Staphylococcus spp.

Staphylococci

a gram positive cocci that belong to the family Micrococcaceae

staphylococci

are non-motile, non spore forming aerobic facultative, obligate, anaerobe

Staphylococcus aureus and Staphylococcus epidermidis

2 staphylococcus spp. that have the capability to produce capsulated-slime layer/biofilm

pathogenic

pathogenic or non pathogenic: capsulated bacteria

• resistance to phagocytosis

pinhead colonies

colonies of staphylococcus spp. appear creamy, white or light gold

“buttery looking”

Staphylococcus epidermidis

species that has gray colonies

Staphylococcus aureus

species that are β-hemolytic

• drying

• heating at 50C - 30 mins.

• 10% NaCl

staphylococcus spp are resistant to

18-40C

Incubation temp for growing Staph in most culture medium

37C

Incubation temp for RAPIDly growing Staph in most culture medium

20-25C

Temp on which staphylococcus spp. have pigment productions

Staphylococcus

Gram + cocci (spherical , clustered)

catalase

differentiate Staph + vs Strep -

Coagulase

differentiate S. aureus + vs. CoNS -

Coagulase Negative Staphylococci

• S. epidermidis

• S. saprophyticus

• S. simulans

• S. intermedius

• S. sciuri

• S. hyicus

• S. lugdunensis

Staphylococcus epidermidis

nosocomial-acquired infection/implanted medical devices

• endocarditis

Staphylococcus saprophyticus

UTI, cystitis

Staphylococcus lugdunensis

catheter-related bacteremia and infective endocarditis

S. haemolyticus

occasionally recovered from native valve infection, septicemia, and UTI

Staphylococcus aureus

most clinically significant species

staphylococcus aureus

true coagulase positive and most virulent

Coagulase

principal virulence factor of Staphylococcus aureus

Staphylococcus epidermidis

causes infection of native heart valves and intravascular prostheses

Staphylococcus aureus, 7.5% -10% NaCl

they are halophilic in MSA with what percent

golden yellow color with narrow zone of B-hemolytic pattern

Staphylococcus aureus colony on BAP

Hyaluronidase

virulence factor of Staphylococcus aureus that also is a spread factor

exfoliatin A and B

toxin of staphylococcus spp. that causes SSS

Rabbit plasma

reagent for coagulase test

clot formation within 30 seconds

(+) result for slide method

0.5 mL

volume of rabbit plasma for coagulase test tube method for S. aureus

35C for 1-4 hours

coagulation time and duration of tube method for coagulase test

clot formation after incubation

(+) result for tube method coagulase test

1. Coagulase test

2. Mannitol fermentation

3. DNase Test

4. Tellurite Glycine Agar test/ Baird-Parker Agar

differential test for S. aureus

mannitol salt agar

culture medium of Mannitol fermentation

yellow colored colonies

(+) result for mannitol fermentation

phenol red

pH indicator of Mannitol fermentation

DNase agar with methyl green dye and sodium chloride

reagents of DNase test

remains green

(-) result for DNase test

clear zone around test

(+) result for DNase Test

jetblack colonies of S. aureus

result of tellurite glycine agar test

Methicillin Resistant S. Aureus

a type of S. aureus stain that is resistant to antibiotics

Methicillin, Nafcillin, Oxacillin

antibiotics that S. aureus are resistant to

Nasal swab

the most common specimen used for detection of resistant strain

Chromogenic/CHROM agar test

this test gives a (+) result of PINK to MAUVE color colonies after 24-48 hours of incubation at 35C

mecA gene

it encodes for PBP2a

Linozolid

actual “reserve-antibiotic” is _____ (last line of defense; only in severe cases

Staphylococcus albus

other name of Staphylococcus epidermidis

Staphylococcus epidermidis

most frequently isolated species

Staphylococcus spahrophyticus

affects the normal flora of females: Female GUT, perineum and GIT

Staphylococcus saprophyticus

causes honeymoon cystitis

uroepithelium

where does S. saprophyticus adheres to human

staphylococcus saprophyticus

an opportunistic pathogen that does not produce exotoxins

nosocomial infections: use of in-dwelling catheter

Staphylococcus lugdunensis

emerged as a virulent organism

• has hemolysin and clumping factor and causing a disease spectrum like s. aureus