A biofilm model developed to investigate survival and disinfection of Mycobacterium mucogenicum in potable water

Water in healthcare environments can be a source for healthcare-associated infections (HAI). However, information on the exposure risk to opportunistic pathogens in potable water distribution systems (PWDS) is lacking. Laboratory studies characterizing the interaction of opportunistic pathogens with biofilms are needed to understand their role in water systems within healthcare facilities. A stable, repeatable, PWDS multi-species biofilm model comprising Sphingomonas paucimobilis, Methylobacterium sp., Delftia acidovorans, and Mycobacterium mucogenicum was developed in the CDC Biofilm Reactor (CBR), reaching 6 log10 CFU cm−2 within 6 days. The model was used to investigate the interaction of the opportunistic pathogen M. mucogenicum with the other species, and to determine the efficacy of monochloramine (NH2Cl) as a disinfectant against 2-week-old biofilms. Addition of 1 or 2 mg l−1 NH2Cl resulted in the same or an increased log density of viable M. mucogenicum in the biofilm while inactivating some of th...