Clarithromycin Resistance in Mycobacterium abscessus

We read with interest the article by Sanguinetti et al. titled “Fatal Pulmonary Infection Due to Multidrug-ResistantMycobacterium abscessus in a Patient with Cystic Fibrosis,” which appeared in the February 2001 issue (5). We would like to point out some additional information relating to the authors' comment, “to our knowledge, this is the first evidence of true resistance to clarithromycin, which is considered the most active drug against M. chelonae.” First, the case report involves Mycobacterium abscessus, notM. chelonae. The two names are not synonymous and should not be used interchangeably (10). The organisms have different biologies, are readily differentiated in the laboratory, and have different drug susceptibilities (2, 3, 6, 8). (Essentially all cases of chronic lung disease caused by rapidly growing mycobacteria in the setting of cystic fibrosis are due to M. abscessus [3].)