Lab practical Flashcards
pork worm
Trichinella spiralis
*Causes trichinosis when undercooked (or raw) pork is ingested. Although symptoms may vary, nausea, diarrhea, vomiting, and abdominal discomfort may occur. More severe symptoms include: aching joints, muscle pain, itchy skin, and headaches.
pin worm
Enterobius vermicularis
Pinworm infections can cause itching around the anus and difficulty sleeping as a result of the female pinworm laying her eggs. Transmission is common in young children
MAC (MacConkey’s agar)
*Selective- contains bile salts that inhibit gram + bacteria, while growing gram – species to grow
*Differential- bacteria that are coliforms and ferment lactose (sugar) will grow pink on the media. If the Gram – does not ferment lactose, the colonies will be off white, cream colored
MSA (Mannitol Salt agar)
*Selective- the mount of salt (sodium chloride 7.5-10%) in the media will kill gram – species, making it selective for gram positive bacteria that can withstand moderate amounts of salt such as Staphylococcus aureus.
*Differential- S. aureus will have yellow agar around its growth because it ferments mannitol, while other staphylococci, do not ferment mannitol (pink) (Staphylococcus epidermidis)
Tryptic Soy agar (TSA)
will show bacteria growth and perform a plate count to determine whether there’s enough bacteria to be considered an UTI
Sugar fermentation- glucose, lactose, mannitol
Yellow/bubble = + acid/+ CO2 gas
Yellow/no bubble = + acid/- CO2 gas
Red/no bubble = - acid/- CO2 gas
Nitrate reduction test
Red = positive nitrate reductase
Yellow = negative nitrate reductase
Reagent = Nitrate test solution
Methyl red (MR) test - 30 degrees Celsius
Red = + mixed acid fermentation
Yellow = - mixed acid fermentation
Reagent- methyl red
Vogues- Proskauer (VP) test - 37 degrees Celsius
Red = +2,3 butanediol fermentation
Yellow or clear = -2,3 butanediol fermentation
Reagent = Barritt’s reagents (VP-A and VP-B)
Urease test
Orange (no color change) = - urease
Bright pink = + urease
Indicator = phenyl red
H2S production
No black (red or yellow) = -H2S production
Black = +H2S production
No reagent
Indole test
Red oily layer = + indole production
Yellow oily layer = - indole production
Reagent = Kovac’s reagent
Citrate utilization test
Green (no color) = -citrate utilization test
Blue = +citrate utilization test
Indicator: Bromothymol blue
Phenylalanine deamination test
Yellow (no change) = - phenylamine deamination
Green = + phenylamine deamination
Reagent = ferric chloride 10%
Mesophiles
20-50 degrees Celsius. Optimally 37 degrees Celsius
Optimum growth temperature
temperature where the bacteria have the fastest rate of binary fission; generation time is the fastest
Psychrophiles
-15 – 20 degrees Celsius. Optimally 0 degrees Celsius
Thermophiles
45-80 degrees Celsius
Hyperthermophiles
67-105 degrees Celsius
Prodigiosin
red pigment protein produced by Serratia marcescens
Spectrophotometer
quantitatively measure bacteria growth
Antimicrobial sensitivity testing
determination of which abx to use
Beta-hemolysis
complete lysis/clear zone around the colony; Ex: Streptococcus pyogenes
Alpha-hemolysis
partial hemolysis/ greenish zone around colony; Ex: Streptococcus pneumoniae (usually NF)
Gamma-hemolysis
no hemolysis/ remains red (usually NF)
Bubbling is a
+ catalase result (staph)
no bubbling is a
- catalase result (strep)
Halophiles
bacteria capable in high salt concentrations
Osmophiles
tolerate hypertonic solutions and more than 1 solute
what is the most halotolerant bacteria?
Staphylococcus aureus
