Detection of cfxA2, cfxA3, and cfxA6 genes in beta-lactamase producing oral anaerobes

Abstract

Purpose 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.

Comparative Metagenomics and Network Analyses Provide Novel Insights Into the Scope and Distribution of β-Lactamase Homologs in the Environment

“…In both human and bovine feces, cfxA homologs dominated the β-lactamase gene pool, indicating a selective advantage of this gene in the mammal feces. This gene is ubiquitous to Bacteroidetes isolates from anaerobic human-associated environments (Meggese and Abratt, 2015; Binta and Patel, 2016), which as describe above was highly copious in both the human and bovine feces analyzed in this study. The fact that cfxA , is frequently associated with the Tn4555 transposon (Agga et al, 2015), indicates its capacity to be horizontally transferred between phylogenetically related strains.…”

Linking the resistome and plasmidome to the microbiome

“…Specifically tetQ and ermG or ermF are frequently found in tetracycline and erythromycin resistant Bacteroides isolates, respectively ( ermF was only detected in the WW sample) [34, 36]. We also found links with genes encoding the Class A betalactamases Cfx CblA, and CepA (the latter only in WW), which are naturally found in members of Bacteroides and Prevotella [35, 37, 38].…”

Non-Surgical Periodontal Therapy with Adjunctive Amoxicillin/Metronidazole or Metronidazole When No Aggregatibacter actinomycetemcomitans Is Detected—A Randomized Clinical Trial

“…The capnophilic A. actinomycetemcomitans is most sensitive to amoxicillin but resistant to metronidazole, while the other Gram-negative but strictly anaerobe bacteria (e.g., P. gingivalis ) are most highly sensitive to metronidazole [ 19 , 20 , 21 ]. Contrastingly, there is not always a high susceptibility of bacteria in the subgingival biofilm to amoxicillin [ 22 ]. This raised the question as to whether, in the absence of A. actinomycetemcomitans , the administration of amoxicillin could be avoided.…”