Inhibition of Adherence of Mycobacterium avium to Plumbing Surface Biofilms of Methylobacterium spp.

Both spp. and spp. are opportunistic premise plumbing pathogens that are found on pipe surfaces in households. However, examination of data published in prior microbiological surveys indicates that spp. and spp. tend not to coexist in the same household plumbing biofilms. That evidence led us to test the hypothesis that spp. in biofilms could inhibit the adherence of . Measurements of adherence of cells to stainless steel coupons using both culture and PCR-based methods showed that the presence of spp. biofilms substantially reduced adherence and vice versa. That inhibition of adherence was not reduced by UV-irradiation, cyanide/azide exposure, or autoclaving of the spp. biofilms. Further, there was no evidence of the production of anti-mycobacterial compounds by biofilm-grown spp. cells. The results add to understanding of the role of microbial interactions in biofilms as a driving force in the proliferation or inhibition of opportunistic pathogens in premise plumbing, and provide a potential new avenue by which exposures may be reduced for at-risk individuals.