Midterm Flashcards
Crystal violet & methylene blue are stain usually used for:
Yeasts
lactophenol cotton blue usually used to:
confirm the identity of fungal organisms
All specimens should be treated as potentially
zoonotic
Any material solid or liquid that can support the growth of microorganism
culture medium
what is agar composed of
dried extract of sea algae known as agarophytes
Is a protein that is obtained from animal tissues
gelatin
agar plate should be stored at
5-10 degrees C
six general types of culture medias:
transport (swab) general purpose enriched selective differential enrichment
Enriched media are formulated to meet requirements of the most _________ pathogens.
fastidious
MacConkey is what type of media?
Selective
A growth medium that contains microbial inhibitors that allow the preferential growth desired types of microorganism in preference to others. They may range from narrow to broad spectrum
selective
A growth med. that allows two or more organisms to be distinguished from one another by some characteristics such as growth, ability to metabolize a specific nutrient as an energy source, diff. end products of metabolism … etc
Differential
A growth medium that permits preferential emergence of certain organism that initially may have made up a relatively minute proportion of a mixed inoculum. May be formulated to provide excess nutritional requirements for fastidious organisms.
Enrichment
A non-nutritive, buffered medium for maintaining viability without overgrowth of microorganisms during transport of specimens to the lab for examination
Transport
What can be detected in a blood agar and what type of media is it?
enriched medium & it contain four distinct hemolysis
partial hemolysis that creates a narrow band of greenish or slimy discoloration around colony
Alpha-hemolysis
complete hemolysis that creates a clear zone around the bacterial colony
Beta-hemolysis
Hemolysis that produces no change in the appearance of the medium and no hemolysis around colonies
Gamma-hemolysis
A zone of hemolysis surrounded by a narrow zone of hemolysis around the bact. colony
Delta-hemolysis
Bacteria can be classified on the basis of their pattern of ________on blood agar
hemolysis
MacConkey and Eosin-Methylene blue are what types of media
selective
MacConkey suppress the growth of
gram + bact
Bacteria that cannot ferment ________ attacks the _______ in MacConkey agar, producing a __________ reaction and colorless colonies
lactose
peptone
alkaline
A liquid med. that is used to culture anaerobic bact. to determine the O2 tolerance of microbes
Thioglycollate Broth
__________ will grown on ONLY O2-rich top layer, where as ________ will grown only in the lower part of the tube.
Obligate aerobes
Obligate anaerobes
Med. where it is inoculated with a straight stab depth of appros. one inch. (hydrogen sulfide production is indicated by blackening of the med.)
Sulfide Indole Motility tube
Agar used for presumptive ID of salmonellae and initial diff. of enteric bact.
Triple Sugar Iron Agar
In triple sugar agar if there is acid production it will turn _______. However, if the organism doesnt ferment lactose or sucrose it will revert to ______ (alkaline condition).
yellow
red
Highly rec. med for Staphyloccoci and to isolate staphylococcus from contaminated specimens.
mannitol salt agar
selective med. acts with brilliant green to suppress growth of coliforms while permitting the growth of salmonellae
Bismuth Sulfite Agar
In Bismuth Sulfite Agar Salmonellae reacts with:
black “rabbit eye” colonies
a general purpose media that is primarily usde for the perf. of the agar diffusion antimicrobial sensitivity test
Mueller Hinton Agar
DTM is composed of
sabourad dextrous agar
The most standard test med. for dermatophytes
DTM
Bone and joint samples are collected by
aspiration
Specimens for histopathologic examination should consist of thin tissue placed immediately in
10% formalin
The 2 most common fungal stains are:
gram stain
Ziehl-Neelsen (acid fast)
colonies should be no older than _____ hrs old because older colonies may not yield to proper results and the stained bacteria often becomes _________.
24
decolorized
used to detect TB, Mycobacterium, Nocardia
Ziehl-Neelsen stain
In Ziehl-Neelsen stain: If the stain is not removed the organism is ________ and appears ______ if it is _________ it appears _____.
positive, red
negative, blue
used to diagnose rickettsiae, spirochetes & Bacilli anthracis. Then it will be examined for the purpleish blue stained bact.
Giemsa stain
speciallized stains contain
flagella
capsule
endospore
fluorescent
Fluorescent stains are used for the ID of
Legionella & pseudomonas
specialized stain that uses crystal violet to detect and characterize bacteria motility
flagella
specialized stain used for detection if pathogenic bact.
