Emergence of carbapenem resistant Escherichia coli, Morganella morganii, Providencia rettgeri harboring bla genes in minks from China.

Although carbapenems have not been approved for animal use, carbapenem-resistant Enterobacteriaceae (CRE) strains are increasingly being detected in animals, posing a significant public health risk. However, the epidemiological characteristics of CRE isolates in animals remain elusive. We comprehensively investigated the genetic features of carbapenem-resistant Enterobacteriaceae isolates recovered from minks in Shandong province, China. A total of seven (38.8 %) NDM-positive isolates were identified including three Morganella morganii, three Providencia rettgeri, and one Escherichia coli from 18 samples comprises of mink feed, intestinal content, liver, spleen and lungs collected from four deceased minks. Among these isolates, only one carried the bla gene, while the remaining six harbored the bla gene and exhibited high levels of meropenem resistance (32-128 µg/mL). Genome sequencing confirmed that all M. morganii and P. rettgeri isolates harbored the chromosomally located bla gene while the E. coli isolate belonging to ST602 harbored the bla gene on ∼88 kb IncFII (pHN7A8) plasmid. To extent of our findings, this is the first discovery of carbapenem resistant Enterobacteriaceae in minks specifically the E. coli ST602 mink harboring the plasmid-mediated bla gene. In addition to E. coli, we have also reported a novel ST214 in P. rettgeri isolates harbored bla gene. Moreover, CTX-M-positive E. coli ST602 was also reported in wild birds from Chile while E. coli harboring bla gene on IncFIA/IncFII plasmid was also reported from healthy individuals in China. So, the emergence of these antimicrobial resistance genes in minks and their close association with humans and animals is alarming. Our findings highlight the urgent need for further surveillance of bacterial resistance to last-resort antibiotics in the animal settings One Health approach.