Epidemiology of Streptococcus pneumoniae isolates from patients with meningitis between 1993 and 2002

We studied 304 meningitis cases, including 18 cases pneumococcal meningitis confirmed by direct PCR for cerebrospinal fluid between 1993 and 2003. We analyzed isolates of 199 strains from children and isolates of 105 strains from adults to determine antibiotic susceptibility, genotype of penicillin-binding protein (PBP) genes, and the serotype distribution of isolates. Isolates in which abnormal PBP genes of pbp 1 a, pbp 2 ×, and pbp 2 b were identified by PCR were classified based on PCR results and MIC₉₀ of penicillin G as follows: (i PSSP with 3 normal PBP genes (23.1%, MIC₉₀: 0.031 μg/mL), (ii) PISP with an abnormal pbp 2 × (19.9%, MIC₉₀: 0.063 μg/mL); (iii) PISP with an abnormal pbp 2 b (0.7%, MIC₉₀: 0.125 μg/mL); (iv) PISP with abnormal pbp 2 × and pbp 2 b (5.9%, 0.25 μg/mL); (v) PISP with abnormal pbp 1 a and pbp 2 × (10.5%, 0.25 μg/mL); and (vi) PRSP with 3 abnormal PBP genes (39.9%, 2 μg/mL). The incidence of PRSP, PISP having abnormal pbp 1 a and pbp 2 ×, and PISP having an abnormal pbp 2 × in the last 3 years was significantly higher rather than in preceding years. The encidence of PRSP was also significantly higher in children (45.3%) than in adults (27.1%). Panipenem showed an excellent MIC₉₀) of 0.125 μg/mL against PRSP, followed by biapenem (0.25% μg/mL), meropenem and vancomycin (0.5 μg/mL), cefotaxime (1 μg/mL), ceftriaxone (2 μg/mL), ampicillin (4 μg/mL), and cefotiam (8 μg/mL). Significantly prevalent pneumococcal serotypes of isolates from children were 6 B (25.4%), 19 F (19.0%), 23 F(13.8%), 6 A(10.1%), and 14 (7.9), in that order, compared to 23 F(16.5%), 22 (12.4%), 3 (11.3%), 6 B (10.3%), 19 F (9.3%), and 10=14 (6.2%) in adults. Serotypes of isolates from both generations differed significantly (χ²=56.9656, p=0.0000) (**)). PRSP was more prevalent in serotypes in strains from children. For isolates in the last 3 years, in children, seven-valent pneumococcal conjugate vaccine covered isolates in 76.7% and elevent-valent vaccine 81.7%, but coverage was apparently low in adults at 43.8% and 56.3%. These findings suggest that need to introduce conjugate vaccine at the earliest opportunity and to continue nationwide monitoring of meningitis in Japan.