Abstract
ABSTRACTPurpose The aim of this study was to identify β-lactamase-producing oral anaerobic bacteria and screen them for the presence of cfxA and BlaTEM genes that are responsible for β-lactamase production and resistance to β-lactam antibiotics.Material and Methods Periodontal pocket debris samples were collected from 48 patients with chronic periodontitis and anaerobically cultured on blood agar plates with and without β-lactam antibiotics. Presumptive β-lactamase-producing isolates were evaluated for definite β-lactamase production using the nitrocefin slide method and identified using the API Rapid 32A system. Antimicrobial susceptibility was performed using disc diffusion and microbroth dilution tests as described by CLSI Methods. Isolates were screened for the presence of the β-lactamase-TEM (BlaTEM) and β-lactamase-cfxA genes using Polymerase Chain Reaction (PCR). Amplified PCR products were sequenced and the cfxA gene was characterized using Genbank databases.Results Seventy five percent of patients carried two species of β-lactamase-producing anaerobic bacteria that comprised 9.4% of the total number of cultivable bacteria. Fifty one percent of β-lactamase-producing strains mainly Prevotella, Porphyromonas, and Bacteroides carried the cfxA gene, whereas none of them carried blaTEM. Further characterization of the cfxA gene showed that 76.7% of these strains carried the cfxA2 gene, 14% carried cfxA3, and 9.3% carried cfxA6. The cfxA6 gene was present in three Prevotella spp. and in one Porphyromonas spp. Strains containing cfxA genes (56%) were resistant to the β-lactam antibiotics.Conclusion This study indicates that there is a high prevalence of the cfxA gene in β-lactamase-producing anaerobic oral bacteria, which may lead to drug resistance and treatment failure.
Highlights
The human mouth harbours a complex microbial community containing aerobic and anaerobic bacteria
%DFWHULDO UHVLVWDQFH WR ǃODFWDP DQWLELRWLFV has been attributed to resistance genes, present on chromosomal or plasmid DNA that can be transferred between commensal and pathogenic bacteria30
ZHUH WKH PRVW SUHYDOHQW ǃODFWDPDVH producing bacteria and 43% and 75% of these bacteria, respectively, carried the cfxA gene. 7KHVH ¿QGLQJV DUH VLPLODU WR WKH UHVXOWV REWDLQHG in the North American, French, and Norwegian population9,13
Summary
The human mouth harbours a complex microbial community containing aerobic and anaerobic bacteria These bacteria cause polymicrobial opportunistic oral and extra oral infections. Anaerobic bacteria such as Porphyromonas gingivalis, Treponema denticola, Fusobacterium nucleatum, Prevotella intermedia, Campylobacter rectus, Prevotella nigrescens, Parvimonas micra, and Eubacterium nodatum cause periodontal diseases, odontogenic abscesses, orofacial infections, and have been implicated in brain abscesses. Anaerobic bacteria such as Porphyromonas gingivalis, Treponema denticola, Fusobacterium nucleatum, Prevotella intermedia, Campylobacter rectus, Prevotella nigrescens, Parvimonas micra, and Eubacterium nodatum cause periodontal diseases, odontogenic abscesses, orofacial infections, and have been implicated in brain abscesses26,31 Some of these bacteria are isolated from sputum. Studies have shown that many oral anaerobic bacteria have developed UHVLVWDQFH WR ǃODFWDP DQWLELRWLFV EHFDXVH RI WKH SURGXFWLRQRIǃODFWDPDVHV12. Studies have shown that there is a high prevalence of cfxA genes responsible for WKH ǃODFWDPDVH SURGXFWLRQ LQ Prevotella and
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