Chapter 18 The Cocci of Medical Importance. General Characteristics of the Staphylococci Nonmotile,...

Chapter 18

The Cocci of Medical ImportanceThe Cocci of Medical Importance

General Characteristics of the Staphylococci

Nonmotile, gram-Nonmotile, gram-positive cocci positive cocci arranged in irregular arranged in irregular clustersclusters

Facultative anaerobesFacultative anaerobes FermentativeFermentative Salt-tolerantSalt-tolerant Catalase-positiveCatalase-positive Pyogenic if stimulate Pyogenic if stimulate

pus formationpus formation

Staphylococcus aureus Skin infections:Skin infections:

Local abscess occurs at site Local abscess occurs at site of invasion of hair follicle, of invasion of hair follicle, glandgland

Manifestations:Manifestations: Folliculitis – Folliculitis –

inflammation of hair inflammation of hair folliclefollicle

Furuncle - boilFuruncle - boil Carbuncle – deeper Carbuncle – deeper

lesion aggregation of a lesion aggregation of a cluster of furunclescluster of furuncles

Bullous impetigo – Bullous impetigo – epidermal swellings that epidermal swellings that peel awaypeel away

Staphylococcus aureus

Toxic disease:Toxic disease: Food intoxication due Food intoxication due

to enterotoxinto enterotoxin Staphylococcal scaled Staphylococcal scaled

skin syndrome skin syndrome Toxic shock syndromeToxic shock syndrome

Toxemia in women Toxemia in women due to infection of due to infection of vaginavagina

Associated with Associated with tampon usagetampon usage

Staphylococcus aureus Osteomyelitis Osteomyelitis

Bacteria spread in the circulation from some other infection Bacteria spread in the circulation from some other infection site, enter the artery, and lodge in the small vessels in bony site, enter the artery, and lodge in the small vessels in bony pockets of the marrowpockets of the marrow

Growth of the cells causes inflammation and damage that Growth of the cells causes inflammation and damage that manifest as swelling and necrosismanifest as swelling and necrosis

Principal coagulase-Negative Staphylococci

Staphylococcus saprophyticusStaphylococcus saprophyticus Urinary pathogenUrinary pathogen

Staphylococcus epidermidisStaphylococcus epidermidis Normal resident of skin and folliclesNormal resident of skin and follicles An opportunistAn opportunist One of the most common causes of nosocomial One of the most common causes of nosocomial

infectionsinfections Mainly in surgical patients with indwelling Mainly in surgical patients with indwelling

medical devices or implantsmedical devices or implants

Treatment for Staph infections

S. aureusS. aureus has multiple resistance to antibiotics, has multiple resistance to antibiotics, especially penicillin, ampicillin, and methicillinespecially penicillin, ampicillin, and methicillin

Abscesses require debridement and removal of pusAbscesses require debridement and removal of pus StaphylococciStaphylococci have extreme resistance to harsh have extreme resistance to harsh

environmental conditionsenvironmental conditions Staph infections are frequently complicated by Staph infections are frequently complicated by

their tendency to form biofilms on medical their tendency to form biofilms on medical devicesdevices

General Characteristics of the Streptococci Genera

Gram-positive cocci in Gram-positive cocci in chains of various chains of various lengthslengths

NonmotileNonmotile Non-spore formingNon-spore forming EncapsulatedEncapsulated Catalase negativeCatalase negative

Streptococcus Genus - Genus - StreptococcusStreptococcus

Streptococcus pyogenesStreptococcus pyogenes (Group A streptococci) (Group A streptococci) Streptococcus agalactiaeStreptococcus agalactiae (Group B streptococci) (Group B streptococci) Group D streptococciGroup D streptococci

EnterococciEnterococci• Enterococcus (Streptococcus) faecalisEnterococcus (Streptococcus) faecalis• Enterococcus (Streptococcus) faeciumEnterococcus (Streptococcus) faecium• Enterococcus (Streptococcus) duransEnterococcus (Streptococcus) durans

Non-enterococcalNon-enterococcal Group D Group D• Streptococcus bovisStreptococcus bovis• Streptococcus equinusStreptococcus equinus

