Evaluation of the Lipopolysaccharide of Escherichia coli O157:H7 for prophylactic ability against diarrhoea caused by homologous organism in Wistar albino rats

Ademokoya AA¹*, Adebolu TT² and Ogundare AO²

¹Department of Microbiology, Adekunle Ajasin University, Akungba Akoko, Ondo State, Nigeria

²Department of Microbiology, Federal University of Technology, Akure, Ondo State, Nigeria.

*Corresponding Author`s E-mail: a.ademokoya@yahoo.com

Accepted 11 March, 2015

Abstract

In searching for a prophylactic measure against diarrhoea caused by E. coli 0157:H7, the lipopolysaccharide (LPS) of the organism was investigated for possible protective effect in Wistar albino rats against the organism. The E. coli O157:H7 used in this study was isolated from diarrhoeic patients attending one of the Federal Medical Centers in South West, Nigeria using standard microbiological methods and its identity confirmed using both serological and polymerase chain reactions. The LPS of the organism was extracted using hot-phenol water method while antibodies to the LPS of the isolated E. coli O157:H7 was raised in New Zealand White rabbits by subcutaneous immunization method. The results showed that the LPS of E. coli O157:H7 raised in the rabbits elicited serum antibodies with high titre and bactericidal activity. Active and passive protection in Wistar albino rats against E. coli 0157:H7 with the LPS and the corresponding anti LPS conferred a 70% and 50% protection respectively in the rats used for the assays. This study has been able to show that lipopolysaccharide extracted from E. coli O157:H7 was able to confer protection in Wistar albino rats against diarrhoea caused by the organism. It is therefore conceivable that LPS can be used as a vaccine  for the prevention of the infection  in both animals and human beings.

Keywords: E. coli O157:H7, Lipopolysaccharide, prophylaxis