Antimicrobial susceptibility of intestinal bacteria from Swiss poultry flocks before the ban of antimicrobial growth promoters

Fram the crop and the caecum of Swiss broilers slaughtered between November 1997 and January 1398, Escherichia coli, enterococci, staphylococci, lacto baciili and Campylobacter species were isolated. After identification to th e genus or species level, their minimal inhibitory concentrations (MIC's) f or several clinically used antimicrobial agents were determined with the E- Test stripes and compared to those from studies in other European countries . All strains of Enterococcus faecatis (n = 38), E. faecium (27), staphylococ ci (n = 39) and lactobacilli (n = 14) showed a hundred percent resistance a gainst bacitracin which was included in the feed of the mother animals, but not in the feed of the investigated animals. E. coli strains (n = 60) show ed higher resistance incidences than in comparable studies from Finland and Denmark, bur lower than those in studies from leary and Germany. In staphy lococci, low resistance rates were observed. A high susceptibility of the 1 3 Campylobacter jejuni strains was found against therapeutically used antim icrobials. These data can be used as a baseline to determine antibiotic res istance rates after implementation of the growth promotor ban in 1999 in Sw itzerland.