Distribution of Streptococcus pneumoniae resistant to penicillin in the USA and in-vitro susceptibility to selected oral antibiotics

Surveillance by 33 laboratories in 19 states during a 4 1/2 month period between December 1993 and April 1994 found that 263 of 1627 (16.2%) isolates of Streptococcus pneumoniae were resistant to penicillin. One hundred and seventy (10.4%) isolates were determined to be intermediately resistant to penicillin (MICs 0.1-1.0 mg/L and 93 (5.7%) were found to be highly resistant to penicillin (MICs > 2.0 mg/L). MIC(90s) for intermediately penicillin resistant strains were: amoxycillin/clavulanate 2.0 mg/L, cefaclor 64 mg/L, cefixime 32 mg/L, cefprozil 8 mg/L and loracarbef 128 mg/L. MIC(90s) for highly penicillin resistant strains were: amoxycillin/clavulanate 4.0 mg/L, cefaclor greater than or equal to 128 mg/L cefixime 64 mg/L, cefprozil 32 mg/L and loracarbef greater than or equal to 128 mg/L.