Spread of ESC-, carbapenem- and colistin-resistant Escherichia coli clones and plasmids within and between food workers in Lebanon.

OBJECTIVES

Knowledge on the dynamic of MDR Escherichia coli in the human community is still limited, especially in low- and middle-income countries. Our goal was to decipher the dynamics of E. coli lineages and plasmids resistant to ESC, carbapenem and colistin within and between food workers in Lebanon using genomic-based approaches.

METHODS

Eighty-four healthy adults working in three bakeries were sampled twice at a 6 monthly interval. E. coli resistant to ESC (ESC-E), carbapenem (CP-E) and colistin (CO-E) were collected on selective plates. Non-duplicate isolates were whole-genome sequenced using the Illumina technology and plasmid transmission was assessed by long-read sequencing. Data were analysed using bioinformatics tools and SNP-based phylogeny.

RESULTS

ESC-E carriage rate reached 34.5% (t0) and 52.9% (t6), and 15 workers were positive at both t0 and t6. Carbapenem resistance (blaOXA-181, blaOXA-204, blaNDM-5) was found in five workers at t0 and two at t6, while colistin resistance (mcr-1.1) was found in five workers at t0 and one at t6. Forty-seven different STs were identified, of which three STs were predominant (ST131, n = 9; ST10, n = 5; ST69, n = 5). One worker presented the same ESC-E clone at t0 and t6. Twelve different events of clonal transmission among individuals were exemplified while plasmid transmission was only shown once.

CONCLUSIONS

Our study revealed a high carriage rate of MDR E. coli (60.7%) and the emergence of CP and colistin resistance in the Lebanese community. Incidental and long-term ESC-E carriage was observed in 41.7% and 17.9% of the workers, respectively. The high clonal diversity suggests an important dynamic of acquisition and loss of MDR E. coli and limited plasmid spread.