A new approach by optical coherence tomography for elucidating biofilm formation by emergent Candida species

Abstract

The majority of microorganisms present a community lifestyle, establishing biofilm ecosystems. However, little is known about its formation in emergent Candida species involved in catheter-related infections. Thus, various techniques may be used in the biofilm detection to elucidate structure and clinical impact. In this context, we report the ability of emergent Candida species (Candida haemulonii, C. lusitaniae, C. pelliculosa, C.guilliermondii, C. famata and C. ciferrii) on developing well structured biofilms with cell viability and architecture, using optical coherence tomography (OCT). This new approach was compared with XTT analyses and Scanning Electron Microscopy (SEM). A positive correlation between oxidative activity (XTT) and OCT results (r = 0.8752, p < 0.0001) was observed. SEM images demonstrated cells attachment, multilayer and morphologic characteristics of the biofilm structure. C. lusitaniae was the emergent species which revealed the highest scattering extension length and oxidative metabolism when evaluated by OCT and XTT methods, respectively. Herein, information on C. ciferri biofilm structure were presented for the first time. The OCT results are independently among Candida strains and no species-specific pattern was observed. Our findings strongly contribute for clinical management based on the knowledge of pathogenicity mechanisms involving emergent yeasts.

Intra-colony channels in E. coli function as a nutrient uptake system

“…However, these methods currently cannot resolve sub-micron information over multi-millimetre scales, as with the Mesolens. The same problem accompanies ultrasound [ 45 , 46 ], optical coherence tomography and photoacoustic tomography [ 47 – 49 ] methods used for mesoscale biofilm imaging, where they cannot properly resolve structures on the order of which we report. We have also studied images of bacterial macro-colonies under a widely available conventional stereomicroscope.…”

Functional channels in matureE. colicolonies

“…However, these methods currently cannot resolve sub-micron information over multi-millimetre scales, as with the Mesolens. The same problem accompanies ultrasound 36,37 , optical coherence tomography and photoacoustic tomography 38–40 methods used for mesoscale biofilm imaging, where they cannot properly resolve structures on the order of which we report. We have also studied images of bacterial macro-colonies under a widely available conventional stereomicroscope.…”

Live Monitoring and Analysis of Fungal Growth, Viability, and Mycelial Morphology Using the IncuCyte NeuroTrack Processing Module

“…Although IncuCyte imaging may help to explore these areas, limitations to NT studies of pathogenic fungi need to be considered. As the NT processing module operates strictly in two dimensions, NT analysis is poorly suited to track yeast biofilms, which are often subject to substantial vertical extension (11, 54). Similarly, although it provides reliable quantification of mycelial networks in the focal plane, IncuCyte imaging is not able to accurately represent mycelial biomass in advanced growth stages and thus may underestimate late-onset alterations to growth patterns, e.g., in the context of drug exposure.…”