Subcutaneous Layers Flashcards
(166 cards)
1
Q
Perfringolysin/Theta toxin is produced by _________ causing what disease?
A
C. perfringens type A in Gas Gangrene
2
Q
Phospholipase C/Alpha toxin is produced by _________ causing what disease?
A
C. perfringens type A in Gas Gangrene
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
4
Q
Perfringolysin/Theta toxin causes what effects at HIGH concentrations
A
complete lysis of RBCs and PMNs
5
Q
Perfringolysin/Theta toxin causes what effects on cells
A
lecithinase cytotoxin that destroys cell membranes by cleaving lecithin -> lysing cells
6
Q
Perfringolysin/Theta toxin causes what effects
A
Reduced CO, induction of TNF-alpha
7
Q
Hydrogen gas production by C. perfringens occurs due to what enzyme
A
hydrogen lyase - which recycles ferredoxin
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
9
Q
X-ray showing H2 gas would show
A
feathery pattern of gas formation b/w major muscle bundles
10
Q
Risk Factors for Trichinosis
A
Consumption of undercooked, raw animal flesh, range-fed
Smoked meat consumption: pork, horse, wild game
11
Q
Anaerobes are NF on human
A
mucosal surfaces and skin
12
Q
Obligate anaerobe
A
requires reduced O2 tension for growth, fails to grow in 10% CO2 air
13
Q
Anaerobe NF can cause infection by
A
overgrowth at residing site or displacement
14
Q
Bacteria often in probiotics
A
Bifidobacterium
15
Q
Aggregaitbacter
A
GNC, periodontitis
16
Q
Actinomyces
A
GPR, periodontitis, lumpy jaw, sulfur granules and abscesses
17
Q
Bacteroides
A
GNR, colon and vaginal NF
18
Q
Bacteroides fragilis virulence factors
A
Superoxide dismutase, Capsular Polysaccharide Complex, Heparinase
19
Q
Bacteroides fragilis - Capsular Polysaccharide Complex functions
A
Abscessogenic, antiphagocytic, adhesin
20
Q
Bacteroides fragilis abscess/infection of the
A
GIT, genital tract, abdomen, soft tissue, brain, bacteremia (virtually everywhere)
21
Q
Most anaerobic infections are polymicrobic, except
A
Bacteroides fragilis
22
Q
Bacteroides fragilis is becoming resistant to ____________ due to nitroreductase genes
A
Metronidazole - prodrug activated by nitrate reductase
23
Q
Vancomycin resistant agent
A
Enterococcus faecalis and Enterococcus faecium
24
Q
Enterococcus faecalis and Enterococcus faecium are often associated with
A
nosocomial infections in immunocompromised - present on fomites in hospitals
25
Most commonly isolated agent from abdominal infections
Bacteroides fragilis
26
Enterococcus
GPC, aerotolerant, catalase (-)
27
Gardnerella vaginalis infections of
vagina
28
Only GP curved rod
Mobililuncus
29
Mobililuncus infections of
vagina
30
Lactobacillus infections of
periodontitis
31
Peptostreptococcus infections of
vagina, skin and ST
32
Main contaminant of laboratory specimens
P. acnes
33
Prevotella and Porphyromonas infections of
gingivitis, periodontitis
34
Oral streptococci cause infection of
oral, endocarditis
35
Aerotolerant anaerobe
grows in presence of oxygen, but grows better in the absence
36
Obligate anaerobe
extreme sensitivity to oxygen; Oxygen kills
37
All organisms produced toxic oxygen products during metabolism in the presence of O2, including:
superoxide radical (O2 -) & hydrogen peroxide (H2O2 )
38
O2 - & H2O2 cause
growth inhibition and cell death, unless they are detoxified
39
Oxygen tolerant bacteria encode enzymes for
Superoxide dismutase and Catalase
40
Reducing agents include
glutathione, methionine, cysteine, iron - pick up free oxygen
41
Superoxide dismutase converts
Superoxides -----> H2O2
42
Catalase converts
H2O2 ------> H2O + O2
43
Anaerobes use ______ as TEA
Nitrate
44
Anaerobic growth depends on:
O2 level (low), pH (low), reducing substances
45
Human conditions that favor anaerobic growth
compromised circulation/ arterial insufficiency: diabetes, trauma, tissue injury
46
How do anaerobes evade antibiotic therapy?
