[Epidemiological study of Streptococcus pneumoniae in the nasopharynx of healthy children under 5 years of age in Wuhan].
OBJECTIVE
To investigate the population biology of Streptococcus (S.) pneumoniae carried by healthy children under 5 years of age in Wuhan.


METHODS
S. pneumoniae was isolated from nasopharyngeal swabs of healthy children under the age of 5 years (under 5) in Wuhan. The susceptibility to 12 antimicrobial agents was tested by agar dilution method. The erythromycin resistant genes were detected by using the technique of polymerase chain reaction. The quellung reaction was used for serotyping.


RESULTS
The carrier rate of S. pneumoniae was 22.31% (135/605) in under 5 children in Wuhan. Among the 133 alive strains, the proportion of penicillin non-susceptible S. pneumoniae (PNSSP) was 45.9% (61/133). The susceptibility of S. pneumoniae to the first (cefalexin), the second (cefaclor) and the third (cefixime, cefpodoxime and cetriaxone) generations of cephalosporins was 6.0%, 45.1%, 54.9%, 56.4%, and 88.7%, respectively. None of the strains were found resistant to fluoroquinolones except for one strain which was resistant to ciprofloxacin at low level. The susceptibility to macrolides was low, 14.3% - 15.8%. Among totally 114 strains resistant to erythromycin, the genes ermB alone, both ermB and mefA, and mefA alone were found in 76 strains (66.7%), 46 strains (40.4%) and 2 strains (1.8%), respectively. Seventeen serotypes were involved and the prevalent serotypes were 19, 23, 6, 15 and 14. Seven strains remained nontypable for serotype. PNSSP strains were found to be distributed in serotypes 19, 23, 6 and nontypable group.


CONCLUSIONS
The antibiotic resistance of S. pneumoniae was serious in Wuhan area. The ribosomal modification (ermB gene mediated) was the main mechanism of S. pneumoniae resistant to erythromycin. The major prevalent serotypes were 19, 23 and 6.
Sun
Zi-yong
ZY
Department of Clinical Laboratory, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Zhang
Jing
J
Li
Li
L
Zhu
Xu-hui
XH
Wang
Hong-wei
HW
Ma
Yue
Y
D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002353:Carrier State; D002648:Child; D004352:Drug Resistance, Microbial; D024901:Drug Resistance, Multiple, Bacterial; D016021:Epidemiologic Studies; D004917:Erythromycin / Q000627:therapeutic use; D006801:Humans; D018942:Macrolides; D008826:Microbial Sensitivity Tests; D009305:Nasopharynx / Q000382:microbiology*; D010403:Penicillin Resistance; D010406:Penicillins / Q000627:therapeutic use; D015995:Prevalence; D012703:Serotyping; D013296:Streptococcus pneumoniae
D000900:Anti-Bacterial Agents; D018942:Macrolides; D010406:Penicillins; D004917:Erythromycin