A novel multiplex fluorescent-labeling method for the visualization of mixed-species biofilms in vitro
(2024) In Microbiology spectrum 12(7).- Abstract
In nature, bacteria usually exist as mixed-species biofilms, where they engage in a range of synergistic and antagonistic interactions that increase their resistance to environmental challenges. Biofilms are a major cause of persistent infections, and dispersal from initial foci can cause new infections at distal sites thus warranting further investigation. Studies of development and spatial interactions in mixed-species biofilms can be challenging due to difficulties in identifying the different bacterial species in situ. Here, we apply CellTrace dyes to studies of biofilm bacteria and present a novel application for multiplex labeling, allowing identification of different bacteria in mixed-species, in vitro biofilm models. Oral... (More)
In nature, bacteria usually exist as mixed-species biofilms, where they engage in a range of synergistic and antagonistic interactions that increase their resistance to environmental challenges. Biofilms are a major cause of persistent infections, and dispersal from initial foci can cause new infections at distal sites thus warranting further investigation. Studies of development and spatial interactions in mixed-species biofilms can be challenging due to difficulties in identifying the different bacterial species in situ. Here, we apply CellTrace dyes to studies of biofilm bacteria and present a novel application for multiplex labeling, allowing identification of different bacteria in mixed-species, in vitro biofilm models. Oral bacteria labeled with CellTrace dyes (far red, yellow, violet, and CFSE [green]) were used to create single- and mixed-species biofilms, which were analyzed with confocal spinning disk microscopy (CSDM). Biofilm supernatants were studied with flow cytometry (FC). Both Gram-positive and Gram-negative bacteria were well labeled and CSDM revealed biofilms with clear morphology and stable staining for up to 4 days. Analysis of CellTrace labeled cells in supernatants using FC showed differences in the biofilm dispersal between bacterial species. Multiplexing with different colored dyes allowed visualization of spatial relationships between bacteria in mixed-species biofilms and relative coverage by the different species was revealed through segmentation of the CSDM images. This novel application, thus, offers a powerful tool for studying structure and composition of mixed-species biofilms in vitro.IMPORTANCEAlthough most chronic infections are caused by mixed-species biofilms, much of our knowledge still comes from planktonic cultures of single bacterial species. Studies of formation and development of mixed-species biofilms are, therefore, required. This work describes a method applicable to labeling of bacteria for in vitro studies of biofilm structure and dispersal. Critically, labeled bacteria can be multiplexed for identification of different species in mixed-species biofilms using confocal spinning disk microscopy, facilitating investigation of biofilm development and spatial interactions under different environmental conditions. The study is an important step in increasing the tools available for such complex and challenging studies.
(Less)
- author
- Aherne, Olivia LU ; Mørch, Martina ; Ortiz, Roberto LU ; Shannon, Oonagh LU and Davies, Julia R
- publishing date
- 2024-07-02
- type
- Contribution to journal
- publication status
- published
- keywords
- Biofilms/growth & development, Fluorescent Dyes/metabolism, Staining and Labeling/methods, Humans, Bacteria/growth & development, Microscopy, Confocal/methods, Flow Cytometry/methods, Gram-Negative Bacteria/physiology, Gram-Positive Bacteria/physiology
- in
- Microbiology spectrum
- volume
- 12
- issue
- 7
- article number
- e0025324
- publisher
- American Society for Microbiology
- external identifiers
-
- scopus:85198017475
- pmid:38785429
- ISSN
- 2165-0497
- DOI
- 10.1128/spectrum.00253-24
- language
- English
- LU publication?
- no
- id
- 022a0445-b5a2-4891-ac4e-eb3da0aba321
- date added to LUP
- 2026-03-27 10:44:36
- date last changed
- 2026-08-31 00:07:55
@article{022a0445-b5a2-4891-ac4e-eb3da0aba321,
abstract = {{<p>In nature, bacteria usually exist as mixed-species biofilms, where they engage in a range of synergistic and antagonistic interactions that increase their resistance to environmental challenges. Biofilms are a major cause of persistent infections, and dispersal from initial foci can cause new infections at distal sites thus warranting further investigation. Studies of development and spatial interactions in mixed-species biofilms can be challenging due to difficulties in identifying the different bacterial species in situ. Here, we apply CellTrace dyes to studies of biofilm bacteria and present a novel application for multiplex labeling, allowing identification of different bacteria in mixed-species, in vitro biofilm models. Oral bacteria labeled with CellTrace dyes (far red, yellow, violet, and CFSE [green]) were used to create single- and mixed-species biofilms, which were analyzed with confocal spinning disk microscopy (CSDM). Biofilm supernatants were studied with flow cytometry (FC). Both Gram-positive and Gram-negative bacteria were well labeled and CSDM revealed biofilms with clear morphology and stable staining for up to 4 days. Analysis of CellTrace labeled cells in supernatants using FC showed differences in the biofilm dispersal between bacterial species. Multiplexing with different colored dyes allowed visualization of spatial relationships between bacteria in mixed-species biofilms and relative coverage by the different species was revealed through segmentation of the CSDM images. This novel application, thus, offers a powerful tool for studying structure and composition of mixed-species biofilms in vitro.IMPORTANCEAlthough most chronic infections are caused by mixed-species biofilms, much of our knowledge still comes from planktonic cultures of single bacterial species. Studies of formation and development of mixed-species biofilms are, therefore, required. This work describes a method applicable to labeling of bacteria for in vitro studies of biofilm structure and dispersal. Critically, labeled bacteria can be multiplexed for identification of different species in mixed-species biofilms using confocal spinning disk microscopy, facilitating investigation of biofilm development and spatial interactions under different environmental conditions. The study is an important step in increasing the tools available for such complex and challenging studies.</p>}},
author = {{Aherne, Olivia and Mørch, Martina and Ortiz, Roberto and Shannon, Oonagh and Davies, Julia R}},
issn = {{2165-0497}},
keywords = {{Biofilms/growth & development; Fluorescent Dyes/metabolism; Staining and Labeling/methods; Humans; Bacteria/growth & development; Microscopy, Confocal/methods; Flow Cytometry/methods; Gram-Negative Bacteria/physiology; Gram-Positive Bacteria/physiology}},
language = {{eng}},
month = {{07}},
number = {{7}},
publisher = {{American Society for Microbiology}},
series = {{Microbiology spectrum}},
title = {{A novel multiplex fluorescent-labeling method for the visualization of mixed-species biofilms in vitro}},
url = {{http://dx.doi.org/10.1128/spectrum.00253-24}},
doi = {{10.1128/spectrum.00253-24}},
volume = {{12}},
year = {{2024}},
}