formation of abscess, slow multiplication, low pH decrease abx efficacy, lack of perfusion, antibiotics bind folic acids rendering them useless (tissue breakdown products)
47
Treatment of anaerobic infections require
incision and drainage
48
Endogenous sources of anaerobes
Mouth, oropharynx, GIT, vagina, skin and cornea --> polymicrobic
49
Exogenous sources of anaerobes
Soil, water, food ---> mono microbic (Clostridium)
50
Most common sources of anaerobes are
endogenous
51
___________________ initiate the anaerobic infection
Aerobes+facultative anaerobes, depleting the site of O2
52
_________________ now colonize the anaerobic site
tolerant anaerobes --> intolerant anaerobes
53
Sites where anaerobic infections occur
bacteremia (rare), CNS/brain abscess, ENT/mouth, intra-abdominal abscess, gynecologic, wound
54
#1 cause of foot amputation and diabetic foot ulcers
S. aureus, Strep, enterococci, enterics, bacteroides
55
Slow-healing wounds caused by anaerobic infections
diabetic foot ulcers, bed sores, vascular stasis ulcer
56
#1 cause of hospitalization of diabetic patients in the US
Infected foot ulcer
57
Common agents in wound infections
S. aureus, Strep, Eikenella, P. acnes
58
Common agents in intraabdominal infections
B. fragilis
59
Common agents in skin and ST infections
S. aureus, Strp, Enterococci, Enterics, Peptostreptococci, Bacteroides
60
Clues to anaerobic infections
```
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
```
61
Subacute/Chronic pneumonia pathognomonic clue
sweet/foul odor
62
Special culture procedure for anaerobes:
special transport media, culture quickly, anaerobic conditions
63
Which sites should not be cultured anaerobically
throat, gingiva, gastric, small bowel, expectorated sputum, urine, vagina
64
Which sites should be cultured anaerobically
Discharge, blood, near mucosal surface, human bite, obtained by needle, lung puncture, aspirated
65
Stain for weakly staining anaerobes
Carbol-fuschin as counter-stain
66
Treatment for anaerobic infection
drain, debride, delay suturing, ABX, Hyperbaric O2
67
Antibiotic treatment of aerobic infections
Penicillin + beta-lactamase inhibitors, Meropenem, Metronidazole, Clindamycin
68
Metronidazole is a prodrug activated by
reacting with reduced ferredoxin - electron transporter
69
Metronidazole works on anaerobic bacteria by
causing build up of metabolites that react w/ DNA to form unstable molecules
70
B. fragili is resistant to ________ and is developing resistance to ________
Penicillin; Vancomycin
71
Vancomycin resistance in B. fragilis is due to
nitroreductase genes
72
Why are Sulfa drugs useless for anaerobic infections?
antibiotics adhere to folic acid released by the lysed human cell, inactivating them
73
Why are Aminoglycoside drugs useless for anaerobic infections?
