Module 40Understand how clinical samples can be obtained and from whereWhat are the typical sources of specimens-Blood-Urine-Feces-abscesses and wounds-throat / nasal swabs-genital samplesBe able to state the medical terms for bacteria in the blood and urine- Bacteria in the blood: bacteremia or viremia - In the urine: bacteriuriaKnow the Biosafety levels for laboratories working with pathogens- BSL 2, 3, 4- NOT 1Describe how growth-dependent methods are used for diagnosticsBe able to discern the difference between differential and selective media- Differential - induces compounds that allows visualization of certain biochemical pathways and products - gives indicator- Selective - contains substances that inhibit growth of certain types of bacteriaDescribe the three common methods used to test sensitivity of a pathogen to an antibiotic1. MIC - minimum inhibitory concentration - tube dilution to find lowest concentration of an antibiotic that will be effective2. Disk Diffusion Assay - pure culture spread on a plate then disks containing different antibiotics are placed on a plate (does not give numerical MIC) "kiby bauer test"3. Etest - MIC is read from the edge of the clear zone using the scale on the strips (get numerical value)Recognize that the detection of infections can be performed by measuring antibodies in patient’s serumDefine an antibody titer and how it changes during the course of an infectious disease-concentration of antibodies in someone's blood-goes up and then down through out course of diseaseHow is a Mantoux skin test performed and how is it interpreted- inflammatory response to injection of a purified antigen under the skin- testing of previous exposure or current infection with Mycobacterium tuberculosisUnderstand how purified antibodies can be used for diagnostic tests to detect a pathogenDefine serology use of antigen-antibody rxns to detect: 1. antigens in a clinical specimen 2. antibodies in patient's blood (determine antibody titer)Describe what an epitope isIs the part of an antigen that is recognized by the immune systemUnderstand how agglutination assays are used to detect antibodies or antigens from a patientperformed in tubes or on slides- binding of a soluble antibody w/a particle or cell - bound antigen to produce viable aggregation if that antigen is present ex. aggultination of blood cell is blood typing Understand direct and indirect - direct - use antibody to test for antigen from patient- indirect - use antigen to detect antibody from patient- sandwich - another strategy to detect specific antibodies from patient- combination - two types of tests in one kit: test for both antibodies to antigen and antigen from a single patient sampleKnow how PCR is used for diagnostic testingKnow how PCR can be used to identify pathogen DNA in a patientprovide diagnostic primers to pcr rxn that will give specific double stranded dna product ONLY if there is a pathogen dna in patient sample. must exactly pair to produce productBriefly describe what qPCR is and how detects diagnostic pcr productsrequires:1. pcr thermocycler2. flourescent probe included in rxn3. rna from pathogens for reverse
View Full Document
Unlocking...