Exopolysaccharide vaccine extracted from C.freundii induce immunity against infectional pathogens

Eleven isolates of Citrobacter. freundii were isolated from100 stool and urine specimens taken from diarrhea and recurrent –urinary tract infections (UTI) patients attended to AL-Sadar Hospital. specimens were cultured on specific media, then bacterial isolates were identified depending on morphological, biochemical and VITK-2. The results showed that the C. freundii comprise 11 / 78 (14.1 %) of total of positive bacterial growth on macConky agar from which 10.2 % isolated from patients suffering from diarrhea and 3.8 % isolated from UTIs . The results of determine efficient isolate in exopolysaccharide(EXP ) production revealed that C. freundii were isolated from recurrent -UTI was more mucoidy colonies and appeared highly biofilm formation with absorbancy 0.890 . The results of LD50 observed that a live suspension of C. freundii was 1×107 ,while HK E,coli was 2.3×108 finally EXP was 390 mg/ml .The immunomodulatory activity appear that EXP relaease moderate levels of proinflammatory biomarker ( IL-6 , TNF-α and IL-12) that enable immune system to clear pathogen . While HK E.coli and whole bacteria release higher proinflammatory biomarker especially during post-dose that lead to increased the hypersensitivity and hyperresponses of immune system. In other hand EXP stimulate release moderate concentration of anti-inflammatory biomarker IL-10 and higher eleveated during post dose but HK E.coli and whole bacteria higher concentration during primary dose while in post dose lower than EXP vaccine. A significant immunogenicity and effective protection was observed in immunized groups with EXP challenged with 100 of LD50 of a live C. freundii compared with control group of mice which died within first days .