Quinolone co-resistance in ESBL- or AmpC-producing Escherichia coli from an Indian urban aquatic environment and their public health implications.
Quinolone and β-lactam antibiotics constitute major mainstay of treatment against infections caused by pathogenic Escherichia coli. Presence of E. coli strains expressing co-resistance to both these antibiotic classes in urban aquatic environments which are consistently being used for various anthropogenic activities represents a serious public health concern. From a heterogeneous collection of 61 E. coli strains isolated from the river Yamuna traversing through the National Capital Territory of Delhi (India), those harboring blaCTX-M-15 (n = 10) or blaCMY-42 (n = 2) were investigated for co-resistance to quinolones and the molecular mechanisms thereof. Resistance was primarily attributed to amino acid substitutions in the quinolone resistance-determining regions (QRDRs) of GyrA (S83L ± D87N) and ParC (S80I ± E84K). One of the E. coli strains, viz., IPE, also carried substitutions in GyrB and ParE at positions Ser492→Asn and Ser458→Ala, respectively. The phenotypically susceptible strains nevertheless carried plasmid-mediated quinolone resistance (PMQR) gene, viz., qnrS, which showed co-transfer to the recipient quinolone-sensitive E. coli J53 along with the genes encoding β-lactamases and led to increase in minimal inhibitory concentrations of quinolone antibiotics. To the best of our knowledge, this represents first report of molecular characterization of quinolone co-resistance in E. coli harboring genes for ESBLs or AmpC β-lactamases from a natural aquatic environment of India. The study warrants true appreciation of the potential of urban aquatic environments in the emergence and spread of multi-drug resistance and underscores the need to characterize resistance genetic elements vis-à-vis their public health implications, irrespective of apparent phenotypic resistance.
['Bajaj|Priyanka|P|', 'Kanaujia|Pawan Kumar|PK|', 'Singh|Nambram Somendro|NS|', 'Sharma|Shalu|S|', 'Kumar|Shakti|S|', 'Virdi|Jugsharan Singh|JS|']
D000900:Anti-Bacterial Agents D001426:Bacterial Proteins D024881:Drug Resistance, Bacterial D004926:Escherichia coli D029968:Escherichia coli Proteins D006801:Humans D007194:India D008826:Microbial Sensitivity Tests D010957:Plasmids D011634:Public Health D015363:Quinolones D014871:Water Microbiology D001618:beta-Lactamases
Aquatic environment E. coli QRDR PMQR CMY-42 CTX-M-15