Microbiology pt 1 – Flashcards
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| What does staining bacteria help us determine? |
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| the shape |
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| What is the most useful staining technique? |
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| gram staining |
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| What color is gram +? Gram -? What are these colors based on? |
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| Gram += blue Gran -=red **based on the cell wall** |
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| Is the gram + wall thick or thin? What does it contain? |
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| -very thick -containts teichoic acid |
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| Are gram + wall susceptible to antibiotics? How many layers does it have? |
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| -vunerable to pennicillins and lysozyme -has 2 layers |
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| Does gram+ have a high lipid count? Periplasmic space? Entotoxins? |
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| -low lipid count -no periplasmic space or entotoxins |
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| What is the cell wall like with gram - bacteria? |
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| -very thin -3 layers |
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| What does the cell wall gram - bacteria have? Does it have lipid content? |
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| -murein lipoprotein -high lipid count |
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| Does gram - bacteria have periplasmic space and porin channels? What does the outer membrane contain? |
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| -yes -endotoxn(lipid A) |
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| Are gram - bacteria succeptible to antiobiotics like pennicillin or cells like lysozyme? |
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| no |
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| What kind of stain does myobacteria require? |
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| acid-fast stain |
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| What disease does myobacterium cause? |
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| tuberculosis, a bacterial infection |
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| What kind of microscopy does spriochetes require? |
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| dark field microscopy |
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| Most disease-causing organisms are what? |
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| -gram - rods -gram - pleomorphic bacteria |
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| What are the 8 exceptions that cause disease that are not like other bacteria? |
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| -2 gram + cocci -4 gram + rods -1 gram - cocci -1 gram - spiral shaped organism |
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| What are the 2 gram + cocci that are an exception? |
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| strep and staph |
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| What are the gram + rods? |
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| -bacilis -clostridium -cornebacterium -listeria |
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| What is the 1 gram - cocci? |
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| nesseria |
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| What is the 1 gram - spiral shaped organism? |
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| spriochete |
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| How are gram + cocci usually arranged? |
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| in chains or pairs |
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| Are steptococcus catalase negative or positive? |
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| catalase negative |
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| What are the 3 categores of strept based on? |
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| ability to hemolyse RBCs |
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| What are the 3 categories of strept? |
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| -Beta-hemolytic(completely lyse) -Alpha-hemolytic(partially lyse) -Gamma-hemolytic(unable to lyse) |
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| What are the different groups of beta-hemolytic strep calld? What are they? |
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| -Lancefield groups -groups A-U |
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| Which lancefield group is among the most important to humans? |
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| group A |
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| S.pyrogens produce what? |
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| -streptokinase -hyaluronidase **help it spread** |
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| What is hyaluronidase necessary for? |
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| invading tissue during spread of infections |
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| Why is group A so causitive for maladies such as: strep throat, ohygenic infections, tonilitis, scarlet/rheumatic fever? |
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| because of their ability to adhere to pharyngeal epithelium |
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| What is the causitive agent for rheumatic and scarlet fever? |
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| strept |
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| What is rhematic fever? |
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| inflammatory disease caused by untreated strept infection that can involve hearts, joints, brain, etc |
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| Does the viridans group of strept have a lancefield group? |
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| no |
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| What is viridis latin for? Why is it called this? |
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| -green -because it has a green tint when it is cultured |
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| Most of the viridans group is... |
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| alpha-hemolytic |
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| Where does the viridans group of strept normally inhabit? |
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| the nasopharynx and gingival crevices |
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| What is a member of the viridans group that causes caries? |
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| s. mutans, produces glycans which causes acid and caries |
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| How does S. Mutans process sugar? |
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| 1.metabolize sucrose to lactic acid 2.also produces dextrans from sucrose(sticky to allow bacteria to adhere) 3.produces lactic acid from other sugars |
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| What is it a combination of that produces caries? |
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| plaque and lactic acid |
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| Is S. mutans associated with periodontal disease? |
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| no |
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| What allows bacteria to adhere to endocardial surfaces? |
