Clin Bacte Module 2 (Strep)

Bile Esculin Test (+) result

Blackening

Viridans Strp is the no 1 cause of?

Subacute bacterial endocarditis

LAP TEST (Leucine Amino Peptidase)

Presumptive test for catalse (-) gram (+) cocci

Substrate of LAP Test

Leucine-beta-naphthylamide

Reagent of LAP Test

cinnamaldehyde

(+) result of LAP Test

Red

(-) result of LAP Test

no color or slight yellow

Arrangement of strep

chain

shape of strep

spherical to ovoid

Motility and special requirement of strep

Non-motile; Capnophilic

Medium of Choice for Strep

SBA

Uses of SBA in strep

* Isolates
* Growth
* Determines hemolysis pattern

Selective Medium for strep

PEA - Phenyl Ethyl Alcohol Agar

Organisms + for Lap Test

Enterococcus, Streptococcus, Pediococcus

Organisms - for Lap Test

Aerococcus & Leuconostoc

SMITH & BROWN CLASSIFICATION

* Alpha hemolytic
* Beta hemolytic
* Gamma hemolytic

Can cause incomplete/partial hemolysis on BAP

Alpha hemolytic

What hemolysis on BAP can cause greening of agar?

Alpha hemolytic

What hemolysis on BAP can produce clear zones around the colonies?

Beta hemolytic

Beta hemolytic

Can cause complete hemolysis on BAP

Gamma hemolytic

Do not cause hemolysis on BAP

Organisms under Alpha Hemolytic

Streptococcus pneumoniae,

Viridans Streptococci – S. mitis and S. mutans

Organisms under Beta Hemolytic

* S. pyogenes
* S. agalactiae
* S. aureus (staph)

Organisms under Gamma Hemolytic

* Group D Non-Enterococci / Enterococci
* Neisseria
* Moraxella
* Staph. epidermidis
* Staph. saprophyticus
* Micrococci

CAPSULAR SWELLING TEST NEUFELD QUELLUNG +

S. pneumoniae

CAPSULAR SWELLING TEST NEUFELD QUELLUNG -

VIRIDANS

BILE SOLUBILITY TEST -

VIRIDANS

BILE SOLUBILITY TEST +

S. pneumoniae

OPTOCHIN DISK TEST sensitive

S. pneumoniae

OPTOCHIN DISK TEST resistant

VIRIDANS

Which strep is encapsulated?

S. pneumoniae

Which strep is non-encapsulated?

VIRIDANS

BILE SOLUBILITY TEST BAP is added with

10% sodium desoxycholate

BILE SOLUBILITY TEST BAP (+) results

lysis of colonies

BILE SOLUBILITY TEST BAP (-) results

intact colonies

BILE SOLUBILITY TEST broth is added with

2% sodium desoxycholate

BILE SOLUBILITY TEST broth (+) results

clearing

BILE SOLUBILITY TEST broth (-) results

turbidity, partial clearing

Optochin is also known as?

TAXO P

Chemical name of Optochin is –

Ethylhydrocuprein hydrochloride

Zone of inhibition for sensitive optochin disk test

14mm

Zone of inhibition for resistant optochin disk test

VIRIDANS

Normal flora of nasopharynx and oropharynx (URT)

S. pneumoniae

S. pneumoniae is regarded as # 1 cause of

adult bacterial meningitidis

can cause LOBAR PNEUMONIA and OTITIS MEDIA

S. pneumoniae

S. pneumoniae microscopically appears as

s LANCET or BULLET SHAPED DIPLOCOCCI

After 24 hrs of incubation (young colonies) colonies of S. pneumoniae may appear

dome shaped →**Umbonate**

After 48 hrs of incubation (aged colonies) of S. pneumoniae growth may appear

* flat crater like
* like a coin with a raised rim
* Nail head appearing colonies or colonies with checker appearance

S. pneumoniae is also known as

Diplococcus Pneumoniae

Otitis media is a

ear infection

Major Virulence factor of Streptococcus pneumoniae

Capsule

VIRIDANS Streptococci include:

* S.mitis
* S.mutans
* S.salivarius

VIRIDANS Streptococci produce?

glucans & dextrans

glucans & dextrans action

promotes attachment on tooth surfaces

VIRIDANS Streptococci is regarded as the

Major Throat $FLORA$

Beta Hemolytic Streptococci are classified under ?

