Identification of novel genes associated with anti-phagocytic functions in Streptococcus equi subsp. zooepidemicus

Publication date: Available online 17 April 2019Source: Veterinary MicrobiologyAuthor(s): Bin Xu, Ping Zhang, Hong Zhou, Yu Sun, Jinsheng Tang, Hongjie FanAbstractThe anti-phagocytic abilities of bacteria often affect bacterial pathogenicity. Here, random mutant library of Streptococcus equi subsp. zooepidemicus (SEZ) was constructed using transposon mutagenesis. After careful screening, 30 transposon mutants with different transposon insertion sites were identified by conducting quantitative phagocytosis and insertion-site confirmation assays, whose anti-phagocytic abilities were significantly reduced relative to the wild-type strain. Insertion sites of 19 strains were monocistronic, including genes coding membrane proteins, transporters, and enzymes with unknown pathological function, such as sadM, adhP, purD, guaA, alpha-galactosidase coding gene, ABC transporter permease coding gene, metallo-beta-lactamase coding gene, and three secreted enzyme coding genes spuZ, slaB, and endoS, as well as known virulence factor coding genes, such as hasA and szM. The insertion sites of another 11 strains were polycistronic. We focused on four monocistronic-mutant strains: MhtpZ, MspuZ, MslaB, and MendoS. The anti-phagocytic abilities of not only the mutants that were precoincubated with the recombinant proteins, but also the complement strains were significantly more pronounced than those of all four corresponding mutants. The polyclonal antiserum against SlaB or EndoS also significantl...
Source: Veterinary Microbiology - Category: Veterinary Research Source Type: research