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90 Cards in this Set
- Front
- Back
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Infection control is critical and requires the proper: |
disinfectants and antiseptics |
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what is a disinfectant |
destroys most microbes on inanimate surfaces |
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what is an antiseptic |
destroys most microbes on living surfaces |
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2 critical considerations about disinfectant |
optimal conc. and optimal exposure time |
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To be used in hospital, disinfectant must pass what test? |
Use-Dilution test |
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Gene transfer occurs in what three ways |
conjugation, transduction, transformation |
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what are competent bacteria |
bacteria that can take up plasmid DNA made by exposing bacteria to specific chemicals and environmental conditions |
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parts of pGLO plasmid |
ori, araC, GFP, and bla |
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what is GFP on plasmid? |
green fluorescent protein, shows gene transcription |
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what is araC on plasmid |
DNA binding transcriptomal regulatory protein, needed for arabinose utilization |
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what is ori on plasmid |
origin of replication |
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what is bla on plasmid |
B-lactamase gene, makes bacteria resistant to -cillin and -sporin antimicrobials |
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what is an operon |
cluster of functionally related genes under control of one promoter |
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what is a promoter |
region of DNA where transcription begins |
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Result of LB plate with 100uL from tube w/o pGLO? |
growth |
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Result of LB/ampicillin plate with 100uL from tube w/o pGLO? |
no growth |
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Result of LB/ampicillin plate with 100uL from tube with pGLO |
growth |
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Result of LB/ampicillin/arabinose plate with 100uL from tube w/pGLO |
growth that glows green under UV |
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how are bacteria made competent with pGLO |
chilling in presence of Ca |
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what permits plasmid DNA to be taken up by cells |
heat shock: ice to 42C to ice |
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MPN test used for what |
Most Probably Number/Multiple Tube Fermentation test... to get total number of coliforms and E. coli |
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What is in LTB broth |
LTB=lauryl tryptose broth... lauryl sulfate inhibits growth of noncoliforms, lactose for fermentation, durham tube |
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What is in BGLB broth |
BGLB=brilliant green lactose bile broth...contains lactose, 2% bile, and Durham tube |
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What is in EC both |
E coli broth... contains lactose, Durham tube, bile salts... MUST be incubated at 45C |
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MPN formula |
MPN/100mL = 100P/(VnVa)^(1/2) |
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4 ways inhibitors work |
affect: DNA synthesis, gene expression, enzymatic activity, membrane permeability |
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characteristics of coliform (4) |
1. gram neg 2. ferment lactose 3. aerobe or facultative anaerobe 4. non-spore forming |
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purpose of MacConkey agar |
ID coliforms |
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components of MacConkey agar |
bile salts, crystal violet dye, natural red dye, and lactose |
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MacConkey results |
no growth= Gram + colorless growth = not coliform red growth = coliform |
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EMB agar purpose and what does it stand for |
eosin methylene blue, ID coliforms |
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components of EMB |
eosin y dye, methylene blue dye, sucrose, and lactose |
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EMB results |
poor/no growth = gram pos colorless growth = not a coliform pink mucoidy growth = possible coliform green/purple/metallic growth = probably coliform |
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Hektoen enteric agar purpose |
to ID Gram neg Shigella and Salmonella |
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Hektoen enteric agar components |
bile salts, sucrose, lactose, salicin, sodium thiosulfate, ferric ammonium citrate, bromothymol blue due, acid fuschin dye |
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Which enteric species can reduce sulfure |
Salmonella |
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Hektoen agar results |
no growth = Gram +, orange/yellow growth=gram neg, blue/green growth=possibly Salmonella or Shigella, blue/green growth with black precip. = Probably Salmonella |
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TSIA purpose (3) |
1. determine organism's ability to ferment 3 sugars 2. determine organism's ability to reduce sulfide 3. help differentiate between enteric bacteria such as Salmonella, Shigella, E. coli |
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components of TSIA |
sucrose, lactose, glucose, sodium thiosulfate, ferrous sulfate, phenol red |
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what is reversion (TSIA) |
glucose only fermentation + breakdown of AA to make ammonia (basic) so make of slant red again but butt is yellow |
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TSIA results |
~red slant/yellow butt = glucose only fermentation, ~yellow slant/yellow butt = glucose, lactose, and/or sucrose fermentation, ~red slant/red butt = no fermentation, AA degradation...lifting or crack of media = gas produced.... black precip = S reduction |
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blood agar purpose |
culture fastidious organisms and determine hemolytic ability |
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fastidious |
organisms that need strict physiological conditions |
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blood agar results |
greenish zone = alpha, partial full clearing = beta, total no clearing = gamma, none |
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CNA agar what does it stand for and purpose |
Colistin and Nalidixic Acid Agar, grow Gram + organisms and determine hemolytic ability |
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components of CNA agar |
very nutrient rich with sheep blood, colistin, and nalidixic acid |
