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Microbiology Exam 6 > Subcutaneous Layers > Flashcards

Subcutaneous Layers Flashcards

1
Q

Perfringolysin/Theta toxin is produced by _________ causing what disease?

A

C. perfringens type A in Gas Gangrene

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2
Q

Phospholipase C/Alpha toxin is produced by _________ causing what disease?

A

C. perfringens type A in Gas Gangrene

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3
Q

Perfringolysin/Theta toxin causes what effects at LOW concentrations

A

primes and degranulation of PMNs, increased production of adherence molecules by PMNs, and PAF production by endothelial cells (mediating adherence of PMNs to endothelial cells), resulting in leaky vessels

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4
Q

Perfringolysin/Theta toxin causes what effects at HIGH concentrations

A

complete lysis of RBCs and PMNs

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5
Q

Perfringolysin/Theta toxin causes what effects on cells

A

lecithinase cytotoxin that destroys cell membranes by cleaving lecithin -> lysing cells

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6
Q

Perfringolysin/Theta toxin causes what effects

A

Reduced CO, induction of TNF-alpha

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7
Q

Hydrogen gas production by C. perfringens occurs due to what enzyme

A

hydrogen lyase - which recycles ferredoxin

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8
Q

Hydrogen gas causes what effects on tissues

A

Insoluble in tissue causing tracks along fascial planes, causing increased compartmental pressure -> collapses blood vessels for anaerobic environment

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9
Q

X-ray showing H2 gas would show

A

feathery pattern of gas formation b/w major muscle bundles

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10
Q

Risk Factors for Trichinosis

A

Consumption of undercooked, raw animal flesh, range-fed

Smoked meat consumption: pork, horse, wild game

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11
Q

Anaerobes are NF on human

A

mucosal surfaces and skin

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12
Q

Obligate anaerobe

A

requires reduced O2 tension for growth, fails to grow in 10% CO2 air

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13
Q

Anaerobe NF can cause infection by

A

overgrowth at residing site or displacement

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14
Q

Bacteria often in probiotics

A

Bifidobacterium

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15
Q

Aggregaitbacter

A

GNC, periodontitis

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16
Q

Actinomyces

A

GPR, periodontitis, lumpy jaw, sulfur granules and abscesses

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17
Q

Bacteroides

A

GNR, colon and vaginal NF

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18
Q

Bacteroides fragilis virulence factors

A

Superoxide dismutase, Capsular Polysaccharide Complex, Heparinase

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19
Q

Bacteroides fragilis - Capsular Polysaccharide Complex functions

A

Abscessogenic, antiphagocytic, adhesin

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20
Q

Bacteroides fragilis abscess/infection of the

A

GIT, genital tract, abdomen, soft tissue, brain, bacteremia (virtually everywhere)

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21
Q

Most anaerobic infections are polymicrobic, except

A

Bacteroides fragilis

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22
Q

Bacteroides fragilis is becoming resistant to ____________ due to nitroreductase genes

A

Metronidazole - prodrug activated by nitrate reductase

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23
Q

Vancomycin resistant agent

A

Enterococcus faecalis and Enterococcus faecium

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24
Q

Enterococcus faecalis and Enterococcus faecium are often associated with

A

nosocomial infections in immunocompromised - present on fomites in hospitals

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25
Q

Most commonly isolated agent from abdominal infections

A

Bacteroides fragilis

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26
Q

Enterococcus

A

GPC, aerotolerant, catalase (-)

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27
Q

Gardnerella vaginalis infections of

A

vagina

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28
Q

Only GP curved rod

A

Mobililuncus

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29
Q

Mobililuncus infections of

A

vagina

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30
Q

Lactobacillus infections of

A

periodontitis

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31
Q

Peptostreptococcus infections of

A

vagina, skin and ST

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32
Q

Main contaminant of laboratory specimens

A

P. acnes

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33
Q

Prevotella and Porphyromonas infections of

A

gingivitis, periodontitis

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34
Q

Oral streptococci cause infection of

A

oral, endocarditis

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35
Q

Aerotolerant anaerobe

A

grows in presence of oxygen, but grows better in the absence

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36
Q

Obligate anaerobe

A

extreme sensitivity to oxygen; Oxygen kills

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37
Q

All organisms produced toxic oxygen products during metabolism in the presence of O2, including:

