Comparative adherence to human A549 cells, plant fibronectin-like protein, and polystyrene surfaces of fourPseudomonas fluorescensstrains from different ecological origin

Abstract

The main objective of this study was to compare the adherence properties of four Pseudomonas fluorescens isolates from different ecological niches (human tissue, rhizosphere, drinking water, and cow milk). The substrates used to test P. fluorescens adherence were as follows: cultured human respiratory epithelial cells A549, immobilized plant fibronectin-like protein, and polystyrene. For all the experiments, bacteria were grown at 27 degrees C. The adherence assay to human cells was performed at 37 degrees C, whereas adherence to fibronectin and polystyrene was done at 27 degrees C. The four strains tested adhered to A549 cells but showed different adherence patterns. At 3 h, the milk isolate showed an aggregative adherence phenotype, whereas the three other isolates showed a diffuse adherence pattern. With a longer incubation time of 24 h, the aggregative pattern of the milk isolate disappeared, the adherence of the clinical strain increased, the adherence of the water isolate decreased, and morphological changes in A549 cells were observed with the clinical, water, and soil isolates. The four strains tested formed biofilms on polystyrene dishes. The clinical and milk isolates were the more efficient colonizers of polystyrene surfaces and also the more adherent to immobilized plant fibronectin-like protein. There was no relation between bacterial surface hydrophobicity and P. fluorescens adherence to the substrates tested. The main conclusions of these results are that P. fluorescens is an adherent bacterium, that no clear correlation exists between adherence and ecological habitat, and that P. fluorescens can adhere well to substrates not present in its natural environment.

Effect of Temperature on the Shift of Pseudomonas Fluorescens from an Environmental Microorganism to a Potential Human Pathogen

“…P fluorescens is an opportunistic pathogen the isolation ofwhich, as agent ofnosocomial infectionsmainly respiratory -has recently increased. Although little is known about the mechanism of pathogenicity of this microorganism, bacterial infection of the respiratory tract implies colonization of the epithelial mucosa and P fluorescens has been shown to be able to adhere to cultured A549 human respiratory epithelial cells (20). Adhesiveness is considered as the initial event leading to bacterial colonization of host tissues and eventually to infection (21).…”

Characterization of structures in biofilms formed by a Pseudomonas fluorescens isolated from soil

“…Cossard et al . determined that the adherence properties of four P. fluorescens isolates were independent of their ecological habitat [15]. P. fluorescens WCS365 was found to produce a cell surface protein (LapA) that promoted the colonization of glass, plastic, and quartz sand via adhesion [16].…”