EN
In 1991-1995 the incidence of Salmonella infection was studied in poultry from chicken farms in the Warsaw, Ciechanów, Siedlce and Radom voivodeships. Since 1994 infections with Salmonella enteritidis have been increasing dramatically. This serotype was most commonly isolated in chickens under 3 days of age, which suggests transovarian transmission from infected breeder flocks. Chemioterapeutic susceptibility patterns have been monitored in Salmonella strains including Salmonella enteritidis isolated in the years 1994 and 1995. The percentage of resistance in Salmonella sp. was as follows: amoxycylin 81.6% in 1994 and 56.8% in 1995, neomycin 16% in 1994 and 26.2% in 1995, terramycin 48% in 1994 and 71.9% in 1995, enrofloxacin 6.1% in 1994 and 34.2% in 1995. The common use of antibiotic leads to a resistance tendency of isolated strains of Salmonella.