Imported One-Day-Old Chicks as Trojan Horses for Multidrug-Resistant Priority Pathogens Harboring < em > mcr-9 < /em > , < em > rmtG < /em > and Extended-Spectrum β-Lactamase Genes

In this study, we have performed a microbiological and molecular investigation of priority pathogens carrying transferable resistance genes to critical antimicrobials in one-day-old chickens imported from Brazil to Uruguay. Bacterial identification was performed by MALDI-TOF mass spectrometry and antibiotic susceptibility was determined by Sensititre. Antimicrobial resistance genes were sought by polymerase chain reaction and clonality was assessed by PFGE. Four multidrug-resistant (MDR) representative strains were sequenced by Illumina and/or Oxford Nanopore Technologies. Twenty-eight MDR isolates identified as Escherichia coli (n= 14), Enterobacter cloacae (n= 11) and Klebsiella pneumoniae (n= 3). While resistance to oxyiminocephalosporins was due to blaCTX-M-2, blaCTX-M-8, blaCTX-M-15, blaCTX-M-55 and blaCMY-2, plasmid-mediated quinolone resistance was associated with qnrB19, qnrE1, and qnrB2 genes. Finally, resistance to aminoglycosides and fosfomycin was due to the presence of 16S rRNA methyltransferase rmtG and fosA-type genes, respectively. Short and long-read genome sequencing of E. cloacae ODC-Eclo3 strain revealed the presence of IncQ/rmtG (pUR-EC3.1, 7400-pb), IncHI2A/mcr-9.1/blaCTX-M-2 [pUR-EC3.2, ST16 (pMLST), 408,436-bp] and IncN2/qnrB19/aacC3/aph(3'')-Ib (pUR-EC3.3) resistance plasmids. Strikingly, the blaCTX-M-2 gene was carried by a novel Tn1696-like composite transposon designated Tn7337. In summary, we report that imported one-day-old chicks can act as Troj...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Source Type: research