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24 Cards in this Set
- Front
- Back
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typical sources of specimens
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blood, urine, feces, abscesses, wounds, throat.nasal swabs, genital samples
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medical term for bacteria in the blood
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bacteremia
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medical term for bacteria in the urine
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bacteriuria
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BSL-1
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few safety controls; open lab bench, non-pathogenic organisms, limited access
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BSL-2
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can have open bench, but gloves, lab coat, eye protection required; used for moderate pathogens
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BSL-3
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designated for pathogens; organisms manipulated in biological safety cabinets; room under slight negative pressure; extensive filtration of air
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BSL-4
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used for life-threatening pathogens that can be transmitted by aerosols; pressurized suits for workers; Ebola, Marburg virus
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differential media
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includes compounds that allow visualization of certain biochemical pathways and products
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selective media
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contains substances that inhibit growth of certain types of bacteria
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three common methods used to measure minimum inhibitory concentration of an antibiotic
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1)minimum inhibitory concentration (MIC) using tube dilution assay (takes different dilutions of antibiotic). MIC is the lowest [ ] of antibiotic that inhibits growth. The lowest MIC is the most effective antibiotic
2) Disk diffusion assay 3) Etest |
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Disk diffusion assay
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-pure culture is spread on plate
-disks containing different antibiotics are placed on plate -higher concentration close to the disk -low antibiotic concentration far from disk |
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Etest
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MIC is read form the edge of the clear zone using the scale on the strips. Look at the zone of inhibition: large zone of inhibition=more sensitive to antibiotic
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antibody titer
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-anitbody concentration
-technique involves making serial dilutions of a patient's serum and determining the highest dilution at which the antigen-antibody interaction can be observed |
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Mantoux skin test
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-because of immune system memory, antibodies resulting from previous exposure to pathogens can be detected from the reaction on the skin. this test is a commonly used TB test today
-considered positive in an person if bigger than 15mm |
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What happens to a Mantoux skin test in an HIV/immunocompromised patient
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+ TB if diameter bigger than 5 mm
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What happens to healthy individuals with exposure history/risk factors and Mantoux skin test
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+ TB if diameter bigger than 10mm
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two types of antibodies used for diagnostic procedures
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-Polyclonal antibodies
-Monoclonal anitbodies |
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Polyclonal antibodies
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many types of antibodies to many antigens are produces by B-cells
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Monoclonal antibodies
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a single type of antibody may by a single B cell hybridoma clone
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how are monoclonal antibodies made?
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-a single antibody-producing B-cell is isolated, fused with an immortal cell line, resulting in a hybridoma which produces a single antibody. Resulting cell line can produce antibodies specific to one eptitope indefinietely
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neutraliztion and precipitation antigien-antibody reactions are used for what
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neutralization and precipitation
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neurtalization
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biological activity of antigen is blocked; snake antivenom, bacterial antitoxins
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precipitation
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antibodies have 2 variable binding sites-can create networks of an insoluble antigen-antibody complex
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what is an immunodiffusion assay and what can it detect
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-a test that can be used with monoclonal or polyclonal antibodies
-Gel agar test, takes antigens A, B, and C and reacts them with antibody S -the [ ] of antigen antibody is highest at the wells and decreasees radially from there. The white precipitate results from the antigen-antibody complex -The precipitation line occurs where the [ ] of antigen and antibody are equivalent |
