Virulence genes of Escherichia coli vaginal isolates associated with postpartum dysgalactia syndrome in sows

Objective: Identify the occurrence of certain virulence genes of Escherichia coli vaginal isolates associated with postpartum dysgalactia syndrome (PDS) in sows. Materials and methods: Two hundred and two sows from 5 Macedonian pig farms were clinically examined for PDS 12 to 24 hours after farrowing. Vaginal swabs for bacteriological testing were taken from PDS-affected (PDSA, n = 47) and PDS-unaffected (PDSU, n = 155) sows. In total, 74 isolates of E coli were tested by multiplex polymerase chain reaction for the presence of virulence genes related to specific pathogenic strains. Results: Genes associated with extra-intestinal pathogenic E coli (ExPEC) strains were the most prevalent among all tested E coli isolates. The most dominant gene among all E coli isolates was fimC. The iss gene was more prevalent in PDSA sows compared to PDSU sows (P = .02). Multivariable logistic regression showed that lower parity sows (P ≤ .001) and presence of the iss (P = .003) and astA genes (P = .03) were correlated with the occurrence of PDS. Implications: Lower parity sows vaginally infected with E coli associated with particular ExPEC strains are at higher risk of developing PDS. Positive vaginal swabs for E coli and iss gene found early after farrowing were associated with PDS in sows. Classification of E coli into specific ExPEC pathotype was not possible by virulence genotyping only.