Jing Wang, Zelin Yan, Yuchen Wu, Hanyu Wang, Xiaoyang Ju, Jiao Qian, Yanyan Zhang, Kaichao Chen, Ling Xin, Yang Wang, Sheng Chen, Zhemin Zhou, Rong Zhang
CRM occur across multiple One Health niches. The findings highlight environmental and non-human reservoirs as potential contributors to their dissemination and identify blaPER-4 and aac(3)-IV as resistance-associated genes requiring further study.
OBJECTIVES: To investigate the prevalence, genomic relatedness, and resistance characteristics of carbapenemase-gene-positive Morganella spp. (CRM) across human, animal, fly, and aquatic sources.
METHODS: A total of 163 Morganella isolates were collected from humans (n=124), animals (n=5), flies (n=21), aquatic environment (n=13) across 13 provinces or municipalities during 2018-2024. A subset of 71 representative isolates was subjected to antimicrobial susceptibility testing (AST), whole-genome sequencing and conjugation experiments.
RESULTS: Among 163 isolates, 18 were carbapenemase-gene-positive: 15 carried blaNDM-1 alone, two carried blaKPC-2 alone, and one carried both genes. They were recovered from humans, flies, and hospital sewage. Five isolates carried blaPER-4; four carbapenemase-negative carriers were resistant to both ceftazidime/avibactam and aztreonam/avibactam. The aac(3)-IV gene was associated with high apramycin MICs and was most frequent in animal- and fly-derived isolates. Phylogenetic analysis showed diverse lineages, with limited low-SNP links between human and urban-river isolates. blaNDM-1 was transferred successfully from 11 of 16 donor isolates.
CONCLUSION: CRM occur across multiple One Health niches. The findings highlight environmental and non-human reservoirs as potential contributors to their dissemination and identify blaPER-4 and aac(3)-IV as resistance-associated genes requiring further study.