The effect of colicin on E. coli K99 in mice

K99 pilus antigen is one of the major adherence factors found on enterotoxigenic Escherichia coli (ETEC) of neonatal calves. It causes severe diarrhea in newborn calves via the production of heat-stable enterotoxin (STa).With increasing concern over the spread of antimicrobial resistance, the development of alternative to conventional antibiotics such as colicin is urgently needed. Colicin is an antimicrobial peptide produced by one strain of E. coli to suppress the growth of other strains of E.coli. The purpose of this study was to investigate the control of E.coli k99 and the efficacy of colicinogenic E.coli (CEC) in adult mice. The mice, used antibiotic were divided into four groups. The first group did not receive any inoculation. The second group was fed just with 0.5 ml colicin solution. The third group was fed just with 0.5 ml E.coli k99 suspension. The fourth group was first fed by 0.5 ml E.coli k99 suspension immediately after oral administration of CEC suspension. Fecal samples of mice in four groups were taken 1, 2, 3, 4, 5, 6 and 7 days after inoculation and colony forming units (CFUs) were monitored per gram feces. The results showed that CEC has inhibitory effect against E.coli k99. There were observed significant differences between the amounts of E.coli k99 recovered from the feces of mice in fourth group with the amount of E.coli k99 recovered from the feces of mice in third group. The data presented here support this claim that CEC plays a significant role against E.coli k99. Furthermore, the study suggested colicin warrants further evaluation as a potential alternative to conventional antibiotics for use to control of E.coli k99.