anaerobic bacteria Flashcards
Name the 6 types of oxygen requirement groups
- Aerobes- require oxygen (Bacillus)
- Microaerophiles - require low oxygen levels (Campylobacter)
- Facultative anaerobes -can grow with or with O2
(Enterobacterales, Staph) - Aerotolerant anaerobes - prefer anaerobic conditions but can grow in O2 (Lactobacillus, Cutibacterium, some Clostridium sp)
- Obligate anaerobes - only grow in absence of oxygen (Clostridium perfringes, Bacteriodes fragilis group, Fusobacterium)
- Capnophiles - require elevated CO2 (Neisseria)
Name the gram positive anaerobes (5 impt. ones)
1) Clostridium
2) Cutibacterium
3) Proprionibactereium
4) ACTINOMYCES
5) Lactobacillus
Peptostreptococcus
Bifidobacterium
Eubacterium
Name the gram negative anaerobes (3 important ones)
and 2 commensals
1) Bacteroides
2) Fusobacterium
3) Prevotella
4) Porphyromonas
5) Veilonella (only gram negative anaerobic dipplococci)
Name the GI anaerobes (3 important)
1) Bacteroides
2) Clostridium
3) Lactobacillus
Bifidobacterium
Eubacterium
Peptostreptococcus
Veilonella
Actinomyces
Name the ORAL anaerobes (2 important)
1) Prevotella
2) Fusobacterium
Actinomyces
Porphyromonas
Peptostreptococcus
Veilonella
Name the SKIN anaerobes (3 important ones)
1) Cutibacterium
2) Propionibacterium
3) Actinomyces
Which anaerobes are associated with skin and soft tissue infections (2)?
1) Bacteroides fragilis group
2) Clostridium
Which anaerobes cause intra-abdominal infections?
1) Bacteroides fragilis group
2) Clostridium
Which anaerobes cause joint infections?
Cutibacterium acnes
Acceptable specimens for anaerobic culture
Only specimens that were collected from sterile body sites
Abscesses/aspirates drained by needle
Pleural fluid/empyema (fluid that accumulates around the lungs)
Surgically collected tissue
Bile
Peritoneal or thoracentesis fluid
Sterile body fluid (CSF, joint, etc.)
BAL (if collected with anaerobic brush)
Name anaerobic agar media (6)
1) Brucella (nonselective)
2) CDC anaerobic blood agar (non selective)
3) Brucella (with lysed blood agar with Kan and Vanc)
4) BBE agar (esculin is hydrolyzed by bacteriodes = black)
5) Anaerobic PEA (inhibits gram negatives and swarmers)
6) Egg yolk plate (Allows determination of lecithinase and lipase activity)
Name anaerobic liquid media
1) Chopped meat broth with glucose (non selective)
2) Thio broth (non selective, but can differentiate based on oxygen tolerance)
Bacteroides fragilis cause which diseases?
1) Intra-abdominal infection (often after ruptured appendix)
2) Skin and soft tissue infection
3) Bacteremia
typically isolated in the lab and forms black colonies on BBE
Intrinsic resistance of bacteroides fragilis group?
Almost all beta lactamase positive
Susceptible to beta lactam + lactamase inhibitors and carbapenems
2nd gen cephalosporins might also work
Culture characteristics of Fusobacterium species
Obligate anaerobe
Gram negative rod
Long and thin, needle-like
Do not grow on BBE
Fusobacterium necrophorum causes what?
Lemierre’s syndrome
starts with an oralpharyngeal primary infection (tonsilitis, pharyngitis, abscess. The bacterial endotoxin induces platelet aggregation and septic thrombus formation. The septic emboli lodge in the lungs, liver, endocardium, or joints.
key symptoms: swollen cervical lymph nodes, and a swollen, tender or painful neck
High mortality without treatment
Treatment: surgery + beta lactase and metronidazole
Name the 2 common Fusobacterium spp isolated in the clinical lab
Fusobacterium necrophorum
Fusobacterium nucleatum
Both are normal flora of the oral and respiratory tract
What infections do Prevotella and Porphymonas cause?
Periodontal infections (polymicrobial) and dental abscesses
Rare cause of systemic disease
Associated with poor oral hygiene
Are Clostridium strict anaerobes?
May (slowly) grow aerobically as well as anaerobically
What are some characteristics of Clostridium species in gram stains?
1) spores are not always seen, only in stressed conditions
2) overdecolorize easily and may appear Gram negative
3) the spores are generally bulging from the spore (terminal)
Bacillus spores are usually in the center
Name the 4 Clostridium pathogens
C. tetani - tetanus
C. botulinum - wound botulism
C. perfringens - food posoining, gangrene (black dead tissue due to lack of oxygen)
C. septicum - colon cancer (like S. bovis)
Diseases associated with Clostridium septicum ?
Presence of this organism (including sepsis) is linked to colon cancer and hematologic abnormalities including leukemia (S. bovis does too)
High mortality rate
Diseases associated with Clostridium perfringes?
1) Food poisoning (due to toxin contamination in heated food (soup, sauces))
2 ) Most commonly associated with gas gangrene - black necrotic tissue due to lack of oxygen
3) Acute intravascular hemolysis is a rare and often lethal complication of Clostridium perfringens septicemia
4) other skin and soft tissue infections (cellulitis and fasciitis)
What disease is Clostridium botulinum associated with?
Botulism
Toxin ingestion
Muscle relaxation (flaccid paralysis)
Causes facial weakness, issues swallowing speaking, breathing, can lead to paralysis
