Purpose: This study assessed biofilms formed by selected strains of M. tuberculosisand investigated the efficacy of three different treatments for biofilm control.
Methods: Two M. tuberculosis strains were inoculated separately in 150 ml Middlebrook 7H9-Tween 80 (0.1%) broth with 5% liver extract and 10% oleic albumin dextrose catalase (OADC), 5% liver extract alone, or 10% OADC alone in sterile jars containing 2 x 2 cm2 coupons of steel, cement or ceramic for biofilm development. The jars were incubated at 37°C with agitation for 2, 3 and 4 weeks, respectively. Biofilms on coupons were subsequently exposed to 10 ml of 2% Iodasteryl®, 0.5% Virocid®and sterile water at 28 and 45°C, respectively for 5 min. Biofilm mass on treated and untreated coupons were assessed.
Results: Tested strains of M. tuberculosisformed biofilms on all three contact surfaces. One tested strain formed more biofilms than the other strain. More biofilms were formed in media containing both liver extract and OADC than media with only liver extract or OADC. Biofilm mass increased as incubation time increased till the 3rd week of incubation. More biofilms were formed on cement followed by ceramic and steel coupons. Chemical treatments at 45°C removed more biofilms than those at 28°C. Treatments with Iodasteryl® and Virocid®were equally effective in removing the biofilms on tested surfaces. However, neither treatment completely removed the biofilms.
Significance: Results suggest that examined M. tuberculosis strains could form biofilms on tested surfaces, and chemical treatments used partially removed biofilms from the surfaces.