Exam B Make Up Material Flashcards
What is the purpose of lysis centrifugation in the clinical lab?
Lyses RBCs to increase the yield of microorganisms in primary cultures
A bacteria is found to have the mecA gene. What is the antibiotic of choice?
linezolid and daptomycin
What’s a synergistic combination of antibiotics…?
Beta lactams + aminoglycosides
A patient is founds to have recurring fevers and a bacteria is found in the patient. The patient was bit by a tick 2 weeks ago. What could the bacteria be?
Borrelia recurrentis, It is spread by ticks. Its not burgdorferi b/c there is no bullseye rash.
What organisms could be used for QC for OF test?
E. Coli for positive fermentation and Pseudomonas aeruginiosa for negative fermentation. I think Klebsiella for green b/c it is assachrolytic
What is the reagent for ONPG?
What is the reagent for the nitrate test?
sulfanilic acid (reagent A)
α-naphthylamine (Reagent B)
What kind of pigments can pseudomonas aeruginosa produce?
Pyocyanin and any other pyopigments
What is the purpose of resin in blood culture bottles?
To inactive antibiotics or medication in the blood of patients
A gran negative rod is isolated from a wound. The bacteria is able to ferment lactose, oxidase positive, and TSI: A/A no gas, no H2S
What are key differential biochemical reactions between Pseudomonas and stenotrophomonas?
A gram negative rod is isolated from a patient’s wound. It is non glucose fermenter, and produces H2S.
What are ideal CO2 levels for anaerobic bacteria’s?
5-10% CO2
What are differentiating biochemical reactions between Aeromonas and shewanella?
What are differentiating biochemical reactions between prevotella and porphyromonas?
What are differentiating biochemical reactions between bacterioides and fusobacterium?
Bacteroides has round ends while fusobacterium has tapered ends.
Bacteroides is resistant to kanamycin and colistin. Fusobacterium is susceptible to kanamycin and colistin
What bacteria is susceptible for SPS disc?
P. Anaerobius
What are visual differences in colonies between M. Hominids and U. Urelyticus?
M. Hominid -> Small pinpoint colonies that are arginine positive
U. Urealyticus -> urease +, large fried egg colonies
What syphilis tests are used to confirm infection?
FTA-ABS and TP-PA
What is the purpose of D-test in the clinical lab?
To assess if the bacteria has an inducible clindamycin resistance due to erythromycin
What are H2S positive bacteria genus?
Citrobacter, Salmonella, and proteus
What are urease positive organisms?
Proteus, Klebsiella, Serratia, and Moraxella
Uncle Pete Knitted Sweaters On Monday
What are differences between in appearance between. B. Fragility, and yersinia pestis?
B. Fragility - safety pin appearance due to vacuoles
Y. Pestis - bipolar staining
What is the appearance of yersinia enterocolitica on CIN agar?
Bull’s eye target
What does full purple on LIA mean about the bacteria?
It has lysine decarboxylase
LIA agar with K/A mean?
Glucose fermentation
What does Red slant and yellow butt mean for LIA agar?
Deamination of lysine which suggest Proteus and Providencia
What are the advantages of broth dilution?
What are disadvantages of broth dilutions?
An in oculus on MH Kirby Bauer broth with an. Equivalent to 2 MacFarland standard. Which of the choices are true?
A. Zone too large
B. Zone too small
C. Zone is correct
D. Needs longer incubation
I think B. Zone too small b/c there is more bacteria than normal.
A plate has bacteria colonies that look like bread. Crumbs. The colonies are yellow, what could this bacteria be?
Fusobacterium nucleatum
A bacteria colony is found to be black pigment. What could this bacteria be?
Peptococcus. Niger
Plate of bacteria colonies show pitted agar characteristic. What could this bacteria be?
Eikenella corrodens
What are key biochemical reactions that differentiate prevotella and porphyromonas
A bacteria growing on BAP is found to have yellow bacteria colonies that resemble ground glass. What bacteria could this be?
C. difficle
What kind of bacteria could have molar tooth colonies they are mature?
Actinomyces
What kind of bacteria could have sulfur granules?
Actinomyces
A man comes into the clinic with dysuria, discharge coming out of his penis. A closer look at the discharge has WBCs but not bacteria. What bacteria could cause this?
