Study of pandrug and heavy metal resistance among E. coli from anthropogenically influenced Delhi stretch of river Yamuna

Abstract

Escalating burden of antibiotic resistance that has reached new heights present a grave concern to mankind. As the problem is no longer confined to clinics, we hereby report identification of a pandrug resistant Escherichia coli isolate from heavily polluted Delhi stretch of river Yamuna, India. E. coli MRC11 was found sensitive only to tobramycin against 21 antibiotics tested, with minimum inhibitory concentration values >256 μg/mL for amoxicillin, carbenicillin, aztreonam, ceftazidime and cefotaxime. Addition of certain heavy metals at higher concentrations were ineffective in increasing susceptibility of E. coli MRC11 to antibiotics. Withstanding sub-optimal concentration of cefotaxime (10 μg/mL) and mercuric chloride (2 μg/mL), and also resistance to their combinatorial use, indicates better adaptability in heavily polluted environment through clustering and expression of resistance genes. Interestingly, E. coli MRC11 harbours two different variants of blaTEM (blaTEM-116 and blaTEM-1 with and without extended-spectrum activity, respectively), in addition to mer operon (merB, merP and merT) genes. Studies employing conjugation, confirmed localization of blaTEM-116, merP and merT genes on the conjugative plasmid. Understanding potentialities of such isolates will help in determining risk factors attributing pandrug resistance and strengthening strategic development of new and effective antimicrobial agents.

Influence of some parameters on the ability of Listeria monocytogenes, Listeria innocua, and Escherichia coli to form biofilms

“…Development was statistically better under microaerophilic conditions (p<0.05). These results corroborate those of the previous studies that reported the ability of E. coli to form biofilms on polystyrene under different conditions [35]. However, this result differs from that reported by Auger [26], who had observed that anaerobic conditions slowed the development of biofilms considerably.…”

“…Zeraik and Nitschke [44] and Azam et al . [35] showed that supplementation of culture medium with various substances influenced significantly their ability to form biofilms.…”

Genomic features of a multidrug-resistant and mercury-tolerant environmental Escherichia coli recovered after a mining dam disaster in South America

“…In this respect, heavy metal resistance genes for mercury ( merACDTPR ), arsenic ( arsRBC ), nickel ( nikABCDE ), copper ( pcoABCDR , cusABCFRS , cueOR , cutA ), zinc ( znuABC , zntAR , zitB , zraR ), and silver ( silABCEFPS ) were identified in E. coli B2C strain. The presence of several heavy metal resistance genes in E. coli strain B2C seems unusual compared to other E. coli strains recovered from the environment ( Azam et al, 2018 ; Siddiqui et al, 2020 ). However, this difference could be due to the use of whole-genome sequencing, whereas most studies describe the detection of a few selected genes using PCR alone.…”

“…In this regard, heavy metals seem to facilitate the conjugative transfer in environmental bacteria. Indeed, copper and zinc were found to accelerate the conjugative transfer of antimicrobial resistance genes in freshwater bacteria ( Wang et al, 2020 ; Wang et al, 2021 ), whereas E. coli strains co-harboring antibiotic and heavy metal resistance (e.g., mer operon and/or silEPS , merBPT , and arsC ) genes have been described in contaminated aquatic environments ( Azam et al, 2018 ; Chen et al, 2019 ; Sultan et al, 2020 ) .…”

“…Strikingly, heavy metals allow co-selection of antibiotic resistance due to co-resistance and cross-resistance mechanisms ( Baker-Austin et al, 2006 ). In fact, heavy metal-resistant E. coli producing ESBLs have been reported abroad ( Azam et al, 2018 ; Sütterlin et al, 2014 ; Freitas et al, 2019 ; Yang et al, 2020 ).…”