Not effective at low pH and require oxidative enzymes
74
Sporotrichosis agent
Sporothrix schenckii
75
Sporotrichosis lesion
Chronic infection w/ nodular lesions of cutaneous and subcutaneous tissues and adjacent lymphatics that suppurate, ulcerate and drain (travels along lymphatics)
76
Sporotrichin skin test
DTH is (+) for less severe infection
77
Disseminated form can have visceral organ involvement
Sporotrichosis
78
Sporotrichosis Treatment
Itraconazole
| Amphotericin B in AIDS pts
79
Mycetoma
Infectious process w/ tumefaction, usually involving the foot or hand, caused by organisms that stimulate grain formation
80
Grains of Mycetoma
organism + embedded in a matrix composed of Ag-Ab complexes and Splendore-Hoeppli material deposition of eosinophilic material
81
Mycetoma lesion
Hard, painless, slow-growing lump under the skin. Eventually involves underlying muscle and bone, Center of lesion caves in, ulcerates, discharges pus (grains)
82
Lobomycosis agent
Loboa loboi
83
Lobomycosis lesion
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
Chromoblastomycosis agent
pigmented fungi
85
Chromoblastomycosis
Characterized by raised lesions w/ cauliflower-like appearance may evolve to include entire extremity
86
Phaeomycotic Cyst lesions
Well circumscribed subcutaneous abscess w/ surrounding cyst formation
87
Erysipelas involves an infection of
upper dermis and superficial lymphatics
88
Necrotizing Fasciitis involves necrosis of
fascia, fat, tissues and vasculature w/ or w/o skin and skeletal mm involvement
89
Necrotizing Fasciitis involves systemic illness including 1 or more:
shock, DIC, organ failure
90
Necrotizing Fasciitis Polymicrobial form agents
facultative anaerobes and obligate anaerobes
91
Necrotizing Fasciitis Monomicrobial form agents
invasive GAS (type M1)
92
Predisposing Factors of Polymicrobial Form of Necrotizing Fasciitis
Surgical procedures (bowel resection)
Vulvovaginal infections
Infections involving abscesses, ulcers
IVDU
93
Predisposing Factors of Monomicrobial Form of Necrotizing Fasciitis
Arteriosclerotic vascular disease, Venous insufficiency, Diabetes
94
First 24 hour Sx of Necrotizing Fasciitis
acutely ill and in severe pain, slowly advancing cellulitis w/ severe, excoriating pain
95
Day 2-4 Sx of Necrotizing Fasciitis
site turns from red -> purple -> blue and blisters/bullae containing clear yellow fluid appear
96
Palpation of subcutaneous tissue of Necrotizing Fasciitis feels
firm and cannot be discerned by palpation (woody feel)
97
Pain subsides in Necrotizing Fasciitis bc
Occluded blood vessels -> severe pain, blisters, bullae, and anesthesia -> gangrene
98
Bacteremia with Necrotizing Fasciitis is
Common
99
Abrupt onset of severe, excruciating pain (10/10)
Necrotizing Fasciitis
100
"dishwater exudate” is seen with
Necrotizing Fasciitis and Clostridial Myonecrosis
101
Distinctive odor of putrefaction indicates
anaerobic infection
102
Treatment for Necrotizing Fasciitis
Resection, 2-3wks of ABX (penicillin), Hyperbaric O2, NPWT
103
STSS is caused by what agent
invasive GAS (type M1)
104
invasive GAS (type M1) expresses what exotoxin
SPE
105
SPE acts to
activate T-cells expressing the Vbeta-2 family of Vbeta-chains causing massive cytokine release
106
Superantigens bind
outside the antigen binding area for broad activation of many T-cells
107
Symptoms of STSS
1-2 days of High fever, malaise, myalgia, n/v, watery diarrhea followed by Abrupt onset of severe pain increasing to excruciating levels
108
STSS can often result in
Hypotensive shock and multi-organ failure (renal, CNS/confusion, ARDS, liver), bacteremia, DIC
109
STSS rash appearance
diffuse macular erythroderma which evolves into a scarlatiniform rash which desquamates (palms and soles) 1-2 weeks after onset
110
STSS CBC would show
profound left-shift in granulocyte series
111
STSS Treatment
Penicillin + Clindamycin
112
Cutaneous Anthrax lesions
Small painless papules -> Vesicles (black fluid-filled) -> vesicle rupture -> eschar
113
Eschar of ___________ is painful, while the eschar of ____________ is painless
P. aeruginosa; B. anthracis
114
Treatment for Cutaneous Anthrax
Ciprofloxacin for 60 days
115
Ecthyma gangrenosum is caused by
Pseudomonas aeruginosa infection of small veins
116
Traumatic Clostridial Myonecrosis is caused primarily by
Clostridium perfringens, type A histolytic strains
117
Atraumatic Clostridial Myonecrosis is caused primarily by
Clostridium septicum (GIT malignancy)
118
histolytic strains express
