Examination 4: Part 0: Extra Anaerobe Questions Flashcards
Bacteria that are not killed in the presence of oxygen but still use fermentation as their primary source of energy-conversion are referred to as being ____.
Obligate anaerobes can survive up to _____ in the presence of oxygen.
Anaerobic organisms lack _____ and _____, enzymes required to break down reactive oxygen species harmful to the bacteria during aerobic metabolism.
aerotolerant
10 minutes
Superoxide dismutase
catalase
_____ cannot grow anaerobically (grow well in 21% O2).
Obligate aerobes
_____ grow only in or near 0% O2 levels (5-10% hydrogen and CO2 both, 80-90% N). These microorganisms lack superoxide dismutase, generally lack catalase, and are fermenters that cannot use oxygen as a terminal electron acceptor.
Obligate anaerobes
_____ only grow under reduced oxygen levels (5-10% O2), CO2 (8-10%).
Microaerophiles
_____ can grow under aerobic or anaerobic conditions, thus some can be normal skin flora. These microorganisms are capable of respiring until oxygen is depleted and are then able to ferment.
Facultative anaerobes
_____ survive better under conditions of increased CO2 (5-10%) and around 15% 02.
Capnophiles
_____ are the most abundant type of bacteria in terms of oxygen requirements within the human gastrointestinal tract. The most abundant genus of normal flora bacteria in the human colon is _____.
Anaerobes
Bacterioides spp
Which spp. of bacteria is…?
CAT- G+ thin rods w/ spiral forms N Flora of the female GU tract Grows in pin point colonies Shows alpha hemolysis (resembling streptococci)
Lactobacillus spp.
What type of infection involves opportunistic pathogens gaining access to sterile sites, e.g., through trauma?
endogenous infections
Only _____% of isolates from urine are anaerobes.
Generally, only _____ urine specimens are acceptable for anaerobic collection and culture?
T or F: Needle aspirites are preferred over swabs
1%
suprapubic aspirate
T
What are the preferred specimens for anaerobic collection and culture?
aspirates, tissue, blood
What are some of the disadvantages of swab collection?
Swabs may dry out, become contaminated with normal flora, or expose the microorganism to air toxicity.
Blood culture needs to be carefully collected by first ___
sanitizing the collection site (skin)
- with iodine or clorhexidine gluconate
- combined with 70% isopropyl alcohol.
T or F
Blood specimens should always be collected utilizing both aerobic and anaerobic blood culture bottles.
T
_____ is a commercially available media for the oxygen-free transport of anaerobes.
Staph, Strep spp. and enterobacteriaceae are facultative anaerobes which are capable of _____ infections in humans
PRAS media
polymicrobic
What are some possible modes of anaerobic transmission? (4)
1) Endogenous infections
2) Exogenous source (rusty, nails, skin puncture)
3) Ingestion of improperly canned foods (botulism)
4) Human to human spread (C. difficile)
What are three possible means of storage for anaerobes?
Jar containing a GasPak
Glove box
Holding jar
What are two ways in which an MT can achieve an anaerobic storage environment?
- Evacuation and replacement (vacuum removal of O2 and replacement with N2, CO2, and/or H2)
- Use of a GasPak
What is contained within a GasPak? (2)
Tablet 1
Na+ bicarbonate Citric acid
Tablet 2
2) Na+ borohydride w/ paladonium CATALYST
What does PRAS stand for? What are five PRAS media and what are they used for (overall)?
Pre-Reduced Anaerobically sterilized media
PEA KVLB KVBA BBE Thioglycollate broth
When using a GasPak, what indicates that you have achieved an anaerobic environment? (3)
How long will this take?
- Heat will be produced
- Condensation will collect on walls of the jar
- Methylene indicator will turn from blue to white
30 mins
Anaerobic PEA inhibits _____ and _____ but allows for growth of _____
The process of _____ involves the use of chemicals to remove dissolved O2 in the media iteself
Enterobacteriaciae
Proteus swarming
G+ anaerobes
reduction
All primary isolation media for anaerobes should be supplemented with ____ as they have specific nutrition requirements.
hemin, vitamin K, blood,
in addition to PRAS media what other media should typically be used when culturing from anaerobic infection sites?
- Chocolate
- SBAP
- MacConkey’s
KVLB agar is a ____ media for _____ anaerobes
What genus is this most commonly used for?
Selective, Gram- obligate
Prevotella and Bacteriodes spp.
The freezing and thawing of blood to improve pigment production is called
laked blood
Gentamicin inhibits _____.
_____ supports the growth of most anaerobes in clinical specimens and provide a good back-up for slow growing anaerobes.
Most G- anaerobes (esp facultative)
Thioglycollate broth
Which media provides presumptive ID of Bacteroides fragilis? How does it appear on this media?
BBE agar. Brown-black colonies
Which anaerobic bacteria is known for producing black pigments on KVLB?
Prevotella melaninogenica
What is the gold standard for definitive ID of Anaerobes?