Lymphogranuloma venerum. If there
QC using Klebsiella oxytoca on an API strip test, shows all positive results except VP. What is the best course of action?
A. Return the api test reagent strips back to the manufacturer
B. Make new VP reagents and retest
C. Streak a new isolate of Klebsiella and retest
D. Report to supervisor about…
I think C is the correct answer. The previous colony might have been a contaminant that has the same physical characteristic as K. oxytoca. Streaking a new isolate may fix the negative VP.
How do automated incubators determine a positive culture versus a negative culture?
A change in CO2 in the culture container.
Anerobic gram negative bacteria was detected from a neck abcess. The colonies looked like bread crumbs. What are the expected biochemical test results?
A. Growth on LK laked agar
B. Positive for bile esculin
C. Susceptible to Kanamycin and colistin
D. Resistant to vancomycin and kanamycin
C. Susceptible to Kanamycin and colistin. The bacteria is most likely fusobacterium.
3 Sets of blood cultures were collected and grew the following
Set #1
Aer- s. Aureus
Ana- nothing
Set #2
Aer- S. aureus and Strep
Ana- S. aureus
Set #3
Aer- S. aureus
Ana- S. aureus and Strep
I would go with the answer choice that has Set 2 as the answer. Streptococcus is an aerobic question. It would not make sense if strep was growing in the anaerobic culture unless it was compromised.
Patient came in with a wound with dark pigment to it, what would the bacteria be
What nonspecific tests are used to monitor syphilis treatment?
RPR and VDRL
What media is used to culture leptospira?
Fletcher’s or Stuart’s media
Gram negative, oxidase positive, catalase positive, grow on thayer martin agar, DNAse positive, and assachrolytic. The colonies look like hockey pucks and slide around on the agar. What bacteria could this be?
Moraxella catarhalis
What biochemical test is used to determine if the microbe possesses tryptophanase?
Indole test.
What is the reagent used in the indole test?
Kovac’s reagent - consisting of isoamyl alcohol, para-dimethylaminobenzaldehyde, and concentrated hydrochloric acid.
In the citrate test, what is used for carbon source and what is used for nitrogen source?
Carbon source - Sodium citrate
Nitrogen source - Inorganic ammonium salts
What is the reagent used in the MUG test?
A disk containing 4-methylumbelliferyl-𝝱-D-glucuronide (MUG) to detect the presence of Beta - glucuronidase
What biochemical test is used to detect the presence of Beta - galactosidase enzyme in the microbe?
ONPG test - a positive is yellow. It uses ONPG (o-nitrophenyl-𝝱-D-galactopyranoside) that is hydrolyzed in the presence of Beta galactosidase into galactose and o-nitrophenol (both yellow colored product).
What is the ideal number of blood cultures for bacteremia and endocarditis?
3 - 5 blood cultures in 24 hours required for a correct diagnosis
What organisms may be encountered as skin contaminants at a venipuncture site?
S. epidermidis, Bacillus spp., and Propionibacterium acnes
What are 4 factors in visual observation that indicates bacterial growth?
Turbidity, hemolysis, gas production, and color change
What is the ideal number of blood cultures and time interval between blood culture collections?
At least two cultures from different sites with at least 30 minutes interval during a 24-48 hours
What are the purpose of resins in blood cultures?
Resins are added to reduce the activities of several antibiotics
What gene in Klebsiella pneumoniae is thought to be responsible for producing beta lactamase that inactivates ampicillin?
Bla (SHV) gene
Why doesn’t vancomycin work on lactobacilli and leuconostoc spp.?
They lack the appropriate cell wall precursor target
If a bacteria has the Erm gene what antibiotic resistance would they have?
Clindamycin resistance
If a bacteria has rpoB gene what antibiotic resistance would they have?
Rifampin resistance
What bacteria does rifampin increase mutations in?
M. tuberculosis which are spontaneous mutations in the rpoB gene encoding beta subunit of RNA polymerase
What is the Nagler’s test?
Test to identify organisms that have lecithinases for example C. perfringens.
What bacterias would be good QC for IMVIC tests?
E. coli, & morganella -> + / + / = / =
Klebsiella & Eneterobacter -> = / = / + / +
Note: Not K. oxytoca
What two antibiotics are synergistic?
Beta lactams and aminoglycosides
