Evaluation of Oral Antiseptic Rinsing before Sputum Collection To Reduce Contamination of Mycobacterial Cultures

To assess whether rinsing with oral antiseptics before sputum collection would reduce contamination of mycobacterial cultures, 120 patients with suspected tuberculosis were randomly assigned to rinse with chlor-hexidine or cetylpyridinium mouthwash before collection. The culture contamination rate was significantly lower after rinsing with chlorhexidine before collection, especially for cultures grown in MGIT medium. One of the main limitations of sputum culture for mycobac-teria is contamination and overgrowth with organisms from the oral flora. Antiseptics have been used to supplement oral hy-giene to minimize the proliferation of pathogenic organisms (13). Due to their glycolipid-containing cell wall, mycobacteria are relatively resistant to many common disinfectants (14, 15). Chlorhexidine (CHX) and cetylpyridinium chloride (CPC), two of the most widely used antiseptic compounds in mouth-washes, are active against common oral bacteria and fungi at low concentrations (2, 3, 4, 9, 11, 16) and are relatively non-toxic to human cells. Mycobacteria are highly resistant to CH