Development of an in vitro Assay, Based on the BioFilm Ring Test®, for Rapid Profiling of Biofilm-Growing Bacteria

Abstract

Microbial biofilm represents a major virulence factor associated with chronic and recurrent infections. Pathogenic bacteria embedded in biofilms are highly resistant to environmental and chemical agents, including antibiotics and therefore difficult to eradicate. Thus, reliable tests to assess biofilm formation by bacterial strains as well as the impact of chemicals or antibiotics on biofilm formation represent desirable tools for a most effective therapeutic management and microbiological risk control. Current methods to evaluate biofilm formation are usually time-consuming, costly, and hardly applicable in the clinical setting. The aim of the present study was to develop and assess a simple and reliable in vitro procedure for the characterization of biofilm-producing bacterial strains for future clinical applications based on the BioFilm Ring Test® (BRT) technology. The procedure developed for clinical testing (cBRT) can provide an accurate and timely (5 h) measurement of biofilm formation for the most common pathogenic bacteria seen in clinical practice. The results gathered by the cBRT assay were in agreement with the traditional crystal violet (CV) staining test, according to the κ coefficient test (κ = 0.623). However, the cBRT assay showed higher levels of specificity (92.2%) and accuracy (88.1%) as compared to CV. The results indicate that this procedure offers an easy, rapid and robust assay to test microbial biofilm and a promising tool for clinical microbiology.

Effects of Lysozyme, Proteinase K, and Cephalosporins on Biofilm Formation by Clinical Isolates of Pseudomonas aeruginosa

“…According to the intensity of the violet color of the stained biofilm, the biofilm-forming ability of different P. aeruginosa isolates was classified as strongly adherent, moderately adherent, weakly adherent, or nonadherent. In this work, P. aeruginosa strain PAO1 and strain PA14 were used as references for strong and weak adherent strains, respectively, where the biofilmproducing abilities for these standard strains were confirmed in previous reports [27][28][29].…”

Microbial biofilm correlates with an increased antibiotic tolerance and poor therapeutic outcome in infective endocarditis

“…Biofilm production for each bacterial isolate was assessed by the clinical Biofilm Ring Test (cBRT) [27]. The results showed that S. aureus isolates were moderate (2/4 cases, including the MRSA) or high (2/4 cases) biofilm-producers.…”

“…Biofilm production was analyzed by the clinical BioFilm Ring Test (cBRT) (Biofilm Control, Saint Beauzire, France) as previously described [27]. S. aureus strains ATCC 25923 and Staphylococcus epidermidis ATCC 12228 were included in each plate as standard reference and internal control.…”

Association between gentamicin resistance and stress tolerance in water isolates of Ralstonia pickettii and R. mannitolilytica

“…The capacity to form biofilm may be an advantage in Ralstonia spp. to face adverse conditions (Adley et al 2005;Anderson et al 1990;Di Domenico et al, 2016;Ryan et al 2011). Hence, it was hypothesized that the stressors aminoglycosides and arsenite could stimulate the capacity to produce biofilm (Fig.…”