Identification and typing of Pasteurella multocida: a review.

Pasteurella multocida is an important pathogen of many avian species. This review critically examines recent developments in new-generation tests for the identification and typing of this bacterium. Two polymerase chain reaction (PCR) tests have been reported for P . multocida. Both tests show promise as diagnostic tests that could be considered for routine use. However, there have not yet been effective evaluation studies that examine the ability of these new tests to distinguish between P. multocida, both typical and atypical isolates, and the range of other P. multocida-like organisms found in avian species. One PCR, reported by Townsend et al. (Journal of Clinical Microbiology, 36, 1096-1100), has been the more fully evaluated and is the better choice, at this stage, for laboratories considering the use of PCR technology for detection of P. multocida. An important point is that the PCR tests have been validated by use on pure cultures or enrichment broths - not on direct examination of body tissues. To date, there have been five different technologies used to type avian P. multocida: restriction endonuclease analysis (REA), ribotyping, pulsed field gel electrophoresis, repetitive extragenic palindromic-PCR (REP-PCR) and multi-locus enzyme electrophoresis (MLEE). The methodology underlying these techniques is briefly explained and the performance of these techniques with regards to the typing of avian P . multocida is critically examined. For smaller laboratories that are investigating outbreaks of fowl cholera, it would appear that REA and REP-PCR are the typing methods of choice. For central reference laboratories that are considering studies of large collections of isolates, MLEE supported by two of the other methods would appear the most suitable techniques.