A

superoxide radical (O2 -) & hydrogen peroxide (H2O2 )

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38
Q

O2 - & H2O2 cause

A

growth inhibition and cell death, unless they are detoxified

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39
Q

Oxygen tolerant bacteria encode enzymes for

A

Superoxide dismutase and Catalase

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40
Q

Reducing agents include

A

glutathione, methionine, cysteine, iron - pick up free oxygen

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41
Q

Superoxide dismutase converts

A

Superoxides —–> H2O2

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42
Q

Catalase converts

A

H2O2 ——> H2O + O2

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43
Q

Anaerobes use ______ as TEA

A

Nitrate

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44
Q

Anaerobic growth depends on:

A

O2 level (low), pH (low), reducing substances

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45
Q

Human conditions that favor anaerobic growth

A

compromised circulation/ arterial insufficiency: diabetes, trauma, tissue injury

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46
Q

How do anaerobes evade antibiotic therapy?

A

formation of abscess, slow multiplication, low pH decrease abx efficacy, lack of perfusion, antibiotics bind folic acids rendering them useless (tissue breakdown products)

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47
Q

Treatment of anaerobic infections require

A

incision and drainage

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48
Q

Endogenous sources of anaerobes

A

Mouth, oropharynx, GIT, vagina, skin and cornea –> polymicrobic

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49
Q

Exogenous sources of anaerobes

A

Soil, water, food —> mono microbic (Clostridium)

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50
Q

Most common sources of anaerobes are

A

endogenous

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51
Q

___________________ initiate the anaerobic infection

A

Aerobes+facultative anaerobes, depleting the site of O2

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52
Q

_________________ now colonize the anaerobic site

A

tolerant anaerobes –> intolerant anaerobes

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53
Q

Sites where anaerobic infections occur

A

bacteremia (rare), CNS/brain abscess, ENT/mouth, intra-abdominal abscess, gynecologic, wound

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54
Q

1 cause of foot amputation and diabetic foot ulcers

A

S. aureus, Strep, enterococci, enterics, bacteroides

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55
Q

Slow-healing wounds caused by anaerobic infections

A

diabetic foot ulcers, bed sores, vascular stasis ulcer

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56
Q

1 cause of hospitalization of diabetic patients in the US

A

Infected foot ulcer

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57
Q

Common agents in wound infections

A

S. aureus, Strep, Eikenella, P. acnes

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58
Q

Common agents in intraabdominal infections

A

B. fragilis

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59
Q

Common agents in skin and ST infections

A

S. aureus, Strp, Enterococci, Enterics, Peptostreptococci, Bacteroides

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60
Q

Clues to anaerobic infections

A 
Infection near mucosal surface
Foul or sweet odor
Severe tissue necrosis/abscess
Gas production
Polymicrobial infection
Failure to culture organism
Failure to respond to ABX
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61
Q

Subacute/Chronic pneumonia pathognomonic clue

A

sweet/foul odor

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62
Q

Special culture procedure for anaerobes:

A

special transport media, culture quickly, anaerobic conditions

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63
Q

Which sites should not be cultured anaerobically

A

throat, gingiva, gastric, small bowel, expectorated sputum, urine, vagina

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64
Q

Which sites should be cultured anaerobically

A

Discharge, blood, near mucosal surface, human bite, obtained by needle, lung puncture, aspirated

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65
Q

Stain for weakly staining anaerobes

A

Carbol-fuschin as counter-stain

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66
Q

Treatment for anaerobic infection

A

drain, debride, delay suturing, ABX, Hyperbaric O2

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67
Q

Antibiotic treatment of aerobic infections

A

Penicillin + beta-lactamase inhibitors, Meropenem, Metronidazole, Clindamycin

68
Q

Metronidazole is a prodrug activated by

A

reacting with reduced ferredoxin - electron transporter

69
Q

Metronidazole works on anaerobic bacteria by

A

causing build up of metabolites that react w/ DNA to form unstable molecules

70
Q

B. fragili is resistant to ________ and is developing resistance to ________

A

Penicillin; Vancomycin

71
Q

Vancomycin resistance in B. fragilis is due to

A

nitroreductase genes

72
Q

Why are Sulfa drugs useless for anaerobic infections?

