Prevalence of serotypes and molecular epidemiology of Streptococcus pneumoniae strains isolated from children in Beijing, China: Identification of two novel multiply-resistant clones
L. Mcgee et al., Prevalence of serotypes and molecular epidemiology of Streptococcus pneumoniae strains isolated from children in Beijing, China: Identification of two novel multiply-resistant clones, MICROB DR R, 7(1), 2001, pp. 55-63
Three-hundred and seventy-six strains of Streptococcus pneumoniae isolated
from clinical specimens and nasopharyngeal swabs from children at daycare c
enters 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 Ii-valent conjugate vaccine formulation,
while inclusion of vaccine-related serotypes, increased the potential vacci
ne coverage to 79.4%. Serotypes 7, 6B, 23F, 19F, 15, and 3 accounted for 62
% of clinical strains, with 70% vaccine-related serotypes. DNA fingerprinti
ng of 47 penicillin resistant and 71 penicillin-susceptible/macrolide-resis
tant strains by BOX polymerase chain reaction (PCR), pulsed-field gel elect
rophoresis (PFGE), and penicillin binding protein (PBP)-fingerprinting iden
tified two novel clones: one a serotype 23F multiresistant clone resistant
to penicillin, tetracycline, erythromycin, clindamycin, and variably resist
ant to chloramphenicol and trimethoprim-sulphamethoxazole; and the second a
multiresistant penicillin-susceptible, macrolide-resistant serotype 6A clo
ne, highly resistant also to tetracycline, clindamycin, and trimethoprim-su
lphamethoxazole. The macrolide resistance determinant in 89% of erythromyci
n-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,vith dual mef and erm r
esistance determinants.