Unit 3 Anaerobes Flashcards
List some obligate anaerobes
Prevotella, Fusobacterium, Bacteroides, and Clostridium perfringens
What are normal habitats of obligate anaerobes in the human body?
Mucosal surfaces, bowel, and skin
What are normal microbiotas for obligate anaerobes?
Feces, skin, vagina, mouth, upper respiratory
What other microorganisms inhabit the colon besides obligate anaerobes?
Facultative organisms like E. coli, and enterococci.
What are ideal conditions in the human body for an infection by obligate anaerobe to take place?
Reduced oxidation of tissues and reduced blood flow
List as much clues to an active anaerobic infection?
Foul odor from the specimen, lesion close to the mucosal surface, presence of underlying disease that causes tissue necrosis, and/or impaired blood supply, previous antibiotic therapy (failed), infection following a bite wound, and sulfur granules exuding from lesion.
What are clinical manifestations in the head, throat, mouth, and respiratory?
Anaerobic tonsillitis (Vincent’s angina), Ludwig’s angina, Otitis media, sinusitis, aspiration pneumonia, and cervico - facial actinomyces
List suitable specimen for anaerobic culture.
Bile, biopsy of endometrial tissue from endometrial suction curette, blood, bone marrow, bronchial washings (using a double lumen plugged catheter), CSF, culdocentesis aspirate, decubitus ulcer, fluid from normally sterile site (joint), abscess material, percutaneous lung aspirate, peritoneal fluid, sulfur granules from fistula, suprapubic bladder aspirate, thoracentesis fluid, tissue from biopsy, transtracheal aspirate, and uterine contents (collected from protected swab)
List unsuitable specimen for anaerobic culture
Bronchial washing using no double lumen catheter, coughed sputum, feces (except for C. diff), gastric or small bowel contents (except in blind loop syndrome), Ileostomy or colostomy drainage, nasopharyngeal swab, rectal swab, secretions from nasotracheal or orotracheal suction, swab of superficial skin lesion, throat swab, urethral swab, vaginal or cervical swab, voided or catheterized urine.
List general anaerobic culture media
CDC anaerobic agar, brucella agar, thioglycollate broth, and chopped meat broth
What are selective media for anaerobic cultures?
PEA (phenylethyl alcohol), LKV (Laked kanamycin Vancomycin), and BBE (Bacteroides Bile Esculin)
Can you use the candle jar method for obligate anaerobes?
No, the candle jar method cannot reduce oxygen levels further than 5% - 10% in the jar.
What are ideal conditions for anaerobic bacterias? Includes temperature and length of incubation.
35 - 37C, Incubate 48 hrs before initial check of plates, and cultures are finalized 5 - 7 days.
What is a reason for a culture to be incubated more than 7 days?
To check for presence of priopionibacterium
What are two ways to create an anaerobic environment?
CO2 packs or hydrogen generators (creates water using oxygen in container I think)
Anoxomat II machine creates an ideal anaerobic condition how?
Removes air inside containers including the oxygen and replaces it with 3 gases. 1. 80% - 90% nitrogen, 5% - 10% hydrogen, and 5 - 10% CO2
How does an anaerobic glove box create an anaerobic environment with 5% CO2, 10% hydrogen, and 85% nitrogen?
Uses a palladium catalyst that reacts with water to produce hydrogen and CO2 to create an anaerobic environment.
Culturing for anaerobic bacteria also means looking for what other kind of bacteria?
aerotolerance too not only obligate anaerobes
What kind of agar must be used for obligate anaerobes and maybe aerotolerance?
Chocolate agar in CO2
What are the criterias for examining obligate anaerobes and aerotolerant microbes?
Colony morphology, hemolysis, and pigment / fluorescence
What identification tests are used to identify anaerobes and aerotolerant microbes?
Catalase, Indole, and special potency antibiotic disks
What antibiotics are used to test for sensitivity in obligate anaerobes?
Kanamycin, vancomycin, colistin, and SPS (only for GPC)
Describe the features of Bacteroides Bile Esculin Agar (BBE).
Gentamicin and oxgall used to inhibit facultative anaerobes and most GN anaerobes. Esculin hydrolysis is used to differentiate bacteroides species observed as dark brown or black complexes.
Describe the features of Egg Yolk Agar.
Its non selective and differential using lecithinase (Nagler test), lipase, and proteolytic activity. A positive for lecithinase is the appearance of opaque precipitate surroudning areas of growth. Lipase activity is seen as iridescent sheen on colony surface, and proteolytic activity is observed as clear space bordering colonies. This media is useful for differentiation clostridium.
Describe the purpose of reverse CAMP test.
Used to differentiate clostridium perfringens from other clostridiums. Alpha toxins produced by C. perfringens interacts with CAMP factor from Streptococcus agalactiae that produces a synergistic hemolysis effect.
What is SPS susceptibility test for?
Stands for sodium polyanetholsulfonate disk. Its used to differentiate P. anaerobius.
What are methods used to identify microbes?
Commercial ID kits, MALDI - TOF, Gas - Liquid chromatography (not routinely used in clinical lab)
ID pathway for Gram negative rods?
- Indole, Antibiotic susceptibility tests, bile esculine, LK agar (optional)
ID pathway for large gram positive rod?
EYA, and reverse CAMP test (optional)
ID pathway for small Gram positive Rod?
Catalase and Indole
ID pathway for Gram positive cocci?
Disk, vancomycin disk, colistin disk, and indole
ID pathway for Gram negative cocci?
No further testing
List anaerobic gram positive cocci genus
- Peptostreptococcus
- Peptococcus
- Finegoldia
- Staphylococcus saccharolyticus
- Gallicola
- Parvimonas
- Peptoniphilus
- Murdochiella
- Anaerococcus
List normal microbiota of anaerobic gram positive cocci.
*Oral cavity
* Upper respiratory tract
* GI tract
*Female genitourinary tract
*Skin
What are the clinical manifestations of anaerobic gram positive cocci?
*Abscesses
*Gangrene
*Cellulitis
*Bacteremia
*Pneumonia
*Peritonitis
*Bite wounds
*PID (pelvic inflammatory disease)
*Brain abscesses (40% mortality rate)
List difficult to speciate obligate anaerobes
- P. anaerobius
- P. asaccharolyticus
*P. micros
*Peptococcus niger
*Finegoldia magna
Describe the physical characteristic of peptostreptococcus under the microscope
Anaerobic GPC, forms tetrads, chains, clusters, pairs or clumps and vary in size of cocci
What am I? I am gram negative cocci, part of the oral cavity, genitourinary, respiratory, and GI tract fauna, usually mixed in mixed infections, rarely medically important, and biochemically inert.
Veillonella sp. (historically only one in human infections)
List less common generas that are gram negative cocci?
*Megasphaera
*Anaeroglobus
*Negativicoccus
*Acidaminococcus
List generas of anaerobic gram-negative rods
*Bacteroides
*Prevotella
*Porphyromonas
*Fusobacterium
What group am I? I am a group of anaerobic gram negative rods, often found in human infections, common out of all the anaerobes, and produce life threatening illness.
Bacteroides fragilis group (BFG)
What are the benefits of beneficial bacteroides provide to its host?
*Produce butyrate (SCFA) which provides energy to enterocytes
*Role in bile acid recirculation & biotransformation/help ferment carbs
*Compete with pathogenic microorganisms
*Synergy with other coliforms
*30% - 50% of poop weight is B. frag
What are the negatives of nonbeneficial bacteroides?
*Resistant to human body with the help of capsule
*Fibrin deposition and abscess formation because of capsular material
*Most common infections are abscesses which may lead to septicemia if ignored
