Efficacy of cyclic lipopeptides obtained from Bacillus subtilis to inhibit the growth of Microsporum canis isolated from cats

Abstract

Background and aim Microsporum canis ( M. canis ) is a dermatophyte fungal pathogen that causes ringworms. Cats are considered to be a dominant reservoir host enabling M. canis transmission to humans. The concerns of dermatophyte resistance were raised among the usage of antifungal drugs to treat the ringworm. This study aimed to evaluate the fungal activity of cyclic lipopeptides (CLPs) obtained from Bacillus subtilis ( B. subtilis ) as an alternative method for the inhibition of M. canis growth. Materials and methods The culture plate of M. canis from confirmed cats with ringworm infection was provided. The purification of CLP extract, fengycin, iturin A, and surfactin was carried out from B. subtilis by preparative thin-layer chromatography (PTLC) coupled with solid-phase extraction (SPE) methods. Half-maximal effective concentration (EC 50 ) and agar well diffusion assays were performed to determine the efficacy of Bacillus CLP extract, fengycin, iturin A, and surfactin to inhibit the growth of M. canis isolated from cats. Results All purified Bacillus substances displayed antifungal activity to control the growth of M. canis when compared with 80% ethanol (control). EC 50 values for CLP extract, fengycin, iturin A, and surfactin were 0.23, 0.05, 0.17, and 0.08 mg/mL, respectively. In agar well diffusion assay, the ability of CLP extract, fengycin, iturin A, and surfactin on fungal inhibition had no statistically significant difference at 24 and 48 h after treatment (p < 0.05). However, CLP extract showed a statistically significant difference on M. canis inhibition at 62.21% followed by surfactin with 59.04% at 72 h after treatment. Conclusion In vitro , Bacillus CLPs revealed an inhibitory effect on M. canis growth which is a zoonotic pathogen that causes ringworms. This study suggests an alternative approach to control the growth of M. canis using substances obtained from B. subtilis as a biomedicine agent with antifungal activity.

WITHDRAWN: Global metabolic changes by Bacillus cyclic lipopeptide extracts on stress responses of para rubber leaf

“…Solid phase extraction (SPE) was carried out to increase the purity of the fengycin, iturin A, and surfactin using a solution of step gradients at 25% to 80% of acetonitrile in 0.1% of tri uoroacetic acid as a mobile phase. To identify each CLP, MALDI-TOF MS was performed by the National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani, Thailand to verify the molecular mass of the fengycin, iturin A, and surfactin compared to their commercial standards (Sigma-Aldrich, USA) as detailed in previous published articles (Tunsagool, et al 2019b;Tunsagool, et al 2021).…”

“…The ability of the Bacillus CLP extracts, fengycin, iturin A, and surfactin to hinder the growth of P. palmivora was tested by an EC 50 assay according to the previous reports (Picman et al 1990;Tunsagool, et al 2021). Brie y, a two-fold serial dilution in the range of 0.625−10 mg mL -1 for the CLP extracts and 0.156−2.5 mg mL -1 for the fengycin, iturin A, and surfactin concentrations were prepared.…”

“…The antifungal property of the CLP extracts and individual CLPs on the inhibition of the growth of P. palmivora was determined using the agar well diffusion assay following the method described in previous studies (Olila et al 2001;Tunsagool, et al 2021). Brie y, the 0.1 cm diameter of the actively growing mycelial plug earned from 5-day-old P. palmivora (Sunpapao and Pornsuriya 2014) was placed on the center of a PDA plate and incubated at room temperature for 48 h prior to starting the experiment.…”

“…The EC 50 assay is one of the microbiological methods for the indication of the chemical agent concentration, which was applied to an in vitro culture of pathogens that reduced their density to 50% of the control produced without applying the chemical agent (Alexander et al 1999;Huber and Koella 1993). Several studies used an EC 50 assay to explore the substance e cacy of the inhibitory effect on the fungal pathogen growth (Alu et al 2020;Tunsagool, et al 2021;Xavier et al 2021). In this study, a 50% growth rate reduction of P. palmivora in vitro by the applications of the CLP extracts, fengycin, iturin A, and surfactin was conducted using the EC 50 assay.…”

Some prospects in the reseach of Microsporum canis (review)

“…Особое место занимают исследования, направленные на разработку методов лечения. Так, было показано, что циклические липопептиды, полученные из Bacillus subtilis, оказывают ингибирующий эффект на рост M. сanis, полученного от кошек [33].…”