Segmentation of hyphae and yeast in fungi-infected tissue slice images and its application in analyzing antifungal blue light therapy

Med Mycol. 2024 May 3;62(5):myae050. doi: 10.1093/mmy/myae050.

Abstract

Candida albicans is a pathogenic fungus that undergoes morphological transitions between hyphal and yeast forms, adapting to diverse environmental stimuli and exhibiting distinct virulence. Existing research works on antifungal blue light (ABL) therapy have either focused solely on hyphae or neglected to differentiate between morphologies, obscuring potential differential effects. To address this gap, we established a novel dataset of 150 C. albicans-infected mouse skin tissue slice images with meticulously annotated hyphae and yeast. Eleven representative convolutional neural networks were trained and evaluated on this dataset using seven metrics to identify the optimal model for segmenting hyphae and yeast in original high pixel size images. Leveraging the segmentation results, we analyzed the differential impact of blue light on the invasion depth and density of both morphologies within the skin tissue. U-Net-BN outperformed other models in segmentation accuracy, achieving the best overall performance. While both hyphae and yeast exhibited significant reductions in invasion depth and density at the highest ABL dose (180 J/cm2), only yeast was significantly inhibited at the lower dose (135 J/cm2). This novel finding emphasizes the importance of developing more effective treatment strategies for both morphologies.

Keywords: blue light therapy; convolutional neural network; hyphae; image segmentation; yeast.

Plain language summary

We studied the effects of blue light therapy on hyphal and yeast forms of Candida albicans. Through image segmentation techniques, we discovered that the changes in invasion depth and density differed between these two forms after exposure to blue light.

MeSH terms

  • Animals
  • Antifungal Agents / pharmacology
  • Antifungal Agents / therapeutic use
  • Candida albicans* / radiation effects
  • Candidiasis / microbiology
  • Disease Models, Animal
  • Hyphae*
  • Image Processing, Computer-Assisted / methods
  • Light
  • Mice
  • Neural Networks, Computer
  • Phototherapy / methods
  • Skin / microbiology