Newly identified colistin resistance genes, mcr-4 and mcr-5, from upper and lower alimentary tract of pigs and poultry in China

Abstract

Antimicrobial resistance against colistin has emerged worldwide threatening the efficacy of one of the last-resort antimicrobials used for the treatment of Enterobacteriaceae. To investigate the presence of the recently identified colistin resistance genes (mcr-4, mcr-5) in China, we established PCRs to detect mcr-4 and mcr-5 on 213 anal and 1,339 nasal swabs from apparently healthy pigs (n = 1,454) in nine provinces, and 1,696 cloacal and 1,647 oropharyngeal samples from poultry (n = 1,836) at live-bird markets in 24 provinces of China. The prevalence of the mcr-4 in swine swabs (41.4%; 642/1,552) was significantly higher than in swabs from poultry (11.5%; 384/3,343). The mcr-4 gene was found in geese (49.5%, 54/109), chickens (17.2%, 257/1,498), pigeons (17.2%, 17/99) and ducks (15.4%, 20/130). In a similar trend, the prevalence of the mcr-5 in swine swabs (33.1%; 514/1552) was significantly higher than in swabs from poultry (5.6%; 187/3,343). The mcr-5 was identified in geese (17.4%, 19/109), chickens (9.9%, 148/1,498), ducks (7.7%, 10/130) and pigeons (3%, 3/99). The mcr-4 prevalence in the nasal swabs from pigs (59.2%, 58/98) was significantly higher than that in anal swabs (29.6%, 29/98) (P<0.001). Similarly, the mcr-5 prevalence in the nasal swabs from pigs (61.2%, 60/98) was significantly higher than in anal swabs (44.9%, 44/98) (P = 0.02), and significantly higher in oropharyngeal swabs (7.2%, 109/1,507) than in the cloacal swabs (3.7%, 56/1,507) (P<0.001). This study further confirms the presence of the mcr-4 and mcr-5 in animals and indicates these genes are prevalent and widespread in food producing animals (pig and poultry) in China. Future studies are needed to characterize the bacteria carrying the mcr-4 and mcr-5 and their locations on plasmids and/or the bacterial chromosomes, and determine co-resistances in the mcr-4 and mcr-5 positive strains.

Resistome in Lake Bolonha, Brazilian Amazon: Identification of Genes Related to Resistance to Broad-Spectrum Antibiotics

“…The P3 site appears to have particular characteristics in terms of the resistome. In addition to the genes already mentioned above (i.e., bla IMP , bla VIM and bla CTX−M ), other clinically relevant genes have also been detected at this site, such as mcr-5 genes, which confer resistance to colistin and which have recently been detected in plasmids from environmental, human and animal derived isolates (Sun et al, 2017;Tacão et al, 2017;Chen et al, 2018). Furthermore, in this site, the diversity of resistance genes found was superior to that of the other two sites (Supplementary Table S4).…”

Characterization of mcr-5 -Harboring Salmonella enterica subsp. enterica Serovar Typhimurium Isolates from Animal and Food Origin in Germany

“…Generally, the high variation of mcr-5-carrying plasmids in only eight analyzed Salmonella isolates as well as the presence of Tn6452 in two of the host genomes indicate a high mcr-5 mobility, an independent acquisition of mcr-5-harboring plasmids by individual strains, and a successful integration in and adaptation to different genomic environments. This is supported by the increasing number of publications reporting the presence of mcr-5 in various bacterial species worldwide (10,(15)(16)(17)(18)(19)(20)(21)(22)(23). However, mcr-5 is only reported sporadically, and so far, no links can be made between isolates from the environment, livestock, food, and humans.…”

A review on the current situation and challenges of colistin resistance in poultry production

“…In a concurrent study in Algeria and France, low prevalence and absence of mcr-1, respectively, was found in chickens (Chabou et al, 2016). In contrast, a Chinese study on chicken, duck and goose flocks not only reported high prevalence of the mcr-1 gene, but also identified for the first time the presence of all novel mcr genes (mcr-1 to mcr-5) in the examined poultry species (Zhang et al, 2018;Chen et al, 2018).…”

“…Chromosomal mutations and other mcr genes seem to contribute as well. The recent discovery of all novel mcr genes in poultry (Zhang et al, 2018;Chen et al, 2018) and the development of a multiplex PCR protocol for their fast detection (Rebelo et al, 2018) prompt for surveillance of all mcr genes in future investigations. Furthermore, the higher prevalence of mcr-like genes when all Enterobacteriaceae are considered and the role of the "phantom resistome" should not be overlooked (Wang et al, 2017b).…”