Characteristics of lactose-fermenting Salmonella strains from Poland.

In this study 184 lactose-fermenting Salmonella strains, collected in the National Salmonella Centre from the northern and central parts of Ponad were examined. Epidemiological, serological and biochemical investigations were carried out. Apart from this, chemotherapeutic resistance and male-phage sensitivity were determined. Most of strains belonged to S. agona serotype (S. typhimurium and S. oranienburg were also presented) which apart from the lactose-fermenting ability retained all the remaining biochemical features typical of Salmonella bacilli, were male-phage M13 resistant and showed a high resistance to a wide spectrum of chemotherapeutics. In order to establish the way of the acquiring lac+ property by Salmonella bacilli P22 phage transduction and conjugation experiments, with E. coli F'lac and Hfr H as donors, were performed. S. agona lac- strains were shown to acquire the lactose-fermenting ability by mating with E. coli.