Exam 3 Flashcards by Sara Buitrago

Are staph motile? what color is there colony morphology and what hemolysis result do they show on BA

non motile, white/ creamy, variable beta hemolysis

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What staph organisms are resistant to novobiocin, which ones are susceptible

R- saphrophyticus

S-epidermidis, hominis, lugdunensis

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What does it mean to be a persistent carrier? intermittent? non-carrier?

a single strain of staph over a long time
multiple strains over a long time
no strains

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What environments (in society) are staph often found in

gyms, prisons, dormitories, educational settings, military, opioid crisis

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What are staph the leading cause of infection for?

US healthcare facilities

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MRSA rates have ___ but MSSA rates are _______

Methicillin resistant staph aureus- dropped

Methicillin susceptible staph aureus-increasing

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What color does staphylococcus aureus have on a chocolate plate? and BA?

choc- gold pigment

BA- beta hemolytic, white

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Math how alpha, beta, gamma and sigma hemolysin virulence factors in staph affect their pathogenicity

lysing RBCs, damage to macros and platelets, tissue damage
hot-cold lysin, affects sphingomyelinase in plasma membrane of RBCs
exotoxin PVL that kills WBCs and suppresses phagocytosis
staph a and others, not as toxic as alpha and beta

alpha-lysing RBCs, damage to macros and platelets, tissue damage
beta- hot-cold lysin, affects sphingomyelinase in plasma membrane of RBCs
gamma- exotoxin PVL that kills WBCs and suppresses phagocytosis
sigma- staph a and others, not as toxic as alpha and beta

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Match the virulence factors to their functions: capsule, lipase, hyaluronidase, peptidoglycan, protease, protein A, coagulase

-prevents phagocytosis and opsonization
capable of destroying tissue
binds to Fc region of IgG
cell survival and inactivates complement IL-1 chemotaxis
enzyme hydrolyzes hyaluronic acid
acts on lipase present on surface off skin
helps prevent phagocytosis

capsule-prevents phagocytosis and opsonization
protease-capable of destroying tissue
Protein A-binds to Fc region of IgG
peptidoglycan-cell survival and inactivates complement IL-1 —-chemotaxis
Hyaluronidase-enzyme hydrolyzes hyaluronic acid
lipase-acts on lipids present on surface off skin
coagulase-helps prevent phagocytosis

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What causes
toxic shock syndrome, scalded skin syndrome, folliculitis, impetigo, furuncles, carbuncles, toxic epidermal necrolysis, food poisoning, bacteremia/ sepsis, pneumonia, osteomyelitis

staph aureus

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What virulence factor aids in toxic shock syndrome, what causes it

enterotoxin F, tampons

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What virulence factors aid staph aureus in scalded skin syndrome

exfoliative toxins- epidermolytic toxins

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Match the condition to the description: folliculitis, furuncles, carbuncles, bullous impetigo

large pustules, highly contagious
cluster of boils, invasive lesions
mild inflammation of hair follicle or gland
large raised boil

-bullous impetigo-large pustules, highly contagious
-carbuncles-cluster of boils, invasive lesions
folliculitis-mild inflammation of hair follicle or gland
furuncles-large raised boil

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What virulence factors aid S. aureus in causing food poisoning?

enterotoxins A, D and B

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What is the most common coagulase negative staph species

epidermidis

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What illness is staph saprophyticus likely to cause

UTIs in young women, concern in pregnancy

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What are the results of a coagulase test free and bound if the organism is staph lugdunensis

tube/ free- negative

slide/ bound- positive

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What illness is staph lugdunensis known for? what other characteristics distinguish it

endocarditis, aggressive, high mortality rate

might have mecA gene- oxacillin resistant

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What test distinguishes staph lugdunensis?

oxacillin resistance-mecA gene

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Which staph species is known for vancomycin resistance

staph haemolyticus

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What characteristics can distinguish micrococcus from staphylococcus

staph- glucose fermenters

micrococcus- non glucose fermenters, TETRAD formation, MOTILE

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What organisms grow on MacConkey? Which ones do not.

does grow GNR

does not grow GPO

What plates will GPC grow on? What plates won’t it grow on

will grow- chocolate and BA

will not grow- MacConkey

If there is a sample from a sterile body fluid, which staph species could it be, what test can be used to confirm its presence

