The relationship between hospital and catchment area utilization of antimicrobial agents and the antibiotic sensitivity of bacteria isolated from primary infections has been studied after 750 gastric operations performed between 1972 and 1986 at the Huddinge University Hospital. Over 80% of the antibiotics were used in the catchment area. Penicillins (G and V) overall were the most commonly used drugs and comprised 37% of the total antibiotic consumption in 1977-1986. Narrow-spectrum antibiotics dominated throughout the period under investigation. No change in the bacterial resistance to antimicrobial agents was found over time. Many strains of Klebsiella/Enterobacter and E. coli resistant to ampicillin and tetracyclines were recovered throughout the period under investigation. No aerobic Gram-negative bacteria were resistant to gentamicin. All Bacteroides strains except two were sensitive to cefoxitin. Tetracyclines and ampicillin/amoxycillin were mainly used in the catchment area, and cefoxitin and aminoglycosides were almost exclusively used in the hospital. Antimicrobial agents primarily used for out-patients in the catchment area seemed to have more influence on the susceptibility of microorganisms isolated from post-operative infections than agents primarily used in the hospital.
