Biofilm formation by Mycobacterium avium ssp. paratuberculosis in aqueous extract of schmutzdecke for clarifying untreated water in water treatment operations.

AIMS: To determine the effect of aqueous extract of schmutzdecke on adhesion and biofilm formation by three isolates of Mycobacterium avium ssp. paratuberculosis (Map) under laboratory conditions. METHODS AND RESULTS: Strains of Mycobacterium avium ssp. paratuberculosis in aqueous extract of schmutzdecke were subjected to adhesion tests on two topologically different substrata i.e. aluminium and stainless steel coupons. Biofilm formation was then monitored in polyvinyl chloride (PVC) plates. All the three strains adhered onto both coupons, howbeit greatly on aluminium than stainless steel. In the PVC plates, however, all strains developed biofilms which were observed by spectrophotometric analysis. CONCLUSIONS: The environmental isolates of Map attained higher cell proliferation in both filtered and unfiltered aqueous extracts of schmutzdecke (FAES and UAES respectively) compared with the human isolate. Furthermore, the results showed that irrespective of the media used, Map might have developed biofilm by its genetic competence to do so under favourable conditions that the immediate environment might have provided.