Glossary of Anaerobic Bacteriology
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- What TYPE of anaerobes are most anaerobic bacteria?
- Aerotolerant. not obligate anaerobes; O2 is toxic to them, but they can tolerate it while we work on them.
- Clinical symptoms unique to anaerobes:
- Foul odor
Gas in tissues/discharge
Sulfur granules (not really, but YELLOW)
Infection proximal to mucosal surface
1. abdom. wound/surgery 2. human bite, 3. aspirationfrom oral to lungs.
- Are anaerobes normal or pathogenic in humans?
- mostly NORMAL - everywhere and anywhere in the body.
can be pathogenic - often in mixed infections, because aerobic pathogens create a microaerophilic environment suitable.
- why do anaerobes produce a foul odor?
- because in anaerobic metabolism volatile acids are produced.
- what type of anaerobic infection do sulfur granules appear in?
- only one - actinomycosis; these arent really sulfur, but YELLOW granules
- 6 types of specimens that should be cultured anaerobically:
bladder urines (suprapubic aspirations)
- Which Specimens should you NEVER culture for an anaerobe?
- Eye, ear, nose, throat
Sputum unless transtracheal
Vaginal, cervical, urethral, stool, urine.
- How are specimens for anaerobic bacterial cultures collected?
- Preferred: Biopsy, or Aspiration
Less Preferred: Swabs - they tend to collect surface fluids, which will not contain anaerobic bugs that prefer deep, anaerobic environments.
- In what type of tube are anaerobic specimens transported?
What is in the media
- in Transport tubes, which have no O2.
In case O2 does get in, an indicator is in the semisolid media in the tubes.
- 3 special methods to transport anaerobic specimens:
- -Transport tube
-Use syringe, aspirate air out. (outdated)
-Use Swab transport biobag with tablet to react with air and remove it.
- What is Rezazarin?
- pink indicator of O2 found in swab transport systems
- 4 types of plate media used to grow/identify obligate anaerobic bacteria:
- 1. Anaerobic BA + Vit K1 & Hemin
2. KV agar w/ laked blood
3. PEA agar
4. aerobic BA
- Describe anaerobic BA ingredients, what grows on it:
- Blood Agar
All anaerobes grow - facultative and obligate. From a stool, that's bad.
- Describe KV agar ingredients, what grows on it.
- Kanamycin - aerobic gnb inhibitor
Vancomycin - gpos inhibitor
Laked blood - shows black pigment of some anaerobic bugs.
Only Anaerobic gnb will grow
- Describe PEA agar ingredients, what grows on it.
what does PEA stand for?
- Phenylethyl alcohol agar
-Inhibits facultative anaerobes
-only obligate anaerobic bugs will grow from an enteric specimen.
Alternate to CNA; selective for gPOS bugs
- Why is an aerobic plate useful in identifying/isolating obligate anaerobic bacteria?
- Because if it grows on the aerobic, you know it's not the kind of anaerobe WE'RE lookin fowr.
- When would a bug grow on both aerobic and anaerobic blood agar?
- If it is facultatively anaerobic, often the case in enteric specimens.
- What are 2 Types of anaerobic broth media:
- 1. Sodium Thioglycollate w/ Vit K1 & hemin
2. Cooked meat broth - a protein source
- 2 Things that must be done to prepare media for anaerobic cultures:
- Plates: reduce for 24 hours to take out any oxygen.
Broths: Boil for 10 min to remove any O2 that was absorbed.
- What is Sodium Thioglycollate?
- a REDUCER; keeps the oxidation/reduction potential low in anaerobic broths
- What's required of LOOPS for anaerobe culture setups?
- Type of Loop
-If metal, only Tungsten or Platinum
-Plastic loops best
Inoculate quickly to prevent O2 absorption
- List four different systems for incubating obligate anaerobes:
- 1. GasPak jar
4. Oxyrase system
- what reaction takes place in a Gaspak jar?
What is the visible result?
Components of the jar:
- 2H2 + 02 -> 2H2O
Condensation forms, CO2 also released.
Palladium pellet catalyst
gasket, screw clamp, indicator ensures it is an anaerobic environment
- With a gaspak jar, what should you wait to see, and how soon?
- Condensation formation within 2 hours.
The indicator will not probably ensure an anaerobic environment that soon.
- What's a Glove box?
- like a fume hood, with a sliding door to keep anaerobic bugs in anaerobic cond.
- What are the incubation conditions for anaerobic bugs in Broths vs. Plates?
- Broths - can be incubated as usual, with caps screwed tight.
Plates - must be in anaerobic environment, for at least 48 hours.
- If you only test for anaerobic bugs now and then, what type of incubation system should you use?
- Biobag - cheaper, easier, can see through plastic. What we use.
- What is the Oxyrase system?
- Plates that can be incubated for anaerobic bugs, but not in any special bag or jar.
