Bacteriology Sample Submission
Used correctly, microbiologic cultures can identify a significant pathogen, or pathogens, and contribute key information towards a diagnosis. However, improperly collected microbiologic cultures can result in growth, or overgrowth, of contaminants which can lead to erroneous diagnoses and result in inappropriate antimicrobial therapy. The importance of proper transport medium, proper transport environment, and proper preservation techniques cannot be overemphasized.
The value of microbiologic culture depends to a considerable degree on the care and skill with which cultures are taken, stored and shipped to the laboratory. Learn about how our new MALDI-TOF mass spectrometer provides results faster than ever!
We offer the following guidelines to optimize these procedures:
- Collect samples aseptically.
- Place samples in an appropriate transport system (sterile plastic bags or containers, bacterial transport systems). Ensure transport systems are sealed tightly and are leak-proof. Do not use plastic gloves or sleeves.
- In general, it is advised to keep specimens cold from the time they are collected until they arrive at the laboratory. Specimens should be shipped in insulated containers with a sufficient number of ice packs to last 48 hours.
Note: Specimens for anaerobic culture, dermatophyte culture, blood culture, as well as cerebral spinal fluid and joint fluid, should be maintained at room temperature to preserve sample integrity.
- When collecting large numbers of samples (e.g. >30 milk samples for mastitis diagnosis or fecal samples for Johne's disease diagnosis), please call the laboratory for scheduling. This permits the laboratory to have personnel and media available for prompt processing.
- Where there is any doubt as to what samples to collect and how to transport them - - CALL THE LABORATORY FIRST!
Label all samples with:
- Client and animal information
- Type or location of sample (feces, small intestine, uterine swab)
Completely fill out accession form including:
- Signalment (age, breed, and sex)
- Clinical signs and duration
- Location of sample site, if not indicated by sample type (swabs)
- Treatments associated with case
- If possible, specify the test(s) you want done, and the pathogens you suspect, particularly in the case of specimens with normal bacterial flora (feces, intestinal contents, skin, or oral mucus membranes). If we don't know what you're looking for, we may not inoculate the proper media to find it.
- Please note: Information provided to the lab is critical for proper case set-up and interpretation as the same bacterial species may be highly significant or a meaningless contaminant, depending on the tissue and/or species from which the sample was obtained. Also, depending on the tissue/species of origin, different culture conditions may be necessary to isolate and identify specific pathogens
- Use sterile instruments to collect samples.
- Collect other samples before opening the gastrointestinal tract.
- Tissue samples (lung, liver, spleen, kidney, etc.) should be 5 grams or larger to allow surface searing in the laboratory to reduce contaminants.
- Place each sample in a separate container to prevent cross-contamination. If the intestine is to be cultured, tie off both ends of a segment and place it in a separate container.
- Use screw top containers for fecal samples. Fecal samples should not be submitted in stoppered tubes, as fermentation will dislodge the stoppers.
- Except in the case of abortions, please separate samples that are to be examined by different laboratory sections. If a specimen is to be examined by both the virology and bacteriology sections, the specimen should be divided, each piece placed in a separate container, and labeled with the source of the tissue and the desired laboratory service.
- Require special care as they are very susceptible to oxygen exposure.
- Tissue or fluid specimens are preferred.
- If swabs are the only practical sample, the Port-a-Cul system, or similar, is preferred.
DO NOT SUBMIT DRY SWABS OR SYRINGE CAPPED NEEDLES. THEY WILL BE REJECTED FOR CULTURE.
Approximate culture times are as follows:
|Aerobic (culture and sensitivity)||2-7 days|
|Listeria spp.||7 days|
|Mycobacteria paratuberculosis (culture)|
*Note, direct PCR is recommended for this agent.
|Category||Example Product||Purpose/Function||Sample Type||Notes|
Swab Transport Systems
|Amies+/- charcoal||Suitable for aerobic culture. Improved recovery of fastidious organisms. Charcoal enhances maintenance of fastidious organisms by scavenging bacterial waste products. May have gel, sponge, or liquid in tube.|
|Stuart’s Transport System||Suitable for aerobic culture. General bacteriostatic media designed to preserve bacterial viability and reduce overgrowth. May have gel, sponge, or liquid in tube.|
|Media-free swabs (BBL EZswab)||Suitable for aerobic culture. Swab designed to preserve viability of bacteria and will not be diluted with transport media.|
|Port-A-Cul, or similar||Maintains anaerobic environment and is suitable for both facultative anaerobic (most bacteria) and strictly anaerobic bacteria. Contains pre-reduced gel media.||If anaerobic culture is needed, maintain sample at room temperature.|
|Transport system for anaerobic culture||Port-A-Cul, or similar||Maintains anaerobic environment and is suitable for both facultative anaerobic (most bacteria) and anaerobic bacteria. Systems designed for fluids, tissues or swabs.|
|Transport system for blood culture||Blood culture bottle||Nutritive support of microorganisms; contains additive to neutralize bacteriocidal components of blood and prevent coagulation.||Blood||See Blood Culture Collection for proper sample collection.|
|Transport system for blood culture||Isolator Tube||Designed for isolation and concentration of microorganisms; lyses leukocytes and erythrocytes in the blood and helps prevent coagulation.||Blood|
|Other||Sterile Red Top Tube||Sterile tube without preservatives|
|Modified Cary-Blair Transport Media||Maintains enteric pathogen viability and helps prevent overgrowth of normal flora. Media is buffered to prevent pH changes. Only add fecal material to the fill line.||Feces||Only acceptable for bacterial culture. A second specimen in clean container is needed for fecal floats and molecular assays.|
|Universal Transport Media||Maintains viruses, Ureaplasma, Mycoplasma, and Chlamydia sp. for up to 48 hours.||Urine||Not acceptable for urinalysis or PCR testing.|
|Universal Transport Media||Maintains viruses, Ureaplasma, Mycoplasma, and Chlamydia sp. for up to 48 hours|
|Clark or Weybridge Media||Aids in isolation of Campylobacter fetus subsp. venerealis from bovine reproductive tract||If testing bulls, three samples are recommended to increase sensitivity.|
|Whirl-Pak (or similar) bag||Sterile bag|
|Source||Collection Method and/or Sample||Container||Temperature Requirements|