Characteristics of macrolide-resistant Mycoplasma pneumoniae strains isolated from patients and induced with erythromycin in vitro

Some patients with Mycoplasma pneumoniae infection are clinically resistant to antibiotics such as erythromycin, clarithromycin, or clindamycin. We is olated M. pneumoniae from such patients and found that one of three isolate s showed a point mutation in the 23S rRNA gene. Furthermore, 141 EM-sensiti ve clinical isolates of M. pneumoniae were cultured in broth medium contain ing 100 mug/ml of erythromycin (EM). Among 11 EM-resistant strains that gre w in the medium, point mutations in the 23S rRNA were found in 3 strains at A2063G, 5 strains at A2064G and 3 strains at A2064C. The relationship betw een the point mutation pattern of these EM-resistant strains and their resi stance phenotypes to several macrolide antibiotics was investigated.