Data-driven, integrated control of Streptococcus suis substantially reduces mortality and antimicrobial use in a commercial swine herd

Abstract

Abstract Streptococcus suis is a major cause of meningitis, septicemia, and arthritis in swine, and its control is complicated by antimicrobial resistance and the absence of broadly protective vaccines. We evaluated a data-driven, integrated control program in a 3-year prospective, single-site quality-improvement study using an interrupted time-series design in a PRRSV-free, 1,000-sow herd comprising approximately 126,000 liveborn piglets. The program combined clinical, pathological, and bacteriological surveillance, including capsular polysaccharide ( cps ) serotyping, antimicrobial susceptibility testing with performance and antimicrobial-use monitoring. Interventions included sow vaccination with a herd-specific autogenous bacterin (serotypes 2 and 1/2), strengthened internal biosecurity, structured colostrum management supported by Brix refractometry, and antimicrobial stewardship. Data were captured using an in-house animal-health monitoring and decision-support platform. Within 6 months of program implementation, S. suis -associated mortality had markedly declined, and pathological lesions detected at necropsy decreased by approximately 50%. Within 1 year, use of Category B antimicrobials, including ceftiofur and enrofloxacin, was eliminated. By the end of year 2, metaphylactic amoxicillin use had been discontinued, and florfenicol metaphylaxis had decreased by nearly 25%. Total antimicrobial use, expressed as active antimicrobial ingredient, in suckling and weaned piglets decreased by 98.2% (from 615.8 to 11.1 kg), S. suis -associated mortality declined by approximately 90%, post-weaning mortality decreased from 2% to < 1%, and mean weaning weight increased by 10% (from 6.8 to 7.5 kg). These findings demonstrate a strong temporal association between implementation of the integrated herd-health program and substantial reductions in S. suis -associated disease and antimicrobial use, including elimination of Category B antimicrobials. Because multiple interventions were implemented concurrently and no contemporaneous control herd was available, the observed improvements cannot be attributed to any single program component.

The authors' abstract, as published at the source. Scientific Reports, 2026 · DOI ↗