Agar contains fragments of bacterial cell membranes that convert oxygen to waer.
- What are the 2 Anaerobic GPC?
- Which anaerobic GPC is more important?
What does it resemble?
Resembles streptococcus - especially viridans because can cause SBE.
- Where are these peptos mostly found as normal flora?
- mucous membranes
- where is peptostreptococcus pathogenic?
- almost anywhere in the body
- if you see GPC on a gram stain, what do you know?
- they could be either aerobic streptococus or anaerobic peptostreptococcus.. never should assume you know
- What are the 3 Anaerobic GNC genera?
- 1. Veillonella
- where are veillonella, acidaminococcus, and megasphaera located in the body?
- mucous membranes and intestine, but rare.
- How can you differentiate anaerobic GNC from aerobic?
- They are much smaller and tend to be in clusters.
Neisserias and M. catarrhalis tend to be diplococci that are big and round.
- What are the three genera of anaerobic gnb?
Prevotella and Porphyromonas
- Bacteroides is broken down into what two groups?
- B. fragilis group
Bacteroides sp. - not B. fragilis
- What 2 specimens of B. fragilis group do you need to know?
- Bacteroides fragilis
- What species of Fusobacterium do you know?
- Fusobacterium nucleatum
- What is the unique characteristic of Prevotella and Porphyromonas
- they are black pigmented
- Which anaerobic bacteria are normal flora in the mouth?
- Fusobacterium, Prevotella, and Porphyromonas
- Which anaerobic bacteria are normal flora in the intestine?
- B. fragilis - it is the PREDOMINANT group in the intestine - more than 1000x greater than even E. coli!
- Which anaerobic bacteria are normal flora in the vagina?
- Fusobacterium and Bacteroides species
- where is bacteroides potentially pathogenic in the body?
B. fragilis group?
- almost anywhere.
B. fragilis species can cause peritonitis after abdominal wounds and surgery
- Where do Fusobacterium, Prevotella, and Porphyromonas typically cause infection?
What five types of infections?
- In the oral cavity.
head and neck
human bite wound
Fusospirachaetal disease - Vincent's Angina with Borellia species
- What are the two symptoms of Vincent's angina? caused by what two bugs?
often this is confused with:
- Pharyngeal membrane and gingivitis
Borrelia species and Fusobacterium sp.
Confused with Diphtheria
- What are two ways to identify anaerobic gnb on a gram stain?
- Bacteroides, Prevotella/Porphyrom. may balloon out and look weird.
Fusobacterium fuses in long chains and they're very thin, long, tapered at ends.
- what is the characteristic colonial morphology of Bacteroides?
- very similar to enterococcus, difficult to differentiate on a plate - off white, milky, etc.
- what is the colonial morphology that distinguishes PREVOTELLA AND PORPHYROMONAS?
how can you best see them?
- Black-pigmented colonies.
best seen on KV agar with laked blood, after shining with a flourescent light (this speeds pigmentation to 48 hrs instead of 5-7 days.
- what is the characteristic colonial morphology of fusobacterium?
- ground-glass appearance, breadcrumb-like.
- What are three Antibiotics that the anaerobic GNB are susceptible to,
At what concentrations?
- Kanamycin - 1mg
Vancomycin - 5 microg
Colistin - 10 microg
- what does the 20% bile sensitivity show, how?
- B. fragilis - it is resistant to it.
- what is the "anaerobic gram variable bacilli", really?
- really, it's an aerobic gram positive bacilli. it's just that the gram stain is variable due to a thinner than normal peptidoglycan layer, and it grows better on anaerobic agar.
- what is the name of this gram variable species?
- Gardnerella vaginalis
- What is the characteristic gram stain of a gardnerella vaginal swab?
- -decreased lactobacillus
-gram variable bugs with GULL-WING shape
-various bacteria adhere to the cells
- What is bacterial vaginosis?
- an annoying infection with burning discharge but no pain really.
- what are the 3 complications of bacterial vaginosis?
- -premature birth
-Septicemic mothers or babies
- what is the role of another organism in bacterial vaginosis, what is its name?
- mobiluncus is another anaerobic bug that is associated with the disease - it's just found there.
- what are the 3 main methods of diagnosing bacterial vaginosis?
- -gram stain shows clue cells
-alkaline vaginal discharge = cloudy, runny.
-Discharge has fishy odor when mixed with 10% KOH.
- what is used to treat bacterial vaginosis?
- what are the 7 non-sporeforming anaerobic gram positive bacilli?
- Propionibacterium acnes
- which non-spore anaerobic GPB is found on skin normally?
- propionibacterium acnes
- which anaerobic gpb (nonspore) is actually a very aerotolerant anaerobe so that is classified as aerobic?
- which anaerobic gpb nonspore forms sulfur granules?
what are its other characteristics?
