Drug Resistance Determinants in Clinical Isolates of Enterococcus faecalis in Bangladesh: Identification of Oxazolidinone Resistance Gene optrA in ST59 and ST902 Lineages.

Enterococcus faecalis is one of the major causes of urinary tract infection, showing acquired resistance to various classes of antimicrobials. The objective of this study was to determine the prevalence of drug resistance and its genetic determinants for E. faecalis clinical isolates in north-central Bangladesh. Among a total of 210 E. faecalis isolates, isolated from urine, the resistance rates to erythromycin, levofloxacin, and gentamicin (high level) were 85.2, 45.7, and 11.4%, respectively, while no isolates were resistant to ampicillin, vancomycin and teicoplanin. The most prevalent resistance gene was erm(B) (97%), and any of the four genes encoding aminoglycoside modifying enzyme (AME) were detected in 99 isolates (47%). The AME gene aac(6')-Ie-aph(2")-Ia was detected in 46 isolates (21.9%) and was diverse in terms of IS256-flanking patterns, which were associated with resistance level to gentamicin. Tetracycline resistance was ascribable to tet(M) (61%) and tet(L) (38%), and mutations in the quinolone resistance-determining region of both GyrA and ParC were identified in 44% of isolates. Five isolates (2.4%) exhibited non-susceptibility to linezolide (MIC, 4 µg/mL), and harbored the oxazolidinone resistance gene optrA, which was located in a novel genetic cluster containing the phenicol exporter gene fexA. The optrA-positive isolates belonged to ST59, ST902, and ST917 (CC59), while common lineages of other multiple drug-resistant isolates were ST6, ST28, CC16, and CC116. The present study first revealed the prevalence of drug resistance determinants of E. faecalis and their genetic profiles in Bangladesh.

Prevalence and Molecular Epidemiology of Clinical Isolates of Escherichia coli and Klebsiella pneumoniae Harboring Extended-Spectrum Beta-Lactamase and Carbapenemase Genes in Bangladesh.

Spread of Gram-negative bacteria producing extended-spectrum beta-lactamases (ESBLs) and carbapenemases constitutes a growing challenge in control of bacterial infections. In this study, prevalence and genetic characteristics of Escherichia coli and Klebsiella pneumoniae harboring ESBL and/or carbapenemase genes, with other beta-lactamase/resistance genes, were investigated for a total of 375 clinical isolates in Mymensingh located in north-central Bangladesh. The major ESBL gene was blaCTX-M-1 group, which was detected in 33.9% and 51.4% of E. coli and K. pneumoniae, respectively, with CTX-M-15 gene being dominant. SHV-type beta-lactamase genes, including newly identified alleles (SHV-201 and SHV-202) were detected at higher rate in K. pneumoniae (27%). Nine isolates of E. coli (3.9%) harbored carbapenemase genes; blaNDM-1 (phylogenetic group A-sequence type 2104 (A-ST2104), B2-ST73), blaNDM-5 (A-ST167, B2-ST38/ST2659-related STs), and blaNDM-7 (B1-ST101/ST224, D-ST6682). AmpC beta-lactamase genes (blaCMY-2 and blaCMY-42) were detected in E. coli, which mostly harbored blaCTX-M-15 and plasmid-mediated quinolone resistance (PMQR) determinants (aac6'-Ib-cr, qnrB, qnrS, qepA, and oqxAB). A new CMY allele (CMY-160) belonging to CMY-2 group was identified in phylogenetic group D E. coli. Among K. pneumoniae, carbapenemase gene was detected in three isolates (2%); blaNDM-1 in ST11 and ST1322, and blaOXA-181 in ST43 isolate. As well as higher rate of aac6'-Ib-cr in K. pneumoniae (39%), PMQR gene oqxAB was also commonly found among isolates analyzed. These findings indicated spread of blaNDM genes to diverse E. coli clones and emergence of blaOXA-181 in K. pneumoniae, with increased prevalence of ESBLs represented by CTX-M-15 in Bangladesh.

Detection of Chlamydia trachomatis by immunological and genetic methods in female sex workers and the local female population of reproductive age in Mymensingh, Bangladesh.

To investigate the accurate prevalence of genital Chlamydia trachomatis infection in Mymensingh, a local area in central-northern Bangladesh, 40 female sex workers (FSW) and 110 sexually active women (SAW, non-FSW) of reproductive age from a local community with clinical symptoms were examined by an immunochromatography test (ICT) and plasmid-based polymerase chain reaction (PCR) during a 1-year period from July 2011 to June 2012 using the endocervical swab as a specimen. By ICT and/or PCR, the C. trachomatis detection rate was 58% and 27% in FSW and SAW, respectively, showing a significant difference (P < 0.01). Two C. trachomatis strains from FSW were determined to be serovar D by ompA-based PCR and sequencing analysis. The highest prevalence was found among women aged 15 to 35 years. A lower socioeconomic status was considered to be an important risk factor for C. trachomatis infection in FSW but not in SAW. This is the first study to determine the prevalence of C. trachomatis infections in FSW and SAW in the same local area in Bangladesh.