Trueperella pyogenesis the primary pathogen of the abscess disease of forest musk deer (Moschus berezovskii), but a large amount ofPseudomonas aeruginosacan usually be detected in the purulent lesions of dying or dead deer. Although these 2 pathogenic bacteria can be co-isolated, their interaction relationship and the transition mechanism of predominant bacteria in abscess lesions are largely unknown. In this study, the interspecific interaction ofP. aeruginosawithT. pyogeneswas explored by constructing different mutant strains inP. aeruginosaquorum-sensing (QS) system and performing a series of detailedin vitroproximity assays. The results showed that the extracellular product ofP. aeruginosacould significantly inhibit the growth of neighboringT. pyogenes. In comparison to the wild-typeP. aeruginosa, knock-out of any core regulatory genes ofP. aeruginosaQS system would impair the inhibition ofP. aeruginosaonT. pyogenes, albeit the growth ofT. pyogenescould still be blocked by the presence of the extracellular products ofP. aeruginosaQS mutants. Notably, the double mutant strain PAO1-ΔlasRrhlRhad the slightest inhibitory effect onT. pyogenes. These findings suggested thatP. aeruginosahad significant competitive advantage overT. pyogenesby producing various QS-controlled extracellular products. Therefore, the current study provides a reasonable explanation for the transition of dominant bacterial species during the development of forest musk deer abscess diseases, contributes to further understanding the pathology of forest musk deer abscess diseases, the improvement of treatment options and the development of novel anti-infective drugs.
