A combination of biofilm-associated protein (Bap) and Outer membrane protein A (OmpA) protects mice against Acinetobacter baumannii infection

Background and Aim : Acinetobacter baumannii is the leading cause of nosocomial infection. A.baumannii is the etiologic agent for various illnesses including pneumonia, meningitis, andbloodstream infections. Due to multiple antibiotic resistance of the bacterium, the treatment is verydifficult, and hence specific and economical test for early diagnosis and control of infection isneeded. The development of such a test requires targeting specific cell surface antigens. Biofilmassociatedprotein (Bap), a specific cell surface protein, is directly involved in A. baumanniibiofilm formation. Production of antibodies can be used for inhibition of biofilm and control ofthe diseases caused by A. baumannii. Outer membrane protein A (OmpA) is the most promisingvaccine candidate against one of the most successful nosocomial pathogens, A. baumannii. In thisstudy, the immunogenicity of Bap and OmpA proteins in BALB/c mice was investigated.Methods : The conserved regions from OmpA and Bap genes determined by in-silico studies werecloned. The construct was transferred to E. coli BL۲۱(DE۳). The recombinant proteins werepurified by Ni-NTA affinity chromatography. The recombinant proteins were injected intoBALB/c mice. The titer of IgG was measured by the indirect ELISA method. The intraperitonealchallenge was performed with A. baumannii ۱۹۶۰۶ in immunized mice and the number of bacteriacounted in the spleen, liver, and lungs of the control and test mice groups.Results : IgG level was significantly increased in the immunized mice sera. A substantialdifference was observed between bacterial counts in the organs of test and control mice afterintraperitoneal challenge with A. baumannii ۱۹۶۰۶.Conclusion : The immunization with Bap and OmpA proteins could prevent Acinetobacterbaumannii infection.

کلیدواژه ها:

OmpA. ، Bap. ، Acinetobacter baumannii. ، Immunization