Prevalence and phenotypes of erythromycin-resistant Streptococcus pneumoniae in Shanghai, China

Bacterial resistance of Streptococcus pneumoniae against erythromycin and clindamycin and resistance phenotypes of erythromycin-resistant Streptococcus pneumoniae were investigated. The MICs of erythromycin and clindamycin against 345 strains of Streptococcus pneumoniae were tested with agar dilution method; the phenotypes of erythromycin-resistant Streptococcus pneumoniae were detected by double-disk test. One hundred and eighty-three and 171 of 345 (53.0% and 49.6%) of isolates had MICs > or =1 microg/ml for erythromycin and for clindamycin. Among erythromycin-resistant Streptococcus pneumoniae, the percentage of cMLS, iMLS and M phenotype was 90.3% (159/176), 5.7% (10/176) and 4.0% (7/176), respectively. The incidence of erythromycin-resistant Streptococcus pneumoniae is very high in Shanghai. The main phenotype is cMLS.