A

antibiotics adhere to folic acid released by the lysed human cell, inactivating them

73
Q

Why are Aminoglycoside drugs useless for anaerobic infections?

A

Not effective at low pH and require oxidative enzymes

74
Q

Sporotrichosis agent

A

Sporothrix schenckii

75
Q

Sporotrichosis lesion

A

Chronic infection w/ nodular lesions of cutaneous and subcutaneous tissues and adjacent lymphatics that suppurate, ulcerate and drain (travels along lymphatics)

76
Q

Sporotrichin skin test

A

DTH is (+) for less severe infection

77
Q

Disseminated form can have visceral organ involvement

A

Sporotrichosis

78
Q

Sporotrichosis Treatment

A

Itraconazole

Amphotericin B in AIDS pts

79
Q

Mycetoma

A

Infectious process w/ tumefaction, usually involving the foot or hand, caused by organisms that stimulate grain formation

80
Q

Grains of Mycetoma

A

organism + embedded in a matrix composed of Ag-Ab complexes and Splendore-Hoeppli material deposition of eosinophilic material

81
Q

Mycetoma lesion

A

Hard, painless, slow-growing lump under the skin. Eventually involves underlying muscle and bone, Center of lesion caves in, ulcerates, discharges pus (grains)

82
Q

Lobomycosis agent

A

Loboa loboi

83
Q

Lobomycosis lesion

A

indolent, chronic, subcutaneous infection that begins well circumscribed, indurated, asymptomatic keloidal nodule, nodules that develop into slowly growing tumors of the dermis, that present smooth, verrucoid or ulcerated surfaces

84
Q

Chromoblastomycosis agent

A

pigmented fungi

85
Q

Chromoblastomycosis

A

Characterized by raised lesions w/ cauliflower-like appearance may evolve to include entire extremity

86
Q

Phaeomycotic Cyst lesions

A

Well circumscribed subcutaneous abscess w/ surrounding cyst formation

87
Q

Erysipelas involves an infection of

A

upper dermis and superficial lymphatics

88
Q

Necrotizing Fasciitis involves necrosis of

A

fascia, fat, tissues and vasculature w/ or w/o skin and skeletal mm involvement

89
Q

Necrotizing Fasciitis involves systemic illness including 1 or more:

A

shock, DIC, organ failure

90
Q

Necrotizing Fasciitis Polymicrobial form agents

A

facultative anaerobes and obligate anaerobes

91
Q

Necrotizing Fasciitis Monomicrobial form agents

A

invasive GAS (type M1)

92
Q

Predisposing Factors of Polymicrobial Form of Necrotizing Fasciitis

A

Surgical procedures (bowel resection)
Vulvovaginal infections
Infections involving abscesses, ulcers
IVDU

93
Q

Predisposing Factors of Monomicrobial Form of Necrotizing Fasciitis

A

Arteriosclerotic vascular disease, Venous insufficiency, Diabetes

94
Q

First 24 hour Sx of Necrotizing Fasciitis

A

acutely ill and in severe pain, slowly advancing cellulitis w/ severe, excoriating pain

95
Q

Day 2-4 Sx of Necrotizing Fasciitis

A

site turns from red -> purple -> blue and blisters/bullae containing clear yellow fluid appear

96
Q

Palpation of subcutaneous tissue of Necrotizing Fasciitis feels

A

firm and cannot be discerned by palpation (woody feel)

