Antimicrobial resistance of Salmonella isolated from animals and feed in Poland

Five hundred and sixty Salmonella isolates belonging to 42 serovars were tested for antimicrobial resistance with ATBVET. The strains were collected from poultry, pigs, animal feed, and several other sources during two-year period (2000-2001). The survey showed the recent trends in Salmonella antimicrobial resistance. A frequency of the isolation of resistant strains has been increasing. A high number of tested Salmonella strains were resistant to nitrofurantoin, doxycycline, streptomycin, tetracycline, flumequine, and oxolinic acid. Of the 20 antimicrobials used only colistin was active against all tested isolates. Few strains revealed apramycin, gentamycin, kanamycin and ciprofloxacin resistance. A decrease in quinolone efficacy was observed. No Salmonella showing extended-spectrum beta-lactamase activity was found. Differences were noted in antimicrobial resistance depending on Salmonella serovar and the source of isolation. Multiresistance was observed in the majority of S. Hadar and S. Gallinarum strains. However, S. Typhimurium revealed the most complex resistance patterns. Salmonellas originating from swine were more resistant than those from poultry and feed. It is concluded that Salmonella antibiotic resistance should be evaluated continuously because of serious human and animal health implications.