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Because of the current concern for health care reform and the demands placed in the clinical microbiology laboratory by decreased resources, questions regarding appropriate work-up of anaerobes remains unresolved. Although anaerobes are ubiquitous, the number of anaerobes causing disease is relatively few. This article focuses on the need for isolation and identification of these anaerobes and emphasizes proper collection, culture, and identification techniques. Varying levels of expertise in isolation and identification of anaerobes are proposed, and the role of "rapid" identification kits in identification of these organisms is discussed.

The purpose of this study was to determine if enzyme profiles of anaerobic bacteria, obtained with the API ZYM system, are sufficiently distinctive and reproducible to merit future development of the system and an expanded data base for the four major groups of clinically encountered anaerobes. Of the total 155 clinical isolates and reference strains that were tested, 88% had distinctive patterns. It was possible to differentiate between 89% of the anaerobic gram-negative bacilli, 64% of anaerobic cocci, 100% of anaerobic gram-positive non-sporeforming bacilli and 100% of the Clostridium spp. using only the API ZYM plus Gram reaction, morphology and relation to oxygen. Overall reproducibility for 1,330 enzyme-substrate reactions was 97%. It was concluded that the API ZYM could be a practical system for rapid identification of clinical anaerobe isolates provided that an expanded data base is developed and that certain additional recommended tests are used.

Diabetic patients with foot infections were prospectively evaluated over a two-year period. Cultures from reliable specimens avoiding contamination with foot ulcers were obtained in 54 infectious episodes. Staphylococcus species, Enterococcus species, Corynebacterium species, and various species of Enterobacteriaceae were commonly isolated. Common anaerobic isolates included Peptostreptococcus magnus, Peptostreptococcus prevotii, and Bacteroides species. Results of cultures from 94 unreliable specimens were similar. Results of reliable and unreliable specimens obtained simultaneously in 26 patients agreed in seven (27%), but antibiotics selected for organisms isolated from unreliable specimens would have adequately covered pathogens found in the reliable culture in 24 (93%). Diabetic foot infections usually involve mixed bacterial flora, including aerobic, facultatively anaerobic, and anaerobic microorganisms. Specimens should be obtained from infected tissue that does not communicate directly with the foot ulcer if possible. If such specimens are not available, cultures of purulent exudate within the foot ulcer or soft-tissue sinuses may provide useful information on which to base decisions about antibiotic therapy. Broad-spectrum beta-lactam antibiotics or a combination of antibiotics active against facultatively anaerobic cocci and bacilli as well as anaerobes provide the best empirical antimicrobial coverage in these patients.