ASSESSMENT OF PROBIOTIC THERAPY AS AN ALTERNATIVE TO ANTIBIOTICS IN LIVESTOCK INFECTIONS

Abstract

Background

Livestock gastrointestinal infections require effective management, but routine antibiotic use drives antimicrobial resistance. Whether commercial probiotics offer a viable, microbiome-sparing alternative remains unclear in real-world agricultural settings. This study evaluated the comparative effectiveness of probiotics versus antibiotics for pathogen clearance.

Methods

In a prospective multicenter cohort study across 15 agricultural sites in Lahore, Pakistan, livestock with microbiologically confirmed endemic enteric infections were observed following treatment with exclusive commercial probiotics or standard antibiotics. The primary exposure was management strategy. The primary outcome was 14-day microbiological clearance (negative index pathogen culture or qPCR). Models adjusted for animal species, age, and baseline bacterial load. Secondary endpoints included antimicrobial resistance emergence and 30-day opportunistic infections.

Results

More than the required sample was screened to enroll 660 livestock; 642 (97.3% completion) were followed for 30 days (312 probiotic, 330 antibiotic). Probiotic therapy was associated with lower 14-day microbiological clearance (68.9% vs 84.2%; adjusted odds ratio, 0.58 [95% CI, 0.39 to 0.86]; p=0.007). However, probiotics were associated with markedly lower antimicrobial resistance emergence (11.9% vs 47.0%; p<0.001) and fewer secondary opportunistic infections (3.5% vs 10.3%; p=0.003). No systemic adverse events unrelated to natural disease progression occurred.

Conclusions

Although associated with lower primary pathogen clearance, probiotic therapy significantly reduced antimicrobial resistance emergence and secondary opportunistic infections. Given the observational design and potential confounding by indication, probiotics may serve as microbiome-sparing alternatives for non-critical infections, warranting cluster-randomized controlled trials.