Staphylococci

BA

Blood agar plate

CHOC

Chocolate agar plate

MAC

MacConkey agar plate

THIO

Thioglycollate broth

Where does Staphylococcus grow on?

BA, CHOC, and in THIO but do not grow on MAC

Staphylococcus Description

Gram positive cocci in clusters, catalase positive

Staphylococcus infections

spread person to person in the hospital setting and are difficult to treat

What are any Staph other than Staph aureus called in the clinical micro lab?

“Coag negative Staph”

What type of techniques have been developed due to the seriousness of Staph infections?

PCR

Staphylococcus Family

Staphylococcaceae

What is included in the Staphylococcaceae family?

Staphylococci, Micrococcus, Kocuria, Arthrobacter, Stomatococcus / Rothia and Planococcus.

Genus of Staph?

Staphylococcus

What is the G/S of staphylococcus?

GPC singly, pairs, clusters

Characteristics of Staphylococcaceae

Nonmotile, non-sporeforming, aerobic or and facultative anaerobe

Where do staph inhabit?

skin & other mucous membranes

Micrococcus General Characteristics

G/S: GPC singly, pairs, tetrades; cannot distinguish by morphology or gram stain; aerobic or facultative anaerobe; and non-sporeforming, nonmotile

Micrococcus Catalse

POS CATALSE & Coagulase: NEG

Where do micrococcus occur and what type of pathogen are they?

Occurs worldwide & are ubiquitous in environment; normal/indigenous skin flora. (commonly M. luteus)

Micrococcus General Characteristics

• Most have yellow pigment on BA

• Modified Oxidase: Positive

• Susceptible to bacitracin (0.04 U)

What are micrococcus considered?

• Usually considered contaminants when isolated from clinical specimens.

• Opportunistic pathogens for immunocompromised

Which infections are micrococcus associated with?

abscesses, septic arthritis, endocarditis, pneumonia, & meningitis

Micrococcus Key Biochemical reactions

Microdase (Modified Oxidase) Test

Microdase (Modified Oxidase)

rapid test which detects the cytochrome enzyme

What do all microccocci possess?

Cytochrome C enzyme whereas most staphylococci lack it

What type of color does Micrococcus species give?

Blue = positive result for cytochrome C

What type of color does Staphylococcus species give for the microdase test?

No color = negative for cytochrome C

Micrococcus

Produces pigment, G/S: GPC in prs., tetrads, no fermenting glucose

What does Staphylococcus aureus cause?

Many types of skin infections and more.

Sir Alexander Ogston (1880)

• Discovered Staphylococcus Aureus

• Greek staphyle (bunch of grapes) and kokkos (berry)

Friedrich Julius Rosenbach (1884)

German physician who differentiated the bacteria by colony color: S. aureus (from the Latin aurum, gold) and albus (Latin for white)

Populations at risk for Staph.

• People with chronic conditions: diabetes, cancer lung, & vascular diseaase, eczema.

• In the hospitals: patients after surgery or have IV catheters (greater risk)

• Sports teams

How is Staphylococcus spreaded?

• Aerosol Transmission

• Contact Transmission: Direct → skin-to-skin contact; Indirect → sharing of items