97
Q

Pain subsides in Necrotizing Fasciitis bc

A

Occluded blood vessels -> severe pain, blisters, bullae, and anesthesia -> gangrene

98
Q

Bacteremia with Necrotizing Fasciitis is

99
Q

Abrupt onset of severe, excruciating pain (10/10)

A

Necrotizing Fasciitis

100
Q

“dishwater exudate” is seen with

A

Necrotizing Fasciitis and Clostridial Myonecrosis

101
Q

Distinctive odor of putrefaction indicates

A

anaerobic infection

102
Q

Treatment for Necrotizing Fasciitis

A

Resection, 2-3wks of ABX (penicillin), Hyperbaric O2, NPWT

103
Q

STSS is caused by what agent

A

invasive GAS (type M1)

104
Q

invasive GAS (type M1) expresses what exotoxin

105
Q

SPE acts to

A

activate T-cells expressing the Vbeta-2 family of Vbeta-chains causing massive cytokine release

106
Q

Superantigens bind

A

outside the antigen binding area for broad activation of many T-cells

107
Q

Symptoms of STSS

A

1-2 days of High fever, malaise, myalgia, n/v, watery diarrhea followed by Abrupt onset of severe pain increasing to excruciating levels

108
Q

STSS can often result in

A

Hypotensive shock and multi-organ failure (renal, CNS/confusion, ARDS, liver), bacteremia, DIC

109
Q

STSS rash appearance

A

diffuse macular erythroderma which evolves into a scarlatiniform rash which desquamates (palms and soles) 1-2 weeks after onset

110
Q

STSS CBC would show

A

profound left-shift in granulocyte series

111
Q

STSS Treatment

A

Penicillin + Clindamycin

112
Q

Cutaneous Anthrax lesions

A

Small painless papules -> Vesicles (black fluid-filled) -> vesicle rupture -> eschar

113
Q

Eschar of ___________ is painful, while the eschar of ____________ is painless

A

P. aeruginosa; B. anthracis

114
Q

Treatment for Cutaneous Anthrax

A

Ciprofloxacin for 60 days

115
Q

Ecthyma gangrenosum is caused by

A

Pseudomonas aeruginosa infection of small veins

116
Q

Traumatic Clostridial Myonecrosis is caused primarily by

A

Clostridium perfringens, type A histolytic strains

117
Q

Atraumatic Clostridial Myonecrosis is caused primarily by

A

Clostridium septicum (GIT malignancy)

118
Q

histolytic strains express

A

exotoxin production: PLC and perfringolysin

119
Q

PLC/Alpha toxin is a

A

lecithinase cytotoxin that destroys cell membranes by cleaving lecithin -> lysing cells

120
Q

PLC/Alpha toxin has what effects

A

Reduces CO, Induces TNF-alpha

121
Q

Perfringolysin/Theta toxin has what effects at LOW concentrations

A

degranulation of PMNs, increased production of adherence molecules by PMNs, and PAF production by endothelial cells -> leaky vessels

122
Q

Perfringolysin/Theta toxin has what effects at HIGH concentrations

A

complete lysis of RBCs and PMNs

123
Q

Hydrogen Gas (H2) is produced in Clostridial Myonecrosis by

A

hydrogen lyase

124
Q

hydrogen lyase action

A

recycles ferredoxin

125
Q

X-ray of Clostridial Myonecrosis shows

A

feathery pattern

126
Q

Risk Factors for Clostridial Myonecrosis

A

Hx of traumatic crushing wounds (car/farm accident, war), surgery (GIT/colon)

127
Q

Describe the exudate of Clostridial Myonecrosis

A

thin, hemorrhagic exudate w/ foul or sweet odor (dishwater exudate, no pus bc no PMNs)

