Roles for Cell Wall Glycopeptidolipid in Surface Adherence and Planktonic Dispersal ofMycobacterium avium

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Abstract
The opportunistic pathogenMycobacterium aviumis a significant inhabitant of biofilms in drinking water distribution systems.M. aviumexpresses on its cell surface serovar-specific glycopeptidolipids (ssGPLs). Studies have implicated the core GPL in biofilm formation byM. aviumand by otherMycobacteriumspecies. In order to test this hypothesis in a directed fashion, three model systems were used to examine biofilm formation by mutants ofM. aviumwith transposon insertions intopstAB(also known asnrpandmps).pstABencodes the nonribosomal peptide synthetase that catalyzes the synthesis of the core GPL. The mutants did not adhere to polyvinyl chloride plates; however, they adhered well to plastic and glass chamber slide surfaces, albeit with different morphologies from the parent strain. In a model that quantified surface adherence under recirculating water, wild-type andpstABmutant cells accumulated on stainless steel surfaces in equal numbers. Unexpectedly,pstABmutant cells were >10-fold less abundant in the recirculating-water phase than parent strain cells. These observations show that GPLs are directly or indirectly required for colonization of some, but by no means all, surfaces. Under some conditions, GPLs may play an entirely different role by facilitating the survival or dispersal of nonadherentM. aviumcells in circulating water. Such a function could contribute to waterborneM. aviuminfection.