Characterization of High-Linezolid-MIC Clostridioides difficile Isolated from a Chinese Hospital: First Genomic Evidence of Cfr(B) Transmission and Tn6218 Association
Year: 2025
Type: article
Abstract: Background: Clostridioides difficile ( C. difficile ) exhibiting high linezolid minimum inhibitory concentration (> 4 μg/mL) remains infrequently reported in clinical settings. Notably, the prevalence of linezolid-resistant C. difficile is exceptionally low (< 3% in Chinese isolates), and the underlying genetic determinants are poorly characterized. Methods: We conducted a genomic study to investigate the genetic characteristics of C. difficil e with high linezolid MIC. To determine the MIC of linezolid and delineate antimicrobial resistance profiles, these isolates were systematically subjected to antimicrobial susceptibility testing. Multilocus sequence typing, antimicrobial resistance genes, and the characteristics of the cfr gene in linezolid-resistant C. difficil e strains were analyzed following whole-genome sequencing. Roary was used to construct a pangenome phylogenetic tree, and a Bayesian evolutionary analysis was performed using BEAST.4. Results: Among 421 screened C. difficile isolates, nine isolates (2.1%) exhibited high-linezolid MICs (≥ 16 μg/mL), including six ST37 (A-B+) and three ST3 strains (two A-B-). All harbored cfr (B) on Tn 6218 , sharing homology with E. faecium (NG_050395.1). Conclusion: This study underscores the risk of cfr (B) dissemination via mobile genetic elements in clinical settings, urging surveillance of co-occurrence in Enterococcus and C. difficile to curb resistance spread. Keywords: Clostridioides difficile , linezolid, cfr (B), transposon, horizontal transmission
Source: Infection and Drug Resistance
DOI: 10.2147/idr.s523333
Authors: Xuyan Fu, Xiajing Bi, Tao Lv, Yunbo Chen
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $2,836
OpenAlex ID: W4414067231