EN
Resistance to 17 antimicrobial substances was tested in 529 Salmonella strains isolated from animals, their environment, and animal feeds during the years 1994-1996. Most of the strains (310) belonged to serovar of S. enteritidis. Other examined serovars were as follows: S. typhimurium (23 strains), S. mbandaka (22 strains), S. livingstone (14 strains) and S. agona (12 strains). Ninety-seven of the salmonellas belonged to 35 other serovars, each of them comprising less than 10 strains. Thirty-one Salmonella strains were unidentified because of their roughness. The percentage of tested strains resistant to at least one of the antimicrobial agents was 19.8%. In the case of S. enteritidis serovar, only 13.5% of strains showed resistance to antimicrobial substances. None of the 529 isolates was resistant to ciprofloxacin or colistin and 99% of the strains revealed sensitivity to chloramphenicol, kanamycin, polimyxin, neomycin, suifametaxazol/trimetoprim, gentamycin, amikacin and cefuroxin. Ninety-eight percent of the strains were sensitive to ampicilin or furazolidon. Sensitivity to enrofloxacin, sulfonamide and streptomycin was found in 96%, 95% and 90% of the strains, respectively. Regarding nalidixic acid or tetracycline, sensitivity was demonstrated in 79% and 46% of the Salmonella strains, respectively. Multiple resistance was detected in 49% of salmonellas excluding S. enteritidis strains. This percentage was much lower with regard to S. enteritidis strains (14%). A high percentage of S. typhimurium, S. mbandaka and S. saint-paul strains were resistant to a wide variety of antimicrobial agent combinations. Occurrence of 30 drug resistance patterns was observed in Salmonella strains investigated for resistance to antimicrobial substances.