Susceptibility testing of Haemophilus influenzae to clarithromycin.

Susceptibility testing of Haemophilus influenzae to the macrolide compounds has often been problematic. This is as a result of the inability of many isolates of H. influenzae to grow without the addition of 5% CO2 to the incubation atmosphere and the subsequent detrimental effect that CO2 has on the activity of the macrolide group of compounds. This report describes refinements and recommendations for susceptibility testing of H. influenzae to the macrolide clarithromycin.