Anaerobic Infections Flashcards
1
Q
Anaerobes primarily reside where?
A
Mucosa (surfaces/membranes) oral cavity, GI, female genital
2
Q
3 important roles of anaerobes
A
Colonization (depletion of nutrients)
Vitamin K production
Bile production
3
Q
High likelihood of anaerobe infection
A
Intra-abdominal abscess (GI perf) Brain abscess Liver abscess Diabetic foot infection Suspect them even if they don't grow on culture
4
Q
Cranial neuropathies and descending flaccid paralysis ddx
A
botulism
5
Q
Peptostreptococcus is found where?
A
oral cavity
6
Q
Sterile pus (no growth on culture) a clue for what?
A
Anaerobes
7
Q
Good specimens for anaerobes
A
purulent material
debrided tissue
process in an anaerobic environment
8
Q
Good abx for anaerobes
A
Metronidazole Clindamycin (above diaphragm) Carbapenems Cephamycins Tigecycline Moxifloxacin
9
Q
B. fragilis resistance via?
A
Increased B-Lase production
10
Q
Anaerobic toxin-mediated disease
A
*Clostridia –> pseudo colitis
Also tetanus, botulism
11
Q
Risk factors for anaerobic infections
A
Malignancy Airway/vessel occlusion (ischemic tissue) Vascular disease Diabetes Trauma Immunocompromise Foreign bodies Antibiotic pressure
12
Q
Important G- rod anaerobes (BFP2)
A
Bacteroides spp
Prevotella
Fusobacterium
Porphyromonas
13
Q
Important GPC anaerobes
A
Peptostreptococcus
14
Q
Important GPR anaerobes (spores)
A
Clostridia
15
Q
Important G- rod anaerobes (no spores)
A
Actinomyces
Propionibacterium
16
Q
Abscess formation, increasing drug resistance
A
B. fragilis (clinda/BL)
17
Q
Long, thin, (pointed ends) found in mouth and gingiva and produce endotoxin
A
Fusobacterium (pointed=fusiform)
18
Q
Nearly always found in mixed infections
A
Peptostreptococci
19
Q
Organisms in the oral cavity
A
High #’s in saliva, gingival scrapings
Pepto/Prevo/Fuso/B.spp/Actino
20
Q
Common oral cavity anaerobe infections
A
CNS, mouth, H/N, lungs, pleural space
21
Q
bug causing brain abscess via hematogenous spread
A
s. aureus
22
Q
Vincent’s angina/trench mouth
A
Necrotizing gingivitis
ulcerations/bleeding
common in AIDS/chemo
23
Q
Ludwig’s angina
A
SSTI of submandibular/sublingual spaces
Respiratory compromise by forcing tongue into airway
24
Q
Lemierre’s syndrome (assoc. w/which bug?)
