Molecular characterization of erm(B)- and mef(E)-mediated erythromycin-resistant Streptococcus pneumoniae in China and complete DNA sequence of Tn2010.
OBJECTIVE
To characterize the erm(B)- and mef(E)-mediated erythromycin-resistant Streptococcus pneumoniae clinical isolates obtained from ten hospitals located different cities in China.


RESULTS
Totally 83 S. pneumoniae were collected, and eighteen representative strains of 66 strains that exhibited erythromycin resistance were used for further characterization by antibiograms, serotyping, PFGE, MLST, DNA sequencing of the macrolide-resistance elements and mapping of the elements on the chromosome. Twelve isolates showed a high-level resistance to erythromycin, and six other isolates showed a low-level resistance to erythromycin. Thirteen isolates harboured a Tn2010 transposon (26·4 kbp) encoding the erm(B), tet(M) and mef(E) genes and were classified into three types by Tn2010 structures. The remaining five isolates harboured a Tn6002 transposon (20·9 kbp) encoding the erm(B) and tet(M) genes and were classified into three types by Tn6002 locations on the chromosome. Three of the Tn6002 elements were located within the Tn5252-like element, implying that these composed a large mobile element. The MLST analyses showed that several clones had been disseminated and that the CC271 strains carrying the Tn2010 element expressing the high-level resistance to erythromycin were predominant in China. Four new MLST strains, which were designated as ST3262, ST3263, ST3397 and ST3398 were also identified.


CONCLUSIONS
The erythromycin resistance determinant of S.pneumoniae that had been isolated in China was located in Tn2010 or the Tn6002 element and several clones had been disseminated, and the CC271 strains carrying the Tn2010 element expressing the high-level resistance to erythromycin were predominant in China.


CONCLUSIONS
This is the first molecular analysis of erythromycin-resistant Streptococcus pneumoniae clinical isolates in China, and the first report of the complete nucleotide sequence of Tn2010 (26,390 bp).
Department of Bacteriology, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
Y
Y
Li
H
H
Tomita
Y
Y
Lv
J
J
Liu
F
F
Xue
B
B
Zheng
Y
Y
Ike
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D002681:China; D004251:DNA Transposable Elements; D024881:Drug Resistance, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004917:Erythromycin / Q000494:pharmacology*; D005838:Genotype; D008565:Membrane Proteins / Q000235:genetics; D010641:Phenotype; D017422:Sequence Analysis, DNA; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification / Q000187:drug effects* / Q000235:genetics*
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; C431304:MefE protein, Streptococcus pneumoniae; D008565:Membrane Proteins; D004917:Erythromycin