Infection and Drug Resistance (Jan 2022)
Detection of Two Copies of a blaNDM-1-Encoding Plasmid in Escherichia coli Isolates from a Pediatric Patient with Diarrhea
Abstract
Bo-Wen Jiang,1,2,* Xue Ji,1,2,* Zhong-Qing Lyu,3 Bing Liang,1,2 Jian-Hang Li,3 Ling-Wei Zhu,1,2 Xue-Jun Guo,1,2 Jun Liu,1,2 Yang Sun,1,2 Yan-Jing Liu3 1Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, Jilin, People’s Republic of China; 2Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun, Jilin, People’s Republic of China; 3Third Affiliated Clinical Hospital to Changchun University of Chinese Medicine, Changchun, Jilin, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yang Sun; Yan-Jing Liu, Tel +86 431-86986933, Email [email protected]; [email protected]: To elucidate the contribution of a transferable plasmid harboring the blaNDM-1 gene in an Escherichia coli clinical isolate to the spread of resistance determinants.Methods: Nine extended-spectrum β-lactamase-producing E. coli were collected from diarrhea samples from a pediatric patient and genetic linkage was investigated through enterobacteriaceae repetitive intragenic consensus polymerase chain reaction (PCR). Bacterial species were identified by 16s rRNA sequencing, susceptibility testing with the use of a BD PhoenixTM-100 Automated Microbiology System, and assessment of virulence genes by PCR. The transferability of blaNDM-1 in E. coli strain TCM3e1 was confirmed by conjugation experiments. Complete sequencing of E. coli strain TCM3e1 was determined with the PacBio and Illumina NovaSeq platforms and the characteristics were analyzed with bioinformatics software.Results: The results showed that all nine E. coli strains were the same clone. E. coli strain TCM3e1 was resistant to 12 antimicrobial agents and carried the virulence gene EAST-1. Conjugation transfer analysis showed that blaNDM-1 was carried on a self-transmissible plasmid. Two copies of the blaNDM-1 gene were present on an IncC plasmid and some resistance genes with two or three copies were located downstream of the blaNDM-1 gene and formed a tandem repeat fragment (blaDNM-1-bleo-sul1- aadA17- dfrA12).Conclusion: A transmissible plasmid harboring two copies of the blaNDM-1 gene, including clonal dispersions of the blaNDM-1 gene, was identified in clinical isolates. These findings emphasized the necessity of surveillance of the plasmid-borne blaNDM-1 to prevent dissemination.Keywords: diarrheagenic Escherichia coli, multi-drug-resistant, New Delhi metallo-β-lactamase, blaDNM-1 gene
