Activity of vancomycin, teicoplanin and cephalosporins against penicillin-susceptible and penicillin-intermediate Streptococcus pneumoniae

To report in vitro susceptibilities of penicillin-susceptible and penicillin-intermediate Streptococcus pneumoniae isolates to cephalosporins, vancomycin and teicoplanin. Minimal inhibitory concentrations (mic) were determined according to National Committee for Clinical Laboratory Standards guidelines for 17 penicillin-susceptible isolates (mic 0.06 mg/L or less) and 16 isolates showing intermediate susceptibility to penicillin (mic 0.12 to 1.0 mg/L). Tertiary care university centre. Comparison of the mic(90) values with those of other antibiotics tested demonstrated that ceftriaxone, cefotaxime and teicoplanin were the most active agents against penicillin-susceptible strains. However, teicoplanin had the lowest mic and was superior to other agents against strains with intermediate penicillin susceptibility. The mics of all cephalosporins increased in concordance with the mic of penicillin. Isolates demonstrating intermediate susceptibility or resistance to penicillin should be routinely evaluated for susceptibility to clinically important cephalosporins.