ABSTRACT
Acinetobacter nosocomialis is an important nosocomial pathogen that causes a variety of human infections. However, the specific virulence factors of this microorganism have not yet been determined. We investigated the role of outer membrane protein A (OmpA) in the pathogenesis of A. nosocomialis. A ΔompA mutant of the A. nosocomialis ATCC 17903T strain was constructed using markerless gene deletion. The ΔompA mutant displayed reduced biofilm formation in polystyrene tubes and reduced adherence to A549 cells in comparison to the wild-type strain. These virulence traits of the ΔompA mutant strain were restored when the ompA gene was complemented. Cytotoxicity was not significantly different between the wild-type strain and the ΔompA mutant when A549 cells were infected with bacteria or treated with outer membrane vesicles (OMVs). However, OMVs from the wild-type strain induced cytotoxicity in HEp-2 cells, whereas OMVs from the ΔompA mutant did not induce cytotoxicity. Proteomic analysis of OMVs revealed that OmpA influenced the distribution of envelope and periplasmic proteins. Overall, this study is the first report that links OmpA to A. nosocomialis pathogenesis, and highlights OmpA as a putative target to develop anti-virulence agents or vaccines against A. nosocomialis infection.
Disclosure of potential conflicts of interest
No potential conflicts of interest were disclosed.
Funding
This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health &Welfare, Republic of Korea (grant number: HI14C0257).
Author contributions
All authors contributed to the design of the experiments, analysis of the data, and writing of the manuscript. SWK and KHK performed the biofilm formation and bacterial adherence assays. MHO constructed the ompA deletion mutant and its complemented strain and performed biofilm assay and SEM analysis. SHJ and HJ performed cytotoxicity assay. SIK and YCL performed proteomic analysis.