Viridans streptococciViridans streptococci Streptococcus pneumoniaeStreptococcus pneumoniae

Classification scheme for streptococci Based on hemolytic propertiesBased on hemolytic properties

Types of hemolysisTypes of hemolysis Beta (clear, complete)Beta (clear, complete) Alpha (green, incomplete) - Alpha (green, incomplete) -

also called viridans; green also called viridans; green color = production of a color = production of a hemoglobin reducing agenthemoglobin reducing agent

Alpha prime = large zone of Alpha prime = large zone of alpha hemolysis encircled by alpha hemolysis encircled by a narrow zone of betaa narrow zone of beta

Gamma (none) - commonly Gamma (none) - commonly called non-hemolytic strepcalled non-hemolytic strep

Reasons for being unreliable Reasons for being unreliable criteriacriteria

Some strains become Some strains become hemolytic after 24 hrs hemolytic after 24 hrs incubationincubation

Type hemolysis cell Type hemolysis cell dependent - sheep blood used dependent - sheep blood used in U.S.in U.S.

Classification scheme for streptococci Based on antigenic propertiesBased on antigenic properties

Lancefield grouping = carbohydrates in cell wall (C groupLancefield grouping = carbohydrates in cell wall (C group carbohydrates)carbohydrates) Found in all strep except viridansFound in all strep except viridans Classifies into 13 groups (designated A-O)Classifies into 13 groups (designated A-O) Methods for detection have been time consuming andMethods for detection have been time consuming and difficult - new difficult - new

easier methods now availableeasier methods now available Definitive method of classificationDefinitive method of classification Most common groups encountered = A, B, C, D, F, and GMost common groups encountered = A, B, C, D, F, and G

Virulence Factors for S. pyogenes (Group A streptococci)

AnatomicalAnatomical M protein - associated M protein - associated

with pilli and with pilli and lipoteichoic acid; play lipoteichoic acid; play role in attachment; role in attachment; over 70 different types over 70 different types known; immunity to known; immunity to streptococcal infection streptococcal infection M type specificM type specific

Capsule - composed of Capsule - composed of hyaluronic acid; hyaluronic acid; antiphagocyticantiphagocytic


Toxins and other biologically active extracellular productsToxins and other biologically active extracellular products Hemolysins - streptolysinsHemolysins - streptolysins

Streptolysin O - oxygen labileStreptolysin O - oxygen labile

• Binds cholesterol in cell membranes of rbc'sBinds cholesterol in cell membranes of rbc's wbc's, and wbc's, and platelets - lysis causes degranulation of wbc's with platelets - lysis causes degranulation of wbc's with release of hydrolytic enzymes - further damages tissuerelease of hydrolytic enzymes - further damages tissue

• Reversibly inactivated by oxygen - demonstrated in vitro Reversibly inactivated by oxygen - demonstrated in vitro in deep (anaerobic) coloniesin deep (anaerobic) colonies

• Antigenic - antibodies = antistreptolysin OAntigenic - antibodies = antistreptolysin O (ASO)(ASO) Streptolysin S - oxygen stableStreptolysin S - oxygen stable

• Mostly cell boundMostly cell bound

• No neutralizing Ab yet describedNo neutralizing Ab yet described rbc's; inhibit rbc's; inhibit chemotaxis & phagocytosischemotaxis & phagocytosis


Deoxyribonucleases (DNases) - degrade DNA and Deoxyribonucleases (DNases) - degrade DNA and to a lesser extent RNA in pus - facilitates spread of to a lesser extent RNA in pus - facilitates spread of infectioninfection

Hyaluronidase - spreading factor; sometimes find Hyaluronidase - spreading factor; sometimes find both hyaluronic capsules and hyaluronidase in both hyaluronic capsules and hyaluronidase in same organismsame organism

Erythrogenic toxin (also called streptococcal Erythrogenic toxin (also called streptococcal pyrogenic exotoxins)pyrogenic exotoxins) Responsible for rash of scarlet fever and appear Responsible for rash of scarlet fever and appear

toto play role in toxic-like syndromeplay role in toxic-like syndrome

Virulence Factors for S. agalactiae (Group B streptococci)

