[S. typhimurium strains which are H2S negative in TSI medium]

During an epidemic in the premature ward of Ankara Pediatric Hospital which lasted for almost 25 days, 15 cases were diagnosed and H2S (TSI medium) negative S. typhimurium strains were isolated 23 times on the specimens obtained from these patients. Specimens consisted of mainly stools but two were blood samples, one was a lung aspirate and two were pathologic materials obtained from the elbow and hip joints of the same patient. When these strains were transferred to Braun-Ozek B Medium, they were able to produce H2S which was detected because of the strong blackening on the lead acetate paper. Component replacement studies were performed to show which were necessary for the production of H2S in this second media. According to the results of this studies Pepton witte + meat extract broth + Na2S2O3 . 5H2O were found essential for the production of H2S in Braun-Ozek B. Medium. When this medium was prepared with the incorporation of ferrous ammonium sulfate instead of Na2S2O3, 5H2O, the production of H2S decreased and delayed.