New Identification Scheme for Anaerobes

Recent studies at the University of GIFU in Japan have resulted in the development of a completely new identification scheme for non-sporing anaerobes using M W & E's Microring® AN.

Gram-negative anaerobic rods are found in more than half of clinical specimens containing anaerobes. Although difficult to perform precise identifications, in practice most groups can be presumptively identified from their antibiotic susceptibility profile, which is the basis of the Microring® AN test scheme.

Microrings® are unique filter paper ring devices. Microring® AN has 6 tips, each loaded with a different antibiotic. Each tip acts in effect as a single disc because of the isolating hydrophobic barrier which is integral to the main ring.

In the recent studies, an increased concentration of bacterial suspension was used, with altered zone sizes being assigned to resistant, intermediate and sensitive categories. The new scheme allows identification for 24 species or closely related groups.

A flow chart is also available allowing the scheme to be linked in with other simple tests (such as bile sensitivity, and urease) for the identification of further organisms such as Capnocytophaga and Bilophila. The flow chart can be downloaded from M W & E's website or click here for the full brochure on Microrings and Rapid Strip Tests.


References
1. Watanabe, K. & K. Tanaka , 2006, presentation at 17th Annual Meeting of Japanese Society for Clinical Microbiology, Yokohama.
2. Watanabe, K. & K. Tanaka , 2006, presentation at 19th Annual Meeting of Rapid Method Microbiology, Matsuyama
3. Sutter, V.L., & S. M. Finegold, 1971, Applied Microbiology 21:13 - 20
4. Leigh, D. A., & K. Simmons, 1977, J. Clin. Path., 30, 991-2
5. Peach, S., 1975, J. Clin. Path., 28, 388-91
6. Moore, H. B., Am. J. Med. Tech., 47, 705-12
7. Willis, A. T., 1977, Anaerobic Bacteriology: Clinical & Laboratory Practice, 3rd Edition, Butterworth & Co. (Publishers) Ltd., London
8. Willis, A. T., & Phillips, K. D., 1983, Anaerobic Infections. Public Health Laboratory Service, Monograph Series, 3, 2nd Edition, HMSO, London