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23 Cards in this Set
- Front
- Back
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what are the three main ways to identify the orgs?
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serology; direct detection via special stains, antigen detection, toxin detection, and molecular assays; culture
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what is the best way to collect anaerobic bac specimens?
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via aspiration with steril syringe and then injected into anaerobic transport vile. Swabs are discouraged, but if they must be used, place them immediately in anaerobic transport media
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what environments are not acceptable for culture?
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urine from foley catheter; anaerobic cultures from BAL's, nasopharyngeal swabs, sputum, trach, perineal swab, urethral secretions, or urine
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what are three specefic bac species that cause need for alerting the lab that these species may be coming to the lab and why?
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suspected Francisella or Brucella bc of special media needs and they are hazardous to lab personnel. Mycobacteria bc it must be neutralized within 1 hour of collection
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what is the principle form of direct detection for bacteria?
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gram stain
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what does a gram stain report contain?
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presence of host cells, gram reaction, morphology and arrangement, and relative amounts of bacteria and/or cells
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what are the three acid fast stain methods?
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ziehl neelson, kinyoun, auramine-rhodamine (fluorochrome based)
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what are the results for acid fast staining?
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red is acid fast positive while blue is negative
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what orgs stain acid fast?
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mycobacterium, nocardia, rhodococcus, tsukamurella, gordonia, and coccidian parasites (cryptosporidium, cyclospora, isospora)
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what stains are useful in determining if fungal elements are present?
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KOH, calcofluor white, giemsa stain, india ink, and kinyoun stain
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what are stains for parasites?
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wet mount, trichrome, modified trichrome, giemsa, and modified acid fast
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what are the two methods of direct antigen testing and what antigens due they test for?
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latex agglutination (bacterial antigens of CSF and fungal antigens). Enzyme immunoassays (bacterial antigens, bactrerial toxins, fungal antigens, parasitic antigens, viral antigens, and chlamydial antigen).
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what useful data is evidence of a positive blood culture?
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microorgs identity (if it is one that will infect blood), presence of more than a single blood culture positive for the same micro-org, and growth of the same micro-org as that found in the blood from another normally sterile site.
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what are the orgs that almost always represent true infection from blood?
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S. aureus, E. coli, P. aeruginosa, S. pneumoniae, and Candida albicans
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what are bugs that have special media requirements and what are they?
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Legionella pneumphila - charcoal yeast agar. Bordetella pertussis - Bordet Gengou or Regan Lowe. E coli O157 - MacConkey with sorbitol. Neisseria gonorrhoeae - Mod Thayer martin or NYC agar.
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what are the no grow organisms?
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Treponema pallidum and Mycobacterium leprae
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once the bugs are cultured, how can you test to see what they are?
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spot testing, batteries of biochemical tests, or molecular hybridization
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How are disk diffusion (Kirby Bauer) antimicrobial susceptibility tests performed and interpreted.
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The disks are put on the agar and the zone closest to the disk has the highest drug concentration. Results reported as susceptible, intermediate or resistant
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what is an example of a gradient diffusion antimicrobial susceptibility test?
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E-test
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what are the methods of detecting mycobacterial disease? Id-ing species?
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skin test, microscopy and acid fast stain, culture (can take up to 6wks), and direct amplification of nucleic acids. Morphology, biochem rxns, analysis of cell wall lipids, nucleic acid probes, nucleic acid sequencing
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what are techniques used to ID parasites?
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culture, microscopy, antigen detection, antibody detection
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what should be reported in parasite lab work?
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genus and species, quantity, and life cycle stage
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what two infections must be diagnosed by serology?
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HIV and Treponema pallidum
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