Anatomical - capsule; antigenic and Anatomical - capsule; antigenic and antiphagocyticantiphagocytic

Virulence Factors for S. pneumoniae

Anatomical - capsule is polysaccharide; 84 Anatomical - capsule is polysaccharide; 84 different types known;different types known; some types cross-some types cross-react with polysaccharides produced by react with polysaccharides produced by otherother bacteria and with human blood group bacteria and with human blood group B isoantigen; antiphagocyticB isoantigen; antiphagocytic

S. pyogenes (Group A streptococci) Diseases

Suppurative infections - invasive properties related Suppurative infections - invasive properties related to capsule and M proteins; virulence with to capsule and M proteins; virulence with streptolysins (pyogenic)streptolysins (pyogenic) Pharyngitis - common in children; usually self-Pharyngitis - common in children; usually self-

limiting; canlimiting; can lead to non-suppurative sequelaelead to non-suppurative sequelae Puerperal infection (childbed fever) - infection of Puerperal infection (childbed fever) - infection of

endometrium at or near delivery; life threatening; endometrium at or near delivery; life threatening; may spread to other sites in bodymay spread to other sites in body


Impetigo (Indian Impetigo (Indian fire) - localized skin fire) - localized skin infection; common infection; common inin childrenchildren

Erysipelas - Erysipelas - involves skin and involves skin and subcutaneous tissue; subcutaneous tissue; spreadsspreads rapidlyrapidly


Toxic diseaseToxic disease Scarlet feverScarlet fever

Caused by infection with erythrogenic Caused by infection with erythrogenic strains in sensitive individualsstrains in sensitive individuals

Localized infection with systemic Localized infection with systemic manifestationsmanifestations

Characterized by red rash over most of Characterized by red rash over most of body (strawberry tongue)body (strawberry tongue)


Delayed Non-Suppurative Delayed Non-Suppurative ComplicationsComplications Acute rheumatic fever (ARF)Acute rheumatic fever (ARF)

Symptoms - fever and Symptoms - fever and inflammation of joints, heart,inflammation of joints, heart, subcutaneous tissue and CNS subcutaneous tissue and CNS beginning 1-5 weeksbeginning 1-5 weeks after after Group A pharyngitis; may Group A pharyngitis; may cause serious and permanent cause serious and permanent damage to heartdamage to heart

Follows only respiratory strept. Follows only respiratory strept. infection infection

Can be prevented by treatment Can be prevented by treatment of pharyngitis within 9 days of of pharyngitis within 9 days of onset of infectiononset of infection


Delayed Non-Suppurative ComplicationsDelayed Non-Suppurative Complications Acute glomerulonephritis (AGN)Acute glomerulonephritis (AGN)

Symptoms - edema, hypertension, hematuria & Symptoms - edema, hypertension, hematuria & proteinuria; usually benign but may lead to renal proteinuria; usually benign but may lead to renal failure and deathfailure and death

Follows either respiratory or cutaneous infections;Follows either respiratory or cutaneous infections; requires infection with certain M type strains calledrequires infection with certain M type strains called nephritogenicnephritogenic

Typically occurs 6-10 days after onset of Typically occurs 6-10 days after onset of pharyngitis or 14-21 days after cutaneous infection; pharyngitis or 14-21 days after cutaneous infection; not prevented by rapid therapynot prevented by rapid therapy

S. agalactiae (Group B streptococcal) Diseases

Infants - leading cause of pneumonia, sepsis and Infants - leading cause of pneumonia, sepsis and meningitis duringmeningitis during first 2 months of lifefirst 2 months of life Most develop in immediate perinatal period (within 7 Most develop in immediate perinatal period (within 7

daysdays of birth)of birth) Most result from contamination from female genital Most result from contamination from female genital

tract where organism is normal in ~ one-third tract where organism is normal in ~ one-third womenwomen

