MICRO: ANAEROBES Flashcards
Bacteria which grows equally well in absence or presence of oxygen
Facultative anaerobe
Grow in low oxygen and better when CO2 is increased
Microaerophile
Aerotolerant anaerobe
Able to grow 2-8% oxygen
Will grow if oxygen is greater that 0.5%
obligate anaerobe
The ubiquitous species of bacteria which are the commensals of skin, respiratory, intestinal, and urogenital tract
characteristics of anaerobe
Source of infecting microbe / source of the infective anaerobes?
Host’s endogenous flora
This bacterial species is weak, but is involved in polymicrobial infection with aerobes
Anaerobes
The bacterial species causing abscess formation, tissue necrosis, and often gas formation.
Some produce most potent paralytic toxins.
Found in soil, water, food, animals.
Anaerobes
Infection with this anaerobes is both_________and _________
endogenous and exogenous
Exogenous infection of humans by anaerobes is from…
Spore-forming organisms in soil, water, seawage
Endogenous infection of human by anaerobe is from…
endogenous flora
Anaerobes which are a normal floras of the skin
-Propionibacterium
- Peptostreptococcus
Anaerobes which are a normal flora of the upper respiratory tract?
-Propionobacterium
Anaerobes which are a normal flora of the mouth?
-Fusobacterium,
- Actinomyces
Anaerobes which are a normal flora of the small intestine?…
-clostridium
-bacteroides
-fusobacterium
Anaerobes which are a normal flora of the vagina…?
Lactobacillus
How infection via exogenous route occurs?
The anaerobic bacteria gains access via ingestion of contaminated food/water, trauma, or disruption of body surfaces
How infection via exogenous route occurs?
The anaerobic bacteria gains entry via disruption/trauma of mucous membranes____which allows entry of organism into normally sterile sites
Clinical features suggestive of anaerobic infections?…
- Foul smelling discharge
-Infection associated with malignancy
-Blood containing exudates
-Abscess, black necrotic tissue, gangrene
(check more on notes)
Factors predisposing to anaerobic infection?
- co-infection with aerobic infection
- immunosuppression
*check notes
A spore forming bacilli which causes tetanus?…
Clostridium tetani
How clostridium cause tetanus?
Produce a neurotoxin, (tetanospasm) which targets
pre synaptic nerve terminal, blocks release of inhibitory neurotransmitter (GABA) into synapses.
-prolonged muscle spasms, rigidity, respiratory arrest and death result if toxin dose is high
A spore forming bacilli which causes soft tissue, and enteric (food poisoning) infections?…
Clostridium perfringens
*check notes for examples of soft tissue and enteric infections
With this highly resistant spore forming bacteria we see food borne infections, wound infections, and neonatal infections.
Clostridium botulinum
*It’s the reason we do not give kids honey
This an anaerobic bacteria which causes pseudomembranous colitis
- Cause nosocomial infections as well
Clostridium difficile
A gram positive spore forming bacilli
All clostridium spp
A gram positive Non-spore forming bacilli
-propionibacterium
-Uebacterium
-Actinomyces
*more on notes
A gam positive non-spore forming gram positive cocci
peptostreptococcus
A gram negative cocci
veillonella (Normal oral flora)
-isolated from human bites
A gram negative bacilli
Bacteroides fragilis (causes vincent’s angina)
*more on notes
For accurate diagnoses of anaerobic infection, u must…
- Collect specimen from site containing necrotic tissue
- Aspirated material or tissue are the preferred specimen types not swabs
T/F: After sample collection for anaerobe testing, sample must be incubated anaerobically for 48 hours?…
True
Avoid oxygen coz sample will die
Appropriate sample types when testing for presence of anaerobes?
- Aspirated material from abscess
- Tissue
- Sterile fluid (CSF)
- Pulmonary secretions
- GIT (BILE)
- GUT samples (genitourinary)
