Various molecular tools have been used to characterise isolates of M. avium, including restriction fragment length polymorphism (RFLP) [9], sequencing of the hsp65 gene [10] and multilocus sequence analysis (MLSA) [11]. In a previous study, we characterised M. avium isolates from birds, swine and humans in Norway by IS1311- and IS1245-RFLP typing. Our study demonstrated that transmission between animals and/or humans of identical

isolates of M. avium is uncommon in Norway, and that transmission of M. avium from the environment to humans and animals is more likely [12]. The results are in accordance with other studies [13–15]. M. avium has been found in soils and waters worldwide [5], and isolates with identical RFLP-profiles have been found FXR agonist inhibitor in peat and human patients and in peat and swine, respectively [16, 17]. Drinking water has also been shown to be a possible source of M. avium

Daporinad price subsp. hominissuis for both humans and swine [18–21]. M. avium has been shown to survive in water for up to 26 months, and can also survive within amoeba [22, 23]. Additionally, potable hot water systems may contain M. avium concentrations greater than those found in cold water systems [24]. In natural settings, bacteria on surfaces and interfaces are found as multicellular aggregates, called biofilms [25]. M. avium has been detected in naturally occurring biofilms in water distribution systems, and has been shown to persist in drinking water biofilms for weeks [20, 26]. M. avium may survive traditional water disinfection procedures because it is naturally resistant to water treatment with ozone and chlorine, and has been shown to be even more resistant to chlorine treatment when grown in biofilm [22, 27, 28]. Biofilms in drinking water systems may, therefore, be of importance as a reservoir for M. avium, and bacteria could be transmitted old to humans and animals with drinking water. Biofilm formation in M. avium

has been evaluated in vitro, and the ability to form biofilm varies between isolates and under different growth conditions [29, 30]. So far, biofilm studies of M. avium have been performed with only a few human and environmental isolates, and biofilm studies of isolates from birds and swine have, to the authors’ knowledge, not been reported. Glycopeptidolipids (GPLs), present in the outermost layer of the cell wall of M. avium and M. smegmatis, seem to be of importance for biofilm formation in both species [29, 31–33]. The GPLs of M. avium can be divided into non-serovar-specific (nsGPL) and serovars-specific GPL (ssGPL) [34]. Whether different serovars have different abilities to make GPL, is not known. Furthermore, GPLs are associated with colony morphology, and M. avium colonies can be smooth opaque (SmO), smooth transparent (SmT) or rough (Rg) [35, 36]. The Rg variants of M. avium have been shown to have alterations in their GPLs [37]. The aim of the present study was to Selleck ACP-196 screen a large number of M.