Determinants of resistance in B. fragilis strain BFR_KZ01 isolated from a patient with peritonitis in Kazakhstan.

Abstract Objectives Bacteroides fragilis is one of the most important human anaerobic pathogens that are often found during various clinical infections. The purpose of this study was to determine susceptibility of B. fragilis to the most common anti-anaerobic drugs at the local level and to detect genes associated with resistance to these antibiotics. Methods This article describes the B. fragilis BFR_KZ01 clinical strain study. Identification of the bacteria by two modern methods: MALDI-TOF mass spectrometry and 16S rRNA gene sequencing was performed. Sensitivity to broad-spectrum antibiotics (metronidazole, meropenem, ciprofloxacin, clindamycin and tetracycline) most commonly used for intraabdominal infections treatment was studied. Mass spectra groups essential for identifying cfiA-positive strains from clinical isolates were studied using ClinProTools 3.0.22 software. The Ion Torrent PGM platform was used for the whole-genome sequencing of the studied isolates. Results The resulting whole-genome sequence of the BFR_KZ01 strain was imported to GenBank. In total, 5300 coding sequences (CDSs) and 69 RNA genes were determined. Analysis of the whole genome data revealed that the studied strain has cfiA, nimB, tetQ and gyrA genes, which confer resistance to key drugs used in treatment of the intraabdominal infections. MALDI-TOF mass spectrometry analysis has assigned the strain BFR_KZ01 to Group II (cfiA-positive); however, BFR_KZ01 was phenotypically sensitive to meropenem (mean MIC = 1.3 mg/L). Conclusions To sum up, determinants of drug resistance in the BFR_KZ01 strain were identified. It was revealed that the B. fragilis strain BFR_KZ01 from Kazakhstan is multidrug-resistant, since it carries nimB, tetQ and gyrA genes, which confer resistance to metronidazole, tetracycline and ciprofloxacin.