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| dextran |
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| What is the only sugar that s. mutans converts to dextran? |
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| sucrose |
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| S. mutans is responsible for caries where? |
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| pits and fissures |
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| S. sobrinus is respinsible for caries where? |
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| smooth surface caries |
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| Where does S.salivarius colonize? |
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| in the oral tissue |
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| What does S. Mitis cause? |
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| endocarditis |
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| Where is S.sanguis found? |
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| plaque colonization and endocarditis |
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| What is S.Salivarious associated with? |
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| the tongue |
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| What are the most common aroebic organisms implicated in facial cellulitis? |
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| strept viridans |
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| What makes S.pneumoniae very resistant and destructive? |
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| polysacchride layer that it is encapsulated with |
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| Is staph pennicillin resistant? |
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| yes |
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| Is staph: MobileSpore formingShape? |
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| -non-mobile -nonspore forming -spherical gram + cocci |
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| How is staph arranged? |
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| in grape-like clusters |
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| What is a typical lesion of staph? |
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| abscess |
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| Is staph anerobic? |
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| no, faculative areobic |
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| What are 2 significant endotoxins of staph aureus? |
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| -coagulase -hyaluronidase |
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| What are the pigmented compounds produced by s. aureus? |
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| carotenoids |
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| What are the protein produced by s.aureus called? What do they do? |
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| -leukocidins -destroy phaygocytes(make pus) |
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| What is the most resistant disease causing organism? |
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| MRSA(methicillin resistant s. aureus) |
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| What does bacillus cause? What is it? |
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| -gram + rod -causes anthrax and food poisoning |
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| What does clostridium cause? What is it? |
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| -gram + rod -causes tetanus, gangrene, food poisoning, antibiotic resistant pseudomembraeous colitis |
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| What is corynebacterium? What does it cause? |
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| -gram + rod -causes diptheria |
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| What does listeria have? What does it cause? |
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| -has endotoxin -causitive organism for meningitis and sepsis |
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| What is nesseria? What does it cause? |
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| -gram - cocci -causes meninigitis and gonorrhea |
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| What are spirochetes? What do they cause? What is it associated with? |
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| -gram - spiral shaped organism -cause syphilis, lyme disease -in associated with NUG/NUP |
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| What is special about lactobacillus? |
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| can derive lactic acid from glucose which creates an acidic enviornment (aciduric) |
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| What does lactobacillus produce that is like dextran? |
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| lexan |
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| What is lactobacillus associated with? |
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| advanced/deep carious lesions and aciduric |
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| What are actinomyces? What caries are they seen in? |
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| -gram + rods, form large pop of oral flora -root caries |
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| Do the phases of bacteria growth related to each bacteria or the group? |
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| the group |
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| What are the 4 stages of bacteria growth? |
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| 1.lag phase 2.logarithmic/exponential phase 3.stationary phase 4.death phase |
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| What happens in the lag phase? |
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| growth is slow, bacteria aclimate to enviornment |
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| Is metabolic activity increased during the lag phase? |
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| no |
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| Which phase of growth are bacteria most prone to physical and chemical agents? |
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| logarithmic/exponential phase |
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| What can bacteria be classified based on? (2) |
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| 1.oxygen metabolism 2.carbon and energy sources |
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| What is the most commonly used source of energy for humans and bacteria? |
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| glucose |
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| What can oxygen metabolism form? (3) |
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| 1.hydrogen peroxide 2.superoxide radicals 3.hydroxyl radicals |
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| What are the 3 enzymes that bacteria posses to break down oxygen products? |
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| 1.catalase(breaks hydrogen perox) 2.peroxidase(breaks hydro perox) 3.superoxide dismutase(breaks superoxide radical) |
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| What are obligate aerobes? What are some examples? |
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| -like us, use krebs cycle and glycolsis -nesseria, pseudommonas, legionella, mycobacterium |
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| What are faculative anaerobes? examples? |
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| -aerobic but can grow in absence of oxygen using fermantation -staph, listeria, actinomyces, most gram - rods |
