Abstract
Three-hundred and seventy-six strains of
Streptococcus pneumoniae
isolated from clinical specimens and nasopharyngeal swabs from children at daycare centers and hospitals in Beijing China, between
January 1997 and March 1998, were serotyped. Twenty-seven different serotypes were identified. The most prevalent serotypes in the carriage isolates were 6A, 19F, 23F, and 15 and were found in 66.8% of
cases. Serotype data indicate that 51.8% of carrier strains would be included in the 11-valent conjugate vaccine formulation, while inclusion of vaccine-related serotypes, increased the potential vaccine
coverage to 79.4%. Serotypes 7, 6B, 23F, 19F, 15, and 3 accounted for 62% of clinical strains, with 70% vaccine-related serotypes. DNA fingerprinting of 47 penicillin resistant and 71 penicillin-susceptible/macrolide-resistant
strains by BOX polymerase chain reaction (PCR), pulsed-field gel electrophoresis (PFGE), and penicillin binding protein (PBP)-fingerprinting identified two novel clones: one a serotype 23F multiresistant
clone resistant to penicillin, tetracycline, erythromycin, clindamycin, and variably resistant to chloramphenicol and trimethoprim-sulphamethoxazole; and the second a multiresistant penicillin-susceptible,
macrolide-resistant serotype 6A clone, highly resistant also to tetracycline, clindamycin, and trimethoprim-sulphamethoxazole. The macrolide resistance determinant in 89% of erythromycin-resistant strains
tested (penicillin-susceptible and penicillin-resistant) was the
erm
gene, both the
erm
and
mef
genes were simultaneously found in 6%, and
mef
alone in 3.4%. The data demonstrates
that macrolide resistant strains in China include clonal strains and strains with dual
mef
and
erm
resistance determinants.