S. lugdunensis

PYR +

What test helps ID MRSA

Chrom agar-if pink its MRSA | cefoxitin inhibits MSSA

What conditions could cause a false positive on a catalase test

if RBCS from BAP are transmitted

Describe bound vs free coagulase, which one is more convenient?

bound-slide- more convenient | free-tube

What causes false positives in bound coagulase

bound- GNR, intermedius, saphrophyticus, haemolyticus, hominis free coagulase-lungunensis, schleiferi

What organism is associated with dog bite wounds

staph aureus and other staph

Where in the body are strep and enterococcus normally found

pharynx, mouth, lower GI tract and vagina

Where do most strep and enterococcus cause opportunistic infection

in the respiratory system or sterile body fluids

What strep and enterococcus are almost always pathogenic?

Strep pyogenes Strep pneumonia Enterococcus

What is the colony morphology for strep and enterococcus

small pinpoint GPC in pairs or chains

What is the first way to differenciate strep and enterococcus species after finding GPC catalase negative

blood agar hemolysis

What hemolysis are the following strep and enterococcus - pyogenic - lactococcus - enterococcus - viridians

- pyogenic- beta - lactococcus- gamma - enterococcus-gamma/ alpha - viridians- could be alpha, beta, gamma

What are lactococcus associated with

dairy products

How does lancefield grouping help categorize GPC catalase neg

detects surface antigens, proteins and carbs

Name the lancefield grouping | A,B,C,D,F,G,L

A- s. pyogenes B- S. equi and dysgalactiae D- enterococcus faecalis, faecium, and strep bovis F,G,L- strep anginosus

Where are enterococcus found in normal conditions

GI tract, oral, skin

What illness do enterococcus cause

hospital acquired infections, immunocompromised bacteremia, endocarditis, UTIs

What are the characteristics of Strep and enterococcus cell wall

carbohydrates in cell wall helpful for lancefield classification

Lancefield classification is only for ___ hemolytic strep

beta

What does the term pyogenic mean? What are the pyogenic, and non pyogenic strep

fever inducing pyogenic-beta Group A, B, C, F, G non pyogenic- gamma and alpha- non beta

Alpha hemolytic ______ lysis Beta hemolytic _______lysis Gamma hemolytic _____ lysis

partial complete no hemolysis

What do strep pyogenes look like on BA

beta, small pinpoint grey

Where are strep pyogenes capable of causing infection and how are they transmitted

skin, upper respiratory, transmitted person to person- direct aerosolized from cough, fomites or sneezes- indirect

Match the virulence factors to the effects they cause: protein F, hyaluronic acid, M protein, strep O S Dnase hyaluronidase, SPEs, C5a - destroys complement - produce rash - produces enzymes that help invade and destroy tissues - antiphagocytic - inhibits phagocytosis - aids in epithelial cell attachment-fibronectin

- destroys complement- C5a peptidase - produce rash- SPEs - produces enzymes that help invade and destroy tissues- strep O S Dnase hyaluronidase - antiphagocytic- M protein - inhibits phagocytosis- hyaluronic - aids in epithelial cell attachment-fibronectin- protein F

What organism causes these diseases cellulitis, scarlet fever, myositis, sepsis, pneumonia, step toxic shock, strep throat, pyodermal infection, necrotizing fascitis, Rheumatic fever, glomerulonephritis

Strep pyogenes

What treatment is used against Strep pyogenes

penicillin, erythromycin

What virulence factors do strep pyogenes have in terms of toxins

strep O- oxygen unstable, immunogenic | strep S- oxygen stable, non immunogenic

Match the virulence factors to the disease: SPEs, exotoxins, M protein, Toxic shock syndrome Rheumatic fever Pyodermal infection-scarlet fever

Toxic shock syndrome- SPEs Rheumatic fever- M protein Pyodermal infection-scarlet fever- exotoxins

Name the PYR results for Strep pyogenes viridians enterococcus

Strep pyogenes: PYR + viridians: PYR - enterococcus PYR +

Which strep species is a type of viridian strep

anginosus

``` Name the LAP results for viridians strep Aerococcus viridans enterococcus lactococcus ```

viridians strep LAP + Aerococcus viridans LAP - enterococcus LAP + lactococcus +