Study the inhibitory effect of purified lipopolysaccharide extracted from Proteus mirabilis on E.coli O157 H7 isolate from diarrheal infected animals

Abstract

Currentstudy included four parts: the first part is the isolation and identification 4 isolates of Proteus mirabilis from 45 different samples include 20 samples of urirne, 15 samples of feces , 10 samples from ear infection. These isolates were identified by morphological examination and biochemical tests and API20 E system .The second part was the isolation and identification 1 isolates of E. coli O157 H7 from 33 diarrheal infected animals, these isolates were identified by morphological examination , growing on selective media such as( sorbitol MacConkey agar and CHROMagar ) ,biochemical tests and by latex agglutination test. In the third part of this study, lipopolysaccharide (LPS) was extracted from Proteus mirabilis by using hot phenol method ,and after that crude extracted LPS purified by gel filtration chromatography using Sepharose CL-6B gel . And the yield was (180) mg LPS from 26 g from dry weight cell of P. mirabilis. chemical analysis of LPS in 1 ml of crud and partial purified LPS showed that the carbohydrate percentages were (3.23, 5.92) % respectively ,while protein percentage were (0.53, 0.38) % respectively. The fourth part of this study ,determination antibacterial activity of LPS extracted from Proteus mirabilis in different concentration ( 700,800,900,1000,1100,1200) µg /ml against E.coli O157 H7, the mean of inhibitory zone diameter were (27.33 , 30 , 31.33 , 32 , 34 , 37) respectively .The present study provides evidence antibacterial effect of LPS extracted from Proteus mirabilis on the E.coli O157 H7 isolated from diarrheal infected animals. This study was conducted in University of Diyala / Collage of Veterinary medicine / Department of microbiology and in Razi Center for Research and production of personal medical issue, from the period (1/11/2015 to 1/4/2016).