Serological investigation and isolation of Salmonella abortus equi in horses in Xinjiang.
Authors: Mai Zhanhai, Fu Han, Miao Ronghao, Lu Chong, Zhang Xiaosong, Yuan Ziwen, Ji Peng, Hua Yongli, Wang Chen, Ma Yuhui, Deng Haifeng, Wei Yanming
Journal: BMC veterinary research
Summary
# Editorial Summary: Salmonella abortus equi in Xinjiang Horse Populations Salmonella abortus equi remains a significant reproductive pathogen in equine populations, yet regional prevalence data remain sparse outside traditional breeding areas. Researchers conducted serological screening of 971 horses across eight farms in two Xinjiang prefectures between 2020 and 2023, followed by bacterial isolation and antimicrobial susceptibility testing from aborted foetal tissues and vaginal swabs. Overall antibody prevalence reached 20.91%, with marked geographic and demographic variation: the Ili region showed substantially higher seropositivity (29.09%) than Bayingol (11.24%), mares were more frequently exposed than stallions (22.45% versus 14.05%), and self-propagating thoroughbreds demonstrated dramatically elevated risk compared with local breeds (43.22% versus 11.24% in Yanqi horses). Age structure profoundly influenced susceptibility, with juvenile and geriatric horses showing positive rates of 70.00% and 41.86% respectively—more than triple that of young adults. Nine isolated strains displayed resistance to five antimicrobials including penicillin and clarithromycin, whilst remaining susceptible to amoxicillin, ciprofloxacin and gentamicin. These findings underscore the need for breed-specific and age-stratified biosecurity protocols in Xinjiang operations, particularly for imported or intensively managed stock, and support judicious fluoroquinolone or aminoglycoside selection when empirical treatment is warranted.
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Practical Takeaways
- •Monitor pregnant mares closely for S. abortus equi infection, particularly thoroughbred horses and animals at the extremes of age (juveniles and elderly), as these populations show significantly elevated infection rates
- •Regional risk assessment is important—Ili Prefecture horses have double the infection rate of other regions, warranting enhanced surveillance and biosecurity measures in that area
- •When treating confirmed S. abortus equi infections, amoxicillin, ciprofloxacin, and gentamicin are reliable options; avoid clarithromycin, clindamycin, penicillin, sulfamethoxazole, and rifampicin due to documented resistance
Key Findings
- •S. abortus equi antibody positive rate was 20.91% across 971 horse serum samples, with significantly higher prevalence in Ili region (29.09%) compared to Bayingole region (11.24%)
- •Self-propagating thoroughbred horses showed highest susceptibility at 43.22% positive rate, compared to half-bred (28.81%), Ili horses (14.72%), and Yanqi horses (11.24%)
- •Juvenile horses (70.00%) and elderly horses (41.86%) showed significantly higher infection rates than young (10.97%) and adult (19.79%) horses
- •Nine S. abortus equi isolates were resistant to 5 antibiotics (clarithromycin, clindamycin, penicillin, sulfamethoxazole, rifampicin) and sensitive to 13 antimicrobial agents including amoxicillin, ciprofloxacin, and gentamicin