Staph Flashcards

(44 cards)

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)

21
Q

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

(Staphylococcus aureus)

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
Certain strains produce exfoliatin toxins -- destructive to epithelial cells
Scalded skin syndrome
26
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
Scalded skin syndrome
27
Bacteria are not recovered from the ____; only from the initial infection (Scalded skin syndrome)
bullae
28
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
Septicemia/bacteremia
29
Staph A infections of the joint/bone are common after?
device implantation or trauma | osteomyelitis & septic arthritis
30
Though rare, this infection can follow a viral respiratory infection or affect those with altered immune systems...
pneumonia/lower respiratory & lung abscess infections (less than 2%)
31
Toxins and invasive enzymes?
Coagulase Lipase ``` Fibrinolysin Proteases (several varieties) ```
32
Staph's other virulence factors? | besides toxins and enzymes
(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
Most Staph A are resistant to?
Beta lactams | due to beta-lactamase enzymes coded by genes carried on plasmids
34
Resistant to all beta-lactam antibiotics due to mutated penicillin-binding proteins
Methicillin Resistant Staphylococcus aureus (MRSA) (about 30%, percentage increasing)
35
Staph A is developing resistance to?
Vancomycin
36
strains that are resistant to an exceptionally large number of antimicrobic types – Very problematic and serious infections
Multiply Drug Resistant (MDR)
37
Lab considerations for Staph A?
culture/biochemical ID (coagulase positive?) Antigenic ID/confirmation of the lab culture Antimicrobic susceptibility test needed (beta lactamase, MRSA, MDR)
38
Predominant normal flora of the skin
Staphylococcus epidermidis
39
The most common coagulase negative staphylococcus (CNS)
Staphylococcus epidermidis
40
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
Staphylococcus epidermidis
41
Causes wound/incision infections infrequently
Staphylococcus epidermidis
42
Another coagulase negative Staph
Staphylococcus saprophyticus
43
CNS spp?
S. saprophyticus S. epidermidis
44
Second most frequent cause of UTIs in women of child bearing age?
Staphylococcus saprophyticus