Symbiosis of Salmonella and Escherichia coli by MY Phenomenon

Abstract

Background: The symbiotic relationship between E. coli and Salmonella was demonstrated using hydrogen sulfide production named MY phenomenon, which is a feature of Salmonella. Methods: In order to confirm the hydrogen sulfide production of Salmonella by iron sulfide formation, deoxycholate-hydrogen sulfate-lactose agar medium having both a sulfur source and an iron source was used. The case where Salmonella was cultured alone was compared with the case co-cultured with E. coli. In the case of culture with Salmonella alone, the MY phenomenon has not occurred. When Salmonella was co-cultured with E. coli, Salmonella cultured near E. coli existing place showed a black color named MY phenomenon. When E. coli was cultured alone, it turned red due to the organic acid produced. However, when E. coli was cultured in the part where Salmonella. is inoculated on the surface of the medium, the MY phenomenon appeared there. Furthermore, hydrogen sulfide production was more active in Salmonella co-existing with E. coli. Conclusion: The study shows an important relation that E. coli is a promoting factor for Salmonella culture by NY phenomenon. The relation suggests that bacterial symbiosis relation exist in bacterial flora.