Evaluation of Immunogenicity of PLGA - Proteus  mirabilis Detoxified Lipopolysaccharide Conjugate Against Urinary Tract Infection in Mice

Proteus is a gram negative and  facultative anaerobic opportunistic pathogen. This bacterium is responsible for 10% of urinary tract infections. A cause of 90% of proteus-induced infection is the mirabilis. Increasing the multi-drug resistance and the side effects of antibiotics have led to a special concern for this purpose, finding preventive strategies like making a vaccine seems essential. In the present study, LPS from Proteus mirabilis, was extracted, detoxified and conjugated to PLGA nanoparticle. This conjugation was confirmed with ZetaSizer, FTIR and AFM. Vaccination was done intramuscularly, 3 times in two weeks intervals. Then, mices were anesthetized and operated with ethical rights and 6×107 CFU concentrations of P.mirabilis was injected into their bladder. After one week of injection, bladders were removed and suspended in a salt buffer.The results of the challenge test confirmed the success of the PLGA-LPS conjugate in comparison with other groups. In other words, the control and PLGA groups had the highest growth rates, and the average number of colonies was significantly higher than all of the groups. And the number of colonies grown in groups were LPS-PLGA(6.2 *10 cfu/ml) , LPS(3.6 ×103 cfu/ml), PLGA (91.3×102 cfu/ml) and NS(98 × 102 cfu/ml). According to one-way ANOVA, which was done by SPSS software, there was a significant difference between all groups (P <0.05).the PLGA immunogenicity was significantly different with the control group. Therefore, it can be concluded that the PLGA-LPS conjugate has an appropriate immunity and can be a candidate of nano-vaccine for urinary tract infection of P.migrailitis.