Table 2.

Mutations in the 23S rRNA gene and associated MLS phenotypes of clinical H. pylori isolates

H. pylori straina23S rRNA gene mutationMIC (μg/ml)bMLS pheno- typec
ClaClnQnpDfpRP59500
UA802Wild type0.00432482S
AA2143G4256482R-II
BA2143G1256480.5R-II
DA2142G8>5126481R-I
MQA2142G16>51212881R-I
EA2142G16>51212882R-I
Eryr-1A2142G16>51212882R-I
Clar-1A2142G16>51212882R-I
  • a Eryr-1 and Clar-1 are erythromycin- and clarithromycin-resistant strains of UA802, respectively, obtained by transformation of the erythromycin or clarithromycin resistance determinant from strain E (30).

  • b Abbreviations for antibiotics: Cla, clarithromycin; Cln, clindamycin; Qnp, quinupristin (streptogramin B); Dfp, dalfopristin (streptogramin A); RP59500, mixture of quinupristin and dalfopristin.

  • c S, susceptible; R-II, type II resistance; R-I, type I resistance.