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GRAM POSITIVE COCCI
(Staphylococci)










Appearance: arranged in grape-like clusters
Non-motile
Brownian Movement
Facultative anaerobic organism
Non-encapsulated
Non-spore forming
Tolerate 7
...

Resistant to 0-0
...
aureus:
o
o
o
o
o

Lipase- can initiate skin infection
Hyaluronidase- spreading factor
Beta Lactamase/Penicillinase- capable of hemolyzing Beta
lactam ring
Staphylokinase- capable of dissolving clot
Coagulase- capable of clot formation; cause bacterial cell
to agglutinate in plasma
Clumping Factor/Bound Coagulase
-Immediately converts fibrinogen into fibrin
Free Coagulase
-Causes bacterial cell to agglutinate only when incubated
with plasma

o
o

Beta hemolysin
Protein A- enables the organism to attach to the host cells

TOXINS:
o
o
o

o


Causes




Enterotoxins A and B- capable of causing food poisoning
Enterotoxin F/Toxic Shock Syndrome Toxin-1 (TSST)- can
cause the toxic shock syndrome
Exfoliatin- capable of causing Scalded skin syndrome (SSS)
which is common on new borns; capable of skin
desquamation
PVL/Panton valentine Leukocidin- capable of lysine WBCs
Boils, furuncles, carbuncles, folliculitis, cellulitis, wound
infections
Bullous Impetigo and Acne
TOXIN MEDIATED DISEASES:
Food Poisoning
Toxic shock syndrome
Scalded skin syndrome

Staphylococcus epidermidis
Virulence factor

Slime Production
 Enhances ability of organism to attach
to indwelling plastic catheters

Staphylococcus saprophyticcus
-

Considered strict aerobe
Staphylococcus intermedius
Not clinically significant because it is not a frequent cause of human infection
VP test
PYR test

-

Staphylococcus lugdunensis
Frequent cause of endocarditis/bacteremia
Slide Coagulase
Mannitol
PYR test

-

+

+
+
+

Staphylococcus citreus
Producer of lemon yellow pigment
Staphylococcus albus
Producer of white pigment
07/19/16
-Angela V
...
Smith and Brown Classification
- Base on the type of hemolysis on BAP
Alpha hemolytic
Streptococci

Beta hemolytic
Streptococci
Gamma hemolytic
Streptococci
Alpha Prime

Target/Double
hemolysis

-Those that can cause partial/incomplete hemolysis on BAP
 Media will appear GREEN
 Streptococcus pneumoniae, Viridans Streptococci- S
...

mutans
-Those that can cause complete hemolysis on BAP
 Will produce CLEAR ZONE around colonies
 S
...
agalactiae
-Shows no hemolysis on BAP
 No change; but may increase the number of colonies
 E
...
faecium, S
...
Academic or Bergey’s Classification
- Growth either 10degC or 45degC
1
...
Viridans

3
...
Lactic Group

(-) to 10degC and 45degC
 i
...
S
...
e
...
mitis, S
...
sanguis, S
...
constellatus and
S
...
faecalis
(+) to 10degC and (-) to 45degC
 S
...
cremoris

C
...
Group A Streptococci – S
...
Group B Streptococci – S
...
Group C Streptococci – S
...
equl, S
...
zooepidemicus
4
...
bovis group – S
...
equines
5
...
faecalis, E
...
durans, E
...
Group F Beta hemolytic Streptococci – S
...
Group G Streptococci
Group A Streptococci – Streptococcus pyogenes
– Major throat Pathogen
– Flesh-eating bacteria
– (+) to Hemolysis test
Growth/Colony
Morphology

-

Test for identification
Susceptibility Test

-

Best isolated on BAP
Addition of Sulfamethoxazole(SXT) and trimethoprim will enhance
its recovery from contaminated specimen
Susceptible to bacitracin (0
...
04 units)
Catalase negative
Resistant to Sulfamethoxazole(SXT)
PYR positive
PYR Test
a
...
a Pyrrolidonyl B-naphthylamide Test
Reagent: p-dimethylaminocrinnamaldehyde
(+) Result: Red color, orange
(-) Result: No color change

Streptolysin

-

Streptolysin O






Streptolysin S






Virulence Factors
Erythrogenic Toxin
Hyaluronidase
Streptokinase
Mprotein
Protein F

-

Responsible for Beta hemolytic property of
S
...
Anthony’s fire
a skin infection
rapidly progressing skin infection
may develop Acute Glomerulonephritis
[affecting kidneys]
repeated episode of Pharyngitis(Tonsillitis)
and Rheumatic fever
form of pharyngitis with rashes

Diagnostic Tests for Scarlet Fever


Dick’s Test – Susceptibility for Scarlet Fever
(+) Result: Redness at the site of injection



