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.
Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
Priyanka
P
Bajaj
Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
Pawan Kumar
PK
Kanaujia
Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
Nambram Somendro
NS
Singh
Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
Shalu
S
Sharma
Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India.
Shakti
S
Kumar
Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India. virdi_dusc@rediffmail.com.
Jugsharan Singh
JS
Virdi
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007194:India; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011634:Public Health; D015363:Quinolones / Q000494:pharmacology*; D014871:Water Microbiology; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D015363:Quinolones; C048795:AmpC beta-lactamases; D001618:beta-Lactamases
Aquatic environment; CMY-42; CTX-M-15; E. coli; PMQR; QRDR