Endemic contamination of clinical specimens by Mycobacterium gordonae. Clin. Infect. Dis

Contamination of clinical specimens by Mycobacterium gordonae is a signi®cant endemic problem in many laboratories. To investigate this problem, 84 cases at 1 hospital were retro-spectively identi®ed during 20 months. The overall rate of specimen contamination was 2.4%, and 72 of the contaminated specimens were respiratory. A case-control comparison showed that the risk of respiratory specimen contamination was signi®cantly increased if the specimen was expectorated (odds ratio [OR], 3.62; 95 % con®dence interval [CI], 1.36±9.50) or if the patient consumed ¯uids within 2 days before specimen collection (OR, 8.92; 95 % CI, 1.40±71.20). Cultures of tap water, ice, and iced drinking water all yielded M. gordonae at 1022±100 cfu/mL. A culture survey of consenting patients showed contamination of 8 (24%) of 34 sputum specimens collected immediately after a tap water mouth rinse. These ®ndings demonstrate that endemic specimen contamination arises from mycobacteria in hospital tap water and provide a foundation for control efforts. Mycobacterium gordonae, like other nontuberculous myco-bacteria, is found primarily in natural waters and tap water systems [1, 2]. It rarely causes human infection or colonizatio