I wanted to share with you all the latest tidbit I found at the medical library. There is an article in Journal of  Antimicrobial Chemotherapy (1997) 40, 153-55. “Macrolides for the treatment of Pseudomonas aeruginosa infections?”

Macrolides are oral antibiotics such as azithromycin (Zithromax), clarithromycin (Biaxin) and erythromycin. By conventional criteria (MIC testing) Pseudomonas aeruginosa is resistant to macrolides. However, it has been shown that patients with diffuse panbronchiolitis (DBP, a chronic lung disease found in Japan, clinically and bacteriologically similar to cf, involving persistent infection with mucoid P.a.) show clinical improvement and much longer survival with long-term use of macrolides.

The article discusses the possible mechanisms — effects on the immune system to modify the inflammatory response to infection or direct effects on P.a. to decrease its virulence factors. The mechanisms and mode of action for sub-MIC concentrations of macrolides is largely unknown, but the authors give several possibilities based on other research.

There is much scientific info here which I don’t have the background to process, but the bottom line is “Whatever the mechanism, long-term low-dose macrolides are of proven value in the treatment of DPB patients chronically infected with P. aeruginosa and clinical trials should now address their potential use in cystic fibrosis.”

Personally, I thought this was pretty interesting to find that the Biaxin my daughter has been taking recently might be causing improvement for more reasons than just getting rid of the suspected staph infection.