Bile

Bile is a normally sterile fluid. The preferred sample is obtained at the time of initial drainage which is often done in the radiology department.

Samples are often sent from drains that have been left in the biliary tract. The finding of microorganisms in samples from indwelling drains is much more difficult to interpret as the drains are commonly colonized with skin flora.

Setup Inoculate one drop of specimen onto each media and smear. If stent is received, “wash” the specimen in 0.5 ml of sterile saline and inoculate the media with the solution.

Direct Examination

Gram stain

Culture

Media Incubation
Blood Agar (BA) CO2, 35°C x 48 hours
MacConkey Agar (MAC) O2, 35°C x 48 hours

If sample was collected in radiology or the operating room or if anaerobic culture is specifically requested, add:

Wilkins Chalgren Agar (WC) AnO2, 35°C x 48 hours
WC Nalidixic acid – Tween 80 (NAT) AnO2, 35°C x 48 hours
WC Nalidixic acid – Vancomycin (NAV) AnO2, 35°C x 48 hours
Thioglycolate broth (THIO) O2, 35°C x 48 hours

Interpretation Examine the aerobic culture plates after 24 and 48 hours incubation and the anaerobic plates after 48 hours incubation. Any growth of Salmonella spp, S. aureus, beta-haemolytic streptococci, Streptococcus anginosus group and P. aeruginosa are significant.

For other organisms, a significant result is determined by the isolation of <2 organisms. Consult with charge technologist or microbiologist if unsure.

All non-lactose fermenters (NLF) should be screened for Salmonella spp.

Reporting

Gram stain

Report without quantitation the presence of pus cells and organisms.

Culture

Negative Report “No growth” or “Mixed faecal flora”

Positive Report Report all significant isolates with appropriate susceptibilities, without quantitation. If faecal flora is also present, report without quantitation

References H.D. Isenberg. 2004. Specimen Collection, Transport and Acceptability p. 2.1.1 – 2.1.28. In Clinical Microbiology Procedures handbook, 2nd Edition, Vol 1 ASM Press, Washington, D.C

H.D. Isenberg, 2004. Wound Cultures – Wound and Soft Tissue Cultures, p. 3.13.1.1 – 3.13.1.16. In Clinical Microbiology Procedures Handbook, 2nd Edition, Vol 1 ASM Press, Washington, D.C.

H.D. Isenberg. 2004. Culture for anaerobes p. 4.3.1 – 4.3.9 In Clinical Microbiology Procedures Handbook, 2nd Edition, Vol 1 ASM Press, Washington, D.C.