OXA-48-producing Enterobacterales in different ecological niches in Algeria: clonal expansion, plasmid characteristics and virulence traits.

OBJECTIVES

To investigate the prevalence and molecular characteristics of OXA-48-carbapenemase-producing Enterobacterales strains recovered from various ecological niches in Algeria.

METHODS

In total, 3309 samples were collected from different ecological niches (human carriage, animal farms, wild animals, pets, food products, aquatic environment and wastewater treatment plants) distributed among six provinces in Algeria between December 2015 and April 2017. The potential presence of OXA-48-producing Enterobacterales isolates was screened on selective medium. Resistance and virulence profiles were characterized by PCR and sequencing. The clonal relatedness of the different isolates was studied using Rep-PCR and MLST. Conjugation was performed for all OXA-48-producing isolates. The plasmids were analysed by PCR-based replicon typing and WGS.

RESULTS

A total of 78 OXA-48-producing Enterobacterales isolates were detected from 3309 samples (2.4%). OXA producers were observed in all the screened sources. The blaCTX-M-15 gene was only observed in two isolates. Clonality analysis revealed distinct lineages of the isolates and a clonal expansion of Klebsiella pneumoniae ST13. K. pneumoniae and Escherichia coli had few virulence factors. Plasmid analysis confirmed that all the isolates harboured a very similar transferable plasmid (belonging to IncL) with a similar structure to the pOXA-48a plasmid carried by K. pneumoniae strain Kp11978.

CONCLUSIONS

This study suggests a global dissemination of OXA-48-producing Enterobacterales in different niches due mainly to the spread of an epidemic plasmid. Furthermore, it clearly shows that K. pneumoniae and commensal E. coli can be reservoirs of the blaOXA-48 gene, contributing to the dissemination and transfer of this gene to diverse bacteria among different sources.