Staphylococci 1 & 2

Front 1

Staphylocci - morphology & gram stain, oxygen type, hemolysis type

Back 1

clusters, gram positive, facultative anaerobes, beta hemolytic

Front 2

Coagulase positive test

Back 2

Staph aureus, also novobiocin susceptible

coagulase + fibrinogen D = clumping

Front 3

S. saprophyticus:
oxygen?
novobiocin resistance?
Hemolysis?

Back 3

aerobe, novobiocin resistant, no hemolysis

Front 4

peptidoglycan properties

Back 4

production of TNF, toxic for PMN leukocytes, endotoxin-like activity, activates complement

Front 5

microcapsule

Back 5

basis for serotyping, found in staphylococci

Front 6

slime

Back 6

loosely attached, imp for adherence on prosthetic devices,

Front 7

Staphylococcal surface proteins

Back 7

protein A - antiphagocytic, binds to Fc of igG except for igG3

MSCRAMMs (microbial surface components recognizing adhesive matrix molecules ) = colonization of host tissues, ex. fibronectin, collagen, and elastin-binding proteins

Front 8

S. aureus toxins

Back 8

alpha, beta, gamma and delta toxins disrupt cell membranes; panton valentine leukocidin (caMSRA), exfoliatins, toxic shock syndrome toxins, enterotoxins

Front 9

exfoliatins causes

Back 9

scalded skin syndrome,
superantigens

Front 10

TSST-1

Back 10

toxic shock syndrome toxin 1, superantigen, causes clonal expansion of T cells --> massive cytokine release; produces fever, enhances susceptibility to shock

Front 11

Enterotoxins produced by s. aureus

Back 11

A,B,C,D, and E are major causes of food poisoning; increases intestinal peristalsis --> vomiting

A, B, C, D, E, and G are superantigens

Front 12

agr gene

Back 12

induces expression of extracellular proteins while suppressing the expression of surface proteins
(sequential expression of virulence factors)

Front 13

people more at risk for s. aureus

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those with breaks in the skin: atopic dermatitis/eczema pts; parenteral drug addicts, diabetics on insulin, hemodialysis pts, recipients of allergy shots

Front 14

Job's syndrome

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inherited disorder characterized by hyper igE, eczema, recurrent skin infections

Front 15

Chediak-Higashi syndrome

Back 15

albinism and recurrent infections

Front 16

chronic granulomatous disease

Back 16

characterized by recurrent infection due s. aureus bc of defects in PMN oxygen dependent killing

Front 17

furuncles, carbuncles

Back 17

deep seated infections around hair follicles

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characteristic of s. aureus impetigo

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bullous impetigo

Front 19

hidradenitis suppurativa

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disfiguring infection due to a disorder of the apocrine sweat glands that occurs in axilla, groin and perineum; most common in Af. Americans

Front 20

s. aureus is one of the most common causes of (25-35%)

Back 20

endocarditis, can attack normal valvues (in IV drug addicts) or abnormal valves (prosthetic, rheumatic, or congenital), right sided endocarditis common in IV drug addicts

Front 21

s. aureus is the most common cause of _____ by spread thru bloodstream

Back 21

osteomyelitis (bacteremic spread to long bones of children, vertebrae of adults)
septic arthritis; vascular insufficiency due to artherosclerosis, treat with sugrical debriment and prolonged antibiotics

Front 22

pneumonia occurs by 2 pathogenic mechanisms

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aerogenous from aspiration of oral flora
hematogeneous from another source - IV drug addicts with endocarditis, pts with IV catheters

Front 23

clinical syndromes as a result of toxin production

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scalded skin syndrome, toxic shock syndrome,

Front 24

majority of coagulase neg staphylococci are acquired by

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hospital acquired, altered immunity, breaks in tissues

Front 25

coagulase neg staphylococci

Back 25

s. epidermidis, s.saprophyticus; think slime

Front 26

coagulase neg staphylococci cause

Back 26

UTI, hospital acquired (s. epidermidis)
outpatient (s. saprophyticus),
responsible for 30% of post operative sternal wound infections
osteomyelitis (rarely causes hematogeneous osteomyelitis)
native valve endocarditis (rare)
bacteremia

Front 27

2nd most common cause of urinary tract infections in young women

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s. saprophyticus

Front 28

antimicrobial resistance of s. aureus

Back 28

beta lactamase destroys penicillin; extracellular enzyme can disrupt the beta lactam ring of penicillins by hydrolysis

Front 29

order of susceptibility of beta lactamase

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penicillin >>>dicloxacillin > cloxacillin > oxacillin>nafcillin

Front 30

hospital associated strains of MRSA and MRSE

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have SCCmec Types II and III, carries multiple antibiotic resistances; more resistant to antibiotics than community acquired MRSA

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community acquired strains of mrsa and mrse

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have SCCmec Type IV, fewer antibiotic resistances; associated with soft tissue infections; resistance to oxacillin, possibily erythromycin

Front 32

MRSA strains with VISA

Back 32

(VANCOMYCIN INTERMEDIATE staph aureus)
strains have thicker more disorganized cell wall , pts have been exposed to vancomycin for long durations previously, pts have prosthetic devices that should have been removed,; responds to vancomysin+ beta lactamase combinations

Front 33

MRSA strain VRSA results from

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result of conjugative event between MRSA and vancomycin resistant enterococcus

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Skin compartments and infection site

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epidermis - impetigo
dermis - folliculitis, erysipelas
subcutaneous fat & lower dermis - cellulitis
fascia - necrotizing fasciitis

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Cellulitis

Back 35

most complicated staphylococcal soft tissue infections, must drain pus

Front 36

Pyomyositis and most commonly caused by..?

Back 36

infection within a muscle

S. aureus

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Bacteremia and endocarditis due

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to S. aureus is common

Front 38

clinical signs that s. aureus bacteria is due to complicated infection or endocarditis

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younger pt with bacteremia, communit acquired, no primary infections, skin evidence of systemic infection, failure to defervesce by 72 hrs, _+ blood cultures at 48-96 hrs

Front 39

If s. aureus is methicillin susceptible...do not treat with

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vancomycin

Front 40

Staphylococcal scalded skin syndorme

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usually in children younger than 5, due to local infection of nasopharynx, umbilicus or urinary tract, must manage fluid and electrolyte losses

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CDC def for Staph toxic shock syndrome

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hypotension less than 90, fever, rash,desquamation 1-2 weeks on palms and soles; multisystem involvement = THREE

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Conjunctival hyperemia associated

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staphylococcus toxic shock syndrome

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Food poisoning caused by staph, how long before it starts, when it ends, ____not seen

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occurs 2-6 hours after ingestion, no fever, lots of vomiting, resolves within 12-24 hrs

Front 44

Staphylococci cohnii

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tricuspid valve endocarditis, septic pulmonary emboli

Front 45

infections of prosthetic hardware most commonly caused by

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coagulase negative staphylococci

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S. aureus started making ___ to gain resistance to penicillin

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beta lactamase

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mechanism of methicillin resistance

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altered penicillin binding protein 2a --> decreased affinity for the beta lactam antibiotics (penicillins and cephalosporins)

Front 48

mec A gene and mobile staphylococcal chromosomal cassette (SCC mec)

Back 48

methicillin resistance in staphylococci

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MRSA strains that are clindamycin sensitive and erythromycin resistant due to

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1) msrA - atp dependent efflux pump that confers resistant to only macrolides and streptogramins but not lincosamides
2) inducible resistance (iMLS)

Front 50

Positive D test indicates

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clindamycin will develop inducible resistance so you can't use it