Nosocomial infection of nurselings caused by multiple drug resistant strain of Salmonella typhimurium--utilization of a new typing method based on lysogeny of strains.

During a period of 18 months diarrheal diseases appeared among nurselings in one region of Slovakia. Salmonella typhimurium strains were isolated from 265 cases. The diseased nurselings were kept in a nurseling-home and/or were hospitalized in two city hospitals. The isolated Salmonella typhimurium strains were resistant to ampicillin, carbenicillin, tetracyclin, chloramphenicol, neomycin, kanamycin and sulphonamides, and, carried R-plasmids. The tested strains proved identical by phage typing according to the systems of Felix-Callow and Scholtens. The were lysogenic and reacted in an identical way with indicator strains. The results of tests indicate that the nosocomial infection of nurselings was caused by long-term persistance and spread of a single polyresistant strain of Salmonella typhimurium.