Streptococcus Part 2 Flashcards by Kyra Catedral

• Normal flora of the GIT & Vaginal tract
• Gram positive cocci in chains
• Beta hemolytic in BAP

Group B: Streptococcus agalactiae (GBS)

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Component of Group B: Streptococcus agalactiae (GBS)

• Anti-phagocytic
• inhibits complement activation
• able to mimic host molecules, enhancing pathogenicity.

polysaccharide capsule

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Pathogenesis and Clinical Manifestations

S. agalactiae

2 types

• Neonatal Infection: pneumonia, meningitis & sepsis

Early onset - 1st week of life
Late onset - after 1st week to 3rd month of life

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S. agalactiae

Adult Streptococcal infection:

Mostly nosocomial
Immunocompromised
host

• Skin & soft tissue infections
• Pneumonia
• Septic arthritis
• Bacteremia
• UTI
• endocarditis

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GBS: S. agalactiae

Diagnostic Laboratory Tests

CAMP Test
SODIUM HIPPURATE HYDROLYSIS

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CAMP Test

• Christie, Atkins and Munch-Peterson

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GBS: S. agalactiae DIAGNOSTIC test

• ВАР
• Do not incubate anaerobically or with increase CO2 to prevent false reaction

CAMP Test

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Positive indicator for CAMP

(+)= Arrowhead zone of remolysis

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SODIUM HIPPURATE HYDROLYSIS
Procedure:

0.4 ml 1% Na hippurate
+
loopful of organisms
(incubate 32°C for 10 mins.)
+
0.2ml ninhydrin solution
(reincubate 37° for 10 mins)
=
(+) deep purple color

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Group C, F & G: Miscellaneous Beta Hemolytic Streptococcus

•______-hemolytic streptococci
• Normal microbiota:
• Endogenous strain:
• Direct contact:

beta

skin, nasopharynx, GIT, GUT

gain access to sterile site

person to person

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Group C, F & G: on 5% Sheep Blood Agar

• B-hemolytic
streptococci
• Grayish white, glistening;
• wide zone of B-hemolysis

Group C

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Group C, F & G: on 5% Sheep Blood Agar

• B-hemolytic
streptococci
• Grayish white, small, matte;
• narrow to wide zone of B-hemolysis

Group F

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Group C, F & G: on 5% Sheep Blood Agar

• B-hemolytic
streptococci
• Grayish white, small, matte;
• narrow to wide zone of B-hemolysis

Group F

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Group C, F & G: on 5% Sheep Blood Agar

• 8-hemolytic streptococci
• Grayish white, matte;
• wide zone of B-hemolysis

Group G

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Group C & G

• S. equi subsp. zooepidemicus,
• S. equi subsp. equi
• S. dysgalactiae subsp. equisimilis,
• S. dysgalactiae subsp. dysgalactiae
• S. anginosus

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• Cause infection similar to Group A
• Pharyngitis, skin & soft tissue infections, and bacteremia

Group C & G

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Group C, F & G: Species & Diseases

• S. anginosus

• Cause cellulitis
• abscesses
• bacteremia

Group F

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Group C, F & G: Identification
• Negative:
• Susceptible to
• S. dysgalactiae subsp. equisimilis =

• S. anginosus (C,G,F) =

CAMP, PYR, Bile Esculin Hydrolysis, Hippurate

SXT

Vp (-); Vp(+)

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Group C, F & G: Identification

Biochemical reaction & serological testing
• Serological test:

• Extract + antisera (with latex beads for visualization)
• Observe for AGGLUTINATION

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Streptococcus pneumoniae :
GENERAL CHARACTERISTICS
• Gram(+) diplococci
• Requires____ → Capnophilic
•[capsule??], non-motile, non-spore forming
•[growth condition???], fastidious
•____-hemolytic

