03 - Diagnostic Microbiology Flashcards
Test for tuberculosis that yields the most specidifc results rapidly
TB PCR
Term: propagation of microorganisms in media conducive to their growth
culture
Term: nutritive substance in which cultures of microorganisms are grown
culture medium
Agar medium for Mycobacterium tuberculosis
Lowenstein-Jensen
Examples of bacteria that are difficult to culture and in which molecular tests are more useful in diagnosis
Chlamydia
Mycobacterium
Type of test that is done first before the other tests when testing for viruses
serologic tests (testing for the antibodies against viruses)
Common bacteria in which immunofluorescence testing is used
Bordetella pertussis and Legionella pneumophila
Two types of immunofluorescence testing:
Direct and Indirect
Term: screening tests for syphilis. What are their advantages? Enumerate examples.
Non-treponemal tests - easier and cheaper to perform
- Venereal Disease Research Laboratory (VDRL)
- Rapid Plasma Reagin
Term: confirmatory test for syphillis
Treponemal antibody tests
What does ELISA stand for?
Enzyme-linked immunosorbent assay
What does RIA stand for?
Radioimmunoassay
Instrument used to measure the results of ELISA
spectrophotometer
Instrument used to measure the results of RIA
gamma counter
Identify: This test is primarily directed at the detection of carbohydrate antigens of encapsulated microorganisms.
Enumerate examples of microorganisms that can be detected by this test:
Latex agglutination
- Group A streptococcus
- Cryptococcus - CALAS (Cryptococcal Antigent Latex Agglutination System)
- bacterial meningitis
Identify: This test is performed to detect antibodies against specific antigens based upon the separation of major proteins of the organism in a two-dimensional agarose gel.
What is the basis for separation of these proteins? Differences in _______. What is the effect?
Western blot immunoassays
Size - Smaller proteins move faster through the agarose gel.
This is an HIV antigen that is very specific to the virus.
gag p24
Gold standard for diagnosis of gonococcal infecion?
culture on Thayer-Martin medium
This molecular technique involve the use of enzyme to convert viral RNA or messenger RNA to DNA prior to amplification.
Reverse transcriptase PCR
Agar used for detection of Clostridium perfringens. Give two terms.
Egg yolk agar, a.k.a. McClung-Toabe agar
Identify: When combined with the beta-lactamase inhibitor tazobactam, this penicillin possesses the broadest antibacterial spectrum among its kind.
Piperacillin
Mechanism of development of resistance to fluoroquinolones
Mutant DNA gyrase
Mechanism of development of resistance to beta-lactams
hydrolysis and mutant penicillin-binding proteins
Mechanism of development of resistance to tetracyclines
active efflux from the cell
Mechanism of development of resistance to aminoglycosides
inactivation by enzymes
Mechanism of development of resistance to sulfonamides
overproduction of target
Mechanism of development of resistance to chloramphenicol
reduced uptake into the cell
Mechanism of development of resistance to Vancomycin
reprogramming of D-ala-D-ala amino sequence in the peptidoglycan
Mechanism of development of resistance to macrolides (e.g. erythromycin)
RNA methylation, drug efflux
None of the cephalosporins will work against these bacteria (3):
- MRSA - due to altered PBP
- Listeria monocytogenes
- Enterococci
