title: Detection and genetic characterization of β-lactamases in Prevotella intermedia and Prevotella nigrescens isolated from oral cavity infections and peritonsillar abscesses.
abstract: A prospective analysis on β-lactam resistance mechanisms and β-lactamase prevalence was conducted on Prevotella intermedia and Prevotella nigrescens recovered from patients with chronic periodontitis and peritonsillar abscesses. Both phenotypic and genotypic methods were performed to characterize the β-lactamases, their coding genes and their genetic contexts. Overall, β-lactamase production was observed in 64% (16/25) P. intermedia and 23.8% (5/21) P. nigrescens (p < 0.01). Besides higher β-lactamase production rates were observed in P. intermedia (8/16) than in P. nigrescens (2/16) recovered from chronic periodontitis, almost all isolates from peritonsillar abscesses were producers (8/9 and 3/3, respectively). cfxA, but not cepA and cblA, was detected in those isolates, which were previously categorized as β-lactamase producers. CfxA producing isolates displayed higher β-lactam MICs than non-producers in both species. The most frequent allele was cfxA2, followed by cfxA3 and a new allelic variant named cfxA6. The analysis of the downstream flanking region in the three cfxA variants revealed the association with mobA of Tn4555, suggesting their localization in a mobilizable element. β-lactam resistance and cfxA carriage prevalence seems to be not only related to the bacterial species but also to the infection site.
authors.affiliation: Laboratorio de Microbiología, Hospital Alemán, Av. Pueyrredón 1640, Ciudad Autónoma de Buenos Aires, Argentina. Electronic address: lfcanigia@labdl.com.ar.
authors.forename: Liliana
authors.initials: L
authors.lastname: Fernández-Canigia
authors.affiliation: Cátedra de Microbiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Daniela
authors.initials: D
authors.lastname: Cejas
authors.affiliation: Cátedra de Microbiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Gutkind
authors.affiliation: Cátedra de Microbiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Marcela
authors.initials: M
authors.lastname: Radice
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016866:Bacteroidaceae Infections / Q000453:epidemiology / Q000382:microbiology*; D005260:Female; D023061:Gene Order; D005838:Genotype; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D000039:Peritonsillar Abscess / Q000453:epidemiology / Q000382:microbiology*; D015995:Prevalence; D018713:Prevotella intermedia / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D045242:Prevotella nigrescens / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D011446:Prospective Studies; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; C462979:cfxA protein, Prevotella; D001618:beta-Lactamases
keywords: Periodontitis, β-lactamases; Peritonsillar abscesses; Prevotella intermedia; Prevotella nigrescens; cfxA