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46 Cards in this Set
- Front
- Back
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`Biosafety Level |
Classification that laboratories have according to their contamination potential and are designated as BSL-1 through BSL-4 |
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What is the difference in BSL levels ? |
•Mostuniversity labs have BSL-1 and BSL-2 for teaching and research •BSL-3 andBSL-4requires pressurized labs and suits |
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What is HAIs (Health Care Associated Infection) ? |
- A local or systemic infectionacquired at a healthcare facility - 1.7 million patients acquire HAI(1/20 patients) - HAI are acquired from patients,hospital personnel etc. |
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Common HAIS |
- Blood stream infections - Urinary tract infections - Respiratory tract infections - Surgical Site infections |
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Why are the incidents of HAIs so high? |
Because of bacteria resistant to antibiotics |
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Prevention of HAI |
Involves cooperation between the health care facility infection control team and the facility staff. Management of incoming patients at the point of entry, they should be isolated to avoid spread of pathogen. |
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Specificity |
The ability of the test to recognize a single pathogen |
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Sensitivity |
Defines the lowest number of the pathogen or the lowest amount of the pathogen product that can be detected |
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General- purpose media |
Supportgrowth of most aerobic and facultatively aerobic organisms |
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Enriched media |
Contain specific growth factorsthat enhance growth of selected pathogens |
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Selective media |
Allow some organisms to grow whileinhibiting others (due to presence of inhibitory agents) |
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Differential media |
Allowidentification of organisms based on their growth and appearance on the medium |
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Disc diffusion test |
- Standard procedure for assessingantimicrobial activity - Agar media is spread evenly withculture of bacteria |
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Etest |
Is anon-diffusion-based technique that employs a preformed and predefined gradientof an antimicrobial agent immobilized on a plastic strip (flower test) |
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Why is antimicrobial susceptibility testing important?
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These test are used to monitor control of known pathogens, to track emergence of new pathogens and to identify the emergence of antibiotic resistance at the local level |
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Minimal inhibitory concentrations (MIC) |
Measures the smallest amount of agent needed to completely inhibit the growth of the tested organism in vitro |
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Direct agglutination |
- Results when soluble antibodycauses clumping due to interaction with an antigen that is an integral part ofthe surface of a cell or other insoluble particle |
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Passive agglutination |
Theagglutination of soluble antigens or antibodies that have been adsorbed orchemically coupled to cells or insoluble particles (e.g., latex beads, charcoalparticles) |
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Hemagglutination |
Used for human blood typing |
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Direct fluorescent method |
Theantibody targeted against the surface antigen is covalently linked to thefluorescent dye |
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Indirect fluorescent method |
Thepresence of a nonfluorescent antibody on the surface of a cell is detected byuse of a fluorescent antibody directed against the nonfluorescent antibody |
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Applications of fluorescent methods |
- Ifthe pathogen contains surface antigens reactive with the antibody, the pathogencells fluoresce - Fluorescent antibodies can beapplied directly to infected host tissues, allowing for rapid diagnosis - Fluorescent antibody assays arealso used in the diagnosis of noninfectious diseases (e.g., malignant cells) |
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Direct EIA |
Detectionof antigen |
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Indirect EIA and Sandwich EIA |
Detection of antibody |
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Combination EIA |
Combination of direct EIA andsandwich EIA |
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Enzyme immunoassay (EIA) |
- Very sensitive immunological assay |
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Rapid tests |
- Reagents are absorbed to supportmaterial - Body fluid is applied to thesupport matrix -Matrix contains a soluble antigenconjugated to a colored molecule (chromophore) -Matrix also contains a line offixed antigen -Antibodies bind to antigens - Color forms when concentration ofchromophore gets high enough |
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Immunoblots |
- Electrophoresis of proteins,followed by transfer to a membrane and detection by addition of specificantibodies - Methods detectantibodies to specific antigens or the antigens themselves |
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Nucleic acid methods for identification of infectious disease agents |
Quantitative PCR Qualitative PCR Reverse Transcription PCR |
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Penicillin |
- Discovered by Alexander Fleming - Effective primarily againstgram-positive bacteria (gram negative are impermeable0 -Target cell wall synthesis |
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Growth Factor Analogs |
Arestructurallysimilar to growth factors but do not function in the cell Analogs similar to vitamins, aminoacids, and other compounds |
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Quinolones |
Antibacterialcompounds that interfere with DNA gyrase (e.g., ciprofloxacin) |
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Antibiotics |
Arenaturally produced antimicrobial agents. Fewer than 1% are clinically useful |
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B-Lactam Anibiotic |
- One of the most important groups ofantibiotics of all time - Include penicillins andcephalosporins |
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Cephalosporins |
- Broader spectrum of activity thanpenicillins - Resistant to enzymes that destroy β-lactam ring |
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Aminoglycosides |
Areantibiotics that contain amino sugars bonded by glycosidic linkage |
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Macrolides |
Containlactone rings bonded to sugars |
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Nonnucleoside reverse transcriptaseinhibitors (NNRTI) |
Binddirectly to RT and inhibit reverse transcription |
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Tetracyclines |
Widespreadmedical use in humans and animals and contain napthacene ring system |
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Nucleoside reverse transcriptaseinhibitors (NRTI) |
HIVAntiviral agents |
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Protase inhibitor |
- Bind to the active site of HIV proteases - Inhibit the processing of large viralproteins into individual components |
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Fusion inhibitors (entry inhibitors) |
- Prevent viruses from successfully fusingwith the host cell (T lymphocytes) |
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Neuraminidaseinhibitors |
Tamiflu,Relenza |
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Antimicrobialdrug resistance |
- The acquired ability of amicroorganism to resist the effects of a chemotherapeutic agent to which it isnormally sensitive |
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Atleast five reasons that microorganisms are naturally resistant to certainantibiotics |
•Organism is impermeable toantibiotic •Organism can inactivate theantibiotic •Organism may modify the target ofthe antibiotic •Organism may develop a resistantbiochemical pathway •Organism may be able to pump outthe antibiotic (efflux) |
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R-plasmids |
Site where mostdrug-resistant bacteria isolated from patients contain drug-resistance genes |
