody School of Medicine at East Carolina UniversityScott S MacGilvray, MD is a member of the following medical societies: American Academy of Pediatrics and American Medical Association Disclosure: Nothing to disclose.
Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicineDisclosure: Nothing to disclose.
David A Clark, MD, Chairman, Professor, Department of Pediatrics, Albany Medical CollegeDavid A Clark, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, American Pediatric Society, Christian Medical & Dental Society, Medical Society of the State of New York, New York Academy of Sciences, and Society for Pediatric Research Disclosure: Nothing to disclose.
Carol L Wagner, MD, Professor of Pediatrics, Medical University of South CarolinaCarol L Wagner, MD is a member of the following medical societies: American Academy of Pediatrics, American Chemical Society, American Medical Women's Association, American Public Health Association, American Society for Bone and Mineral Research, American Society for Clinical Nutrition, Massachusetts Medical Society, National Perinatal Association, and Society for Pediatric Research Disclosure: Nothing to disclose.
Ted Rosenkrantz, MD, Professor, Departments of Pediatrics and Obstetrics/Gynecology, Division of Neonatal-Perinatal Medicine, University of Connecticut School of MedicineTed Rosenkrantz, MD is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, American Pediatric Society, Connecticut State Medical Society, Eastern Society for Pediatric Research, and Society for Pediatric Research Disclosure: Nothing to disclose.