5 to 10% CO2

encapsulated

facultative anaerobe

alpha

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Streptococcus pneumoniae :
GENERAL CHARACTERISTICS
• Gram(+) diplococci
• Requires____ → Capnophilic
• [capsule???], non-motile, non-spore forming
•[growth condition???], fastidious
•____-hemolytic

5 to 10% CO2

encapsulated

facultative anaerobe

alpha

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Streptococcus pneumoniae :
MAJOR VIRULENCE FACTORS

• CAPSULAR ANTIGENS
- M-CHON
• PNEUMOLYSIN
• Autolysin

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Streptococcus pneumoniae :
MAJOR VIRULENCE FACTORS

• immunologically distinct for each type
• Resist phagocytosis

CAPSULAR ANTIGENS

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Streptococcus pneumoniae :
MAJOR VIRULENCE FACTORS

M-CHON:

Type-specific CHON antigens

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Streptococcus pneumoniae : MAJOR VIRULENCE FACTORS • released in cell lysis, hemolytic • Antiphagocytic, Activates complement

PNEUMOLYSIN

Streptococcus pneumoniae : MAJOR VIRULENCE FACTORS •: aids in the release of pneumolysin

Autolysin

Streptococcus pneumoniae : EPIDEMIOLOGY, PATHOGENESIS & CLINICAL MANIFESTATIONS • RT → sinuses & middle ear →______

sinusitis & otitis media

Streptococcus pneumoniae : EPIDEMIOLOGY, PATHOGENESIS & CLINICAL MANIFESTATIONS DISEASE:

• pneumonia, bacteremia, & meningitis

• community-acquired bacterial pneumonia; • most common in U.S. (rusty sputum)

Streptococcus pneumoniae

Streptococcus pneumoniae : MOT

• person to person contact • respiratory droplets

Diagnostic Laboratory Tests 1. MICROSCOPIC: S. Pneumoniae

• Gram(+) lancet-shaped diplococci

S. pneumoniae 2. CULTURE: BAP:______, @_____ • wide zone of__-hemolysis (aerobically) • MORPHOLOGY??? Colonies later develop a "____"-like appearance

5-10% CO2; 35-37 C (24 hrs.) Alpha Mucoid, dome shape, transparent colonies crater

S. Pneumoniae LAB Diagnosis

Optochin Test/ Taxo P: Bile Solubility Test: Quellung Test:

Optochin Test/ Taxo P: •reagent:_______ =______[suscpetibilty]

Ethylhydrocupreine HCI (5 ug) v (+) 14mm or more, Susceptible

Bile Solubility Test: *reagent: Bile salts (Na deoxycholate; Na taurocholate) v (+). Positive: ____

autolysis (clear solution)

Quellung Test:

Swollen capsule (Ag-Abreaction)

S. pneumoniae TREATMENT • Acquired resistance to penicillin, macrolides, & cephalosporins • Sensitivity testing is necessary → TREATMENT

• Penicillin, ceftriaxone/cefotaxime, tmp/smx (STX)

S. Pneumoniae PREVENTION •

Pneumococcal conjugate vaccine

Streptococcus bovis group : GENERAL CHARACTERISTICS → single species

• S. bovis & S. equinus

S. bovis • Others

: S. gallolyticus, S. infantarius, S. alactolyticus

S. bovis • Characteristics: • Lancefield Group____ • Bile esculin____ PYR___ • Unable to grow in_____ • Alpha or gamma hemolytic

D (+); (-) 6.5% NaCl broth

S. bovis • Diseases:

Bacteremia, septicemia, endocarditis

S. bovis • Diseases:

Bacteremia, septicemia, endocarditis

Enterococcus group : GENERAL CHARACTERISTICS • Lancefield group___ Antigen

Enterococcus • Species:

• E. faecalis • E. faecium • E. durans, E. avium, E. casseliflavus, E. gallinarum, E. dispar, & E. canis

Enterococcus group : GENERAL CHARACTERISTICS •_________ on SBA • may be found in the environment • Normal flora of_______ • Nosocomial infections