Schultz Charlton Test/Blanche Phenomenon – Carried out to
determine if rashes are due to Scarlet Fever or not
(+) Result: Fading of rashes

GROUP B Streptococci – Streptococcus agalactiae
–Normal flora of the GIT, pharynx and vaginal tract
Causes



Septicemia – Number 1 cause of Neonatal meningitis
Post-partum endometriosis in adults


CAMP TEST positive
-Christie,Atkins,Much,Peterson
Media
Known organism
Unknown organism
(+) Result

Tests for presumptive
Identification

BAP
Staphylococcus aureus
Streptococcus agalactiae
Enhanced hemolysis as
indicated by an arrow head
zone of Beta hemolysis

What is CAMP FACTOR?
-extracellular thermostable protein produce by Streptococcus agalactiae


Hippurate Hydrolysis Test positive
-Detects hydrolysis of sodium hippurate to benzoic acid and
glycine
Bacitracin
Resistant
(+) Result
Purple

*To detect Benzoic acid:
Reagent
Ferric Chloride
*To detect Glycine:
Ninhydrin reagent
(+) Result is due to enzyme Hippuricase/Hippurate hydrolase

GROUP C Streptococci – S
...
equl, S
...
zooepidemicus
–Animal pathogens
–May cause severe pharyngitis
–May also cause pneumonia, cellulites and abscess

GROUP D (Non-Enterecocci) – S
...
equines
–Isolation of Non-Enterococci in the blood could be an indication of colon cancer
–Vancomycin Resistant
–Causes UTI, endocarditis and septicemia(infection of the blood)

Enterococci – E
...
faecium, E
...
avium
–Normal GUT, GIT and RT flora
–Common cause of UTI in hospitalized patients
–Bacitracin Resistant
–Cephalosporin Resistant
–Hippurate hydrolysis negative
–Able to tolerate 6
...

–Most common enterococcus isolated from human infection = Enterococcus faecalis
Bile Esculin Test

PYR Test

Penicillin

+

-

S

Growth in 6
...
k
...
Taxo P
-Test that will differentiate Pneumococci from other alpha
hemolytic Streptococci
-Chemical name: ethyl hydrocupreine hydrochloride
Polysaccharide capsule - neufeld quellung (+)
- Number 1 cause of adult bacterial mengitidis and most common
agent of otitis media
- One major cause of lobar pneumonia, pericarditis

Francis Test- skin test for pneumonia

Bile Solubility
Inulin fermentation
Capsular swelling
Quinidine and Optochin


Pneumococci
+
Ferment inulin
+
S

Streptococci
Does not ferment
R

Hemolysis Test- carried out to differentiate Streptococcus pyogenes and Streptococcus
pneumoniae from other Streptococcus
Viridans Streptococci – S
...
sanguis, S
...
mutans, S
...
bovis

– or Alpha hemolytic Streptococci
–Means GREEN

–Normal GUT, GIT and URT flora
–Major throat flora/Causes SBE
–Not classified under Lancefield
–Optochin Resistant
–Bile insoluble
–Alpha hemolytic on BAP
SPECIES:
1
...
Streptococcus sanguis causes sub-acute bacterial endocarditis(SBE)
3
...
pyogenes

Group BS
...
5% NaCl

S
R
R
+
-

R
R
R
+
+
-

Group D
(NonEnterococci)/
S
...
pneumoniae

R
R
R
+
+
+

S
S
S
-

Viridans
Streptococci
R
S
R
-

NUTRINIONALLY VARIANT STREPTOCOCCI
Abiotrophia
–a
...
a
...
B6 for growth
–Growth around S
...
aureus they satellite around colonies of S
...
adjacens and S
...
Dumlao

GRAM POSITIVE COCCI
(Micrococci)
 A normal skin flora
 Strict aerobe
 Appearance: arranged in tetrads under microscope; cuboidal pockets

Modified Oxidase Test
-Detection of Micrococci
Reagent
(+) Result

tetramethyl p-phenylenediamine dihydrochloride in
DMSO(dimethylsulfoxide)
Development of blue color

Cytochrome Test
-Detection of Neisseria
Reagent
(+) Result

tetramethyl p-phenylenediamine dihydrochloride but without
DMSO(dimethylsulfoxide)
Development of purple color

Test to differentiate Staphylococcus and Micrococci
Aerobic growth
Anaerobic growth
Lyostaphin Susceptibility
Bacitracin Susceptibility
Furazolidone/Furoxone Test
Modified Oxidase Test
Catalase Test
Glucose Utilization/OF medium

Staphylococcus
+
+
S
R
R
+
Fermenter (ability to
produce acid aerobically and
anaerobically)

Micrococci
+
R
S
S
+
+
Oxidizer (ability to
produce acid aerobically
only)

“S”-- Sensitive; also mean inhibited
“R” -- Resistant; also mean not inhibited

07/15/16
-Angela V

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