exotoxin production: PLC and perfringolysin
119
PLC/Alpha toxin is a
lecithinase cytotoxin that destroys cell membranes by cleaving lecithin -> lysing cells
120
PLC/Alpha toxin has what effects
Reduces CO, Induces TNF-alpha
121
Perfringolysin/Theta toxin has what effects at LOW concentrations
degranulation of PMNs, increased production of adherence molecules by PMNs, and PAF production by endothelial cells -> leaky vessels
122
Perfringolysin/Theta toxin has what effects at HIGH concentrations
complete lysis of RBCs and PMNs
123
Hydrogen Gas (H2) is produced in Clostridial Myonecrosis by
hydrogen lyase
124
hydrogen lyase action
recycles ferredoxin
125
X-ray of Clostridial Myonecrosis shows
feathery pattern
126
Risk Factors for Clostridial Myonecrosis
Hx of traumatic crushing wounds (car/farm accident, war), surgery (GIT/colon)
127
Describe the exudate of Clostridial Myonecrosis
thin, hemorrhagic exudate w/ foul or sweet odor (dishwater exudate, no pus bc no PMNs)
128
Systemic effects of Clostridial Myonecrosis
low-grade fever, tachycardia, hypotensive shock, death due to exotoxemia
129
Bacteremia with Clostridial Myonecrosis is
RARE
130
Culture of Clostridium perfringens, type A would show
Double zone of hemolysis on culture
131
Reverse CAMP test
ID test for Clostridium perfringens, type A
132
Treatment for Clostridial Myonecrosis
Debridement, amputation, ABX
133
Trichinosis agent
Trichinella spiralis
134
Life Cycle of Trichinella spiralis
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
First Sx of Trichinosis are ___________, but they usually go unnoted
gastroenteritis
136
Risk Factors for Trichinosis
consumption of uncooked pig, horse, wild game
137
Manifestations of Trichinosis are due to
larval migration and host response
138
Parenteral Phase Sx of Trichinosis
Fever, periorbital edema, chemosis, peripheral eosinophilia, fatigue, muscle spasms, muscle aches, splinter hemorrhage
139
Trichinosis Larvae encyst in
striated mm, which it converts to nurse cells
140
Trichinosis Larvae encystment involves calcification by
eosinophils
141
What are the primary immune responses that control Trichinosis
Eosinophils and IgE and ADCC
142
Diagnosis of Trichinosis
Deltoid biopsy (w3), Bentonite Flocculation Test, Indirect Fluorescent Antibody Test (IFA), Latex Agglutination Test, ELISA/EIA (w1), Peripheral Eosinophilia (w2)
143
Peripheral Eosinophila indicates
Trichinosis (helminthic infection)
144
Treatment for Trichinosis
mechanical ventilator, Benzimidazole derivatives (Albendazole), Corticosteroids
145
Benzimidazole derivatives (Albendazole) act by
Inhibit glucose uptake by blocking MT assembly
146
Severely infected Trichinosis patient may develop ____________ after treatment ensues
severe HSN response and death
147
Vaginosis may be caused by overgrowth of
Gardnerella vaginalis, Candida albicans, Prevotella intermedia
148
First step in pregnant females who've been exposed to Rubella?
Check immune status
149
VZIG is often administered to
immunocompromised children w/in 72hr of exposure
150
Secondarily impetiginized lesions are infected w/
S. pyopgenes or S. aureus
151
Rash appearance on palms/soles is common for what to diseases
Erythema Infectiosum and Smallpox
152
Most common complication of Measles in US is ________, but in underdeveloped countries is _______
Otitis Media; Diarrhea/Malnutrition
153
Bacteremia is rare in
Malassezia furfur, cellulitis, Clostridial myonecrosis
154
Mobiluncus is typically found _________ and is a Gram _________
vaginal tract: Gram positive curved rod
155
Trichinosis Sx are due in part to immune responses, which include:
ADCC, Type I HSN, Type III HSN
156
Left shift in granulocytes
STSS
157
NF of vagina that play a role in host defense and keep an acidic pH
Lactobacillus
158
MMR is a
live attenuated virus vaccine and should not be given to immunocompromised or pregnant females
159
Eikenella is a Gram ___________
negative rod
160
Pathogenic form of anthrax is the
spore
161
Agent associated w/ nosocomial bacteremia
Staph epidermidis
162
Antitoxins for Clostridial Myonecrosis are only efficacious when
used prophylactically
163
Enterococcus faecalis typically cause infections of
blood
164
Peptostreptococcus typically cause infections of
skin and ST, vaginosis
165
Agents of nosocomial infections of immunocompromised patients
Enterococcus faecalis and E. faecium
166
Biophila wadsworthia typically cause infections of
abscesses in abdomen, joints, appendicitis