Degree of vaginal & cervical colonization in mother Degree of vaginal & cervical colonization in mother directly related to likelihood & severity of disease in directly related to likelihood & severity of disease in infantinfant

S. agalactiae (Group B streptococcal) Diseases

Children and adultsChildren and adults Infections associated with gynecologic Infections associated with gynecologic

manipulation/surgerymanipulation/surgery Rare cause of upper respiratory Rare cause of upper respiratory

infections, meningitis, bacteremia and infections, meningitis, bacteremia and endocarditisendocarditis

Group D (enterococci and non-enterococcal strains) Diseases

Urinary tract infections - associated with Urinary tract infections - associated with manipulations, malignancies, biliary tract disease manipulations, malignancies, biliary tract disease & GI disorders& GI disorders

Wound and soft tissue infectionsWound and soft tissue infections Endocarditis - bacteremia associated with lon-term Endocarditis - bacteremia associated with lon-term

indwellingindwelling intravenous cathetersintravenous catheters S. bovisS. bovis (non-enterococcal sp.) linked to (non-enterococcal sp.) linked to

neoplasms of GI tract, esp. colon; recovery from neoplasms of GI tract, esp. colon; recovery from adult blood cultures should prompt GIadult blood cultures should prompt GI tract tract evaluationevaluation

Viridans streptococci Diseases Sub-acute bacterial Sub-acute bacterial

endocarditis (SBE)endocarditis (SBE) Organism normally Organism normally

present in oral cavity present in oral cavity showered into blood = showered into blood = transient bacteremiatransient bacteremia

Presence of previously Presence of previously damaged heart valves = damaged heart valves = SBESBE

May be fatalMay be fatal Some species associated Some species associated

with brain abscesses, with brain abscesses, meningitis, liver abscesses & meningitis, liver abscesses & appendicitisappendicitis

S. pneumoniae Diseases PneumoniaPneumonia

Most common cause of Most common cause of community-acquired community-acquired pneumoniapneumonia

Organisms part of normal Organisms part of normal upper respiratory tract – upper respiratory tract – beginsbegins with aspirationwith aspiration

More common in persons More common in persons with chronic lung with chronic lung conditions including conditions including smokers, defects in smokers, defects in phagocyte function or phagocyte function or humoral immunity or those humoral immunity or those with ethanol intoxicationwith ethanol intoxication

The Course of Bacterial Pneumonia

As the pneumococcus As the pneumococcus traces a pathway down the traces a pathway down the respiratory tree, it respiratory tree, it provokes intense provokes intense inflammation and exudate inflammation and exudate formationformation

The blocking of the The blocking of the bronchioles and alveoli by bronchioles and alveoli by consolidation of consolidation of inflammatory cells and inflammatory cells and product is shownproduct is shown

S. pneumoniae Diseases

MeningitisMeningitis One of three leading causes of meningitisOne of three leading causes of meningitis More common in later lifeMore common in later life Signs and symptoms similar in all forms Signs and symptoms similar in all forms

of meningitisof meningitis Upper respiratory infections - sinusitis, Upper respiratory infections - sinusitis,

otitis mediaotitis media Other - endocarditis, arthritis, peritonitisOther - endocarditis, arthritis, peritonitis

S. pneumoniae Diseases

Upper respiratory Upper respiratory infections - sinusitis, infections - sinusitis, otitis mediaotitis media

The direct connection The direct connection between the pharynx between the pharynx and middle ear via the and middle ear via the eustachian tube makes eustachian tube makes this possiblethis possible

Epidemiology of Streptococcus

Natural habitatNatural habitat Group A, pneumococci and viridans strept - upper respiratoryGroup A, pneumococci and viridans strept - upper respiratory

tract of humanstract of humans Group A, B, and D - vaginalGroup A, B, and D - vaginal Group B and D – intestineGroup B and D – intestine

TransmissionTransmission Direct contact with mucosa or secretionsDirect contact with mucosa or secretions Aerosols - droplet produced by coughing, sneezing, talkingAerosols - droplet produced by coughing, sneezing, talking Indirect - fomites (shared inanimate objects)Indirect - fomites (shared inanimate objects) Insects, esp. FliesInsects, esp. Flies Food-borneFood-borne

