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PYOGENIC COCCI Gram + Gram – Micrococcaceae family Streptococcaceae family Neisseriaceae family Micrococcus Streptococcus Neisseria Moraxella S. pyogenes (A) Kingella Staphylococcus S. agalactiae (B) S. pneumoniae N. meningitidis Enterococcus (D) N. gonorrhoeae viridant group S. aureus coagulase negative staphylococci (CNS)

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PYOGENIC COCCI

Gram + Gram –

Micrococcaceae family Streptococcaceae family Neisseriaceae family

Micrococcus Streptococcus Neisseria

Moraxella

S. pyogenes (A) Kingella

Staphylococcus S. agalactiae (B)

S. pneumoniae N. meningitidis

Enterococcus (D) N. gonorrhoeae

viridant group

S. aureus coagulase negative

staphylococci

(CNS)

Neisseria

Gram negative diplococci;

bean-shaped

N. gonorrhoeae on

chocolate agar

Very fastidious bacteria:

chocolate agar and

increased CO2

N. gonorrhoeae, N. meningitidis: obligate human pathogens!

Cell wall: LOS instead of LPS (lipo-oligosaccharide).

Neisseria gonorrhoeae

methylene blue staining

Neisseria gonorrhoeae

Gram staining

Oxidase test

• performance:

– filter paper on microscope slide

– add oxidase reagent

(= parephenylene-diamine derivative)

– add bacteria

– positivity: pink / purple colour

Oxidase +: Pseudomonas, Neisseria, Vibrio, Campylobacter

• purpose: detection of cytochrome-oxidase enzyme

• diagnostic use: differentiation of obligate aerobes

+ -

Neisseria gonorrhoeae

(Gonococcus)

• Virulence factors

– No capsule!

– surface fimbriae, surface proteins (Opa) →

adhesion

– LOS → inflammation

– survives inside neutrophil granulocytes → IC.!

– IgA protease

– complement deficiency → invasive infections

Neisseria gonorrhoeae

• Transmission

– sexual (STI/STD)

– perinatal (birth canal) → conjunctiva of newborn

• Clinical picture

– Acute urethritis (men): dysuria, burning pain, purulent exudate („Bonjour-drop”)

– cervicitis, urethritis (women): often asymptomatic!

– vaginitis in teenagers

– blenorrhoea (ophtalmia) neonatorum → blindness!

Neisseria gonorrhoeae

Purulent urethra exudate

„Bon jour” droplet

N. gonorrhoeae in pus,

methylene blue staining

Diagnostics

– specimen from purulent exudate → direct

Gram or methylene blue staining

– special transport medium (NO cooling)

– immediate inoculation on chocolate agar,

incubation in increased (5%) CO2

– in cervical, rectal specimen: selective media

Treatment

– earlier: penicillin, today rather 3. gen.

cephalosporin (ceftriaxon)

– If suspicion also for chlamydia: additional

macrolide (azythromycin)

– For newborns: Credé eye drops (silver

acetate); today rather tetracycline or

macrolide eye drops

Neisseria meningitidis

(Meningococcus)• Virulence factors

– CAPSULE → 13 serotypes (A, B, C, D, H, I, K, L,

W-135, X, Y, Z, 29E)

– similar to N. gonorrhoeae (fimbriae, proteins,

LOS)

• Transmission

– air droplets

– nasopharyngeal colonisation precedes disease!

– carriage!

Neisseria meningitidis

• Clinical picture

– always bacteremia (meningococcaemia)

first, and not direct spread from

nasopharynx to CNS → purulent meningitis

(meningitis epidemica)

– petechiae, necrotic haemorrhagic rush

– fulminant sepsis

– Waterhouse-Friderichsen sy.: necrosis of

adrenalin glands (both sides)

– rarely: endocarditis, pneumonia, arthritis

Neisseria meningitidis

Disseminated infection

Neisseria meningitidis• Diagnostics

– liquor sediment Gram st. → IC or EC

– liquor latex agglutination

– hemoculture obligatory!

– blood agar, cholcolate agar, increased CO2

– cooling of specimen is forbidden!

• Therapy

– empiric: cefotaxim, ceftriaxon

– targeted: penicillin, ceftriaxon

• Chemoprofilaxis

– rifampin, ciprofloxacin for contacts

Neisseria meningitidisEpidemiology

• more frequent in wintertime

• newborns are most sensitive (after finishing

breast feeding)

• in overcrowded places (e.g. military service,

summer festivals)

• „B” capsular antigen

→ molecular mimicry, no vaccine!

→ identical to E. coli K1 capsular antigen!

Meningococcus vaccines

• Suggested for persons with:

– asplenia, complement deficiency, haemoglobinopathy

• Meningitec, Menjugate, NeisVac C

– against serotype C, conjugated (from 2 months)

• Mencevax ACWY

– against A, C, Y and W135 (polysaccharide)

• Menveo

– against A, C, Y and W135, conjugated

– from 11 years of age

Meningitis belt

• It is endemic here

• Vaccination suggested

before journey!

Apathogen Neisseriae

• Presence

– oral and nasopharyngeal normal flora→ „N.

pharyngitidis”, pharyngococci

• Cultivation

– easier, normal media, also at RT, fermentate

several sugars

• Species

– N. lactamica, N. sicca, N. mucosa, N. flavescens

• Significance

– diff. diagn.!

– rarely respiratory tract infections, endocarditis

Moraxella genus• Moraxellaceae family

• Gram-negative diplococcus

• oxidase-positive

• culture: white colonies

• M. catarrhalis infections:

– otitis media, sinusitis (see: pneumococcus,

Haemophilus!), bronchitis

– in immunocompromised: sepsis, endocarditis

• M. lacunata : subacute conjunctivitis

• Treatment: β-lactam + enzyme inhibitor,

cephalosporins (II. gen.)

Veillonella genus

• obligate anaerobe, diplococci

• oxidase negative

• Species: V. parvula, V. alcalescens, V.

dentocariosa

• normal flora: oral cavity, intestine, vagina

• infections: following oral or gynecological

surgery

• treatment: metronidazole