Anaerobes study questions Flashcards
What is added to Columbia sheep blood agar that makes it suitable for growing anaerobic bacteria?
It contains growth factors, peptides, vitamin K, yeast, hemin
What organisms grow on Columbia sheep blood agar
It grows obligate and facultative anaerobes
(gram - and +)
-Enterobacteriaceae, pseudomonas, nonfermenting gram-rods, strep, staph, candida
What criteria determine if a specimen is acceptable for anaerobic growth?
-if the specimen was collected properly like eswab, syringes
What ingredients are in the leaked KV agar?
KV agar has kanamycin and vancomycin and selects for gram-bacilli like prevotella, bacterioles
-porphyormonas will not grow
List sites that are unacceptable for anaerobic culture
-area with indigenous flora
-throat, mouth, rectum, urine unless suprapubic, tap, sputum, BAL, vaginal, cervical, placenta, catheter tips, Implements except for shunts and spinal/brain types
Holding Jar purpose in anaerobic culturing
-can be used to hold reduced media, or help to keep organisms alive while you work them up
Gas pack gas generating system purpose in anaerobic bacteria culturing
-a packet that when torn open generates H2. In the presence of a catalyst, the H2 combines with O2 to form H2O
Anaerobic glove box chamber in anaerobic culturing
-uses a lot of nitrogen gas to replace oxygen but incubates and everything you need is in the box
What is the aerotolerance test?
-in this test, you subculture the organism onto two chocolate plates and place one into ambient air and CO2. This shows oxygen required for organisms
What is BBE agar?
-Bacteroides Bile esculin agar and contains 20% bile esculin salt. We use this to identify B fragilis
-B frag will grow on the agar and turn black from hydrolyzing the bile salts
How long are anaerobic cultures incubated?
-they are incubated at 35-37 degrees for a minimum of 4 days but up to 14 days depending on the source. Anaeroboes take a longer time to grow
-joints are held longer to rule out cunitebacterium actines
How long are aerobic cultures incubated?
- held for 48 hours (2 days) for nonsterile, sterile sources get held up to
What antibiotics are used to treat anaerobic infections?
-antibiotic treatments are based on empirical treatment which would be ampicillin, penicillin, clindamycin, cefoxitin, carbapenems, metronidazole, beta-lactam combos, imipenem (the others too)
Who would order a susceptibilities test on anaerobic infections?
-The doctor in charge and the infectious disease
-only do this on a true sterile source
What method would be used for the susceptibility test of anaerobic infections?
-MIC, tube dilutions
What is the principle of the rapid ANA identification kit?
is used to identify preformed enzymes used for primarily GNB, GPB, and actinomyces
Propionibacterium
-Gram pos bacilli
-catalase +
-clumpy crabgrass GPB on gram stain
-found in oil glands and skin
-microaerophilic
Bacteroides fragilis group
-most frequently isolated
-Gram neg coccobacilli
-pleomorphic
-grow on KV and BBE
-oxidase, urease, lipase, nitrate neg
Fusobacterium species
-does not grow on KV
-Gram - bacilli
-long and thin with tapered ends (fusiform)
- fluoresce chartreuse
-catalase, oxidase, urease, nitrate neg
Peptostreptococcus
-Gram + cocci
-catalase neg
Prevotella melaninogenica
- Gram neg coccibacilli
- grows on KV but not BBE
- black centers and fluoresces
Clostridium perfringes
-double zone hemolysis on Columbia
-large boxcar gram pos bacilli
-grows on CHOC, BAP, and COL
-RCAMP, lecithinase and Nagler pos
-motility, urease, indole catalase, lipase, fluorescent neg
clostridium septicum
-motile
-thin gram pos bacilli
-subterminal spore
-medusa head colonies
-no double zone hemolysis
- indole, catalase, urease, nagler, lecithinase neg
clostridium tetani
-motile
-terminal spore
-gram pos bacilli
-tennis racket/drumstick appearance
- narrow hemolysis
-may swarm
-indole, lipase, catalase, urease, lecithinase neg
Actinomyces Israeli
-molar tooth colony
- gram-positive
-forms sulfur granules
-catalase neg
-branching beading thin filamentous bacilli
-nonspore forming
