Examination 4: Part 0: Extra Anaerobe Questions Flashcards by Braiden A

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

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_____ cannot grow anaerobically (grow well in 21% O2).

Obligate aerobes

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_____ 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

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_____ only grow under reduced oxygen levels (5-10% O2), CO2 (8-10%).

Microaerophiles

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_____ 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

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_____ survive better under conditions of increased CO2 (5-10%) and around 15% 02.

Capnophiles

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_____ 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

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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.

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What type of infection involves opportunistic pathogens gaining access to sterile sites, e.g., through trauma?

endogenous infections

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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

suprapubic aspirate

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What are the preferred specimens for anaerobic collection and culture?

aspirates, tissue, blood

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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.

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Blood culture needs to be carefully collected by first ___

sanitizing the collection site (skin)

with iodine or clorhexidine gluconate
combined with 70% isopropyl alcohol.

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T or F

Blood specimens should always be collected utilizing both aerobic and anaerobic blood culture bottles.

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_____ 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

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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)

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What are three possible means of storage for anaerobes?

Jar containing a GasPak
Glove box
Holding jar

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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

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What is contained within a GasPak? (2)

Tablet 1
Na+ bicarbonate Citric acid

Tablet 2
2) Na+ borohydride w/ paladonium CATALYST

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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

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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

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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

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All primary isolation media for anaerobes should be supplemented with ____ as they have specific nutrition requirements.

hemin, vitamin K, blood,

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in addition to PRAS media what other media should typically be used when culturing from anaerobic infection sites?

Chocolate
SBAP
MacConkey’s

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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