Putative Inv Is Essential for Basolateral Invasion of Caco-2 Cells and Acts Synergistically with OmpA To Affect <i>In Vitro</i> and <i>In Vivo</i> Virulence of <i>Cronobacter sakazakii</i> ATCC 29544

다국어 초록 (Multilingual Abstract)

<P><I>Cronobacter sakazakii</I> is an opportunistic pathogen that causes neonatal meningitis and necrotizing enterocolitis. Its interaction with intestinal epithelium is important in the pathogenesis of enteric infections. In this study, we investigated the involvement of the <I>inv</I> gene in the virulence of <I>C. sakazakii</I> ATCC 29544 <I>in vitro</I> and <I>in vivo</I>. Sequence analysis of <I>C. sakazakii</I> ATCC 29544 <I>inv</I> revealed that it is different from other <I>C. sakazakii</I> isolates. In various cell culture models, an Δ<I>inv</I> deletion mutant showed significantly lowered invasion efficiency, which was restored upon genetic complementation. Studying invasion potentials using tight-junction-disrupted Caco-2 cells suggested that the <I>inv</I> gene product mediates basolateral invasion of <I>C. sakazakii</I> ATCC 29544. In addition, comparison of invasion potentials of double mutant (Δ<I>ompA Δinv</I>) and single mutants (Δ<I>ompA</I> and Δ<I>inv</I>) provided evidence for an additive effect of the two putative outer membrane proteins. Finally, the importance of <I>inv</I> and the additive effect of putative Inv and OmpA were also proven in an <I>in vivo</I> rat pup model. This report is the first to demonstrate two proteins working synergistically <I>in vitro</I>, as well as <I>in vivo</I> in <I>C. sakazakii</I> pathogenesis.</P>