Sensitivity of 880 blood culture isolates to 24 antibiotics

Blood culture isolates (n = 880) collected during 2.5 years (period I n = 515, July 1988 to December 1989; period II n = 365, January 1992 to December 1992) were analysed with the agar dilution method to ascertain their sensitivity to 24 antibiotics. The susceptibility of bacteria was classified according to MIC values and susceptibility grouping used in the SIR system (sensitive-S, intermediate-I, resistant-R). Comparison of percentage S+I values for the 2 periods revealed no major development of resistance. Co-trimoxazole and some cephalosporins (cefpirom, cefepime and cefotaxime) were active (S+I) against 88-92% of the strains. Imipenem and the combination piperacillin-tazobaclam were active against 95% of the strains. A very large number of strains (98.2 to 98.6%) were inhibited (S+I) by the quinolones tested, ciprofloxacin and ofloxacin. Comparison of the present results with those of our 1980-81 study yielded no evidence of resistance development, except for an increase in betalactamase-producing S. aureus strains, from 67% to 85%.