Dissemination of multidrug-resistant and mcr-1 gram-negative bacilli in broilers, farm workers, and the surrounding environment in Lebanon

Abstract

Poultry are currently regarded as reservoirs from which multidrug resistance can be readily transferred to the surrounding ecosystem. The aim of this study was to explore the prevalence of extended spectrum beta-lactamases (ESBLs) and ampC and mcr-1 Gram-negative bacilli in chicken, farmers, and environment in Lebanon. In May 2017, we revisited the farm where the first mcr-1 was detected in 2015 in Lebanon. Overall 200 chicken fecal swabs, 6 farmers' fecal samples, and 41 environmental samples were collected. Real time (RT)-PCR was performed for beta-lactamases and mcr genes' screening using newly designed primers/probes. Multilocus sequence typing (MLST) was also performed. ESBL/ampCs were found in 118 samples from chicken, 4 from workers, and all environmental ones. mcr-1 was detected in all chicken and farmers' samples from which 314 and 7 strains were isolated, respectively. Three mcr-1 Escherichia coli strains were isolated from litter and feed. Compared to 2015, the prevalence of ESBL/ampC producers, TEM and CTX-M genes increased significantly in 2017. Main spectra profiles dendrogram of isolated E. coli strains in 2015/2017 and MLST revealed the presence of different clones and sequence types. The evolution of resistance appears to be multi-clonal and related to the diffusion of plasmids carrying ESBL and mcr-1 genes. More work is needed to quantify the magnitude of this emerging problem in Lebanon.