Mycoplasma Infection (1)

8/13/2019 Mycoplasma Infection (1)

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By Dr.Sujith S


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Species Mycoplasma pneumoniae

Mycoplasma hominis

Mycoplasma genitalium Ureaplasma urealyticum


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Pathogenesis Pathogenic organisms for humans and animals possess

specialized tip organelles that mediate theirinteractions with host cells.

This host-adapted survival is achieved by i)surfaceparasitism of target cells

ii) the acquisition of essential biosynthetic precursors

iii) cell entry and intracellular survival.


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Toll-like receptor 2for binding of Mycoplasma andactivation of inf lammatory mediators, includingcytokines.

M. pneumoniae grows under both aerobic andanaerobic conditions ,isolated on media supplementedwith serum.

The organism most commonly exists in a filamentousform and has adherence proteins that attach toepithelial membranes with particular affinity forrespiratory tract epithelium


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An immune-mediated mechanism in infants andyoung children developing pneumonia.

In addition, the antibodies produced against theglycolipid antigens of M. pneumoniae may act asautoantibodies, since they crossreact with human redcells and brain cells.


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Epidemiology M. pneumoniae is transmitted from person-to-person

by infected respiratory droplets during close contact.

The incubation period after exposure averages threeweeks .

Infection occurs most frequently during the fall andwinter but may develop year-round


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Mycoplasma pneumoniaeone of the most commoncauses of atypical pneumonia

Atypical pneumonia

account for 7 to 20% ofcommunity-acquired pneumonia

The incidence may be higher in patients with milderdisease that can be managed without hospitalization


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Many infections due to M. pneumoniae areasymptomatic.

The signs and symptoms vary according to the stage ofillness

Headache, malaise, and low grade fever.

Chills are frequent.


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Cough due to M. pneumoniae infection ranges fromnonproductive to mildly productive, with sputumdiscoloration occurring late in the disease.

Wheezing may occur

Pharyngitis

Rhinorrhea and

Ear pain


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Extrapulmonary manifestations These manifestations include

Hemolysis

Skin rashJoint involvement

Symptoms and signs indicative of gastrointestinal tract,central nervous system, and heart disease..


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HaemolysisAntibodies (IgM)I antigen on erythrocyte

membranes appear during the course ; produce a coldagglutinin response in about 60 % of patients .


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Skin Disease Dermatologic manifestationsa mild erythematous

maculopapular / vesicular rash to the Stevens-Johnsonsyndrome.

16 % patients with Stevens-Johnson syndrome hadevidence of mycoplasma infection.


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Central Nervous

SystemCNS involvement occurs most frequently in children,

with encephalitisas the most frequent manifestation.

Other manifestations include aseptic meningitis,peripheral neuropathy, transverse myelitis, cranialnerve palsies andcerebellar ataxia .

Acute transverse myelitis (ATM) and acute disseminated

encephalomyelitis (ADEM)

most severecomplications .

59 percent of patients presenting with spinal cordinvolvement suffered permanent neurologic sequelae .


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Other Systems Rheumatologic symptomsincluding tender joints

and muscles and polyarthritis.

Arthritis is believed to result from immune-mediatedmechanisms

M. pneumoniae has been isolated from synovial fluidin some patients with polyarthritis.


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Cardiac or renal involvement -unusual .

Rhythm disturbances, congestive heart failure, chest

pain, and conduction abnormalities on theelectrocardiogram.

Clinically significant glomerulonephritis is a rarecomplication that is presumed to be secondary to

immune complex deposition


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Chest X-Ray Bronchopneumonia Plate-like atelectasis Nodular infiltration

Hilar adenopathy The most common radiographic finding is the

peribronchial pneumonia pattern, which consists of athickened bronchial shadow, streaks of interstitialinfiltration, and areas of atelectasis; these changes have a

predilection for the lower lobes. Nodular infiltrates and hilar adenopathyless common,

and result in a broader differential diagnosis, includingtuberculosis, mycotic infections, and sarcoidosis


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Lab Diagnosis Subclinical evidence of hemolytic anemia is present in

the majority of patients with pneumoniapositiveCoombs' test and elevated reticulocyte count.

