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Sequence analysis of cfxA2-like beta-lactamases in Prevotella species
Chantal Giraud-Morin1, Isabelle Madinier, Thierry Fosse
1Laboratoire de Bactériologie, Hôpital l'Archet 2, Centre Hospitalier Universitaire, 151 route de Saint Antoine Ginestière, 06202 Nice Cedex 3, France.
Abstract:
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.
Insights
Most oral and non-oral Prevotella bacteria from French patients produce variants of the CfxA enzyme, a beta-lactamase. This finding is crucial for understanding antibiotic resistance mechanisms in Prevotella species.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Prevotella species are increasingly recognized as significant pathogens in various infections.
- Beta-lactamase production in Prevotella contributes to antibiotic resistance.
- The CfxA enzyme is a key beta-lactamase found in Prevotella.
Purpose of the Study:
- To investigate the prevalence and characteristics of the cfxA gene in oral and non-oral Prevotella strains.
- To analyze the genetic variants of the CfxA enzyme produced by these Prevotella isolates.
Main Methods:
- Screening of 62 Prevotella strains (32 oral, 30 non-oral) for the cfxA gene using PCR.
- Amplification and sequencing of the beta-lactamase structural gene from 14 selected strains.
- Deduction and comparison of amino acid sequences with Bacteroides vulgatus CfxA.
Main Results:
- All 62 screened Prevotella strains were positive for cfxA/cfxA2.
- Sequencing revealed that all 14 analyzed strains possessed the E272K substitution characteristic of CfxA2.
- No CfxA sensu stricto was detected; variants of CfxA, including specific amino acid substitutions, were common and not species-specific.
Conclusions:
- The majority of oral and non-oral beta-lactamase-producing Prevotella from French patients harbor CfxA2 or its variants.
- This suggests a widespread presence of CfxA variants in Prevotella, impacting antibiotic susceptibility.
- Further research into these CfxA variants is warranted to understand their clinical implications.