128
Q

Systemic effects of Clostridial Myonecrosis

A

low-grade fever, tachycardia, hypotensive shock, death due to exotoxemia

129
Q

Bacteremia with Clostridial Myonecrosis is

130
Q

Culture of Clostridium perfringens, type A would show

A

Double zone of hemolysis on culture

131
Q

Reverse CAMP test

A

ID test for Clostridium perfringens, type A

132
Q

Treatment for Clostridial Myonecrosis

A

Debridement, amputation, ABX

133
Q

Trichinosis agent

A

Trichinella spiralis

134
Q

Life Cycle of Trichinella spiralis

A

Direct Life Cycle – No external phase required

excysts in GIT, larvae mate and burrow into GIT wall, larvae are released and migrate, encyst in muscle cells

135
Q

First Sx of Trichinosis are ___________, but they usually go unnoted

A

gastroenteritis

136
Q

Risk Factors for Trichinosis

A

consumption of uncooked pig, horse, wild game

137
Q

Manifestations of Trichinosis are due to

A

larval migration and host response

138
Q

Parenteral Phase Sx of Trichinosis

A

Fever, periorbital edema, chemosis, peripheral eosinophilia, fatigue, muscle spasms, muscle aches, splinter hemorrhage

139
Q

Trichinosis Larvae encyst in

A

striated mm, which it converts to nurse cells

140
Q

Trichinosis Larvae encystment involves calcification by

A

eosinophils

141
Q

What are the primary immune responses that control Trichinosis

A

Eosinophils and IgE and ADCC

142
Q

Diagnosis of Trichinosis

A

Deltoid biopsy (w3), Bentonite Flocculation Test, Indirect Fluorescent Antibody Test (IFA), Latex Agglutination Test, ELISA/EIA (w1), Peripheral Eosinophilia (w2)

143
Q

Peripheral Eosinophila indicates

A

Trichinosis (helminthic infection)

144
Q

Treatment for Trichinosis

A

mechanical ventilator, Benzimidazole derivatives (Albendazole), Corticosteroids

145
Q

Benzimidazole derivatives (Albendazole) act by

A

Inhibit glucose uptake by blocking MT assembly

146
Q

Severely infected Trichinosis patient may develop ____________ after treatment ensues

A

severe HSN response and death

147
Q

Vaginosis may be caused by overgrowth of

A

Gardnerella vaginalis, Candida albicans, Prevotella intermedia

148
Q

First step in pregnant females who’ve been exposed to Rubella?

A

Check immune status

149
Q

VZIG is often administered to

A

immunocompromised children w/in 72hr of exposure

150
Q

Secondarily impetiginized lesions are infected w/

A

S. pyopgenes or S. aureus

151
Q

Rash appearance on palms/soles is common for what to diseases

A

Erythema Infectiosum and Smallpox

152
Q

Most common complication of Measles in US is ________, but in underdeveloped countries is _______

A

Otitis Media; Diarrhea/Malnutrition

153
Q

Bacteremia is rare in

A

Malassezia furfur, cellulitis, Clostridial myonecrosis

154
Q

Mobiluncus is typically found _________ and is a Gram _________

A

vaginal tract: Gram positive curved rod

155
Q

Trichinosis Sx are due in part to immune responses, which include:

A

ADCC, Type I HSN, Type III HSN

156
Q

Left shift in granulocytes

157
Q

NF of vagina that play a role in host defense and keep an acidic pH

A

Lactobacillus

158
Q

MMR is a

A

live attenuated virus vaccine and should not be given to immunocompromised or pregnant females

159
Q

Eikenella is a Gram ___________

A

negative rod

160
Q

Pathogenic form of anthrax is the

161
Q

Agent associated w/ nosocomial bacteremia

A

Staph epidermidis

162
Q

Antitoxins for Clostridial Myonecrosis are only efficacious when

A

used prophylactically

163
Q

Enterococcus faecalis typically cause infections of

164
Q

Peptostreptococcus typically cause infections of

A

skin and ST, vaginosis

165
Q

Agents of nosocomial infections of immunocompromised patients

A

Enterococcus faecalis and E. faecium

166
Q

Biophila wadsworthia typically cause infections of

A

abscesses in abdomen, joints, appendicitis

Microbiology Exam 6 (5 decks)

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