Enrichment procedures for the isolation of Salmonella, Arizona, Edwardsiella and Shigella from faeces

Abstract

Strontium selenite A broth incubated at 37 degrees C., and strontium chloride B broth incubated at 43 degrees C., have been found an effective combination for the isolation of Salmonella, Arizona and Edwardsiella from human faeces.Direct plating on deoxycholate citrate agar was superior to enrichment methods for the isolation of Shigella species.Strontium selenite A broth was suitable for the isolation of Salmonella and Arizona bacteria at both 37 degrees and 43 degrees C.Strontium chloride B broth incubated at 43 degrees C. was best for the isolation of Salmonella and Edwardsiella.Modified bismuth sulphite agar, although superior to D.C. agar for the growth of Salmonella and Arizona bacteria, was unsuitable for Edwardsiella and Shigella species.A considerable difference was observed in the distribution of Salmonella, Arizona and Edwardsiella serotypes isolated from humans in remote areas, when compared with isolations from more densely populated urban and agricultural centres.Epidemiological and zoogeographical aspects of host-parasite associations between humans, animals and pathogenic Enterobacteriaceae in Western Australia are discussed.