Capsule
specialized stain that detects the presence, location, shape of spores and can aid differentiation of bact.
Endospore
specialized stain that involves malachite green to specimen on slide
endospore
specialized stain of endospore show + when spore appear _____ and ______with the remainder of the bacterial cell _____ or ____.
dark blue, green
pink, red
This method is designed to help with the isolation of pure bact. culture
quadrant streak method
because most anaerobes survive exposure of air for less than 20 minutes, the collection of samples for anerobic culture on swab is acceptable T/F
False; It is NOT acceptable
Liver abscess seen at slaughter on otherwise healthy feedlot cattle commonly yield the anaerobe _________ _______ and the aerobe _______ _______.
Fusobacterium necrophrum
Actinomyces pyogenes
Most labs used fluorescent antibody technique for diagnoses in
clostridium
_______ approach is needed for the proper evaluation of cultures
Systemic
The most commonly performed method for antimicrobial susceptibility testing
Agar diffusion test
_____ testing is the most precise than direct testing, but results are not available as quickly.
Indirect
Measure the _____________ and compare it against a standard chart to identify the susceptibility of the bact. to the abx being tested.
zone of inhibition
when is reading the zone of inhibition performed (after how many hrs)
overnight incubation 18-24 hrs
the zones are divided into two major categories:
resistant and susceptible to the particular antimicrobial agent
the zone size alone is not indicative of the efficacy of an antimicrobial T/F
true
An in vitro test of the effectiveness of selected antimicrobials agents against microorganism (ie Staph & E. coli)
Antimicrobial susceptibility test
The presence of pathogenic bact. necessarily indicate infection T/F
False; does NOT
For sensitivity testing the diameter of what is being measure with a caliper?
Each inhibition (including the diameter of the disk) from the underside of the plate
the most common type of sensitivity testing performed?
Bauer-Kirby agar diffusion method
what procedures are used to test for motility:
hanging drop, wet prep, motility media
the movement of cells back and forth
Brownian movement
If organism are non-motile under microscopic exam then a ________ test is perf.
motility
motility test + is indicative when
diffuse growth throughout the med.
controls for catalase test include
staph: catalase +
strep: catalase -
Def: Coagulase
an enzyme that coagulates plasma
A + coagulase test will show results within ______ seconds
5-20 seconds
A + oxidase test will show the reagent reduced to a _________ color within 60 seconds, if longer it will be considered negative
deep purple
oxidase test controls
pseudomonas: oxidase +
E. coli: oxidase -
Test perf. to verify cause of bact. mycotic organisms (“cow side”)
California Mastitis Test (CMT)
California Mastitis Test (CMT) is based on _____ formation when the test reagents reacts with _____ in somatic cells.
gel
DNA
precautions to be considered when perf. CMT:
- DNA in somatic cells deteriorate upon standing refrigerate for no more than 2 days
- WBC migrate with mild fat (throughly mix sample prior to test)
- CMT reaction must be scored 10-15 seconds after mixing start.
Test used for ID of bact pathogens , particularly obligate intracellular bact.
immunologic testing
A separate incubator for fungal samples will minimize the cross contamination of bact. samples with fungal spores T/F
true
Most fungal agents of clinical importance in t vet practice are cutaneous mycotic organisms known as ______ and often ref. to as ______.
dermatophyte
ringworm
Only about 1/3 of the cases of M. canis show evidence of fluorescence T/F
False; 1/2
In dematophyte testing after _____ min small globular anthrospores attached to the hair shaft are visible and indicate + results
2-10
always allow the wood lamp to warm for at least ____ before use.
5 min
Standard sabourad dextrous agar will promotes early formation of ______, but it contains _______ indicator.
macroconidia
no color
all dermatophyte infections should be verified with
microscopic evaluations
Fungi grows as yeast when at body temp and molds at
25 degrees C
cutaneous mycotic organisms are also known as
dermatophytes
Forms tubular filaments
hyphae
tangled mass of hyphae
mycelium
fungi contain no
chloraphyll
fungi are strict
aerobic
when environment is very dry fungi produce
spores
optimal temp for fungi
22-33 degrees C
woods lamp false + may be caused by:
pseudomonas, scales, lint, sebum, dandruff, crust and topical meds
