Sequence analysis of cfxA2-like beta-lactamases in Prevotella species

Sixty-two strains of oral (32) and non-oral (30) Prevotella producing beta-lactamases were screened for cfxA by PCR, using an intragenic primer pair. All 62 were cfxA/cfxA2 positive. Fourteen of these strains, representing seven pigmented and seven non-pigmented Prevotella species were submitted to further PCR with specific primers that amplified the whole beta-lactamase structural gene (966 bp). After cloning and sequencing, the deduced amino acid sequences were compared with that of Bacteroides vulgatus CfxA beta-lactamase. All 14 sequences possessed the E272K substitution characteristic of CfxA2. CfxA sensu stricto was not observed in the present series. G83D, F/V189L, W193L and D239Y substitutions were observed more than once, without species specificity. This sequence analysis indicates that most oral and non-oral beta-lactamase-producing Prevotella isolates from French patients produce variants of the CfxA enzyme.