Micro Exam I – Lectures 1-3 – Flashcards
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| What is the study of the occurrence, distribution, & control of disease? |
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| Epidemiology |
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| Define prevalence vs. incidence. |
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| Prevalence - Snapshot in time - how many cases currently. Indicdence - Number of cases over a period of time. |
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| Define mortality, morbidity, comorbidity. |
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| Mortality - incidence of death. Moribidity - incidence of disease - fatal and non-fatal. Comorbidity - other diseases that infect as a result of the 1st disease. |
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| Define endemic, epidemic, pandemic. |
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| Endemic - constantly present, low morbidity. Epidemic - High numbers but localized. Pandemic - an epidemic that's spread to the whole world. |
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| Define virulence, pathogenicity, infectiousness. |
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| Virulence - ability to cause disease. Pathogenicity - ability to cause disease. Infectiousness - ability to cause infection. |
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| T/F Reservoirs must be living objects. |
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| False, soil, bedding, surgical instruments can be reservoirs. |
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| What is the prodromal period of infection? |
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| Mild signs/symptoms. Occurs before accute period. |
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| Describe primary/secondary/tertiary prevention. |
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| Primary - Prevention. Secondary - Diagnose and treat early. Tertiary - Reduce negative impacts of established disease. |
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| What is a carrier? |
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| Subclinically infected ind. that spreads the disease - acts as a reservoir. Can be chronic - carry disease despite no symptoms, or naturally resistant to it (Typhoid Mary). |
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| What is the iceberg effect? |
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| By the time you start to see deaths, you have many more cases that aren't sick yet. |
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| What is the diff. between Direst host-to-host and Indirect host-to-host transmission? |
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| Indirect uses vector, inanimate objects, water; direct is thru the air or direct contact. |
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| What is a nosocomial infection? |
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| Hospital acquired infection. Many are opportunistic due to comp. immune pts. |
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| BEINGS is what? |
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| Major risk factors for disease. Biological/Behavioral Environment Immuno factors Nutrition Genetics Services. |
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| What is the proper way to write genus/species? |
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| Italics (or underline), capitalize first word, lower second. |
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| What does strepto/staphylo mean? |
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| Strepto - chains, staphylo - clusters. |
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| What is cocci/bacilli? |
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| Colli - round, bacilli - rod. |
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| Which type of media allows many to grow, but some look different? |
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| Differential. |
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| What part of a gram + cell stains? |
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| Cell wall. |
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| What is an F plasmid? |
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| Fertility - codes the genes to make pili - which allows for gene transfer. |
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| What is a glycocalyx? |
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| Just outside the cell wall - helps in protection from phagocytes. Also helps form biofilms. |
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| T/F a pili is a gram-negative bacterial appendage that are used to adhere to animal cells. |
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| False - that's a fimbriae. |
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| T/F a pili is used for chromosome transfer. |
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| True. |
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| What is inside of an endospore? |
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| DNA and part of cytoplasm. |
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| T/F Only gram - cells make endospores. |
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| False - only gram + does. |
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| What is serotyping? |
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| Distinct variations w/in a subspecies of bacteria. |
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| What are the 4 phases on a bacterial growth curve? |
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| Lag, Log, Stationary, Death. |
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| T/F Transduction is transferring of DNA from one bacteria to another via a virus. |
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| True. |
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| T/F Transformation is swapping genes over a pili. |
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| False - this is conjugation. |
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| What is transformation? |
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| Taking up naked DNA from the env. and incorporating into your genome. |
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| What are jumping genes? |
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| Transposons. Sequences of DNA that can move to new positions in the genome. |
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| Describe a plasmid. |
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| DNA molecule, separate from the chromosomal DNA. Circular and often DS. Non-essential but often advantageous. |
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| What bacteria is typically on your skin? |
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| Staphs - skin is acidic, can also activate CMI. |
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| Describe the flora of the lungs. |
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| Strep. pneumonia.Defenses are cilia, mucus. |
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| T/F Men are more likely to get UTIs. |
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| False - Urethra of women is much shorter. |
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| What is LD50? |
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| Dose needed to kill 50% of animals in a study. Low LD50 = more virulent. |
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| T/F Attenuation means dead. |
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| False, it's just less virulent. This is used in vaccines. |
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| What are 2 aspects of invasiveness? |
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| colonization and invasion. |
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| What is an exotoxin? |
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| Secreted. Breaks down the ext. env. |
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| Give some examples of exotoxins. |
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| Hemotoxin (break down RBCs), A-B toxins. |
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| What is an endotoxin? |
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| Not secreted - just part of the cell. |
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| T/F LPS is an endotoxin. |
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| True. Part of the cell wall. |
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| What is an enterotoxin? |
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| Exotoxin in the intestines. |
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| What is a pathogenicity island? |
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| A group of genes that can be on a plasmid or main chromosome. Code for a group of things that make them more virulent. Ex. exotoxin & capsule. |
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| How are pathogenicity islands acquired? |
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| Horizontal gene transfer. |
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| T/F Endocarditis and Oral Sterp are 2 examples of organisms that make biofilms. |
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| True. |
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| T/F Antiseptics are for use outside the body. |
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| True. |
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| Give examples of an antisectic? |
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| Mouth wash, Soap, EtOH, Triclyosan, Chlorhexidine, H2O2, |
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| What is the difference between a sterilant and a disinfectant? |
