in vitro activity of telithromycin against Haemophilus influenzae

The aim of this study was to evaluate the in vitro activity of telithromycin against 142 strains of Haemophilus influenzae using determination of MICs by agar dilution method and to evaluate the correlation between MICs and inhibition diameter zones obtained by disk diffusion testing. MIC50 and MIC90 of telithromycin were 1 and 2 mg/L respectively. Telithromycin activity against H. influenzae was similar to that of azithromycin, superior to erythromycin and clarithromycin and irrespective of the susceptibility to betalactams. Distribution of diameter zones showed a similar pattern to that of MICs but correlation between MICs and diameter zones was poor with correlation coefficients inferior to 0.5 whatever the agar media used.