Resistance to erythromycin and resistance phenotypes of Streptococcus pneumoniae

Objective To investigate bacterial resistance of Streptococcus pneumoniae against erythromycin and clindamycin, and resistance phenotypes of erythromycin resistant S. pneumoniae. Methods The MICs of erythromycin and clindamycin against 345 strains of S. pneumoniae were tested with agar dilution method, the phenotypes of erythromycin resistant S. pneumoniae were detected by double disc test. Results The resistance rates of S. pneumoniae to erythromycin and clindamycin were 53.0%(183/345) and 49.6%(171/345), respectively. Among erythromycin resistant S. pneumoniae , the percentages of cMLS, iMLS and M phenotype were 90.3% (159/176), 5.7% (10/176) and 4.0%(7/176), respectively. Conclusions The resistance rate of S.pneumoniae against erythromycin is very high in Shanghai. The main phenotype is cMLS.