Cold agglutinin titers are elevated in 50 percent ofpatients with mycoplasma disease, and the titer

usually exceeds 1:128 in patients with pneumonia

With overt hemolysis, titers may be as high as 1:50,000.


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Elevated Cold Agglutinin Titres Infectious Mononucleosis secondary to Epstein Barr

virus

CytomegalovirusAdenovirus pneumonia

Viral illness

Lymphoma and Collagen vascular disorders


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The white blood cell count (WBC) normal75 to 90percent of cases.

Thrombocytosis can occur

acute phase response.


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CSF-Lymphocytic pleocytosis, elevated protein, andnormal glucose.

Isolation of M. pneumoniae in CSF - possible.

A culture is more likely to be positive in encephalitisrather than myelitis.

PCR testing for Mycoplasma in the CSF can also be

performed.


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Treatment Treatment options for outpatient community-acquired

pneumonia are presented in the 2007 consensusIDSA/ATS guideline:

Macrolide antibiotics (azithromycin, clarithromycinorerythromycin)first line treatment .

Azithromycin (500 mg orally once daily, initially

followed by 250 mg orally for 4 days) has become themost commonly used drug regimen.


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Adjunctive Therapy For hemolytic anemia, case reports indicate some

patients respond to warming, steroid therapy, possiblyplasmapheresis.

For CNS disease, therapy with steroids,

antiinflammatory drugs, diuretics, and plasmaexchange ,used in addition to antibiotics.


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M.Hominis Epidemiology:M. hominis is part of the normal genital

flora of many sexually experienced men and women

Infants & childrren:Newborns are likely to becomecolonized during passage through the birth canal..


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The organism Mycoplasma are the smallest free-living bacteria. M.

hominis cannot be visualized by Gram stain.

M. Hominisproduces nonhemolytic colonies onsheep blood agar after three to five days of incubation.

M. hominis does not alter the appearance of bloodculture media; therefore,routine blind subculturingonto blood is required for detection.


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For optimizing the recovery of M. hominis, clinicalspecimens should be immediately inoculated ontoculture media and not allowed to dry.

After plating, cultures should be promptly incubatedor kept at 4C.

The best laboratory culture media is beef heart

infusion broth (also known as pleuropneumonia-likeorganism) (PPLO) broth with fresh yeast extract andhorse serum.


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PCR is superior to traditional culture methods fordetecting M. hominis in genital secretions.


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Genitourinary infection Pyelonephritis Pelvic inflammatory disease Chorioamnionitis Postpartum and postabortal feverNongenitourinary infections that have been linked to M. hominis

include: Septicemia

Wound infections Central nervous infections Joint infections Lower respiratory tract infections Endocarditis


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Post partum & post abortal fever M. hominis causes approximately 10 percent of all

cases of postpartum and postabortal fever.

There was a fourfold rise in antibody titers in one-halfof all women who had postabortal fever compared to

only 2 of 53 controls who had abortion without fever.


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PID M. hominis was isolated from 4 of 50 fluid samples

taken directly from the fallopian tubes of women withsalpingitis.

Significant rises in antibody titers to M. hominis

occurred in 9 of 16 women with salpingitis who hadpositive lower genital tract cultures for M. hominis .


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UTI M. hominis can frequently be recovered from the lower

genitourinary tract in men and women.


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ChorioamnionitisM. hominis, along with Ureaplasma urealyticum, is

frequently found in the amniotic fluid of women with

i)preterm labor,

ii) preterm premature rupture ofmembranes

iii) spontaneous labor at term

iv) premature rupture of membranes at termv) chorioamnionitis


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CNS M. hominis infection has been associated with non-

functioning CNS shunts , brain abscess , subduralempyema, and meningitis.

M. hominis arthritis can occur in women after childbirth,in conjunction with congenital immune defects, such ashypogammaglobulinemia , in association withimmunosuppression (eg, in solid organ transplantpatients) or lymphoma , or following joint replacementsurgery or trauma.

M. hominis arthritis is usually characterized by fever,leukocytosis, and a purulent joint effusion with largenumbers of polymorphonuclear cells but a negative Gramstain.


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Wound infections

M. hominis has been associated with infected pelvichematoma , infected cesarean wounds, and sternalwound infections


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Treatment Tetracycline is the treatment of choice


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Thank you

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Mycoplasma Infection (1)

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