Introduction: Prevention and control of Pseudomonas aeruginosa infections are still among serious nosocomial problems worldwide, since chemotherapeutic control of the infection generally fails. Therefore, using a safe and reliable vaccine against all wild Pseudomonas aeruginosa serotypes is the only solution to overcome this problem.

Methods: 300 Pseudomonas aeruginosa strains were isolated from patients admitted to four Tehran hospitals. Using standard O-specific typing sera, they were all grouped in 16 out of 17 known Pseudomonas aeruginosa serotypes. The 16 serotypes were lyophilized and each given a code according to the Collection of Standard Bacteria of Pasteur Institute of Iran (CSBPI) for further investigation. Among all clinical samples, CSBPI: 16-190 was the most prevalent Pseudomonas aeruginosa serotype which showed a high agglutination titer against homologous O-specific typing sera. This serotype was selected for extraction of Pseudomonas aeruginosa major outer membrane vesicles (OMP-F).OMP-F vesicles were extracted and purified by deoxycholate ultracentrifuge- differentiation technique. After molecular evaluation, protective activities and safety of the OMP-F vesicles were determined in animal models.

Results: Preset investigation reveals that, purified OMP-F vesicles of Pseudomonas aeruginosa CSBPI: 16-190 is able to induce a high level of protection against all 16 live homologous and heterologous native Iranian Pseudomonas aeruginosa serotypes. Besides, it was pyrogen free and did not produce any detectable abnormal toxicity in rabbits, mice and guinea pigs.

Discussion: The results showed that purified OMP-F vesicles of Pseudomonas aeruginosa CSBPI: 16-190 can be considered a safe and protective immunogen in vaccine therapy against infections caused by all native Pseudomonas aeruginosa immunotypes in Iran.

 Hakim Research Journal 20069(1):38-44.