Growth phase‐dependent surface properties of Legionella pneumophila and their role in adhesion to stainless steel coated QCM‐D sensors

Abstract

Significance and Impact of the Study: The role of growth phase-dependent variations in cell surface hydrophobicity and charge on adhesion of the opportunistic pathogen Legionella pneumophila to plumbing materials remains poorly described. In this study, we characterized the effect of L. pneumophila cell surface properties on adhesion to stainless steel, an increasingly used plumbing material in potable water systems. These results help us understand the persistence of L. pneumophila in engineered water systems. To our knowledge, this is the first report describing the role of growthdependent variations of L. pneumophila cell surface properties in adhesion to a plumbing material surface.

Evaluation of Biopolymer Materials and Synthesis Techniques to Develop a Rod-Shaped Biopolymer Surrogate for Legionella pneumophila

“…Microparticles were produced using the biopolymers identified in the literature, adapting protocols where necessary to achieve uniform microspheres that matched the size of stationary-phase L. pneumophila (1-2 µm in diameter; [25]). Table 1 presents a summary of morphologies, average diameters, and zeta potentials of the microparticles synthesized using the selected biopolymers.…”

“…The hydrophobicity of the microparticles was evaluated by the microbial adhesion to hydrocarbon (MATH) assay [24]. The zeta potential and the relative hydrophobicity values of the microparticles and stationary-phase L. pneumophila cells [25] were compared prior to surface modification to understand the degree of hydrophobicity enhancement required.…”

“…The MATH assay was used to evaluate the relative hydrophobicity of the surfacemodified microparticles. Surface modifications were conducted until microparticle surfaces matched the zeta potential and surface hydrophobicity of stationary-phase L. pneumophila (−25.2 (±2.0) mV and 45.1 (±2.9)%, respectively [25]). These microparticles were further characterized for morphology using scanning electron microscopy (SEM) (JEOL 7000F FE-SEM, JEOL Ltd., Tokyo, Japan), porosity, pore volume using Brunauer-Emmett-Teller (BET) theory and the Barrer-Joyner-Halenda (BJH) model (Gemini VI 2385 surface area and pore size analyzer, micromeritics, Gwinnett County, GA, USA) [28], and particle concentration using qNano (IZON Science, Christchurch, New Zealand) using carboxylated polystyrene beads of 2000 nm diameter as calibration particles.…”

Use of a Novel DNA-Loaded Alginate-Calcium Carbonate Biopolymer Surrogate to Study the Engulfment of Legionella pneumophila by Acanthamoeba polyphaga in Water Systems

“… L. pneumophila serogroup 1 strain Philadelphia, ATCC 33152, and A. polyphaga , ATCC 30461, were obtained from the American Type Culture Collection (ATCC), USA. Stationary-phase L. pneumophila cell suspensions were established according to Ariyadasa et al ( 17 ).…”

“…In our recent study ( 16 ), we developed a novel, DNA-loaded, alginate-CaCO 3 biopolymer surrogate that has a size, shape, cell surface hydrophobicity, and charge similar to those of stationary-phase L. pneumophila , and it displayed similar attachment/detachment behaviors to those of L. pneumophila to/from Pseudomonas fluorescens biofilms grown on stainless-steel in the presence and absence of chlorine in flowthrough bioreactor experiments. The cell surface hydrophobicity and the charge of the surrogate and stationary-phase L. pneumophila were 37.88 (±0.46)%, −21.70 (±0.88) mV and 44.69 (±1.20)%, −27.16 (±0.01) mV, respectively ( 17 ). The surrogate’s DNA tracer enables its detection via quantitative real-time polymerase chain reaction (qPCR).…”