Occurrence, Molecular Characterization, and Antibiotic Resistance of in Goat Milk-Based Infant Formula from Shaanxi Province, China.

This study aimed to investigate the prevalence of in goat milk-based infant formula (GIF) collected from Shaanxi Province, China, and reveal the molecular characterization and antibiotic resistance profile of these isolates. A total of 750 GIF samples were collected from the retail markets in 5 cities in Shaanxi Province from February 2019 to February 2021. Molecular characterization was investigated using multilocus sequence typing and O-antigen serotyping. Antibiotic resistance of isolates was assessed using antimicrobial susceptibility testing. Thirty-two strains of were isolated from GIF samples with a prevalence rate of 4.27% and were divided into 16 sequence types (STs); among them, ST4 (6/32, 18.75%) and ST21 (5/32, 15.63%) were dominant. Five serotypes (O2, O1, O7, O4, and O3) were detected, and serotype O2 (15/32, 46.88%) was the main. Of the 21 antimicrobials, isolates showed higher resistance against cephalothin (87.5%), amoxicillin (25%), azithromycin (18.75%), oxytetracycline (18.75%), ampicillin (12.5%), and streptomycin (12.5%). In addition, three isolates were found to be resistant to three antimicrobials. These findings revealed the potential epidemiological risk and characterization of in GIF from Shaanxi Province, China, and provided reference data for the effective prevention and control of in powdered infant formula.