Epidemiology of Streptococcus

Control and preventionControl and prevention Hand washingHand washing C section (Group B)C section (Group B) Vaccines - M protein antigens for Group A Vaccines - M protein antigens for Group A

strep & capsular antigens for pneumococcistrep & capsular antigens for pneumococci Treatment - penicillin (drug of choice) except Treatment - penicillin (drug of choice) except

enterococci which require combination of enterococci which require combination of penicillin or vancomycin with an aminoglycosidepenicillin or vancomycin with an aminoglycoside

General Characteristics of the Neisseria Genera

Gram-negative diplococci Gram-negative diplococci that have capsules and that have capsules and fimbriaefimbriae

Oxidase-positiveOxidase-positive Non-spore formingNon-spore forming NonmotileNonmotile FastidiousFastidious Do not survive long in the Do not survive long in the

environmentenvironment Common residents of Common residents of

mucous membranesmucous membranes

Neisseria Family

AcinetobacterAcinetobacter - only oxidase negative genera - only oxidase negative genera KingellaKingella - only catalase negative genera - only catalase negative genera MoraxellaMoraxella including including M. catarrhalisM. catarrhalis (former called (former called

Branhamella catarrhalisBranhamella catarrhalis)) NeisseriaNeisseria

N. gonorrhoeaeN. gonorrhoeae (common name = gonococcus or GC) (common name = gonococcus or GC) N. meningitidisN. meningitidis (common name = meningococcus) (common name = meningococcus) N. lactamicaN. lactamica Other Other NeisseriaNeisseria = = N. sicca, N. subflava, N. mucosa, N. N. sicca, N. subflava, N. mucosa, N.

flavescens, N. cinerea, flavescens, N. cinerea, andand N. elongata N. elongata

Virulence Factors for N. gonorrhoeae

AnatomicalAnatomical Pili - mediate adherence; antigenically variablePili - mediate adherence; antigenically variable Endotoxin - mediates local and systemic damage Endotoxin - mediates local and systemic damage

including petechiae and DICincluding petechiae and DIC Biologically active extracellular productsBiologically active extracellular products

IgA1 protease - role unknown; may facilitate IgA1 protease - role unknown; may facilitate invasioninvasion

Beta lactamase - destroys penicillin; not found in Beta lactamase - destroys penicillin; not found in all strainsall strains

Virulence Factors for N. meningitidis

AnatomicalAnatomical Pili - mediate adherence; selective for non-Pili - mediate adherence; selective for non-

ciliated columnar epitheliumciliated columnar epithelium Capsules - polysaccharide; antigenic; Capsules - polysaccharide; antigenic;

subdivides meningococci into 9 groups subdivides meningococci into 9 groups (epidemic groups = A, B, and C); (epidemic groups = A, B, and C); antiphagocyticantiphagocytic

Endotoxin - mediates tissue damage; causes Endotoxin - mediates tissue damage; causes petechiae and DICpetechiae and DIC

Clinical Manifestations of N. gonorrhoeae

PathogenesisPathogenesis Attach via pili to epithelial cells on contact, Attach via pili to epithelial cells on contact,

enter and multiply within cells (intracellular enter and multiply within cells (intracellular parasites)parasites)

Spread via direct extension; cause acute, Spread via direct extension; cause acute, localized inflammatory response - further localized inflammatory response - further spread facilitated by pilus-mediated attachment spread facilitated by pilus-mediated attachment to sperm; may also spread hematogenouslyto sperm; may also spread hematogenously

Clinical Manifestations of N. gonorrhoeae Genital infections are of epidemic proportions (approx. 1M Genital infections are of epidemic proportions (approx. 1M

cases/yr. in US)cases/yr. in US) Genital infections (gonorrhea) - commonly called “clap”; Genital infections (gonorrhea) - commonly called “clap”;

occurs after genital intercourseoccurs after genital intercourse Different for man v. womanDifferent for man v. woman


