Plasmid-Encoded MCP Is Involved in Virulence, Motility, and Biofilm Formation of Cronobacter sakazakii ATCC 29544

Abstract

The aim of this study was to elucidate the function of the plasmid-bornemcp(methyl-accepting chemotaxis protein) gene, which plays pleiotropic roles inCronobacter sakazakiiATCC 29544. By searching for virulence factors using a random transposon insertion mutant library, we identified and sequenced a new plasmid, pCSA2, inC. sakazakiiATCC 29544. Anin silicoanalysis of pCSA2 revealed that it included six putative open reading frames, and one of them wasmcp. Themcpmutant was defective for invasion into and adhesion to epithelial cells, and the virulence of themcpmutant was attenuated in rat pups. In addition, we demonstrated that putative MCP regulates the motility ofC. sakazakii, and the expression of the flagellar genes was enhanced in the absence of a functionalmcpgene. Furthermore, a lack of themcpgene also impaired the ability ofC. sakazakiito form a biofilm. Our results demonstrate a regulatory role for MCP in diverse biological processes, including the virulence ofC. sakazakiiATCC 29544. To the best of our knowledge, this study is the first to elucidate a potential function of a plasmid-encoded MCP homolog in theC. sakazakiisequence type 8 (ST8) lineage.