High Prevalence of Drug Resistance and Class 1 Integrons in Escherichia coli Isolated From River Yamuna, India: A Serious Public Health Risk

Abstract

Globally, urban water bodies have emerged as an environmental reservoir of antimicrobial resistance (AMR) genes because resistant bacteria residing here might easily disseminate these traits to other waterborne pathogens. In the present study, we have investigated the AMR phenotypes, prevalent plasmid-mediated AMR genes, and integrons in commensal strains of Escherichia coli, the predominant fecal indicator bacteria isolated from a major urban river of northern India Yamuna. The genetic environment of blaCTX–M–15 was also investigated. Our results indicated that 57.5% of the E. coli strains were resistant to at least two antibiotic classes and 20% strains were multidrug resistant, i.e., resistant to three or more antibiotic classes. The multiple antibiotic resistance index of about one-third of the E. coli strains was quite high (>0.2), reflecting high contamination of river Yamuna with antibiotics. With regard to plasmid-mediated AMR genes, blaTEM–1 was present in 95% of the strains, followed by qnrS1 and armA (17% each), blaCTX–M–15 (15%), strA-strB (12%), and tetA (7%). Contrary to the earlier reports where blaCTX–M–15 was mostly associated with pathogenic phylogroup B2, our study revealed that the CTX-M-15 type extended-spectrum β-lactamases (ESBLs) were present in the commensal phylogroups A and B1, also. The genetic organization of blaCTX–M–15 was similar to that reported for E. coli, isolated from other parts of the world; and ISEcp1 was present upstream of blaCTX–M–15. The integrons of classes 2 and 3 were absent, but class 1 integron gene intI1 was present in 75% of the isolates, denoting its high prevalence in E. coli of river Yamuna. These evidences indicate that due to high prevalence of plasmid-mediated AMR genes and intI1, commensal E. coli can become vehicles for widespread dissemination of AMR in the environment. Thus, regular surveillance and management of urban rivers is necessary to curtail the spread of AMR and associated health risks.

Predominance of blaTEM and tetA genes in antibiotic-resistant Escherichia coli isolates from Laguna Lake, Philippines

“…To date, this is the first report of detection of strA gene in Philippine waters. Similar findings of the occurrence of strA gene were reported in waterborne (Gomi et al 2017;Singh et al 2021) and foodborne E. coli isolates (Zhang et al 2014;Poirel et al 2018) in several countries.…”

Characterization of Integrons and Quinolone Resistance in Clinical Escherichia coli Isolates in Mansoura City, Egypt

“…In this study, integrons were found in 44.77% of the tested isolates, which is similar to other studies [10,12]. Several studies, on the other hand, found a higher prevalence rate of integrons [33][34][35].…”

“…In this study, integrons were found in 44.77% of the tested isolates, which is similar to other studies [ 10 , 12 ]. Several studies, on the other hand, found a higher prevalence rate of integrons [ 33 – 35 ]. The present study revealed the predominance of integron I among quinolone-resistant isolates (59/80 isolates, 73.75%).…”

Metagenomic Analysis of Urban Wastewater Treatment Plant Effluents in Tokyo

“…Notably, ARG-specific identification revealed that basic gene sets (sul1 and ∆qacE) in the class 1 integron were predominant in the detected ARGs (Figure 4A), suggesting that the class 1 integron plays a pivotal role for HGT among environmental bacteria and human pathogens. 24 Here, we did not completely investigate all the cassette genes in possible class 1 integrons. However, most AMG resistance genes (aadA and aph gene families), MAC resistance genes [msr(E) and mph(E)], and some β-lactamase genes, such as OXA-type carbapenemase, are cassette gene components in class 1 integron.…”