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Micro Exam 1
Info for Micro Exam 1
Question | Answer |
---|---|
Zoonoses | Infections in humans that originate in animals. |
Epidemic | Incidence of disease in higher prevalence than normally expected. |
Pandemic | An epidemic of larger regional areas of infection (or a widespred epidemic) |
Morbidity | Complications of the disease |
Mortality | Amount of death caused by a disease |
Attenuated | Disease is altered in such a way that the organism is weakened so it cannot cause disease |
Virulent | Any pathogen that can get past host defenses and cause disease. |
Prokaryote | Single-celled organism without membrane-bound nucleus or other membrane-bound organelles |
Eukaryote | Cells containing structures with membrane enclosed organelles and nucleus. |
Epigenetic | genetic DNA of cell. |
Plasmid | Pieces of RNA residing separate of the genetic DNA. |
Pathogenic | Can cause disease |
mutualism/symbiosis | Mutually beneficial relationship between organisms where one lives in/on the other and both benefit. |
Parasitism | One-sided beneficial relationship where one organism exclusively benefits. |
Obligate Pathogen | Always causes disease. |
Opportunistic Pathogen | Anything that can cause disease when conditions are right. |
Halophile | Like to grow in and sometimes even require high contents of salt |
Flagella | Structure that provides a means of locomotion |
Bacterial Chemotaxis | Movement system that allows organisms to move towards nutrients. |
Pili | Usually involved in adherence. Looks like the cilia in lungs (little hairs) and is often found in gram negative bacilli. |
Endospore | Inracellularly formed spore that can be retained after death and remain viable. |
Commensal Microorganism | One or both (host and/or microorganism) benefit from symbiosis |
Endogenous Microorganism | An organism that has a source within the body |
Exogenous Microorganism | An organism that has a source not within the body |
Bacterial Toxins | Molecules from microorganisms that are toxic and can cause pathology. |
Disinfection | Destruction/ removal of pathogens by physical or chemical methods. |
Sterilization | Destruction of all microorganisms in or on something |
Disinfectant | Chemical agent used to destroy pathogens or inhibit their growth and viable activity. |
Antisceptic | Aolution that kills/inhibits pathogens on skin or other tissues. |
Bacteriocidal Agent | kills bacteria |
Microbacteriostatic/Bacteriostatic Agent | inhibits the growth, reproduction, metabolism of bacteria but does not kill them. |
What are the steps in gram staining? | Smear, Fix, Primary Stain, Mordant, Decolorize, Counterstain. |
How is a gram stain fixed to the slide? | The smeared slide is flooded with methanol for one minute and allowed to air dry. |
How is the primary stain applied to a gram stain? | After the fixative dries, flood the slide with crystal violet for one minute and then rinse it with water until the water runs clear. |
How is the primary stain locked into the gram positive cells in gram staining? | Once the primary stain has been rinsed from the slide, flood the slide with gram's iodine (mordant) for one minutes and then rinse with water until the water runs clear. |
How is the purple color removed from gram negative cells in gram staining? | Once the iodine has been rinsed from the slide, run 95% ethanol over the slide until no color comes off the slide anymore (no longer than 10 seconds though) and immediately rinse the slide with water. |
How are the gram negative cells stained pink in gram staining? | Once the decolorizer is rinsed, flood the slide with safranin for 30 seconds and then rinse the slide until the water runs clear. Once this dries (can pat it dry with bibulous paper) analyze it under a microscope noting morphology and color. |
Why do gram positive cells stain purple? | Gram positive cells have thicker peptidoglycan layers which the Iodine-bound crystal violet cannot easily be washed from by the ethanol. |
Why do gram negative cells stain pink instead of purple? | Gram negative cells have thinner peptidoglycan layers so the crystal violet can be washed out of the cells by the ethanol so there is no crystal blue left in the cell and only safranin is left at the end of the process which appears pink. |