Genital Gonorrhea in Genital Gonorrhea in the Malethe Male Primary site - urethraPrimary site - urethra Symptoms begin 1-Symptoms begin 1-

14 days post 14 days post infection; purulent infection; purulent urethral discharge urethral discharge and dysuria; rarely and dysuria; rarely mild or absentmild or absent

Local extension Local extension uncommon but uncommon but possible leading to possible leading to prostatitis & prostatitis & epididymitisepididymitis


Genital Gonorrhea in the Genital Gonorrhea in the FemaleFemale Primary site - endocervixPrimary site - endocervix Symptoms begin 2-7 days Symptoms begin 2-7 days

post infection; vaginal post infection; vaginal discharge, dysuria, discharge, dysuria, abdominal pain and abdominal pain and menstrual abnormalities; menstrual abnormalities; usually mild or absentusually mild or absent

Local extension common Local extension common leading to pelvic leading to pelvic inflammatory disease inflammatory disease (PID) and sterility(PID) and sterility


Rectal infections - occurs after rectal Rectal infections - occurs after rectal intercourse or after contamination of rectal intercourse or after contamination of rectal area with infected vaginal secretions in area with infected vaginal secretions in females; symptoms may manifest as rectal females; symptoms may manifest as rectal bleeding but usually asymptomaticbleeding but usually asymptomatic

Pharyngeal infections - follows oral/genital Pharyngeal infections - follows oral/genital sex; generally asymptomatic but may sex; generally asymptomatic but may produce sore throat and cervical adenitisproduce sore throat and cervical adenitis


Pelvic inflammatory disease (PID)Pelvic inflammatory disease (PID) Local extension of cervical infection; causes Local extension of cervical infection; causes

endometritis, salpingitis & peritonitisendometritis, salpingitis & peritonitis Symptoms = fever and lower abdominal pain Symptoms = fever and lower abdominal pain Sterility caused by scarring of fallopian tubes – may Sterility caused by scarring of fallopian tubes – may

follow single attack; occurs in up to 20% of women with follow single attack; occurs in up to 20% of women with gonorrheagonorrhea

Disseminated gonococcal infections (DGI)Disseminated gonococcal infections (DGI) Follows hematogenous spread from any site Follows hematogenous spread from any site Symptoms = rash (petechial, maculopapular or pustular), Symptoms = rash (petechial, maculopapular or pustular),

arthritis (large joints), endocarditis, and meningitisarthritis (large joints), endocarditis, and meningitis


Conjunctivitis and ophthalmia neonatorum (ON)Conjunctivitis and ophthalmia neonatorum (ON) May occur at any age by contamination of May occur at any age by contamination of

conjunctiva (ON - of newborn during vaginal conjunctiva (ON - of newborn during vaginal birth from infected mother)birth from infected mother)

Symptoms = severe, acute, purulent Symptoms = severe, acute, purulent conjunctivitis; may lead to blindnessconjunctivitis; may lead to blindness

Common cause of blindness in newborns until Common cause of blindness in newborns until use of silver nitrate or penicillin drops instituted use of silver nitrate or penicillin drops instituted as standard treatment for all newborns as standard treatment for all newborns

N. Meningitidis - also called meningococcus Pathogenesis Pathogenesis

Pili mediate attachment of Pili mediate attachment of organisms to non-ciliated organisms to non-ciliated columnar epithelial cells in columnar epithelial cells in nasopharynx where organisms nasopharynx where organisms multiply and spread by direct multiply and spread by direct extension to adjacent cells -extension to adjacent cells -may damage adjacent ciliated may damage adjacent ciliated cells via release of endotoxincells via release of endotoxin

Enter blood via cervical lymph Enter blood via cervical lymph nodes (meningococcemia) to nodes (meningococcemia) to spread hematogenously spread hematogenously throughout the bodythroughout the body

Cross blood-brain barrier and Cross blood-brain barrier and infect meningesinfect meninges

