Influence of patient age on the susceptibility patterns of Streptococcus pneumoniae isolates in North America (2000-2001): report from the SENTRY Antimicrobial Surveillance Program.

Risks of developing resistance in Streptococcus pneumoniae can be greatly influenced by antimicrobial use that is often dictated by patterns of prescribing at various patient ages. The results from the SENTRY Antimicrobial Surveillance Program (2000-2001; North America) were examined for differing susceptibility profiles (25 antimicrobials) indexed by five patient age groups. All MIC results were from reference methods performed in central laboratories. Pneumococcal resistance rates in the youngest patient group (0-5 years) were significantly (p < 0.05) higher for penicillin, other beta-lactams, macrolides, tetracyclines and trimethoprim/sulfamethoxazole. In contrast, fluoroquinolone resistance in S. pneumoniae was greatest in the patients >/= 65 years (1.4% resistance to gatifloxacin, levofloxacin and moxifloxacin), where use of this class has been escalating. Continued local and global surveillance of resistances in common respiratory tract pathogens such as S. pneumoniae appears to be prudent practice to guide effective chemotherapy.