Microbiology Sampling

Guidelines for Microbiology Samples and Submissions

• You may always call the laboratory for assistance with sample collection and transport.
• In general, keep samples for microbiology testing cold. Exceptions include the following:
  • specimens for dermatophyte culture, blood culture, cerebral spinal fluid, joint fluid, and specimens for which only anaerobic culture will be requested.
• Submission of tissues and fluids are preferable to the use of swabs for sample collection. When swabs must be used, use appropriate transport media, and submit multiple swabs per site if possible.
• Anaerobic transport systems are appropriate for most bacteria (facultative and obligate anaerobes).
• It is very important that specimens for bacteriology stay moist. Swabs and small pieces of tissue may be placed in a small volume of saline or may be transported in a bacterial transport system. It is difficult to recover tissue specimens from transport systems designed for swabs, so wider-neck systems like Port-a-Cul tubes are preferred.
• Samples in formalin, alcohol, EDTA or heparin are never appropriate for culture.
• MRSA/MRSP and Strep equi screen tests should be selected when the submitter only wants to rule/in that pathogen. If the diagnosis is open, an aerobic culture should be selected instead, which will include looking for any likely pathogens in the specimen.
• Let the laboratory know if you have particular bacterial organisms on your differential diagnosis list. Some organisms, such as Nocardia sp., can require prolonged incubation times that can be accommodated if we know a particular organism is a differential diagnosis for a case.