Results in actinomycosis, with symptoms of Lumpy jaw - swelling under the jawline.
It's actually a fungi.
- what anaerobic gpb nonspore is a commmon cause of gingival plaque?
- Where is Propionibacterium acnes normally flora?
- on the skin
- Where is Bifidobacterium normal flora?
- in the intestine.
ironic, B goes with B - bifidobacterium and bacteroides
- What four gpb anaerobic non-spore formers are normal flora in the mouth?
- Lactobacillus, Eubacterium, Actinomyces, and Rothia.
Remember Rothia causes gingival plaque, and just goes with three others in the mouth
- What is normal flora in the vagina?
- What is the anaerobic GPB spore-former?
- how many species of clostridium are there?
which is the biggest?
it infringens on the others
- What are the characteristics of Clostridium?
(gram stain, natural habitat, virulence factors)
- GS: Spore-former GPB
Nat'l Habitat: soil/intestine
- where in nature is clostridium normally found?
- in the soil
- what are the characteristic virulence factors of clostrdiium?
- what are the 3 most commonly isolated species of clostridium?
- c. difficile
c. ramosum --> like abby ranum only mos instead of n
- what is the number one isolated clostridium species? what diseases does it cause?
- clostridium perfringens
causes gas gangrene and foodborne illness
- what is clostridium dificile associated with?
- antibiotic associated colitis
- what are the characteristics of c. perfringens?
(Gstain, colonies, emissions, special agar)
- -large boxy gpc w/ spores
-large gray colonies with double zone of beta hemolysis.
-produces considerable gas
-stormy fermentation in milk media
-Lec+ Lip- on egg yolk agar
- what is the course of gas gangrene? what causes it?
- caused by c. perfringens
bug in soil, enters wound, proliferates, produces exotoxin, necrosis/blebs start, enters bloodstream and because systemic.
- how is gas gangrene treated?
- with penicillin and wound debredement
- What clostridium species cause
- Foodbn illness = perfringens; bug proliferates after eating.
Food poisoning = botulinum; toxin ingested causes sx.
- what is the course of foodborne illness caused by c. perfringens?
how to test for it?
- the cafeteria germ is ingested with SPORE-containing meat, after incubating 6-8 hrs it causes diarrhea.
to test for it, must culture food, not stool.
- what does Clostridium tetani cause?
- what type of toxin is produced by c. tetani?
- a neurotoxin
- what is the course of tetanus as a disease?
- bug in soil enters wounds. it germinates and produces the neurotoxin, which then acts on the CNS and causes muscle spasms - first local then systemic.
- how is tetanus treated?
- with antitoxin and debridement
- how can tetanus be prevented?
- with a tetanus shot - toxoid - once every 10 years
- List 3 diseases caused by C. botulinum:
which is most common?
- -food poisoning
-infant botulism - most common
- what is the course of food poisoning by botulinum?
- the bug in soil gets in fruits/veggies, then gets canned. forms gas - blows lids off like in holiday inn. passes to intestine, then CNS and causes paralysis.
- what is special about the botulism toxin?
- -most toxic toxin known
-no real good specimen to culture, so test serum.
-can be used to treat facial ticks/crossed eyes
- what is the course of disease of wound botulism?
- from the soil, the bug enters a wound. then it produces the toxin, it enters the CNS and causes paralysis.
- what is the course of infant botulism?
- through honey, the bacteria colonizes the small intestine and produces toxin, which enters the CNS and causes paralysis.
- what age of infants develop botulism?
- under 6 mo
- For which Clostridium species are antitoxins available?
- which infections are caused by the bug entering a puncture wound?
- clostridium tetani
clostridium botulinum - wound botulism
- what disease is caused by ingestion of preformed toxin?
- Food poisoning caused by C. botulinum.
- what diseases are caused by colonization of the intestine by the bug?
- infant botulism
C. perfringens food poisoning
- though it's a spore-former, why is clostridium perfringens difficult to ID?
- only produces spores in direct smear - after culturing, not often seen on gram stain.
- what causes antibiotic associated colitis?
- c. difficile
- what is the pathogenic mechanism of antibiot assoc. colitis?
- use antibiots, reduce normal intestinal flora, c. difficile proliferates/produces toxins a/b, colon lesions develop and diarrhea results
- what are the symptoms of aac?
- -diarrhea, bloody w/ WBCs
-abdominal pain and fever
-plaquey lesions and pseudomemb. on intestinal mucosa.
- how is AAC diagnosed?
-toxin detection from tissue culture and immunologic tests.
- what antibiotics are used for anaerobic infections?
combos of beta-lactam drugs with beta-lactam inhibitors
- how are anaerobes identified?
- 1. traditional biochem testing
2. GLC for volatile acids
3. high-resol GLC - fatty acids
4. disc differentiation - kanamycin/vancomycin/colistin
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