Anaerobic Culture
Specimens are to be collected from a prepared site using a sterile technique. Contamination with normal flora must be avoided. Some anaerobes will be killed by contact with oxygen for only a few seconds. Ideally, pus obtained by needle aspiration through intact surface, which has been aseptically prepared, is put directly into anaerobic transport media. Sampling of open lesions is enhanced by deep aspiration using a sterile plastic catheter or needle. Curettings of the base of an open lesion may also provide a good yield. If irrigation is necessary, non-bacteriostatic sterile normal saline may be used. Pulmonary samples may be obtained by transtracheal percutaneous needle aspiration or by physicians trained in this procedure. If swabs must be used, two should be collected; one for culture and one for Gram's stain.
Clostridial Infections
The common clostridial pathogens of domestic species are briefly outlined below. Fresh affected tissue is especially important since the Clostridia rapidly invade tissues after death.
Blackleg - Submit infected tissue, i.e. heart, diaphragm or muscle. We do a Gram stain, fluorescent antibody test and sometimes culture. Be sure to send fixed tissue for histology. DO NOT send liver.
Enterotoxemia - Submit fresh intestinal contents or ligated small intestine. Refrigerate if there is delay.
Tetanus - Submit infected tissue from the injury site. We make smears from the lesions and look for the characteristic tennis-racket shaped spores. Sometimes, early in the clinical history, serum from the infected animal will produce symptoms of tetanus when injected to mice. We will do this for special cases.
Botulism - Submit suspected food or forage and blood/serum from affected animal(s). Please note that the tests are performed on mice, but animals are not always available in stock.
The following are clinical symptoms suggestive of anaerobic infection:
- Foul-smelling discharge
- Location of infection in proximity to a mucosal surface
- Necrotic tissue, gangrene, pseudomembrane formation
- Gas in tissues or discharges
- Presence of "sulfur granules" in discharges (actinomycosis)