Objective: To investigate the serogroups/types distribution and antimicrobial susceptibility of clinical Streptococcus pneumoniae isolates of different serogroups/types in both children and adults in China, and to explore the significance of vaccines in preventing pneumococcal infections and control of epidemic Streptococcus pneumoniae.
Methods: A total of 580 consecutive and non-repetitive Streptococcus pneumoniae isolates were collected from 13 hospitals between 2005 and 2008. Agar dilution method was used to determine the minimal inhibitory concentrations (MIC) of 11 antibacterial agents. Serotyping was performed by latex agglutination test and the Quellung reaction test.
Results: The most prevalent serogroups/types in 362 isolates from adults were 19F (55, 15.2%), 19A (46, 12.7%), 3 (44, 12.2%), 23F (24, 6.6%), 15 (23, 6.4%), and 17 (11, 3.0%), while in the 218 isolates from children, 19F (71, 32.6%), 19A (31, 14.2%), 23F (13, 6.0%), 15 (12, 5.5%), 14 (11, 5.0%), and 6B (10, 4.6%) were the most prevalent. Resistance to β-lactams was related to the serotypes. 19F and 19A were more resistant toβ-lactams than the other serotypes. The prevalence of Penicillin Intermediate Streptococcus pneumoniae increased from 7.4% in 2005 to 24.9% in 2008. The coverage of pneumococcal conjugate vaccine (PCV)-7, PCV-10 and PCV-13 among all age groups was 35.5% (206/580), 38.7% (224/580) and 61.8% (358/580), respectively. The coverage of PCV-7, PCV-10 and PCV-13 among children under 5 years was 55.7% (78/140), 58.6% (82/140), and 77.9% (109/140) respectively.
Conclusion: Penicillin intermediate isolates were on the rise with years. PCV-7, PCV-10 and PCV-13 vaccines showed a higher coverage in children than in adults.