Alpha or non hemolytic GIT, skin, oral cavity, & GUT

Enterococcus High risk: immunocompromised, patients with invasive procedure, & prolonged antibiotic treatment

• immunocompromised, patients with invasive procedure, & prolonged antibiotic treatment Diagnostic Laboratory Tests

Diagnostic Laboratory Tests Name of the test:______ Example A: Positive - Group D streptococcus (Enterococcus species) Example B: Negative - Group B streptococcus

Bile Esculin test

The selective agent Die, innions most gram positive bacteria

Acid family far

in the medium is hydrolyzed to esculetin and dextrose The_____ reacts with ferrie chloride in the media to form a _____color.

Esculin esculetin black-brown

Diagnostic Laboratory Tests • Purpose: • Differentiate Enterococcus from Streptococcus bovis group which are intolerant

6.5% SALT BROTH OR SALT TOLERANCE TEST

6.5% SALT BROTH OR SALT TOLERANCE TEST • Principle: • If growth is present in both broth (w/ salt & w/o salt), the organism is salt tolerant.

FACTS: • has intrinsic resistance to beta lactam antibiotics • Combination treatment: beta lactam (penicillin or vancomycin) with aminoglycosides • Vancomycin resistant Enterococci (VRE) → first reported in 1986

Enterococcus

Viridans

• S. mutans • S. salivarius • S. mitis • S. sanguinis • S. constellatus • S. intermedius

VIRIDANS GROUP BAP:

a-hemolytic w/ greenish discoloration

Normal flora of the human oropharynx, GIT & female genital tract

Viridans

Viridans • Diseases:

> subacute bacterial endocarditis > Bacteremia & septicemia > Dental caries

VIRIDANS GROUP: Laboratory Diagnosis _____to bile (sodium deoxycholate), & _____optochin to most presumptive tests for Streptococcus _____to mannitol & sorbitol _____to urease & VP reaction

Resistant Negative Positive Positive

= requires cysteine or pyridoxal (vitamin B6) for growth

NUTRITIONALLY VARIANT STREPTOCOCCI (NVS)

= Given the new genus Abiotrophia & Granulicatella

NUTRITIONALLY VARIANT STREPTOCOCCI (NVS)

Other Catalase (-) Streptococcal Like Organisms

Aerococcus viridans Leuconostoc spp. Pediococcus Leuconostoc & Pediococcus Lactococcus & Gemella

• rare cause of endocarditis & meningitis Intracerebral hemorrhage (ICH)

Aerococcus viridans

• NF of LGIT, isolated occasionally from abscesses

Pediococcus

Leuconostoc & Pediococcus • exhibit resistance to____

Vancomycin

Summary of Laboratory Diagnosis: GAS • Wide zone of beta hemolysis • Bacitracin • PYR • SXT • CAMP

susceptible positive resistant negative

Summary of Laboratory Diagnosis: GBS • beta hemolysis (narrow zone) • CAMP _____ • Hippurate ____ • Bacitracin____ • SXT ____ • PYR_____ • Bile-esculin hydrolysis _____

positive positive resistant resistant negative negative

Summary of Laboratory Diagnosis: Pneumococci • Optochin Test/ Taxo P: (+) • Bile Solubility Test: • Quellung Test:

14mm or > autolysis (clear solution) swollen capsule

Group D Enterococcus Bile- Esculin media 6.5% NaCl PYR

+ + +

Group D Non-Entero-coccus Bile- Esculin media 6.5% NaCl PYR

+ - -

Not Group D Bile- Esculin media 6.5% NaCl PYR

- - -

Treatment (GAS; also, pneumococci)

• Penicillin G

Treatment (TSS)

Clindamycin

Treatment (enterococci, pneumococci)

Ampicillin or vancomycin

Treatment (pneumococci) (meningitis)

• 1st gen. cephalosporin • 3rd generation cephalosporin with or without vancomycin

T or F Most are sensitive to Erythromycin

True