Avian Pathogenic Escherichia coli (APEC) strains belong to the extra-intestinal pathogenic group of E. coli (ExPEC) that causes colibacillosis in poultry. A variety of putative virulence factors of APEC are recognized as potent causes of pathogenicity, the mechanisms underlying their pathogenicity are still not fully understood. The role of yicS in the virulence of pathogenic E. coli is still unclear. Thus, yicS may be related to biofilm formation, which in some bacteria plays a role in pathogenicity. Therefore, the fact that this gene appears to be under positive selection pressure suggests that yicS may be associated with the pathogenicity of APEC. To better understand the role of yicS protein in APEC biological characteristics and pathogenicity, we deleted yicS in an APEC Swollen Head Syndrome strain (APEC strain SCI-07) and studied its effects by comparing wild type and isogenic mutants through comprehensive in vitro and in vivo assays. We demonstrated that yicS plays a role in pathogenicity of APEC. We suggest that the yicS gene, which encodes an exporter protein, has a significant role in biofilm formation, motility, invasion of CEC-32 and Hep-2 cells and APEC pathogenicity in a day-old chick model.

禽致病性大肠埃希菌（APEC）菌株属于大肠埃希菌（ExPEC）的肠道外致病菌群，可导致家禽大肠杆菌病。公认的APEC多种致病性因素是致病性的潜在原因，其致病性的潜在机制仍未完全了解。yicS在致病性大肠杆菌毒力中的作用仍不清楚。因此，yicS可能与生物膜形成有关，生物膜的形成在某些细菌中具有致病性。因此，该基因似乎处于正选择压力下的事实表明，yicS可能与APEC的致病性有关。为了更好地理解角色yicS蛋白在APEC生物学特性和致病性，我们删除yicS在APEC肿头综合征株（APEC株SCI-07），并研究通过综合比较野生型和等位基因突变的影响在体外和体内分析。我们证明了yicS在APEC的致病性中起作用。我们建议，yicS基因编码一个出口蛋白，在一天大的雏鸡模型中，对生物膜形成，运动，CEC-32和Hep-2细胞的侵袭以及APEC致病性具有重要作用。