What does it mean to be fetid?
Gas chromatography
Foul-smelling
Gram negative rods
Saccharolytic
Non pigmented
Bacteroides fragilis
What two organisms are known for a foul odor upon opening the anaerobic jar after incubation?
C.difficile and Fusobacterium
Gram-, asaccharolytic, produces bright red pigment
Porphyromonas
This organism is Gram- normal flora of the GI tract mucosal surface. It is esculine positive
Bacteriodes Fragilis
What is the most common anaerobic infection causer of the head?
Porphyromonas
Gram- slightly-curved appearance
Normal flora of the oral cavity
Infections above thorax
Fusobacterium
How is Porphyromonas spp. distinguished from Prevotella Melaninogenica?
Prevotella is saccharolytic
G+ CAT- Subterminal tennis-racket endospores
C botulinum
C tetani
What groups of C. botulisum cause disease in people?
What virulence factors(toxin types) cause human disease?
I and II
A,B,E,F
Normal flora of oral cavity, respiratory system, and GI tract. Gram negative. Has both pigmented and non-pigmented strains. Pigmented is brick red.
Prevotella melaninogenica
G+ rods
Produces endospores
CAT-
Normal flora of gut, female GU, and oral mucosa
Clostridium spp.
what form of C. botulinum is the only form that antibiotics are used to treat?
why are antibiotics typically not used in other forms?
- Wound form
- antibiotics speed up the release of toxin in other forms
Infant form of C. botulinum is typically associated with
the ingestion of honey
what is the toxin associated with foodborne botulism?
how do physicians typically treat this?
preformed toxin
-antitoxins and durgs to induce vomiting and bowel movements
tests for ID of Type of botulinum toxin
ELISA
PCR
Mouse Bioassay
Infant-type Mt toxin occurs _____ and is not _____.
in vivo
not pre-formed
types of Clostridium not included on Vitek 2 ANC card
- Clostridium botulinum (foodborne)
- C. tetani
Ricus sardonicus, a common Clostridium tetani symptom, is _____.
characteristic smile due to sustained facial muscle contractions
G+ Rods, CAT-, single narrow zone of beta-hemolysis on anaerobic BAP
What is the organism?
What is the vaccine used against it?
- C. tetani
- DTaP
-gram positive rods
-catalase negative
- some strains are found in contaminated soil and water and also kitchen counters
-causes soft tissue infections
such as: cellulitis, myonecrosis, food poisoning and enteritis necroticans
Clostridium perfringens
A double zone of hemolysis on anaerobic media is characteristic of _____.
C. perfringens
toxin produced by Clostridium tetani that disrupts nerve impulse to muscles
Tetanospasmin toxin
What is the test used for dx C perfringens?
With C perfringens food poisoning, feces needs to be sent to public health lab for confirmation of ID at ____ degrees C
Reverse CAMP test
4
Bacteria that is the 3rd most common cause of bacterial food poisoning in the US?
what is the toxin associated with this food poisoning?
- Clostridium perfringens
- CPE toxin
- gram pos rods
- catalase negative
- round subterminal endospores
- reverse CAMP test
C. perfringens
media that is selective for C.difficile
CCFA (cycloserine-cefoxitin fructose agar)
C. difficile exotoxin that causes cellular death
Toxin B
Egg yolk is selective for C.diff how does C.diff appear on this media?
what antibiotic is commonly used to treat severe disease caused by C.difficile
creates yellow ground glass colonies
vancomycin
The C. difficile exotoxin that causes inflammation of intestinal mucosa is _____.
Toxin A
G+ non spore forming. Fungus like -bacteria (appears filamentous)
actinomyces israelii
- gram positive
- normal flora: mouth, gums, teeth
- molar tooth appearance on agar
Actinomyces israelii
Chronic infection caused by Actinomyces israelii.
Characterized by local abscesses and oozing sinus tracts containing sulfur granules.
Gains access to tissues through injuries such as decaying teeth
Actinomycosis
Gram positive coccobacillus, part of normal flora. Can cause endocarditis, infection of GU and GI. Implicated in periodontal disease, gingivitis.
Peptostreptococcus anaerobius
G+ cocci in pairs/tetrads. Normal GI flora. Produce tiny black, convex, smooth colonies on anaerobic BAP which turn light gray if exposed to air.
peptococcus niger
Gram negative, diplococci in pairs, clusters and/or short chains. Normal flora of human mouth, GI tracts.
Veillonella parvula
G- microorganism that can cause infection in sinuses, lung, heart, bone and CNS. Produces red fluorescence under UV. Has been found to create a biofilm along with. Streptococcus mutans (normal flora of the mouth) that in combination imparts greater resistance to S. mutans to various antimicrobials.
Veillonella parvula
Difference between Middlebrook 7H10 and Middlebrook 7H9
7H10 is solid agar
7H9 is broth
CCFA
Cycloserine-Cefoxitin Fructose Agar
