High prevalence of plasmid-mediated Fosfomycin resistance in waterfowl-derivedstrains: insights into genetic context and transmission dynamics in China.

Abstract

Fosfomycin (FOS) is a critical antibiotic for treating multi-drug resistant (MDR)infections, but its effectiveness is jeopardized by the dissemination of plasmids encoding enzymes that modify FOS. Despite the prohibition on its use in animal breeding in China, 100 strains of() exhibiting high resistance to FOS (MIC≥512 mg/L) were isolated from samples of waterfowl origin collected in Hainan, Sichuan, and Anhui. These strains commonly carried theA(88/100, 88.0%). In addition, 21 other antimicrobial resistance genes (ARGs) were detected in these strains, with high positivity rates forA,,,,, and. It is noteworthy that there was a significant positive correlation between theA3 and(OR = 15.162, 95% CI: 1.875-122.635). The results of pulsed-field gel electrophoresis (PFGE) demonstrated the existence of multiple dispersed clonal clusters. Multilocus sequence typing (MLST) analysis identified 45 ST types, with ST48 and ST10 representing the most dominant clones. In the conjugation experiments, 53A-like genes positive transconjugants were obtained with measurable conjugation frequency, which strongly demonstrated that theseA3 may mainly locate on different types of plasmids possessing an efficient transmission ability. Whole genome sequencing (WGS) analysis further showed that theA3 was co-localized with theon plasmids that showed a high degree of similarity in genetic structure. Of particular interest is the observation that theA3 is frequently accompanied by ISon either side of the gene. This structure may play a pivotal role in the horizontal transfer of theA3. The study revealed the alarming prevalence of FOS resistance inof waterfowl origin and delved deeply into the genetic characteristics and transmission mechanisms of theA3. The discovery of plasmid-mediated, transmissible FOS resistance in waterfowlposes a threat to "One Health". There's an urgent need for thorough monitoring and control measures against FOS resistance.