Biochemically aberrant Salmonella enteritidis ser. newington from human sources in Connecticut

Three isolates of a lactose-fermenting, xylose-negative variety of Salmonella enteritidis ser. newington, identical in biochemical and serological reactions and in the antibiogram, were recovered from three patients in different areas of Connecticut in January 1974. Hydrogen sulfide production was not visible in Salmonella-Shigella agar, in triple sugar iron agar, and in Kligler iron agar but was noticed in lysine iron agar and on XLD agar, among others. The amount of fermentable carbohydrates present was found to correlate with failure to show hydrogen sulfide production (pH effect). In contrast to lactose-fermenting Salmonella strains reported by other authors, we could not elicit a direct transfer of the lac(+) character at frequencies above 10(-6). An epidemiological follow-up remained unsuccessful. Recommendations for the recognition of similar strains are presented.