Streptococcus pneumoniae resistant to penicillin: Incidence and potential therapeutic options

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Abstract
Streptococcus pneumoniae was recovered from 12 (50%) samples of middle ear fluid of 24 consecutive patients with AOME and in mixed culture of middle ear pathogens from one (4%) additional specimen. Two (15.3%) isolates had intermediate resistance to penicillin (minimal inhibitory concentration (MIC) 0.125 and 1.0 μg/mL). The antimicrobial susceptibility to various antimicrobials of 30 S pneumoniae strains recovered from patients seen in the last 12 months was also determined. One of the patients with AOME developed bacteremia that resolved uneventfully, whereas the other developed meningitis. MIC90 was determined from penicillin (2 μg/mL), erythromycin (>32 μg/mL), cefaclor (32 μg/mL), loracarbef (≥64 μg/mL), cefixime (16 μg/mL), ceftibuten (>64 μg/mL), chloramphenicol (16 μg/mL), cefpodoxime (4 μg/mL), ciprofloxacin (2 μg/mL), cephalexin (≥64 μg/mL), augmentin (2 μg/mL), cefprozil (8 μg/mL), clindamycin (64 μg/mL), TMP-SXT (>64 μg/mL), clarithromycin (32 μg/mL), rifampin (0.06 μg/mL), cefuroxime (2 μg/mL), cefotaxime (0.25 μg/mL), vancomycin (0.25 μg/mL), and imipenem (0.5 μg/mL). Cefprozil, vancomycin, and rifampin inhibited all strains, whereas cefpodoxime, cefuroxime, clindamycin, and clarithromycin exhibited very good activity.