Regulation of gene expression of , a core gene of the type VI secretion system in causing respiratory tract infection.

The objective of the current study was to investigate whether plays a role in the process of infection and to examine clinically relevant factors that may affect expression. Seventy-seven isolates from patients with a respiratory infection at the Second Affiliated Hospital and Yuying Childrens Hospital of Wenzhou Medical University (Wenzhou, China) were included in this study. PCR was performed to screen for the presence of Quantitative real time polymerase chain reaction (qRT-PCR) was carried out to examine the expression of . A total of 77.9 % (60 of 77) of the clinical isolates possessed the gene. Expression of was found to be strain-specific and associated with the infection status. Higher gene expression of was found for invasive isolates causing an infection relative to the colonization group, and for the same strain at a post-infection status compared with that prior to infection. Acid environment was also found to be a trigger of gene expression. The type VI secretion system and predominate in causing respiratory infections. Expression of is regulated by the infection status and acid environment, and might play a role in the process of triggering infection by the colonizer.