Environmental scanning electron microscopy analysis of Proteus mirabilis biofilms grown on chitin and stainless steel

Abstract

Proteus mirabilis is a human pathogen able to form biofilms on the surface of urinary catheters. Little is known about P. mirabilis biofilms on natural or industrial surfaces and the potential consequences for these settings. The main aim of this work was to assess and compare the adhesion and biofilm formation of P. mirabilis strains from different origins on chitin and stainless steel surfaces within 4 to 96 h. Using environmental scanning electron microscopy, the biofilms of a clinical strain grown on chitin at 4 h showed greater adhesion, aggregation, thickness, and extracellular matrix production than those grown on stainless steel, whereas biofilms of an environmental strain had less aggregation on both surfaces. Biofilms of both P. mirabilis strains developed different structures on chitin, such as pillars, mushrooms, channels, and crystalline-like precipitates between 24 and 96 h, in contrast with flat-layer biofilms produced on stainless steel. Significant differences (p < 0.05) were found in the frequency of pillars and channels. Images of transmission electron microscopy demonstrated abundant fimbriae in 100 % of cells from both strains, which could be related to surface adherence and biofilm formation. This represents the first study of P. mirabilis showing adhesion, biofilm formation, and development of different structures on surfaces found outside the human host.

Evaluation of the ability of Acinetobacter baumannii to form biofilms on six different biomedical relevant surfaces

“…; Fernandez‐Delgado et al . ). Aside from cellular properties and pathogen adhesion mechanisms, variations in surface roughness, hydrophobicity and chemical structure can impede or promote a pathogen's ability to attach and populate on that surface.…”

“…() who compared the biofilms of Staphylococcus aureus on stainless steel with copper‐treated stainless steel and by Fernandez‐Delgado et al . () who evaluated the biofilms of P. mirabilis on stainless steel reveals similarity in biofilm development with regard to this metal.…”

Three‐dimensional bright‐field scanning transmission electron microscopy elucidate novel nanostructure in microbial biofilms

“…The electron microscopy methods applied most frequently for biofilm studies have been scanning electron microscopy (Castro et al, 2014;Sztajer et al, 2014;Fernandez-Delgado et al, 2015;Hu et al, 2015;Pereira et al, 2015;Sena-Velez et al, 2015) or transmission electron microscopy (Hunter & Beveridge, 2005;Schooling & Beveridge, 2006;Moe et al, 2010;Kay et al, 2011;Sandal et al, 2011;Granillo et al, 2015;Ray et al, 2015). These methods differ in that scanning electron microscopy (SEM) enables visualization of topographic features, whereas transmission electron microscopy (TEM) yields information about internal ultrastructure.…”

Response of Formed‐Biofilm of Enterobacter cloacae, Klebsiella oxytoca, and Citrobacter freundii to Chlorite‐Based Disinfectants

“…With the constant advancement of food industrialization, biofilms have become a public health issue and economic concern due to the potential for cross‐contamination of instruments and surfaces that contact with food. The factors responsible for attachment and biofilm formation, such as bacterial strains, temperature, and contact surfaces, which are commonly encountered during food processing, are critical for biofilm removal (Fernándezdelgado et al., ; Vivas et al., ). Most studies regarding the control of biofilms have focused on the biofilms grown in standard lab conditions and are not applicable to food processing environments.…”