Serotype Distribution and Antimicrobial Resistance of Adult Streptococcus pneumoniae Clinical Isolates over the Period 2001–2008 in Crete, Greece.

Background: We report on the serotype distribution and the antimicrobial susceptibility patterns (ASP) to 19 antibiotics of 195 Streptococcus pneumoniae isolates (41 invasive) collected over the period 2001–2008 from adult patients. Material and Methods: Pneumococcal isolates were serotyped by the Quellung reaction, and ASP testing was performed using E-test. Results: Isolates with intermediate and high-level resistance to penicillin increased from 17 and 12.4% over the period 2001–2004 to 31.1 and 16.7% over the years 2005–2008, respectively (p = 0.03). Macrolide resistance increased from 27.6 to 38.9%, but this was not significant (p = 0.13), while resistance to trimethoprim-sulfamethoxazole did not change over time, with approximately one fourth of the isolates being resistant. Only one isolate was resistant to fluoroquinolones. Multi-resistance was observed among 42 (58.1%) penicillin non-susceptible strains. The isolates tested belonged to 20 different serotypes. Serotypes 19F and 19A were the most common among penicillin-resistant isolates. The currently licensed 23-valent pneumococcal polysaccharide vaccine covered 98.4% of all 186 typeable S. pneumoniae strains. Conclusion: Our study emphasizes the importance of continued serotyping and surveillance of antimicrobial susceptibility of all S. pneumoniae clinical isolates, especially invasive ones, in order to guide the clinician in the choice of appropriate empirical antibiotic therapy for serious pneumococcal infections. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]