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| What are microaerophilic bacteria? |
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| -uses formantation -can tolerate LOW levels of oxygen b/c they contain superoxide dismutase -Strept., spirochetes, camphylobacter |
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| Which bacteria is implicated in pregnancy gingivitis? |
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| camphylobacter |
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| What are obligate anaerobes? |
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| -can't stand oxygen -prevotella, porphy g. |
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| What is prevotella most often associated with? |
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| preg ging, facial cellulitis, NUP/NUG |
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| What allows porphymonas gingivalis to adhere to epithelial and tooth surfaces? |
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| surface fimbrae |
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| What does porphymonas gingivalis produce? What is it? |
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| collagenase, an enzyme that breaks down collagen |
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| What are most fungi? |
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| obligate aerobes |
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| What does fungi require for nutrition? |
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| organic source of carbon |
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| Fungi are BLANK, bacteria are BLANK. |
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| Fungi are eukaryotes, bacteria are prokaryotes. |
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| What does fungi cell walls contain that makes it insensitive to antibiotics that inhibit peptidoglycan synthesis? |
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| chitin |
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| What does the cell membrane of fungi contain? |
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| ergosterol and zymosterol |
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| Which drugs is used topically to treat oral candidiasis? |
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| nystatin |
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| Which drug is used systemically to treat candidiasis? |
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| fluconazole |
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| What may systemic infection of candida albicans involve? |
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| -lungs -kidneys -heart -esophagus |
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| Do viruses have energy? |
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| no, they have to have a host cell |
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| What is the protein core of viruses called? |
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| capsid |
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| What is the outer lipid bilayer of viruses called? |
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| envelopes |
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| What is a complete virus particle called? |
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| virion |
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| Are viruses big or small? |
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| small |
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| What are the 4 possible outcomes once a cell has been infected by a virus? |
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| 1.death 2.transformation 3.latent infection 4.chronic slow infection |
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| What can RNA genomes be? |
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| -similar to mRNA(positive) -template for production(negative) |
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| What are some examples of RNA viruses? |
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| -hep A -rhino -flu -measles, mumps -rabies -HIV |
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| Do DNA viruses have DNA or RNA strands? |
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| both |
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| What has to be done before DNA viruses can be translated into proteins? |
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| it must be transcribed into mRNA |
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| What is the role of mRNA? |
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| translation |
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| What is transcription? |
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| from DNA-->RNA |
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| What are some examples of DNA viruses? |
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| -HPV -herpes I and II -Varicella zoster -smallpox |
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| What is the causative organism for epstein barr? |
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| herpes virus |
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| What does epstein barr cause? |
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| mono, burkitts lymphona, nasopharyngeal carcinoma |
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| How is measles spread? |
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| nasopharygeal secretions, can cross placental barrier |
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| What are the spots seen with measles? What do they look like? |
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| kopliks spots, res lesions with blue centers in the mouth |
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| What is the causitive organism for herpangina? |
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| coxsackie virus |
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| What are the RNA hepatitus viruses? |
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| hep a, c, d, e |
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| What is the 1 DNA hep virus? |
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| hep B |
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| What is the intact hepatitis B virus called? Size? |
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| -Dane particle -BIG(42 NM) |
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| What is the hep b surface antigen? What antibody confers immunity? |
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| HBsAg, Anti-HBsAg confers immunity |
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| When is a soluble component of the core(HBeAg) of HBV released? |
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| during active infection and viral growth |
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| What is the marker for active disease? |
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| HBeAg |
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| What is the HBV vaccine? Can you get HBV from it? |
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| artificial acquired active immunity, NO risk of developing HBV from it |
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| What is an example of passive immunity? |
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| gamma globulin |
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| HBsAg= Anti-HBsAg= HBcAg= HBeAg= Anti-HBeAg= |
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| HBsAg= active disease Anti-HBsAg=immune HBcAg= acute, chronic, resolving HBeAg=high infectivity Anti-HBeAg=low infectivity |