A
SSTI of lateral pharyngeal space
Suppurative thrombophlebitis of JUGULAR VEIN
–> septic PE and bacteremia w/ Fuso. necrophorum
25
Sinusitis or OM >3 months
most likely due to anaerobes
26
Conditions predisposing to aspiration
Neuro disorders
Alcohol, drugs
GI reflux
Thick sputum
27
Commonly develops after aspiration pneumonia
Lung abscess
28
FETID, foul sputum with weight loss, low fever
Lung abscess
| Tx: weeks of abx, no resection/drainage
29
Infection of pleural space requiring drainage thru chest tubes or decortications (S3a)
Empyema - 2ndary to pneumonia
S. aureus, S. pyogenes, S. pneumo + anaerobes
Tx: weeks of abx
30
Common infections of GI anaerobes
peritonitis
intra-abd abscess
liver abscess
biliary tract infections
31
Common GI anaerobes --> peritonitis, intra-abd abcess, liver abscess, biliary
B. fragilis
Peptostrepto
Fuso
Clostridia
32
Infection of ascitic fluid seen in end stage liver disease
| Results from a mono microbial, aerobic bacteremia
Primary peritonitis
33
Severe abd pain, rebound tenderness (irritation of peritoneum), requiring surgery and broad-spec abx
```
Secondary peritonitis (large anaerobe role)
B. fragilis, E.coli, enterococci most common bugs
```
34
Predisposing conditions to 2ndary peritonitis
Ruptured viscus (appendix, bowel perf)
Abd surgery
Trauma
35
Contained infection 2ndary to incompletely treated peritonitis, w/PERSISTENT abd pain, non-resolving LEUKOCYTOSIS
Intra-abd abscess
36
Most common visceral abd abscess
Liver abscess
37
Common female GU anaerobes
Prevotella
Peptostrepto
B. fragilis group
Clostridia
38
infection of the uterine lining, may follow incomplete abortions - caused by what bug
endometritis
| C. perfringens
39
mixed aerobic/anaerobic infection can lead to need for drainage, scarring of repo sys, infertility
tuboovarian abscesses and PID
40
Decline of acid-producing lactobacilli normal flora and increase in anaerobic bacteria leading to vaginal discharge
Bacterial vaginosis
41
bug assoc w/acne and orthopedic/neurosurgical fixation device/shunt infections
propionibacterium
42
common SSTI anaerobes (BPC)
bacteroides
peptostrepto
clostridia
43
plantar ulceration --> polymicrobial mixed infection
diabetic foot infection
| prolonged antibiotics and debridement
44
on sacrum, mixed infection of bugs from GI tract
pressure ulcers
| prolonged abx
45
deep SSTI mixed infection
necrotizing faciitis e.g. Fournier's
46
resulting from contamination of an open fracture
contiguous osteomyelitis
47
most frequent isolated anaerobe from blood cultures (bacteremia)
B. fragilis (from GI/GU/lung/soft tissue)
48
large "boxy" gram positive rods
clostridia
| produce spores which survive in soil, decaying vegetation, marine environments)
49
sustained muscle contraction first manifest as a "lock jaw" and painful spasms that are triggered by sensory stimuli, potentially leading to airway obstruction and autonomic dysfunction (mimics strychnine poisoning) up temp, BP, pulse, sweating
Tetanus (C. tetani)
| tetanospasmin aka tetanus toxin prevents release of INHIBITORY NT's from presynaptic cells
50
treatment of tetanus
```
ICU supportive care
Benzos for spasm control
Immunization with HTIG(globulin)
Metronidazole
Dx CLINICALLY, not based on lab ID
Takes weeks to months for toxin to clear
```
51
tetanus vaccine
DTaP during childhood
| Routine Td/Tdap boosters for adults
52
pt is alert and afebrile; weakness and flaccid paralysis due to bilateral cranial nerve abnormalities (blurred vision, dysphagia) and descending motor weakness leading to respiratory failure and autonomic dysfunction
Botulism (C. botulinum)
| Neurotoxin prevents ACh release
53
ingestion of preformed botulinum toxin (sx w/in 36 hr)
foodborne botulism
54
"floppy baby syndrome" what is ingested?
infant botulism
spores (honey...ok after 1st year of life)
colonic normal flora is not yet established
55
longest botulinum form to develop due to infection of a wound and release of toxin (sx in 4-14d)
wound botulism (penicillin)
56
inhalation botulism
biowarfare
57
how to dx botulism? (4 things)
clinical
stool, blood, soft tissue, food source
anaerobic culture and toxin typing
58
botulism tx?
supportive
trivalent antitoxin (hypersensitivity)
infant --> HBIG
wound --> penicillin
prevention via food handling and prep
59
gram + rod with "boxcar appearance"
C. perfringens
60
GI illnesses
food poisoning
enteritis necroticans
clostridial myonecrosis
C. perfringens
61
C. perfringens toxins
lethicinase (a-toxin)
| hemolysin
62
risk groups for gas gangrene
trauma wounds (miliatry, motor vehicle, agricultural) or surgery (colon, septic abortion)
63
nontraumatic (spontaneous) gas gangrene assoc w/?
