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-Hemolytic Streptococci. Ali Somily MD,FRCPC,D(ABMM). G+ve cocci in chains and/or pairs Colonize MM(Resp.,GIT& GUT) Catalase –ve Ferment CHO lactic acid. Grouped by either A.phenotypic Hemolysis( ,ß or ) Lancefield antigen Cell wall CHO A,B,C,D,Fand G ect Or B.Genotypic.

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-Hemolytic Streptococci

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-Hemolytic Streptococci

Ali Somily MD,FRCPC,D(ABMM)


G+ve cocci in chains and/or pairs

Colonize MM(Resp.,GIT& GUT)

Catalase –ve

Ferment CHOlactic acid

Grouped by either A.phenotypic

Hemolysis(,ß or )

Lancefield antigen

Cell wall CHO

A,B,C,D,Fand G ect

Or B.Genotypic

Introduction


&ß Hemolysis


Lancefield Agglutination


-Hemolytic Streptococci

  • Partial hemolysis of blood

  • Green zoon around the colony

  • Examples:

    • S.Pneumoniae

    • S.Viridans

    • S.Bovis


STREPTOCOCCUS PNEUMONIAE


VIRULANCE VACTORS

Capsule

Autolysin

Pneumolysin

CLINICAL PRESENTATION

NF Resp.20-40%/pharynx

Inhalation/droplets

STREPTOCOCCUS PNEUMONIAE


Primary infection

CAPalveoli

Blood

Endocarditis

Meningitis

Localized

Sinusitis

O.M

Secondary Infection

Non-capsulated

Opportunistic infection

Lungs only

Impair or poor ciliary activity

Viral, Smoking, dust

Risk factor

Hyposplenism

Splenectomy

Asplenia

Sickle Cell Diseases

Liver disease

Hypogammaglobinaemia

Alcoholism

Cigarette smoking

Malnutrition

CLINICAL PRESENTATION


Blood,CSF,Sputum& swab/aspirate

DIRECT SMEAR

G+ve diplococci

Lancet shape

Capsulated halo (antiphagocytic)/pathogenic

Diagnosis


Quellung test(AB’s swelling of capsule)

Diagnosis


CULTURE

BAP; 5-10%CO2

-hemolytic

Mucoid (capsule)SR

Concave (punched out/collapse)

IDENTIFICATION

Bile solubility (NaDC)

Optochin S (disk 5g&6mmzoon>=14 mm)

80 serotype(vaccine) capsular structure

STREPTOCOCCUS PNEUMONIAE


Treatment &Prevention

  • TTT

    • Penicillin(↑R recently)PBP

    • Ceftriaxon +/-Vancomycin or Rifampicin

  • Vaccination

    • Polsaccharide capsule

    • Conjugate vaccine

    • Indication

      • Children

      • SCD

      • Splenectomised patient

      • HIV

      • Elderly

      • Cardiopulmonary and renal diseases


VIRIDANS STREPTOCOCCI


Mitis

Mutans

Salvarius

Angionosis

Grouping of viridans streptococci


CLINCAL PRESENTATION

NF (GIT,UGT&Oral cavity)

Opportunistic organisms

Dental caries

Endocarditis

VIRIDANS STREPTOCOCCI


Formation of dental plaque by Streptococcus mutans

bacteria adhere to the tooth by a protein on the cell surface, grow and synthesize a dextran capsule

binds the bacteria to the enamel and forms a biofilm 300-500 cells of thickness

bacteria can cleave sucrose to glucose + fructose

glucose is polymerized into an extracellular dextran polymer that cements the bacteria to tooth enamel and becomes the matrix of plaque

this dextran slime can be depolymerized to glucose for use as a carbon source, resulting in the production of lactic acid within the plaque that decalcifies the enamel and leads to dental caries

Example of a biofilm


Damage ,prosthetic valve

Predisposing factor

RHD

CHD

Mitral valve prolapse

Degenerative H diseases

PV

Pathogenesis

Dextran adhere to the damaged valve vegetation(fibrin,bacteria & platelets)

Symptoms

Fever

Murmurs

Immunological manifestations O,P,S

SBE

2-5 Wks

Diagnosis

Blood culture

ECHO

Endocarditis


Treatment


DIRECT SMEAR

G+ve cocci in chains

CULTURE

Can be  OR  rarely ß hemolytic

Most lack distinct LA

IDENTIFICATION

Urea

VP( acetoin production)

Arginine hydrolysis

Esculin hydrolysis

CHO ferementation

Microbiology


Enterococcus


Introduction

  • Fecal strep separated genus/by molecular

  • Harsh conditionAbiquitous/soil,water,plants, GIT, GU human

  • 15 Spp/E.faecalis80-90% of clinical isolate

  • Colonization/infection


NC BACTEREMIA 1/3

NC UTI 16%

WOUND

ENDOCARDITIS

CNS

PNEUMONIA (rare)

ELDERLY

I’C

TTT

Vancomycin

VRE (Van A,B&C ect)

Plasmid/chromosomal

High/low level

VDE

Direct smear

Short chain/pairs/coccobaccilary

CLINICAL PRESENTATION


CULTURE

Facultative anaerobs

 OR  hemolysis

Catalase weak +ve

Group D

IDENTIFICATION

Growth B/W 10-42 Co

6.5% NaCl

Esculin hydrolysis(40%)bile salt

Pyrrolidonyl arylamidase(PYR)+ve

Leucine arylamidase(LAP)+ve

Motility ,Pigmentation,arabinose and methyl --D-glucopyranoside


All Group D

Enterococcus

S.Bovis

Bile esculin


PYR/PYR-LAP


Endocarditis


BOVIS GROUPNew NameStreptococcus gallolyticus(Group D Streptococci)


CLINICAL

Human intestine and animals

Endocarditic

Septicemia

Link to colon cancer

Stool isolation

Two biotypes I&II

Mannitol and glucan I

DIRECT SMEAR

G+ve cocci in chains

BOVIS GROUP


CULTURE

 OR  on BAP

IDENTIFICATION

LG group D

Differed from viridans

Growth in 40% bile salt

Hydrolyze esculin


S.bovis

Unable to grow in

45 Co

6.5% salt @ 37dC

PYR –ve

S to penicillin and cephalosporins

R to vancomycin(rare)

Enterococcus

Able to grow in

45 Co

6.5% salt @ 37Co

PYR +ve

S to ampicillin

How you differentiate S. bovis from enterococcus?


Summary


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