Anaerobic Culture, Extended Incubation

Some anaerobes will be killed by contact with molecular oxygen for only a few seconds. Overlying and adjacent areas must be carefully disinfected to eliminate contamination with indigenous flora. Ideally, pus or other fluid obtained by needle aspiration through intact skin or mucosal surface that has been cleaned with antiseptic should be collected. Sampling of open lesions is enhanced by deep aspiration using a sterile plastic catheter. Curettings of base of an open lesion are optimal. If irrigation is necessary, nonbacteriostatic sterile normal saline may be used. Lower respiratory samples must be obtained by transtracheal percutaneous needle aspiration, transbronchial biopsy, transthoracic needle biopsy, or open lung biopsy by physicians trained in these procedures. If swabs must be used, collect two; use one for Gram stain and one for culture. Anaerobic transports must be used for swabs and for aspirates. Specimens are to be collected from a prepared site using sterile technique. Contamination with normal flora from skin, rectum, vaginal tract, or other body surfaces must be avoided.

Specimens for anaerobic culture should be maintained at room temperature. Under these conditions, anaerobes will survive 24 to 72 hours when properly collected in the anaerobic transport tube. Storage of specimens in the ESwab™ transport at room temperature for greater than 48 hours may result in diminished recovery of certain anaerobic species.

Unlabeled specimen or name discrepancy between specimen and test request label; specimen not received in appropriate anaerobic transport tube; expired transport; swab not in gel transport medium or ESwab™ transport; swab not stored in oxygen-free atmosphere (any swab is suboptimal); specimen refrigerated. Note: Refrigeration inhibits viability of certain anaerobic organisms. If an unacceptable specimen is received, the client will be notified and another specimen will be requested before disposal of the original specimen. Specimens from sites that have anaerobic bacteria as indigenous flora will not routinely be cultured anaerobically (eg, throat, feces, colostomy stoma, rectal swabs, bronchial washes, cervical-vaginal mucosal swabs, sputa, skin and superficial wounds, voided or catheterized urine, ulcer surfaces, drainages onto contaminated surfaces).