Antimycobacterial efficacy of silver nanoparticles as deposited on porous membrane filters

• Silver nanoparticles are an effective antimycobacterial agent in liquid culture.
• Deposited silver nanoparticles inhibit colonization on a filter surface.
• Pathogenic M. avium is more resistant to silver than other mycobacteria.
• Silver nanoparticle applications in medical devices that use water

Environmental mycobacteria pose a significant health burden. Non-tuberculous mycobacteria infections have been traced to water treatment networks, where mycobacterial biofilms are ubiquitous. Filters that remove potential pathogens have significant medical applications. The purpose of this study is to demonstrate that an antibacterial silver nanoparticle (AgNP) coating can prevent colonization and growth of a mycobacterial biofilm on a filter material. The antibacterial efficacy of commercially available AgNPs was measured against Mycobacterium avium, Mycobacterium smegmatis, and Mycobacterium marinum after 48 h in liquid culture. Nanoparticles were deposited on micro-porous track etched polycarbonate membranes. The growth of biofilms on the membranes was observed by microscopy and counting colony forming units. M. smegmatis was most susceptible to AgNPs, with a 98.7% reduction at 100 μM AgNP concentration. M. avium was reduced by 97.3% at 539 μM AgNP after 48 h. Deposited nanoparticles inhibited colonization and growth for both M. smegmatis and M. avium on the membrane surface. Similar to the liquid culture, M. avium (84.2% survival) was more resistant than M. smegmatis (0.03% survival).

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