Related Experiment Video
Updated: Dec 10, 2025
Quantifying the Antifungal Activity of Peptides Against Candida albicans
Published on: January 13, 2023
The Postbiotic Activity of Lactobacillus paracasei 28.4 Against Candida auris
Rodnei Dennis Rossoni1,2, Patrícia Pimentel de Barros1,2, Iatã do Carmo Mendonça3
1Department of Biosciences and Oral Diagnosis, Institute of Science and Technology, São Paulo State University/UNESP, São José dos Campos, Brazil.
Abstract:
Candida auris has emerged as a medically important pathogen with considerable resistance to antifungal agents. The ability to produce biofilms is an important pathogenicity feature of this species that aids escape of host immune responses and antimicrobial agents. The objective of this study was to verify antifungal action using in vitro and in vivo models of the Lactobacillus paracasei 28.4 probiotic cells and postbiotic activity of crude extract (LPCE) and fraction 1 (LPF1), derived from L. paracasei 28.4 supernatant. Both live cells and cells free supernatant of L. paracasei 28.4 inhibited C. auris suggesting probiotic and postbiotic effects. The minimum inhibitory concentration (MIC) for LPCE was 15 mg/mL and ranges from 3.75 to 7.5 mg/mL for LPF1. Killing kinetics determined that after 24 h treatment with LPCE or LPF1 there was a complete reduction of viable C. auris cells compared to fluconazole, which decreased the initial inoculum by 1-logCFU during the same time period. LPCE and LPF1 significantly reduced the biomass (p = 0.0001) and the metabolic activity (p = 0.0001) of C. auris biofilm. There was also a total reduction (~108 CFU/mL) in viability of persister C. auris cells after treatment with postbiotic elements (p < 0.0001). In an in vivo study, injection of LPCE and LPF1 into G. mellonella larvae infected with C. auris prolonged survival of these insects compared to a control group (p < 0.05) and elicited immune responses by increasing the number of circulating hemocytes and gene expression of antimicrobial peptide galiomicin. We concluded that the L. paracasei 28.4 cells and postbiotic elements (LPCE and LPF1) have antifungal activity against planktonic cells, biofilms, and persister cells of C. auris. Postbiotic supplementation derived from L. paracasei 28.4 protected G. mellonella infected with C. auris and enhanced its immune status indicating a dual function in modulating a host immune response.
Insights
Lactobacillus paracasei 28.4 cells and their postbiotic extracts show significant antifungal activity against Candida auris. These natural compounds effectively combat planktonic cells, biofilms, and persister cells, offering a promising alternative to conventional treatments.
Area of Science:
- Microbiology
- Antimicrobial Research
- Probiotics and Postbiotics
Background:
- Candida auris is a significant multidrug-resistant fungal pathogen.
- Biofilm formation is a key virulence factor for C. auris, contributing to treatment resistance.
- Novel therapeutic strategies are needed to combat C. auris infections.
Purpose of the Study:
- To evaluate the antifungal efficacy of Lactobacillus paracasei 28.4 probiotic cells and its postbiotic components against Candida auris.
- To investigate the effects of these agents on C. auris biofilms and persister cells.
- To assess the in vivo efficacy and immunomodulatory effects in a Galleria mellonella model.
Main Methods:
- In vitro testing of L. paracasei 28.4 live cells and postbiotic crude extract (LPCE) and fraction 1 (LPF1).
- Determination of Minimum Inhibitory Concentration (MIC) and killing kinetics.
- Assessment of biofilm biomass, metabolic activity, and persister cell viability.
- In vivo study using Galleria mellonella larvae infected with C. auris.
Main Results:
- Both live L. paracasei 28.4 cells and postbiotic extracts (LPCE, LPF1) demonstrated potent antifungal activity against C. auris.
- LPCE and LPF1 significantly reduced C. auris biofilm biomass and metabolic activity.
- Complete eradication of viable C. auris cells, including persister cells, was observed with LPCE and LPF1 treatment.
- In vivo, LPCE and LPF1 prolonged the survival of G. mellonella larvae and enhanced immune responses.
Conclusions:
- Lactobacillus paracasei 28.4 and its postbiotic derivatives exhibit significant antifungal properties against C. auris.
- These agents are effective against planktonic, biofilm, and persister forms of C. auris.
- Postbiotic supplementation from L. paracasei 28.4 offers a dual benefit of direct antifungal action and host immune modulation.