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| Sterilants kill everything, disifenctans kill most microbes. |
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| What are indicators for high level sterilization? |
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| Spores - Bacillus and clostridium. |
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| What is an indicator for medium level sterilization? |
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| Mycob. Tb. |
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| What are indicators for low level sterilization? |
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| Viruses. |
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| T/F Quaternary ammonium is a good disinfectant. |
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| Not true. It is a low level one, not good at killing naked viruses. |
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| How does H2O2 work? |
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| Oxidation. Allows it to destroy a wide range of pathogens. |
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| T/F H2O2 has a short cycle time. |
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| True - as low as 28 mins for high concentrations. |
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| Describe what bleach is used for. |
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| Disinfectant - diluted and can kill Mycob. TB, inactivate prions. It will kill many but not all spores. |
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| T/F Leave bleach to soak for 15 mins to disinfect. |
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| False -- 20 mins. |
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| How does heat work? |
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| Penetrates and coagulates proteins. Good at penetration - Dry is worse than moist. |
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| T/F Ethylene oxide is good at penetration. |
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| False - it's a gas - used on medical equipment/instruments. Only works on the surface. |
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| T/F Gluteraldehyde is a sterilizing agent. |
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| True - as long as you let it soak in long enough. 22 hours. |
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| What are temperature and pressure levels for an autoclave? |
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| 121 C 15 psi, 15 min. |
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| What is the indicator typically used for autoclaves? |
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| Bac. stearothermophilus. |
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| T/F prions are removed w/ filtration. |
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| False. |
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| When is filtration used? |
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| For liquids that will be damaged by heat, irradiation or chemical sterilization. Can remove bacteria and viruses if the pores are small enough. |
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| When is radiation used? |
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| For heat-sensitive products. It's a cold process. |
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| T/F Radiation has deep penetration power. |
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| True. Sterilization can be achieved in densely packed material of any geometry. |
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| Which microscopy is used on live specimens? |
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| Phase contrast. |
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| What allows us to see viruses? |
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| EM - TEM and SEM. |
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| T/F Gram staining is a differential stain. |
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| True. Allows you to differentiate. |
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| What color does TB stain in an acid fast test? |
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| Pink. Otherwise it's blue. |
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| What is used in fluorescent staining to give the specimen a staining? |
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| Antibody. |
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| What are the 4 types of culture media? |
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| Enriched, Selective, Differential, Specialized. |
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| What color does a alpha hemolytic organism appear on a differential agar? |
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| Green. |
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| What color does a beta hemolytic organism appear on a differential agar? |
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| Beta is clear/yellow. |
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| What color does a gammy hemolytic organisms appear on a differential agar? |
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| No change - no hemolysis occurs. |
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| What factors influence success of a culture? |
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| Biology of the organism (ex. extremophiles like hotsprings), site of infection - how hard is it go get, Immune response, Media. |
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| What is a copy machine for DNA called? |
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| PCR - make copies - amplifies a single or a few copies thousands/millions of times. |
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| What is RFLP? |
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| Cut DNA, put it in a gel, and you get a fingerprint. |
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| What is used for RFLPs? |
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| Restriction enzymes. |
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| What is DNA Hybridization? |
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| Allow you to look for certain DNA in a sample. |
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| What is using DNA probes to look for DNA in a sample called? |
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| In situ hybridization. Ex. scanning for a virus in a solid tumor. |
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| What is the theory behind a serological diagnosis? |
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| Inject a mouse, collect the B cells, fuse them w/ a tumor cell. Then screen 1000s of fused cells looking for Abs. |
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| What is being tested for in a serological diagnosis? |
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| Antibodies. |
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| What is a precipitaiton test? |
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| Test for antigen/antibody in body fluids by the degree of precip. that occurs in gel/solution. Low sensitivity b/c a large amt of antibody and antigen are needed. |
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| What is an agglutination test? |
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| A particle is coupled w/ a reagent antigen or antibody. If the tgt antibody or antigen is present, it cross links and agglutination occurs. |
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| T/F agglutination test are less sensitive and slower than other tests. |
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| False - they are more rapid typically, but still less sensitive. |
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| T/F Agglutination test can determine serotypes of some bacteria. |
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| True. |
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| What is FLOW cytometry? |
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| Cells are suspended in a stream of fluid and a detection apparatus counts them. Allows for analysis of many parameters at once. |
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| T/F Flow cytometry is used for diagnosis of blood cancers. |
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| True. Also used for research/clinical. |
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| What is an ELISA? |
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| Uses an antibody to look for an antigen. Put viral proteins in a well, add patient serum, if it binds then test is positive. |
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| What is a Western Blot used for? |
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| HIV - run proteins on a gel from the HIV virus, along w/ patient antibodies. |
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| What are pathignomonic symptoms? |
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| symptoms that indicate a certain disease - Koplic spots, pseudomembrane on the tonsils. |
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| What do Koplic spots indicate? |
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| Measles - a pathagnomonic symptom. |
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| What does idiopathic mean? |
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| We don't know the cause. |
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| What does Iatrogenic mean? |
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| Came from a health care setting. |
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| What is the lowest concentration of an antimicrobial that will inhibit growth of an organism called? |
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| MIC - Minimum Inhibitory Concentration. |