What is the sequence of bacterial growth? | Lag phase, Log phase, stationary phase, and decline (death) phase. |
What is the lag phase of growth? | This is the first phase of bacterial growth when bacteria are starting to establish colonies. |
What is the log phase of growth? | this is the second phase of bacterial growth where they are growing exponentially in or on their substrate. |
What is the stationary phase of growth? | This is the third phase of bacterial growth where the bacterial colonies neither grow more or die off. |
What is the decline or death phase of growth? | The decline phase is when the bacteria are dying off because they have used up all the available resources. |
What are the types of sterilization? | Heat, Gas, Radiation, Ultrasonic waves, Filtration |
What is dry heat used to sterilize? | anything that will not melt like glassware. |
What is gas used to sterilize? | Large items like beds and large medical equipment. |
What is radiation used to sterilize? | very small areas of microorganism. |
What are ultrasonic waves used to sterilize? | |
what is filtration used to sterilize? | This is used in labs and operating rooms to filter air before allowing it into the community or hospital air. |
What are the two types of heat used for sterilization? | Dry heat and autoclaving |
What is autoclaving used to sterilize? | media, liquids, instruments, and infectious medical waste. |
What bacteria are virulent because of their capsulation? | MRSA, S. aureus, group B Strep (S. agalactiae), S. pyogenes, |
What is the relationship between beta lactamase and beta lactamase inhibitor drugs? | Beta-lactam antibiotics bind to the penicillin binding protein to inhibit the cell wall synthesis. Beta-lactamase destroys beta-lactam so that this feature does not occur. In response, beta-lactamase inhibitors were created. |
What are the standard media used at Augusta Health's Microbiology lab? | Blood Agar Plate (BAP), Chocolate, and Macconkey (MAC) |
What is significant about the Mac plate? | It is selective for gram negative organisms and differentiates lactose fermentors. |
what is Mannitol salt agar used for? | Selective differentiation of staph |
What order should plates be set up? | Plating should be performed from least specific to most specific. (BAP, Choc, Mac) |
What plate is taken out of the normal setup for urines? | urines are performed on the normal plates except the Choc (done on BAP and Mac) |
What setups require Thayer Martins added to? | Genital setup is performed on BAP, Choc, Thayer Martin, and Mac plates. |
What media are added and removed for stool cultures? | Add HEKT plates and selenite broth, remove Choc plates |
What is added to the normal media in a anaerobe setup? | A second BAP is placed in an anaerobic bag (bag requires to plates at Augusta's Micro lab). |
What is added to the fluids other than CSF plating? | thio broth |
What is removed from CSF plating? | No Mac is plated for CSF. |
What organisms (that we've studied) are catalase positive? | Staphylococcus, Micrococcus, |
what organisms (that we've studies) are catalase negative? | streptococcus, enterococci species. |
What is Toxic Shock Syndrome? | this is a condition that was rarely seen with tampons and caused by S aureus. Can also be seen with strep infections typically following wounds. |
What is the mode of action for Beta-lactams? | Inhibit the cell wall synthesis, (bactericidal) |
What is the mode of action for beta-lactamase inhibitors? | inhibits the bacteria that cleave beta-lactam rings so that beta-lactam antibiotics are effective. |
What is the mode of action for aminoglycosides? | inhibit protein synthesis at the 30S ribosomal subunit (bactericidal) |
What is the gas mix in Ambient air? | 21% O2, 0.03% CO2, 78% N2, and a mix of others |
What is the gas mix in CO2 incubators? | 15-20% O2, 5-10% CO2, and then a mix of N2 and others |
what is the gas mix in Microaerophilic atmosphere? | 5% O2, 10% CO2, 85% N2 |
What is the gas mix in anaeroic atmospheres? | 85% nitrogen, 10% hydrogen, 5% CO2 |
which specimen sites are normally sterile? | CSF, Lower respiratory tract, urine, urethra, cervix, prostate, and middle/inner ear are all normally sterile. |