Late-term abortion associated with Trueperella abortisuis in Austria: a case report combined with six years of retrospective diagnostic data

Trueperella (T.) abortisuis is an emerging Gram-positive bacterium increasingly associated with reproductive failure in pigs, yet its pathogenic role remains incompletely understood. This study describes a late-term abortion in a sow linked to T. abortisuis and integrates six years of retrospective diagnostic data from Austria. A clinically anorectic sow aborted eleven foetuses at gestational day 100 despite systemic antimicrobial treatment. T. abortisuis was isolated in high quantities from foetal stomach contents, umbilical cord blood, and amniotic fluid in most foetuses. Histopathology revealed severe suppurative bronchopneumonia in seven foetuses and necro-suppurative placentitis with intralesional Gram-positive bacteria in four placentae. Common viral and bacterial abortifacient agents were excluded by PCR. Retrospective analysis of routine diagnostics between 2019 and 2025 identified T. abortisuis in 31 samples from 14 farms, predominantly associated with genital tract specimens and abortion material, with consistently high bacterial loads in pooled foetal stomach contents. This report provides further evidence supporting the abortifacient potential of T. abortisuis in swine. The combination of characteristic suppurative and necrotizing placentitis, foetal infection, exclusion of common abortifacients, and supportive institutional diagnostic observations suggests that T. abortisuis should be considered in the differential diagnosis of porcine reproductive failure. The apparent lack of clinical response to systemic β-lactam treatment may reflect the advanced stage of foetal and placental infection at the time therapy was initiated, in addition to the limited knowledge regarding placental transfer of systemically administered antimicrobials in pregnant sows.