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a type of electromagnetic energy that travels in waves and can be classified as either UV-A (longest wavelenghts), UV-B (medium) and UV-C (short)
how does UV light impact bacteria?
cannot survive UV-C rays; causes thymidine dimers to form in bacterial DNA
results for organisms & temperature
P. fluorecens = psycrophile, B. subtilis = mesophile, B. stearothermophilis = thermophile
results for organisms & pH
A. faecalis = alkalinophile, E. Coli = neutrophile, S. Cerevisae = Acidophile
results for organisms & UV exposure
E. coli barely survived beyond the 1 minute mark; B. Subtilis was much more resilient
the antimicrobial susceptibility test
a test examining the effectiveness of various antibiotic and chemotherapeutic agents.
zone of inhibition
a measurable area devoid of growth due to the effectiveness of a disinfectant or antiseptic
the kirby bauer method
uses a mueller hinton plate to streak bacteria then stamp via dispensor various antibiotics to determine their effectiveness
which bacteria were examined in the antibiotics and antiseptic/disinfectant labs?
S aureus & P aerigenosa
results of the antiseptic/disinfectant lab
S Aureus (+): relatively affected by lysol & iodine; very affected by peroxide & formaldehyde; almost resistant to isopropyl and phenol; P aeriginosa (-): relatively affected by lysol & iodine; very affected by peroxide & formaldehyde (moreso than aureus), almost resistant to isopropyl and phenol
results of the antibiotic lab: Gram positives
S aureus + B Subtilis: P10 was highly/moderately effective since it targets cell wall peptidoglycan; CIP5 was moderately effective; GM10 affected S Aureus the least & RA5 affected B subtilis the least
results of the antibiotic lab: Gram negatives
E Coli + P aerigenosa: completely resistant to P10 (peptidoglycan attack), CIP5 was most effective; p aeriginosa completely resistant to E15
which antibiotics were studied in lab?
gentamicin, ciprofloxacin, rifampin, sulfisoxazole, chloramphenicol, erythromycin, penicillin, tetracycline
a structure within penicillin that beta-lactamase can break, which some bacteria have, rendering it ineffective
either alpha (partial, green), beta (complete, clear) or gamma (no change); the break down of red blood cells, in this case as a result of microbial activity
throat & nose culture procedural steps
swab the body part and streak a quadrant (blood for throat, mannitol for nose), then carry it over for a full quadrant streak and incubate it; looking for beta hemolysis of throat and yellow of nose
the camp effect
the way that bacterial polypeptides react with s. aureus to promote/facilitate beta-oxidation; tested on s aureus and s pyogenes on a blood agar
optocian vs. bactracian tests
alpha hemolysis on blood plate of strep pneomo and strep mitis vs. beta hemolysis on blood plate of s agalactiae and s pyogenes
results of throat & nose cultures
some alpha hemolysis (not strep strep) and some staph but not yellow so no pH change for nose
results of the mannitol experiment with s aureus and s epidermidis
s aureus turned yellow (+, low pH) an s epidermidis did not change (-)
results of the camp effect
agalactiae had a very clear improvement in beta-hemolysis as it approached s aureus; pyogenes did too, though it's uncharacteristic for it to be this good
results of optocian vs. bactracian tests
mitis was negative while pneumo was positive; pyogenes was positive while agalactiae was negative; positive indicates a susceptibility, negative indicates a resistance
purple broth experiment: procedure
innoculate purple lactose, sucrose & dextrose tubes w/ E coli, E aerogenes, P vulgaris & durham tubes; incubate overnight & observe color changes; yellow w/ bubble = fermentation & gas production (A/G); yellow w/o bubble = fermentation w/o gas (A/-); purple w/o bubble = no fermentation (-/-)
methyl red experiment: procedure
innoculate MRVP broths with E coli & E aerogenes, incubate overnight; divide each tube in half & add 3 drops methyl red to one of each (red = mixed acid fermentation, nothing = nothing), then add .6mL of 15KOH + 15Napthol to the other 2 (red = acetoin +, nothing = acetoin -)
catalase experiment: reagents, experiment
hydrogen peroxide, smear a slide then add H2O2 and look for bubble production (catalase presence) ---> e coli = negative, b subtilis = positive
oxidase experiment: reagents, experiment
dry slide?; apply one bacterium to each square of a dry slide and watch for color change (blue = cytochrome oxidase --> e coli slow & minimal, p aerigenosa blue/positive, p vulgaris nothing/negative)
nitrate reduction test: experiment & results
innoculate nitrate broths w/ durham rods with bacteria and incubate; observe gas production in tube (denitrification: e coli); add A & B and observe color change to red (nitrate to nitrite +), otherwise add a pinch of Zn to catalyze the reaction further (red = no nitrate reduction)
citrate experiment: reagents, experiment
innoculate a simmons citrate tube with bacteria and incubate; blue or growth (vulgaris) = citrate utilized; no color change or growth (e coli) = no citrate utilized
starch hydrolysis: reagents, experiment
iodine; streak half a labeled starch plate with each bacterium and incubate overnight, cover with iodine and if it clears around growth (subtilis) it's positive for amylase
urease experiment: reagents, experiment
urease; innoculate broths with bacteria and incubate; pink = positive (vulgaris)
SIM experiment:reagents, experiment
Kovac's reagent; innoculate SIM tubes with bacteria and incubate overnight; if black sulfur reduction via cystein desulfhydrase (neither one); add 10 drops kovac's to test for tryptophanase (e coli)
E Coli and: sugar fermentation, MRVP, amylase, sulfide, tryptophanase, urease, citrates, nitrate reductase, catalse, cytochrome oxidase
D+/S-/L+; A-/MR+; -; -; +; -; -; ++; -; -
B subtilis and: sugar fermentation, MRVP, amylase, sulfide, tryptophanase, urease, citrates, nitrate reductase, catalse, cytochrome oxidase
N/A, N/A, +, N/A; N/A; N/A; N/A; N/A; +; N/A
P aeruginosa and: sugar fermentation, MRVP, amylase, sulfide, tryptophanase, urease, citrates, nitrate reductase, catalse, cytochrome oxidase
N/A, N/A, N/A, N/A, N/A, N/A, N/A, +-, -, +
E aerogenes and: sugar fermentation, MRVP, amylase, sulfide, tryptophanase, urease, citrates, nitrate reductase, catalse, cytochrome oxidase
D+/S+/L+, A+/MR-, N/A, -, -, N/A, N/A, N/A, N/A, N/A
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