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 i solates of H. influenzae to grow without the addition of 5% CO2 to the incu bation atmosphere and the subsequent detrimental effect that CO2 has on the activity of the macrolide group of compounds. This report describes refine ments and recommendations for susceptibility testing of H. influenzae to th e macrolide clarithromycin.