Hydrogen sulphide producing variants of Escherichia coli, widespread occurrence in animals and humans within a confined environment.

Of 178 strains of E. coli isolated on non-selective medium from faeces of pigs and humans living in the same farm 14 produced hydrogen sulphide. The HS producing variants all belonged to different clones suggesting that the HS character was plasmid-mediated. Attempts to transfer the HS character were not successful nor were attempts to motilize the gene by introduction of a transmissible R factor.