Emergence of carbapenem‐resistant Citrobacter spp. across human, animal, and water environments in China

IF 4.9 2区医学 Q1 INFECTIOUS DISEASES

International Journal of Antimicrobial Agents Pub Date : 2025-02-12 DOI:10.1016/j.ijantimicag.2025.107463

Xiaoyang Ju , Panfeng Xiong , Zelin Yan , Gongxiang Chen , Chang Cai , Rong Zhang

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引用次数: 0

Abstract

Objective

With the rise of carbapenem-resistant Citrobacter spp. (CRC), it is essential to investigate their distribution and resistance characteristics across diverse ecological niches. This study aims to collect CRCs from humans, animals, and water environments to analyze their epidemiology, genetic characteristics, and resistance mechanisms, providing insights into transmission dynamics.

Methods

CRCs were isolated from different samples using methods including filtration, enrichment, screening, and purification. Antimicrobial susceptibility tests were conducted using the broth microdilution method. Transconjugation experiments were performed through filter mating. Whole genome sequencing and bioinformatics analysis were carried out to analyze genomic features of CRCs.

Results

Total of 171 CRCs were isolated from diverse Chinese provinces between 2016 and 2023. All strains are classified into seven Citrobacter species. Citrobacter freundii is the most common (76.02%), with ST116 and ST22 being the predominant strains. Among all strains, 63.16% carried bla_NDM-1, and 41.52% carried bla_KPC-2. Hospital wastewater was the primary source of CRCs harbouring two carbapenemase genes, with the most prevalent combination being bla_NDM-1 and bla_KPC-2 (85.71%, 24/28). All strains showed multi-drug resistance, with over 95% resistant to various carbapenems. Transconjugation experiments showed that carbapenemase genes in the majority of CRCs were located on the plasmids and can be transferred to the recipient strains. Phylogenetic analysis displayed that clonal transmission was observed among a few CRCs.

Conclusions

Multiple mobile genetic elements mediate the spread and prevalence of carbapenem resistance in Citrobacter spp. Monitoring carbapenemase genes and CRCs across ecological niches is needed to controlling carbapenem resistance, particularly in high-risk sources like hospital wastewater.

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来源期刊

International Journal of Antimicrobial Agents 医学-传染病学

CiteScore

21.60

自引率

0.90%

发文量

176

审稿时长

36 days

期刊介绍： The International Journal of Antimicrobial Agents is a peer-reviewed publication offering comprehensive and current reference information on the physical, pharmacological, in vitro, and clinical properties of individual antimicrobial agents, covering antiviral, antiparasitic, antibacterial, and antifungal agents. The journal not only communicates new trends and developments through authoritative review articles but also addresses the critical issue of antimicrobial resistance, both in hospital and community settings. Published content includes solicited reviews by leading experts and high-quality original research papers in the specified fields.