In Vitro Comparison Of Clarithromycin, Clarithromycin plus 14-Hydroxy Clarithromycin, and Azithromycin Against Haemophilus influenzae

Abstract

The antibiotic activities of clarithromycin, clarithromycin plus 14-hydroxy clarithromycin and azithromycin against Haemophilus influenzae were compared. This comparison was performed because both clarithromycin and azithromycin have proven to be effective against infections due to H. influenzae. H. influenzae is partially responsible for the prevalence of community-acquired pneumonia (CAP) in the United States. Currently, many infectious and non-infectious conditions can mimic CAP, thereby hindering diagnoses of the causative agents and the administration of the most effective treatments. The initial treatment of CAP is crucial in reducing the mortality and morbidity due to CAP, yet the difficulties in diagnosis and administration of appropriate treatments prevent the initial treatment from being precise. Since H. influenzae is partially responsible for CAP, the use of an antibiotic that actively inhibits its growth would decrease the prevalence of CAP due to this bacteria. Minimum inhibitory tests, minimum bactericidal tests, and time kill assays were performed on five different strains of H. influenzae in order to determine if one antibiotic was more active over another. The results were not conclusive, but did show that all three antibiotics were bactericidal towards H. influenzae. Further studies will need to be performed to determine if one antibiotic over another or a combination of antibiotics should be initially administered to CAP patients in which H. influenzae is the responsible pathogen.