Staphylococci

what bacterial genus is associated with the following:

• GPC

• grapelike clusters

• part of normal flora of skin and mucous membranes of humans/other warm blooded animals

• facultative anaerobes

staphylococcus

staphylococci is catalase ____.

positive

staphylococci can produce heat tolerant ____ (thermonuclease).

DNase

media containing toluidine blue is generally used to detect the enzyme _____ and appears pink if positive.

DNase

staphylococcus aureus may appear ____ in color with beta hemolysis.

yellowish

coagulase negative staphylococci are usually _____ in color and non-hemolytic.

white

what test differentiates staphylococci and streptococci (and other catalase negative bacteria)?

catalase

what refers to the enzyme that breaks down hydrogen peroxide (H2O2) into water (H2O) and oxygen (O2)?

catalase

the following procedure describe the ____ test:

• smear colony onto glass slide

• add drop of H2O2 on top of it

  • bubbles = positive

catalase

a reverse order of steps for the catalase test such as using an iron loop (colony added to H2O2 with loop) may cause a ____ result.

false positive

blood taken from a BAP taken up with colony for a catalase test may cause a false positive result because _____ contain a small amount of catalase.

RBCs

which enzyme form of coagulase refers to a clumping factor attached to the staphylococcus aureus cell wall?

bound

the _____ enzyme form of coagulase refers to a slide coagulase test being used.

bound

which enzyme form of coagulase refers to extracellular?

free

the _____ enzyme form of coagulase refers to a tube coagulase test being used.

free

which enzyme form of coagulase testing will show clumps as a positive result?

bound

which enzyme form of coagulase testing will show clot formation as a positive result?

free

for coagulase testing, the latex agglutination kits detect a clumping factor and _____.

protein A

what refers to the staphylococcus aureus wall antigen?

protein A

MRSA may give false ____ results for latex agglutination kits for coagulase testing.

negative

what is the most commonly isolated coagulase negative staphylococci?

staphylococcus epidermidis

staphylococcus epidermidis is susceptible to ____.

novobiocin

which coagulase negative staphylococci is associated with UTIs (young women/older men)?

staphylococcus saprophyticus

staphylococcus saprophyticus is novobiocin ____.

resistant

resistant to novobiocin is denoted by a zone of ____mm.

<16

novobiocin resistance is a presumptive ID for ____.

staphylococcus saprophyticus

which coagulase negative staphylococci is a frequent cause of endocarditis?

staphylococcus lugdunensis

staphylococcus lugdenensis ferments ____.

mannitol

staphylococcus lugdenensis is PYR ____.

positive

which coagulase negative staphylococci is clumping factor positive and is frequently slide coagulase positive?

staphylococcus lugdunensis

coagulase negative staphylococci is catalase ____.

positive

____ is associated with indwelling medical devices such as catheters and shunts.

coagulase negative staphylococci

which staphylococci is described below:

• BAP: opaque, smooth, beta-hemolytic

• catalase positive

• coagulase positive

• PYR negative

staphylococcus aureus

staphylococcus aureus can tolerate high ____ concentrations.

salt

what media (with 7.5% salt) inhibits most gram negative bacteria and many gram positive bacteria and has a pH indicator of phenol red?

MSA

staphylococcus aureus ferments mannitol (acidic) on MSA resulting in ____ colonies.

yellow

most coagulase negative staphylococci do not ferment mannitol on MSA resulting in ____ colonies.

red/pink

approximately 20-40% of individuals with staphylococcus aureus infections are carriers, often in the ____.

nares

which staphylococcus aureus infection is described below:

• superficial → deep: abscesses, wounds, furuncles, carbuncles

skin

which staphylococcus aureus infection is described below:

• food poisoning (via enterotoxin - there are 6 types)

  • staph multiplies and enterotoxins increase

  • incubation 1-5 hours → vomiting, cramps, diarrhea (fever uncommon)

  • recovery is usually rapid (within 24 hours)

gastrointestinal

scalded skin syndrome in staphylococcus aureus infections are caused by ____ (toxin).

exfoliatin

what toxin is produced in a staph lesion, enters the bloodstream, causes erythema and intraepidermal desquamation in remote sites from which staphylococcus aureus cannot be isolated?

exfoliatin

which staphylococcus aureus infection is described below:

• most common in neonates and children <5 years or immunocompromised

• milder version: staphylococcal scarlet fever

scalded skin syndrome

toxic shock syndrome in staphylococcus aureus infections are via toxin ____.

TSST-1

which staphylococcus aureus infection is described below:

• associated with high absorbency tampon use

toxic shock syndrome

MRSA antimicrobial resistance is not just to methicillin, but also other beta lactams such as ____.

oxacillin; cefoxitin

what gene is the most important mechanism for the MRSA?

mecA

which gene codes for a new penicillin binding protein, PBP2A, with a low affinity for beta lactam antimicrobics?

mecA

severe MRSA infections are often treated with ____.

vancomycin

vancomycin resistant staphylococcus aureus (VRSA) is due to ____ operon that alters vancomycin’s cell wall target.

VanA

VISA refers to vancomycin ____ staphylococcus aureus.

intermediate

the following describes the hospital screening for MRSA within 24 hours of admission known as the _____:

• patients scheduled for inpatient surgery and have documented medical condition making them susceptible to infection, based either upon federal CDC findings or recommendations of the committee or its successor

• patients who are admitted and were previously discharged from an acute care hospital within the past 30 days

• all admissions to ICU or burn unit

• patients who receive inpatient dialysis treatment

• patients transferred from a skilled nursing facility

• nares specimen → selective/differential media (e.g., chromagar)

CA law (SB 1058)

what bacteria is described below:

• commensal, free-living

• larger than staphylococcus aureus

• often arranged in regular packets of 4 or 8 as tetrads

• catalase positive

• coagulase negative

micrococcus

micrococcus cannot grow anaerobically (metabolizes oxidatively) and often appears ____ and non-hemolytic on a BAP

yellow

bacitracin and furazolidone susceptibility testing are differential tests for ____.

micrococcus

micrococcus is bacitracin ____.

susceptible

micrococcus is furazolidone ____.

resistant

bacitracin and furazolidone susceptibility testing should only be done on ____ because staphylococcus aureus can show sensitivity to bacitracin.

coagulase negative staphylococci

what micrococcus differential test tests for the presence of enzyme cytochrome oxidase?

modified oxidase test

for the modified oxidase test, the color ____ (within 30 seconds) is considered positive.

blue

rothia mucilaginosus is also known as _____.

stomatococcus

what refers to gram positive cocci with a tendency to form clumps or tetrads?

stomatococcus

what bacteria is often referred to as “sticky staph” because they are grey-white colonies strongly stuck to the agar surface?

stomatococcus

stomatococcus is part of normal ____ flora.

oral

staphylococcus and micrococcus are catalase ____.

positive

which bacteria is catalase negative but may produce a weak pseudocatalase?

stomatococcus

which bacteria is modified oxidase positive?

micrococcus

which bacteria is cannot ferment glucose anaerobically?

micrococcus