Cadmium Modulates Biofilm Formation by Staphylococcus epidermidis

Xueqing Wu,Johanna Fink-Gremmels,Regiane Santos

doi:10.3390/ijerph120302878

Xueqing Wu, Johanna Fink-Gremmels + Show 1 more

Open Access

https://doi.org/10.3390/ijerph120302878

Copy DOI

Abstract

The aim of the study was to evaluate the effect of cadmium exposure on Staphylococcus epidermidis (ATCC 35984) biofilm formation. Bacteria were cultured in the absence or presence of different concentrations (0–50 µM) of cadmium. Biofilm formation and bacterial viability were assessed. Quantitative Real Time-PCR (qRT-PCR) was used to determine the mRNA expression of molecular markers of S. epidermidis biofilm formation and dispersion. S. epidermidis biofilm formation was stimulated (p < 0.001) by 1.56 and 3.13 µM cadmium. Confocal laser scanning microscopy (CLSM) analysis confirmed an increase in biofilm thickness (23 and 22 µm, versus 17.8 µm in the controls) after exposure to 1.56 or 3.13 µM cadmium, respectively. qRT-PCR was performed showing the up-regulation of atlE, embp, aap, icaA and icaB after exposure to 3.13 µM cadmium. Taken together, these findings show that cadmium at low, sub-toxic concentrations acts as inducer of S. epidermidis biofilm formation.

Highlights

Heavy metal contamination of soil and water is a worldwide risk affecting food and feed safety [1,2].Among various heavy metals, cadmium is considered to be the most toxic element, predominantly due to its long biological half-life resulting in accumulation in the body, the kidneys [3]
These findings show that cadmium at low, sub-toxic concentrations acts as inducer of S. epidermidis biofilm formation
Thereafter, by plating the cadmium-exposed (12.5, 25, and 50 μM) bacteria, we found that the minimal bactericidal concentration (MBC) of cadmium on

Summary

Introduction

Heavy metal contamination of soil and water is a worldwide risk affecting food and feed safety [1,2]. Cadmium is considered to be the most toxic element, predominantly due to its long biological half-life resulting in accumulation in the body, the kidneys [3]. Sub-toxic concentrations of heavy metal have been described as potential inducers of biofilm formation [6]. This effect might be desirable, when microorganisms are used to decontaminate soil or water in industrial areas, but is undesirable in pathogenic bacteria, as biofilm formation confers resistance to most commonly used antibiotics and protects pathogens from host defence mechanisms [7,8]. One of the organisms known for its rapid biofilm formation is Staphylococcus epidermidis, which can be isolated from soil [9] and wastewater [10], but is a common commensal organism on the human skin and a facultative pathogen [8]

Objectives

Methods

Results

Discussion

Conclusion