Bacteriology & Mycology

What are reasons to submit a tissue sample?

For surgery, biopsy, necropsy (outside first, then thorax/abdomen), or abortion cases (placenta, abomasal fluid, fetal lung).

How should a blood sample be collected?

At least two samples from different veins, taken within a 24 hour period.

What kind of fluid specimens can be taken?

Urine, feces (freshly voided), eye via conjunctival swab, or to check for mastitis. Can also take joint, CSF, bronchoalveolar, nasal, or milk samples.

What is the specimen collecting procedure for superficial skin issues?

Disinfect surface with 70% alcohol, aspirate with fine needle & swab lesions.

What are the five steps of specimen submission?

1. Stage (collect early, prior to Ab treatment).

2. Site (collect from actual infection site).

3. Collect (collect tissue or fluid, never use dry swabs).

4. Label (label specimens & fill out a form).

5. Store & ship (keep chilled, except anaerobic & blood cultures, & send within 24-36 hours).

What are buffers?

Maintain the viability of organisms while in transit, using a special solution.

What kind of medium is appropriate for the following: aerobic organisms, fecal samples, toxic samples, Mycoplasma / Ureaplasma, anaerobic organisms

Aerobic: Stuart

Fecal: Cary-Blair

Toxic: Amies with charcoal

Mycoplasma/Ureaplasma: Amies without charcoal

Anaerobic: Thioglycollate

Where should aerobic or anaerobic cultures be collected?

Aerobic: urine, ears, skin, feces

Anaerobic: septic abdomen, feces, wounds

Good specimen collection for aspirates?

Remove oil, debris, resident flora around sampling site. Apply 70% alcohol with wipe, let dry & then aspirate.

Good specimen collection for blood culture?

Surgical skin prep & bottle prep (aseptic techniques),

Good specimen collection for wound sampling?

Irrigation & debridation with sterile saline, cleaning of debris, & rubbing of the wound with a swab.

How should you collect a sample for dermatophytes?

If obvious lesions: disinfect area, remove hairs & skin scales from the edges of the inflamed area.

If no obvious lesions (cats): rub area with toothbrush.

What kind of specimens aren’t appropriate for culture tests?

Unculturable pathogens, old decomposed tissue, or fecal/serum toxins. Can be tested by PCR, serology, or ELISA.