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what is colistin (CNA agar) |
antibiotic against Gram -, distrupts integrity of outer membrane |
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what is nalidixic acid (CNA agar) |
disrupts DAN replication/synthesis enzymes |
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CNA agar results |
only Gram + grows green zone = a clearing = b no zone = gamma |
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MSA Agar what does it stand for and purpose |
Mannitol Salts Agar to ID pathogenic vs. nonpathogenic Staph |
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components in Mannitol Salts Agar |
7.6% salt, mannitol, phenol red... only staph can grow in hi salt and only pathogenic can ferment mannitol |
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MSA results |
poor/no growth = not Staph, yellow growth or halo = possibly S. aureus (pathogenic) red growth/no color = non-pathogenic Staph |
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DNA Hydrolysis test purpose |
to ID pathogenic Staph vs. nonpathogenic... possess DNase |
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components of DNase agar |
DNA, methyl green dye |
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DNase agar results |
green/blue color = DNase negative, zone of clearing = DNase positive |
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PYR test purpose |
to determine if organism is Gram + Streptococcus or Enterococcus by seeing if it has PYRase |
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what is PYRase |
enzyme/peptidase that degrades proteins by removing a specific AA from beginning of protein chain |
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alpha-hemolytic bacteria examples |
partial hemolytic... S. pneumonia and S. mutans |
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beta-hemolytic bacteria examples |
Group A and Group B Streptococcus GAS: Strep throat, necrotizing fasciitis GBS: bacteria from genital tract pass onto newborns at birth, can cause death or permanent brain damage |
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gamme-hemolytic bacteria examples |
E. faecalis, opportunist |
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drug of choice to treat Enterococcus |
vanocmycin |
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PYR test components |
paper with PYR PYR reagent that reacts w/PYRase end products to form red precipitate |
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Coagulase test purpose |
to determine if organism has coagulase, which indicates a pathogenic Staphylococcus |
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Two biochemical tests to differentiate between S. aureus and S. epidermidis |
MSA agar test and coagulase test |
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what is coagulase |
protein that binds to prothrombin which is involved in blood coagulation and fibrin clotting |
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Two types of coagulase tests and what do they detect |
tube= detects bound and free coagulase slide= detects bound coagulase only |
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What is bacitracin |
antibiotic secreted by Bacillus lichenformis that works against both Gram + and - organisms, targets PEPTIDOGLYCAN |
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Bacitracin resistant pathogenic bacteria include |
Streptococcus pyogenes and Staphylococcus sp. |
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What is optochin |
antibiotic w/ several side effecs of visual loss... inhibits ATP synthase... now only used for differentiation of a-hemolytic Streptococcus species |
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5 mechanisms used by antimicrobials against microbes |
1. disruption of bacterial cell wall 2. inhibition of protein synthesis 3. inhibition of nucleic acid replication 4. disruption of folic acid metabolism 5. disruption of bacteria cell membrane |
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Four main factors that influence antimicrobial susceptibility of organism |
1. type of bacteria cell wall 2. differences in metabolic pathways and/or enzymes 3.environmental bacteria reside in aerobic 4. acquisition of drug resistance |
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Kirby-Bauer method pros (2) |
quick and easy, many antimicrobials tested simultaneously |
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Kirby-Bauer method cons (1) |
does not give info on therapeutic dose (conc.) |
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E-test pros (3) |
quick and easy, many antimicrobials tested simultaneously, and approx MIC |
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E-test cons (1) |
only approx MIC |
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Tube Dilution Test pros (2) |
precise MIC, automated |
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Tube Dilution Test cons (2) |
before automation more complicated and time consuming, before automation only test single antimicrobial at a time |
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what do beta-lactam antimicrobials target |
cell wall (peptidoglycan) by stopping transpeptidase |
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mechanisms for microbes to get drug resistance (7) |
natural selection, transfer of plasmids, use of alternative metabolic pathways, changes to drug binding sites, activation of drug pump, decreased bacterial cell permeability, drug inactivation |
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what is nitrocefin |
chromogenic -sporin compound that has B-lactam ring-- used in B-lactamase test |
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what is beta-lactamase test purpose |
to determine if organism has B-lactamase |
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how long does beta-lactamase test take |
1 hr at room temp |
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B-lactamase test results |
red/pink=B-lactamase positive yellow=B-lactamase negative |
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IONIZING RADIATION example |
gamma, cannot penetrate lead |
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nonionizing radiation example |
UV light |
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three groups of UV radiation |
UVA= 300-400nm in sunlight UVB=200-300nm tanning UVC=100-200nm bactericidal |
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how does UVC cause damage |
forms thymine dimers that stop replication and transcription |
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2 mechanisms to repair damaged DNA |
photoreactivation and excision repair |
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what is photoreactivation |
use DNA photolyase to break covalent bond between thymines |
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what is excision repair |
endonuclease cuts either side of DNA strand w/dimer, helicase removes damaged piece, DNA polymerase puts in missing nucleotides, DNA ligase connects segments |