Clinical Manifestations of N. meningitidis

Meningitis (acute, epidemic meningitis)Meningitis (acute, epidemic meningitis) Most common form of meningococcal infectionMost common form of meningococcal infection Peak incidence = 6 months - 2 years and 5-18 Peak incidence = 6 months - 2 years and 5-18

yrs. (common in military recruits) yrs. (common in military recruits) Symptoms = fever, headache, stiff neck, Symptoms = fever, headache, stiff neck,

paralysis; coma and death occurs if not treatedparalysis; coma and death occurs if not treated If present, petechial rash diagnostic for MCIf present, petechial rash diagnostic for MC

Clinical Manifestations of N. meningitidis

Meningococcemia and petechial Meningococcemia and petechial rashrash Occurs with or without Occurs with or without

meningitismeningitis Rash caused by Rash caused by

thrombocytopenia and thrombocytopenia and endotoxemia may also be endotoxemia may also be accompanied by DICaccompanied by DIC

Waterhouse-Friderichsen syndromeWaterhouse-Friderichsen syndrome Occurs in fulminant Occurs in fulminant

meningococcemiameningococcemia Characterized by DIC with Characterized by DIC with

bilateral hemorrhagic bilateral hemorrhagic destruction of adrenal glands destruction of adrenal glands due to endotoxemiadue to endotoxemia

Clinical Manifestations of M. Catarrhalis

Occurs in individuals with compromised Occurs in individuals with compromised respiratory tract function; respiratory tract function;

Normally part of upper respiratory floraNormally part of upper respiratory flora Lower respiratory infection - acute Lower respiratory infection - acute

bronchitis and pneumonia bronchitis and pneumonia Also cause on rare occasion endocarditis, Also cause on rare occasion endocarditis,

meningitis, conjunctivitis and septicemiameningitis, conjunctivitis and septicemia Other = Otitis media and maxillary sinusitis Other = Otitis media and maxillary sinusitis

Epidemiology of Neisseria

Habitat - strict human parasites; mucous membranesHabitat - strict human parasites; mucous membranes M. CatarrhalisM. Catarrhalis and all and all NeisseriaNeisseria except except N. gonorrhoeaeN. gonorrhoeae

part of normal flora - high normal carrier ratepart of normal flora - high normal carrier rate All except All except N. gonorrhoeaeN. gonorrhoeae norm in upper respiratory tract norm in upper respiratory tract

Routes of transmissionRoutes of transmission N. gonorrhoeaeN. gonorrhoeae - most by direct venereal (sexual) routes; - most by direct venereal (sexual) routes;

rarely involves fomitesrarely involves fomites N. meningitidisN. meningitidis - respiratory droplets; requires close - respiratory droplets; requires close

contact and a susceptible (non-immune) hostcontact and a susceptible (non-immune) host M. catarrhalisM. catarrhalis - endogenous; droplet - endogenous; droplet

Epidemiology of Neisseria Prevention and ControlPrevention and Control

N. gonorrhoeaeN. gonorrhoeae - “safe” sex; case-contact - “safe” sex; case-contact tracking/treatmenttracking/treatment

N. meningitidisN. meningitidis - chemoprophylaxis (rifampin) if - chemoprophylaxis (rifampin) if exposed; vaccines to susceptible individuals; vaccines exposed; vaccines to susceptible individuals; vaccines directed against polysaccharide capsular antigens directed against polysaccharide capsular antigens available - used primarily in military recruitsavailable - used primarily in military recruits

TreatmentTreatment N. gonorrhoeaeN. gonorrhoeae - penicillin for non-resistant strains; - penicillin for non-resistant strains;

spectinomycin or ceftriaxone for PPNG (penicillinase spectinomycin or ceftriaxone for PPNG (penicillinase producing producing Neisseria gonorrhoeaeNeisseria gonorrhoeae))

N. meningitidisN. meningitidis - penicillin (ampicillin) - penicillin (ampicillin) M. catarrhalisM. catarrhalis - most strains produce penicillinase; may - most strains produce penicillinase; may

use erythromycin or tetracyclineuse erythromycin or tetracycline

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Chapter 18 The Cocci of Medical Importance. General Characteristics of the Staphylococci Nonmotile,...

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