C. septicum
| originating via diseased / cancerous colon
64
bug causing: severe pain out of proportion than what is seen, followed by rapid evolution of gas in soft tissues (crepitus) with MAGENA/BRONZE then followed by hemorrhagic bullae and DIRTY BROWN discharge; systemic illness
C. septicum
65
dx C. septicum?
culture and gram stain
66
C. septicum tx?
debridement
PEN + clinda (decrease toxin production)
hyperbaric oxygen
67
mucosal damage and diarrheal illness due to VEGETATIVE forms proliferating and producing exotoxins A&B
C. diff --> pseudomembranous colitis
68
RF's of pseudo-colitis
age
severity of illness
antibiotic use (80% of the time)
20% 4 weeks after abx are stopped
69
most common cause of unexplained leukocytosis in hospitalized pts
C. difficile
70
C. diff dx?
PCR of STOOL for toxin A or B gene
| endoscopy to find pseudomembranes
71
C. diff tx? (mild v. moderate/severe)
```
stop antibiotics
no antiperistaltics
Mild --> METRONIDAZOLE
Mod/severe --> oral VANCO
IVIG
colectomy to save life
```
72
Recurrent C. diff tx?
lacking of IgG to toxins
avoid unnecessary abx
oral vanco, probiotics, rifaximin, fidaxomicin
FECAL TRANSPLANT
73
cramps, diarrhea 8-16 hours after ingestion and end within 24 hours. RARE VOMITING
C. perfringens food poisoning
meats, poultry, gravy temperature control
toxin production in-vivo (not-preformed such as S. aureus)
74
outstanding drug for Gram negative anaerobe infections i.e. abscess, peritonitis, GI, GU
Metronidazole
75
outstanding drug for gram positive anaerobes above diaphragm (i.e. come from mouth)
clindamycin
| e.g. good for aspiration pneuma, not peritonitis
76
abx for G+ not G-
Vanco and Pen
77
how do chemo drugs allow anaerobes to cause disease?
via mucositis (e.g. of the mouth) or enterocolitis
78
Gram positive anaerobes
Peptostrepto
Clostridia
Actinomyces
79
hallmarks: abcess formation
Bacteroides (up resistance to clinda/BL)
fragillis --> GI
other --> mouth/GU
80
purple G+ cocci
peptostrep (mouth, GI, GU)
81
why do abx work so well for lung abscesses?
wonderful blood supply
82
pleural fluid analysis:
positive culture/gram stain
Low pH (60)
empyema
83
removal of pleural lining
decortication
84
tennis racket terminal spore
tetanus
85
spores enter via wound, incubate for 3-21d (avg 8) under low O2 conditions --> germinate and produce toxin at wound site which spreads via blood and lymphatics
C. tetani
86
Tetanospasmin route of entry
via retrograde axonal transport to CNS, diffuses to terminals of inhibitory cells
87
```
trismus
neck stiffness
trouble swallowing
abdominal muscle rigidity
spasms
autonomic: inc temp, pulse, BP, sweating
```
lock jaw
tetanus
88
Wound comparison: tetanus or no?
age of wound: >6 = tetanus
configuration: stellate, avulsion (T); linear (non)
depth: >1cm = tetanus
mechanism: missile/crush/burn/frostbite (T); sharp surface, glass/knife (non)
contaminants: yes (T)
devitalized tissue: yes (T)
89
GNR anaerobes
```
B. fragilis
Bacteroides spp
Prevotella
Fusobacterium
Porphyromonas
```
90
GPR anaerobes
clostridia
actinomyces
propionibacterium
91
brain abscess via direct extension: mono/polymicrobial?
poly
92
brain abscess via hematogenous spread: mono/polymicrobial?
mono
93
thick, fetid sputum
aspiration pneumonia
94
tx of aspiration pneumonia
clindamycin
| ampicillin-sulbactam
