In vitro activities of oral antimicrobial agents against penicillin-resistant Streptococcus pneumoniae: implications for outpatient treatment.
We tested 83 penicillin-intermediate (Peni) and 50 penicillin-resistant (Penr) isolates of Streptococcus pneumoniae against eight oral antimicrobials. Clarithromycin's MICs (minimal inhibitory concentration) were generally the same or one to two dilutions less than those of azithromycin. Seventy-two percent of Peni isolates were susceptible to clarithromycin and azithromycin, in contrast to 42% and 40%, respectively, of Penr isolates. Cefuroxime activity exceeded that of cefprozil, which exceeded that of cefaclor, in Peni isolates. For all three cephalosporins, MICs of 90% of isolates tested were > or = 3 dilutions higher for Penr isolates than for Peni isolates. Percentages of Peni isolates susceptible to clindamycin and tetracycline were 92% and 83%, respectively, and 78% and 82% for Penr. Only 49% of Peni isolates and 4% of Penr isolates were susceptible to trimethoprim-sulfamethoxazole. Azithromycin, clarithromycin, cefuroxime, cefprozil, clindamycin, and tetracycline may be useful in treating infections caused by Peni S pneumoniae, but Penr isolates are frequently resistant to both old and newer agents.
Waites
K
K
Department of Pathology, University of Alabama at Birmingham 35233, USA.
Swiatlo
E
E
Gray
B
B
Brookings
E
E
D000284:Administration, Oral; D000328:Adult; D000553:Ambulatory Care; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D017963:Azithromycin / Q000008:administration & dosage / Q000627:therapeutic use; D002433:Cefaclor / Q000008:administration & dosage / Q000627:therapeutic use; D002444:Cefuroxime / Q000008:administration & dosage / Q000627:therapeutic use; D002511:Cephalosporins / Q000008:administration & dosage / Q000627:therapeutic use; D002648:Child; D017291:Clarithromycin / Q000008:administration & dosage / Q000627:therapeutic use; D002981:Clindamycin / Q000008:administration & dosage / Q000627:therapeutic use; D003470:Culture Media; D006801:Humans; D010403:Penicillin Resistance; D011008:Pneumococcal Infections / Q000188:drug therapy; D013296:Streptococcus pneumoniae / Q000187:drug effects*; D013752:Tetracycline / Q000008:administration & dosage / Q000627:therapeutic use; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000008:administration & dosage / Q000627:therapeutic use; D000097670:Cefprozil
D000900:Anti-Bacterial Agents; D017963:Azithromycin; D002433:Cefaclor; D002444:Cefuroxime; D002511:Cephalosporins; D017291:Clarithromycin; D002981:Clindamycin; D003470:Culture Media; D013752:Tetracycline; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D000097670:Cefprozil