LANCEFIELD CLASSIFICATION

LANCEFIELD CLASSIFICATION

most significant in identifying and classifying Beta Hemolytic Streptococci; based on the extraction of $C carbohydrate$ from the Streptococcal cell wall

Streptococcus pyogenes is regarded as the?

Major Throat pathogen

Streptococcus pyogenes is a ______ bacteria

flesh eating

Streptococcus pyogenes can cause

* Pharyngitis
* Scarlet fever
* Necrotizing fascitis
* Erysipelas

rapidly progressing skin infection

Necrotizing fascitis

level up pharyngitis w/ rashes

Scarlet fever

Erysipelas

skin infection

Post Sequelae

1. AGN (Acute Glomerular Nephritis)
2. Rheumatic Factor

Identification Tests for Strep Pyogenes

1. PYR Test
2. BACITRACIN DISK TEST

PYR TEST

Pyrrolidonyl – alpha-naphthylamide

PYR TEST uses

n-n dimethylaminocinnamaldehyde

PYR TEST (+) result

red

BACITRACIN DISK TEST for S. pyogenes

Sensitive

Purpose of PYR Test:

1. to detect S.pyogenes
2. to detect enterococci

Purpose of Bacitracin Disk Test

1. to detect S.pyogenes
2. to detect staphylococci from micrococci

What strep is the # cause of Neonatal Meningitis

S. agalactiae

In adult of S. agalactiae

Post partum endometriosis

Todd Hewitt Broth

selective enrichment media to detect genetal carriage of S. agalactiae during pregnancy

LIM Broth

enrichment media

Identification Tests for S.agalactiae

1. HIPPURATE HYDROLYSIS TEST
2. CAMP TEST – Christie Atkins Munch Peterson

The positive result of HIPPURATE HYDROLYSIS TEST is due to the organism’s ability to produce the enzyme

HIPPURATE HYDROLASE / HIPPURICASE

HIPPURATE HYDROLYSIS TEST media

Sodium Hippurate Broth

HIPPURATE HYDROLYSIS TEST End products

benzoic acid and glycine

To detect benzoic acid

ferric chloride (indicator)

To detect Glycine

ninhydrin reagent (faster)

CAMP TEST – Christie Atkins Munch Peterson Required media

BAP

CAMP TEST known organism

S.aureus

CAMP TEST manner of streaking

Perpendicular

CAMP TEST (+) result

enhance hemolysis as shown by arrow head zone of beta hemolysis

CAMP TEST (-) result

No enhanced hemolysis

Virulence Factors of S. pyogenes

* M protein
* Streptolysin O
* S Non-antigenic
* Protein F
* Erythrogenic Toxin or Pyrogenic Toxin
* Hyaluronidase; Streptokinase

Prevents phgocytosis

M Protein

Antigenic (anti-streptolysin O) Oxygen labile, can cause sub-surface hemolysis Streptolysin

Streptolysin O

Oxygen stable can cause surface hemolysis

Streptolysin S

promotes attachment to ET cells

Protein F

cause rashes in scarlet fever

Erythrogenic Toxin or Pyrogenic Toxin

Hyaluronidase

spreading factor

Streptokinase

promotes dissolution of clot

DIAGNOSTIC TESTS for SCARLET FEVER

DICK’S TEST

SCHULTZ-CHARLTON BLANCHE PHENOMENON

DICK’S TEST

Susceptibility test for scarlet fever

SCHULTZ-CHARLTON BLANCHE PHENOMENON

test to determine if rashes are due to scarlet fever or not

DICK’S TEST (+) result

redness at the site of injection

Major Virulence factor of S.pyogenes

M protein

SCHULTZ-CHARLTON BLANCHE PHENOMENON (+) result

fading of rashes/gradual disappearance of rashes