Staph Flashcards

1
Q

factors to consider in determination of a pathogen

A

Type of patient (normal v. predisposed/compromised patient)

mode of infection (community v. nosocomial)

geographic distribution and/or work environment

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2
Q

Compromising/Predisposing factors for patients

A

(1) Surgery or trauma
(2) Immunoincompetence or Immunosuppression – e.g. cancer or AIDS patient
(3) Diabetic
(4) Alcoholism or drug use
(5) Pregnancy

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3
Q

With only rare exception, all members of a genus will exhibit the same ____ morphology. Occasionally a species may exhibit a slightly different arrangement of cells (e.g. pairs vs. chains), but nothing very significant.

A

Gram stain

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4
Q

Gram-positive ____ in clusters

Staphylococcus aureus

A

cocci

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5
Q

Large, yellowish ____ hemolytic colonies

Staphylococcus aureus

A

beta

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6
Q

Invasive tissue infections – causes about ____ of invasive tissue infections (along w/ GAS)

(Staphylococcus aureus)

A

90%

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7
Q

Pus- producing = Abscess forming

Staphylococcus aureus

A

Pyogenic

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8
Q

infection of the hair follicle

Staphylococcus aureus

A

Folliculitis

Staphylococcus aureus

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9
Q

deep seated infections (subcutaneous tissue involved) in and around the hair follicle

A

Furuncles (boils)

Staphylococcus aureus

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10
Q

similar to folliculitis/boils in skin or tissues but spreads beneath the skin

A

Cellulitis

Staphylococcus aureus

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11
Q

superficial skin infection characterized by small “blisters”/pustules followed by a thin crust over the area

A

Impetigo

Staphylococcus aureus

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12
Q

Tissue damage due to numerous invasive ____. Some invasive infections can be very severe.

(Staphylococcus aureus)

A

enzymes and toxins

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13
Q

Food poisoning due to ingestion of pre-formed heat-stable ____ (an exotoxin that affects the intestinal tract) (types A, B, C, etc, e.g. “SEB”)

(Staphylococcus aureus)

A

enterotoxin

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14
Q

Certain strains of bacteria produce enterotoxin when growing at 28C or higher for ____ hours

(Staphylococcus aureus)

A

2 to 4

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15
Q

Commonly affected foods are cooked or processed meat (especially ham), salads, and cream-filled desserts

(Staphylococcus aureus)

A

(Staphylococcus aureus)

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16
Q

Bacterial growth on food produces no change in ___

Staphylococcus aureus

A

flavor or odor

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17
Q

Clinical symptoms: nausea, vomiting, abdominal cramps, and watery diarrhea within ____; lasts from a few to about 24 hours

(Staphylococcus aureus… food poisoning)

A

1 to 6 hours

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18
Q

____ enables the Staph A microbe to invade (under proper conditions) the lipid “plug” that surrounds the hair shaft, potentially leading to folliculits

A

Lipase (invasive enzyme)

and Coagulase protects the bacteria

19
Q

Coagulase and ______ are an interplay of protection and expansion

(enzymes of Staph)

A

Fibrinolysin/streptokinase

(coagulase establishes a protective fibrin clot, fibrinolysin breaks this clot down so that the microbial colony can expand)

20
Q

Protective fibrin “walls” can often prevent ___ from reaching the infected site/microbial site

(Staphylococcus aureus)

A

abx

21
Q

Certain strains produce Toxic Shock Syndrome Toxins (TSST) (plasmid mediated) - toxin probably causes massive and unregulated stimulation of the ___ system

(Staphylococcus aureus)

A

immune

22
Q

Produces acute illness with high fever, diffuse rash, hypotension, and skin desquamation (1-2 weeks after onset), plus several other features

(Staphylococcus aureus)

A

Toxic shock syndrome

23
Q

Infection associated with use of highly absorbent tampons (about 75% of cases) (absorption of fluids causes change of microbial growth environment resulting in change of host-microbe dynamics) or with focal or surgical wound infections in men or non-menstruating women

(Staphylococcus aureus)

A

Toxic shock syndrome

24
Q

Tests for toxin usually not performed in routine microbiology labs

(Staphylococcus aureus)

A

Toxic shock syndrome

25
Q

Certain strains produce exfoliatin toxins – destructive to epithelial cells

A

Scalded skin syndrome

26
Q

Initially a localized red rash, often following conjunctivitis or upper respiratory tract infection

Followed by large flaccid bullae which rupture and sheets of epidermis peel off to reveal moist, red, “scalded” dermis

A

Scalded skin syndrome

27
Q

Bacteria are not recovered from the ____; only from the initial infection

(Scalded skin syndrome)

A

bullae

28
Q

bloodstream infection resulting from deep, poorly draining infections which invade the bloodstream and spread to numerous body sites – typically life-threatening unless rapidly treated with effective antimicrobics

A

Septicemia/bacteremia

29
Q

Staph A infections of the joint/bone are common after?

A

device implantation or trauma

osteomyelitis & septic arthritis

30
Q

Though rare, this infection can follow a viral respiratory infection or affect those with altered immune systems…

A

pneumonia/lower respiratory & lung abscess infections (less than 2%)

31
Q

Toxins and invasive enzymes?

A

Coagulase
Lipase

Fibrinolysin 
Proteases (several varieties)
32
Q

Staph’s other virulence factors?

besides toxins and enzymes

A

(2) Adhesive Matrix Molecules – produce biofilms
(3) Quorum-sensing regulators
(4) Superantigens (toxins) – enhance effects of toxins
(5) Pathogenicity of various strains is largely due to genes carried on plasmids and lysogenized viral genes

33
Q

Most Staph A are resistant to?

A

Beta lactams

due to beta-lactamase enzymes coded by genes carried on plasmids

34
Q

Resistant to all beta-lactam antibiotics due to mutated penicillin-binding proteins

A

Methicillin Resistant Staphylococcus aureus (MRSA) (about 30%, percentage increasing)

35
Q

Staph A is developing resistance to?

A

Vancomycin

36
Q

strains that are resistant to an exceptionally large number of antimicrobic types – Very problematic and serious infections

A

Multiply Drug Resistant (MDR)

37
Q

Lab considerations for Staph A?

A

culture/biochemical ID (coagulase positive?)

Antigenic ID/confirmation of the lab culture

Antimicrobic susceptibility test needed (beta lactamase, MRSA, MDR)

38
Q

Predominant normal flora of the skin

A

Staphylococcus epidermidis

39
Q

The most common coagulase negative staphylococcus (CNS)

A

Staphylococcus epidermidis

40
Q

Causes bloodstream infections (bacteremia) and endocarditis (infection of interior heart tissue) in seriously ill patients (e.g. indwelling central line) – 2nd most frequently recovered pathogen from blood culture

A

Staphylococcus epidermidis

41
Q

Causes wound/incision infections infrequently

A

Staphylococcus epidermidis

42
Q

Another coagulase negative Staph

A

Staphylococcus saprophyticus

43
Q

CNS spp?

A

S. saprophyticus

S. epidermidis

44
Q

Second most frequent cause of UTIs in women of child bearing age?

A

Staphylococcus saprophyticus