Bact- lab manual questions

martinezdvm's version from 2015-11-11 01:52

Section 1

Question Answer
What methods are used to demonstrate fungi in body fluids, tissue, skin/hair roots?KOH (10% to break hair)
What species is the most common DERMATOPHYTE of CATS?Microsporums canis (Micro Cats)
Which fungi would you expect find in the ear of a healthy dog?Malassezia pachydermatis
Malassezia shape?Foot-print, bottle shaped
If you find large numb of yeasts in the urine of a cat w/ an in-dwelling catheter, what would u expect to find?Candida albicans (it CAN get IN w/ a Catheter)
Are sensitivity tests normally done on fungi? NO
What drug would you use to treat a candida infection?Nystatin
What conditions other than nasal aspergillosis are cased by Aspergillus?Abortion in cattle, brooder pneumonia in birds, guttural pouch mycosis in horses (among others)
Does aspergillus produce hyphae in tissues?Yes
In the case of dimorphic fungi such as Histoplasma capsulatum & Blastomyces dermatitis, what forms will you see in tissues from an affected animal?Yeasts

Section 2

Question Answer
If you suspect clostridial diarrhea in a dog, which drug would u use for tx? (caused by clostridium perfringens)Metronidazole
How does Nocardia asteroides appear in a gram stain?like a beady staining Gram + branching filament on a pink background
Case: bovine mastitis smear show Nocardia, would you use penicillin for tx?NO, use TMS or Tetracyclin instead
Case: A steer w a deep wound in the pecs due to running into a fence post. The wound is moderately infected. You see purulent material that did not grow on McConkey. What is the expected gram stain result? If you see that the colony morphology is pin-point like, what other test could you use to differentiate the species?Gram + (because these do not grow on McConkey), Can do a Catalase test to differentiate Trueperella from Erysipelothrix BUT if you look at the species affected, you'll see that Trueperella is most likely
What percentage of KOH will you use to differentiate Gram + from Gram -?3 % KOH
If the KOH test was positive? What gram stain would u expect?Gram - (the negatives are positives in KOH)
What does a + KOH test look like?A gel formation = +
What percentage of KOH would you use on a Hair sample?10% KOH (to break the hair follicle)

Section 3

Question Answer
Case: A pet hamster has pyoderma of face & limbs. There was no growth on McConkey. What species should be on your rule/out list if you see double zone hemolysis on BA?S. intermedius, S. aureus (more likely since patient is a hamster)
Follow up on hamster pyoderma case, you see that the bacteria is catalase +, coagulase + & gram +. Who is the culprit?S. aureus because S. intermedius only affects dogs
Case: Cow w chronic, subclinical mastitis on BA medium. Which species are on your top differentials if you notice Beta hemolysis?S. uberis, S. agalactiae, S. dysgalactiae
Follow up on Cow w chronic mastitis. You know bacteria is beta hemolytic, and now you see a + CAMP test. What is your diagnosis?S. agalactiae
Case: uterine swab from mare w suspected endometritis. No growth on McConkey. Likely diagnosis?Strep. equi subsps. zooepidermicus
There was a contaminant in your BA culture. The bacteria has spores, is gram + and rod shaped. What species is it? Should you conduct an Ab sensitivity test?B. cereus. No, not of significance, just a contaminant.

Section 4

Question Answer
Case: 4 yr old terrier w red eye irritation leading to raised conjunctiva. On BA: hemolysis is seen + flat shaped & non swarming colonies. McConkey looks greenish. Oxidase test +. Diagnosis?Pseudomonas (green colonies)
Follow up: Pseudomonas best tx?Gentamicin
Which organism is like to cause septicemia in calves?E. coli
How can you differentiate Salmonella from Proteus in BA?Proteus has swarming growth
How can you differentiate colonies of E. coli from Kleibsiella?Urease test (Kleib is + & E.coli is -) & Citrate test
Out of the gram - bact studied in lab, which one is most likely resistant to ampicillin & TMS?Pseudomonas
If a fecal sample from a piglet w diarrhea yield E. coli only, is it safe to decide E. coli is the cause?No, an agglutination test is necessary!
In the case of diarrhea in a puppy due to campy, what would u use for tx?Erythromycin

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