RT Journal Article SR Electronic(1) A1 Hu, Yin-yin A1 Liu, Cai-xia A1 Liu, Peng A1 Wu, Zhuo-ying A1 Zhang, Ya-dong A1 Xiong, Xiao-shun A1 Li, Xiang-yangYR 2018 T1 Regulation of gene expression of hcp, a core gene of the type VI secretion system in Acinetobacter baumannii causing respiratory tract infection JF Journal of Medical Microbiology, VO 67 IS 7 SP 945 OP 951 DO https://doi.org/10.1099/jmm.0.000753 PB Microbiology Society, SN 1473-5644, AB Purpose. The objective of the current study was to investigate whether hcp plays a role in the process of Acinetobacter baumannii infection and to examine clinically relevant factors that may affect hcp expression. Methodology. Seventy-seven A. baumannii 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 hcp. Quantitative real time polymerase chain reaction (qRT-PCR) was carried out to examine the expression of hcp. Results. A total of 77.9 % (60 of 77) of the A. baumannii clinical isolates possessed the hcp gene. Expression of hcp was found to be strain-specific and associated with the infection status. Higher gene expression of hcp was found for invasive A. baumannii 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 hcp gene expression. Conclusion. The type VI secretion system and hcp predominate in A. baumannii causing respiratory infections. Expression of hcp is regulated by the infection status and acid environment, and might play a role in the process of triggering infection by the colonizer., UL https://www.microbiologyresearch.org/content/journal/jmm/10.1099/jmm.0.000753