Term
| Methods of identifying unknown microbes fall into three categories |
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Definition
| Phenotypic, Genotypic, Immunological |
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Term
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Definition
| Microscopic morphology , Macroscopic morphology, Physiological/biochemical characteristics,Chemical analysis ; observable microscopic and macroscopic characteristics ;1. Immediate direct examination ; Microscopic – differential and special stains – Gram, DFA, direct antigen testing ; 2. Cultivation of Specimen -- Colony appearance, growth requirements, appropriate media 3. Biochemical testing --Physiological reactions to nutrients as evidence of the absence or presence of enzymes |
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| Physiological/biochemical characteristics |
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Definition
| detection of presence or absence of particular enzymes or metabolic pathways |
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Definition
| analyze specific chemical composition; cell wall peptides, cell membrane lipids |
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Term
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Definition
| fresh or stained microorganisms from specimen; shape, size, stain reaction, cell structures |
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Definition
| – colony appearance; texture, size, shape, pigment, growth requirements |
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Term
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Definition
| genetic make up ; 1. DNA analysis --Hybridization- Probes complementary to the specific sequences of a particular microbe ; 2. PCR -DNA and RNA analysis -Ribosomal RNA (Comparison of the sequence of nitrogen bases in ribosomal RNA) ; Assess genetic make-up, Culture is not necessary, Precise, automated methods, quick results |
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Definition
| Specific antibodies are used to detect antigens--Easier than testing for the microbe itself |
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Term
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Definition
| Sampling body sites or fluids for suspected infectious agent ; Results depend on specimen collection, handling, transport, and storage ; Aseptic procedures should be used |
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Term
| Overview of Laboratory Techniques |
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Definition
| 1. Routes taken in specimen analysis ---Direct tests (microscopic, immunologic, or genetic) --- Cultivation, isolation, and identification (general and specific tests) ; 2. Two categories of results –Presumptive -Confirmatory, 4. Miscellaneous tests -Phage typing -Animal inoculation -Antimicrobial sensitivity |
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Term
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Definition
| serology; antibody-antigen reactions ------1. Serology – in vitro diagnostic testing of serum -Antibodies have extreme specificity for antigens , 2. Visible reactions include precipitates, color changes, or the release of radioactivity, 3. Tests can be used to identify and to determine the amount of antibody in serum – titer |
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Term
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Definition
| 1. Agglutination testing – antibody cross links whole-cell antigens, forming complexes that settle out and form visible clumps -Blood typing, some bacterial and viral diseases 2. Precipitation tests – soluble antigen is made insoluble by an antibody -VDRL - Most precipitation reactions are done in agar gels |
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Term
| The Western Blot for Detecting Proteins |
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Definition
| 1. Electrophoretic separation of proteins, followed by an immunoassay to detect these proteins 2. Highly specific and sensitive 3. Sites of specific antibody binding will appear as a pattern of bands 4. Second test used to verify HIV status |
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Term
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Definition
| 1. Lysin mediated hemolysis. , 2. Steps of test A) Test antigen reacts with test antibody, B) Contents of tube from (1.) are mixed with sheep RBCs -Complement used up in first stage, no hemolysis -Unfixed complement, hemolysis |
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Term
| Fluorescent Antibody & Immunofluorescent Testing |
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Definition
| 1. Fluorescent antibody -Monoclonal antibody labeled by a fluorescent dye 2. FABs can be used for direct or indirect testing |
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Term
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Definition
| 1. Extremely sensitive to detect trace antigens and antibodies, 2. Radioimmunoassay (RIA) – antigens or antibodies labeled with radioactive isotopes 3. Enzyme-linked immunosorbent assay (ELISA) – enzyme-antibody complex produces a colored product when an enzyme-substrate reaction occurs –Indirect -Capture |
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Term
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Definition
| Antigens are introduced directly into the body to determine the presence or absence of antibodies -Tuberculin skin test, allergy testing |
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Term
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Definition
| 1. Viruses present special difficulties because they are not cells , 2. Viruses are labor intensive to culture in the laboratory |
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