Characterization of Biofilm Formation by Borrelia burgdorferi In Vitro

Abstract

Borrelia burgdorferi, the causative agent of Lyme disease, has long been known to be capable of forming aggregates and colonies. It was recently demonstrated that Borrelia burgdorferi aggregate formation dramatically changes the in vitro response to hostile environments by this pathogen. In this study, we investigated the hypothesis that these aggregates are indeed biofilms, structures whose resistance to unfavorable conditions are well documented. We studied Borrelia burgdorferi for several known hallmark features of biofilm, including structural rearrangements in the aggregates, variations in development on various substrate matrices and secretion of a protective extracellular polymeric substance (EPS) matrix using several modes of microscopic, cell and molecular biology techniques. The atomic force microscopic results provided evidence that multilevel rearrangements take place at different stages of aggregate development, producing a complex, continuously rearranging structure. Our results also demonstrated that Borrelia burgdorferi is capable of developing aggregates on different abiotic and biotic substrates, and is also capable of forming floating aggregates. Analyzing the extracellular substance of the aggregates for potential exopolysaccharides revealed the existence of both sulfated and non-sulfated/carboxylated substrates, predominately composed of an alginate with calcium and extracellular DNA present. In summary, we have found substantial evidence that Borrelia burgdorferi is capable of forming biofilm in vitro. Biofilm formation by Borrelia species might play an important role in their survival in diverse environmental conditions by providing refuge to individual cells.

New records of the Lyme disease bacterium in ticks collected from songbirds in central and eastern Canada

“…Pathologically, B. burgdorferi can not only circumvent and evade the human immune system but, at the same time, invade host tissue (Kraiczy et al 2001) and cause inflammation (Ramesh et al 2013). As Lyme disease advances in human patients, B. burgdorferi will: (1) cause immune dysfunction (Stricker and Winger 2001;Hastey et al 2012), (2) sequester inside cells (Ma et al 1991;Häupl et al 1993;Dorward et al 1997), (3) take on pleomorphic forms, such as blebs and round bodies (Meriläinen et al 2015) and (4) hide in biofilms (Sapi et al 2011(Sapi et al , 2012. Lack of effective treatment for Lyme disease may sometimes result in fatal outcomes (Liegner et al 1997).…”

The clinical significance of biochemical failure in the first 2 years in patients treated with neo-adjuvant androgen deprivation and radiotherapy for prostate cancer

“…Biofilms of B. burgdorferi have been demonstrated in vitro by Sapi et al, [26]. These biofilms may take the form of "debris" on intravital microscopy, and they may contain organisms that are non-cultivable but still viable and prone to reactivation [26,27]. Biofilms of B. burgdorferi would also be consistent with the "amber hypothesis" proposed as a mechanism of persistent Lyme disease symptoms [28].…”

“…Persistent viable organisms may have been hidden in biofilms, the adherent polysaccharide-based matrices that protect bacteria against the host immune system and antibiotic therapy [1]. Biofilms of B. burgdorferi have been demonstrated in vitro by Sapi et al, [26]. These biofilms may take the form of "debris" on intravital microscopy, and they may contain organisms that are non-cultivable but still viable and prone to reactivation [26,27].…”

First Record of Ixodes affinis Tick (Acari: Ixodidae) Infected with Borrelia burgdorferi Sensu Lato Collected from a Migratory Songbird in Canada

“…In vivo, B. burgdorferi s.l. has several pleomorphic forms (i.e., spirochetes, blebs, granules, round bodies) [54] and, collectively, these aggregates form gelatinous biofilm colonies [55,56]. Since B. burgdorferi s.l.…”