title: Transcriptional Response of Multiple ESBL Genes Within Escherichia coli Under Oxyimino-Cephalosporin Stress.
abstract: The expression of extended-spectrum beta-lactamases directly interferes with the treatment options in a clinical setting. It is not clearly defined why bacteria acquire multiple beta-lactamases and how they are being expressed in antibiotic stress. With this key question, the study was designed to understand the transcriptional response in Escherichia coli harboring multiple blaESBLsagainst different oxyimino-cephalosporin stress. A total of 169 consecutive, nonduplicate oxyimino-cephalosporin-resistant isolates of E. coli were screened and were ESBL positive. Among them six isolates were found to harbor multiple beta-lactamase genes and we, as per our objective, selected them for this study. Molecular characterization was done by multiplex polymerase chain reaction (PCR) assay. Minimum inhibitory concentration, transcriptional expression, transferability, and plasmid incompatibility typing of multiple blaESBLswere carried out. Plasmid stability and antibiotic susceptibility of donor and transconjugants were performed. A total of six isolates were found to be harboring multiple ESBL genes and MIC above the breakpoint level against all the tested antibiotics. Quantitative real-time PCR showed that in basal level without antibiotic stress, SHV-148 expressed more, but with ceftriaxone stressed, expression of CTX-M-15 and SHV-148 was high. In case of PER-1, expression was high with ceftazidime stress. blaESBLswere horizontally transferable and originated through multiple inc types. Plasmids were stable till 115 serial passages. Pulsed-field gel electrophoresis results showed that multiple ESBL genes were spread through six pulsotypes. Our study concludes that acquisition of multiple ESBL genes in E. coli was a specific adaptation for survival against multiple oxyimino-cephalosporin stress in this clinical setting.
authors.affiliation: 1 Department of Microbiology, Assam University , Assam, India .
authors.forename: Anand Prakash
authors.initials: AP
authors.lastname: Maurya
authors.affiliation: 2 Department of Microbiology, Silchar Medical College and Hospital , Assam, India .
authors.forename: Debadatta Dhar
authors.initials: DD
authors.lastname: Chanda
authors.affiliation: 3 Department of Statistics and Mathematics, Chandra Kamal Bezbaruah Commerce College , Jorhat, Assam, India .
authors.forename: Debajyoti
authors.initials: D
authors.lastname: Bora
authors.affiliation: 4 Department of Life Science and Bioinformatics, Assam University , Assam, India .
authors.forename: Anupam
authors.initials: A
authors.lastname: Das Talukdar
authors.affiliation: 3 Department of Statistics and Mathematics, Chandra Kamal Bezbaruah Commerce College , Jorhat, Assam, India .
authors.forename: Atanu
authors.initials: A
authors.lastname: Chakravarty
authors.affiliation: 1 Department of Microbiology, Assam University , Assam, India .
authors.forename: Amitabha
authors.initials: A
authors.lastname: Bhattacharjee
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D002442:Ceftazidime / Q000627:therapeutic use; D002511:Cephalosporins / Q000627:therapeutic use*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics*; D004927:Escherichia coli Infections / Q000188:drug therapy; D029968:Escherichia coli Proteins / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests / Q000379:methods; D008875:Middle Aged; D010957:Plasmids / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D014158:Transcription, Genetic / Q000187:drug effects*; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D029968:Escherichia coli Proteins; D002442:Ceftazidime; D001618:beta-Lactamases
keywords: NDM-1; NDM-5; carba NP test; carbapenem