Genomic characterisation of Escherichia coli isolates co-producing NDM-5 and OXA-1 from hospitalised patients with invasive infections.

OBJECTIVES

Carbapenems are one of the last-report therapeutic choices to treat infections due to multidrug-resistant (MDR) micro-organisms. For this reason, the spread of carbapenemase-producing Enterobacteriaceae represents a serious health-public problem. Here we describe isolates co-producing blaNDM-5 and blaOXA-1.

METHODS

Three Escherichia coli isolates obtained from patients with invasive infections were analysed by phenotypic antibiotic susceptibility testing and whole-genome sequencing (WGS).

RESULTS

All of the isolates were resistant to carbapenems, most β-lactam antibiotics, piperacillin/tazobactam, amoxicillin/clavulanic acid and ciprofloxacin, remaining susceptible to amikacin, fosfomycin, colistin and tigecycline. The isolates belonged to sequence types ST44, ST405 and ST167 and co-harboured the blaNDM-5 and blaOXA-1 genes. Two of the isolates also harboured extended-spectrum β-lactamase (ESBL) genes (blaCTX-M-15 and blaTEM-1b). The blaNDM-5 gene was probably carried chromosomally even if different plasmids were identified. Various virulence genes were also identified.

CONCLUSION

Our results highlight that continuous surveillance is essential to monitor the spread of clinically important MDR pathogens.