Characterization of lincomycin resistance gene lnu(C)-carrying Campylobacter jejuni

Lincomycin is a key veterinary antibiotic for preventing and treating livestock and poultry diseases. Campylobacter jejuni, a major foodborne pathogen, causes diarrhea in animals and gastroenteritis in humans. We previously identified the resistance gene lnu(C) in C. coli. However, lincosamide resistance in C. jejuni remains poorly characterized. This study analyzed a total of 141 lnu(C)-positive C. jejuni strains (from GenBank and our laboratory) and revealed their global distribution, primarily from food animals, food, and humans, with China accounting for 46.1 % (65/141) of isolates. MLST analysis identified 44 distinct sequence types associated with lnu(C) dissemination, with ST573 emerging as the predominant genotype, indicating that lnu(C)-positive C. jejuni strains have the potential for horizontal and clonal transmission. Whole-genome multilocus sequence typing (Wg-MLST) analysis further revealed close genomic relationships among lnu(C)-positive C. jejuni isolates. In addition, 24 genetic environments among lnu(C)-positive C. jejuni isolates, with the MTnSag1-like transposon [insLNU-lnu(C)] representing both the most prevalent and most broadly distributed genetic context across geographical regions and host species. In conclusion, this study provides a comprehensive analysis of lnu(C) gene distribution, elucidating horizontal transferability and regional clonal expansion patterns. The genetic relatedness of lnu(C)-positive C. jejuni strains across poultry, food, and human sources highlights significant zoonotic transmission potential.