The inhibitory effects of zinc oxide nanoparticles on clinical isolates of Microsporum canis in dogs and cats

INTRODUCTION

Microsporum canis is the most common dermatophyte infecting pets and their owners, and its long duration of treatment and increasing rate of drug resistance have caused the attention of researchers to be directed towards the use of nanoparticles and new alternatives for treatment. This study investigated the antifungal effects of zinc oxide (ZnO) nanoparticles on clinical isolates of M. canis in dogs and cats and subtilisin 1 (SUB1) gene expression.

MATERIALS AND METHODS

Zinc oxide nanoparticles were prepared using the wet chemical method at a concentration of 4000 ppm. Its antifungal potential was evaluated at concentrations of 62.5-4000 ppm by disk diffusion and microdilution methods against 10 isolates of M. canis. The effect of this product on SUB1 gene expression was investigated by quantitative real-time PCR method.

RESULTS

The results of the disk diffusion test showed that the highest inhibitory diameter was at the highest concentration of ZnO nanoparticles (34 mm), and the inhibitory zone was observed in dilutions up to 250 ppm. The minimum inhibitory concentration (MIC) of ZnO nanoparticles was between 250 and 500 ppm, and the minimum fungicidal concentration was between 500 and 1000 ppm. There was a significant reduction in SUB1 gene expression in sub-MIC concentration (125-250 ppm) (p < 0.05).

CONCLUSION

This study showed that ZnO nanoparticles have a concentration-dependent inhibitory effect on M. canis. Moreover, ZnO nanoparticles could decrease the expression of SUB1, an enzyme involved in fungi adhesion to the epidermis. Nevertheless, more studies must be done in the future to determine the possible side effects and safety of ZnO nanoparticles along with their efficacy in vivo.

Descriptive epidemiology of dermatophytosis in rodents

INTRODUCTION

Dermatophytosis is a zoonotic disease caused by a group of keratinophilic fungi called dermatophytes.

OBJECTIVES

Since the epidemiology of diseases revolves over time, this research studies the incidence of dermatophytosis among rodents referred to mycology laboratory during 2019-2021.

METHODS

A total of 163 rodents including rabbits, guinea pigs, and hamsters suspecting having dermatophytosis were sampled by scraping lesions. Direct microscopic examination, culture, and polymerase chain reaction were done for diagnosis of dermatophytosis and identification of the etiologic agent.

RESULTS

The results of this study showed that 37.4% of rodents were involved with dermatophytosis, among which 41.13% of rabbits, 25% of guinea pigs, and 26.3% of hamsters were included. Microsporum canis (52.7%) was the most isolated agent. Incidence of dermatophytosis was higher in female in rabbits while in hamsters and guinea pigs male were mostly infected. Rodents less than 6 months were more susceptible for dermatophytosis except for hamsters in which 6-12 months animals had a higher prevalence.

CONCLUSION

In conclusion, it is significant to update our knowledge about the epidemiology of dermatophytosis in rodents and other animals every few years to define valid preventive strategies. Moreover, since dermatophytes are contagious and zoonotic, it is also a priority to apply preventing methods for dermatophytosis and treat infected rodents with appropriate antifungal agents to decrease the risk of infection.

Effects of Bunium persicum essential oil on the reduction of spore germination, growth, and expression of FUM1 and FUM14 genes in Fusarium verticillioides isolates

Background and Purpose

Black Cumin of Kerman (Bunium persicum) is an Iranian plant that is commonly used as an antispasmodic, carminative, and antimicrobial substance. The present study aimed to assess different components of the essence of B. persicum and its effect on antifungal activity, spore germination inhibition, and expressions of FUM1 and FUM14 genes in Fusarium verticillioides strains.

Materials and Methods

The essence was extracted by hydrodistillation and analyzed through gas chromatography-mass spectroscopy. A broth microdilution method was used for the determination of the minimum inhibitory concentration (MIC). In addition, the expression of FUM1 and FUM14 genes of toxigenic F. verticillioides was assessed by using the real-time polymerase chain reaction (RT-PCR) technique.

Results

Based on the findings, most of the essence consisted of γ-terpinene (15.56%), propanal, and 2-methyl-3-phenyl (14.18%). The oil showed a good antifungal activity (mean MIC value: 2556.8 μg/ml) as well as the inhibition of spore germination and mycelial growth (P<0.05). The RT-PCR demonstrated that the expression levels of FUM1 and FUM14 of B. persicum-treated F. verticillioides were 0.43 and 0.53 folds lower than the control samples, respectively.

Conclusion

These findings revealed that the essential oil of B. persicum has different components responsible for the inhibition of mycelial growth and spore germination of F. verticillioides as well as reduction of expressions of FUM1 and FUM14 genes involving fumonisin production.

Microencapsulation of Saccharomyces cerevisiae and its evaluation to protect in simulated gastric conditions

BACKGROUND AND OBJECTIVES

Probiotic yeasts are used in production of functional foods and pharmaceutical products. They play an important role in promoting and maintaining human health. Until now, little work has been published on improving the survival of Saccharomyces in stimulated gastrointestinal condition.

MATERIAL AND METHODS

In this study the exposure of the yeast in the capsulate and free forms to artificial gastrointestinal conditions was assessed and the number of viable Saccharomyces cerevisiae cells during 0 to 120 mines in these conditions was evaluated by a pour plate method using sabouraud dextrose agar.

RESULTS

Results showed the shape of the beads was generally spherical, sometimes elliptical with a mean diameter of about 50-90 μm. Also count of viable probiotic cells obtained for all the microcapsules were above the recommended levels for a probiotic food. Also decrease of approximately 4 logs was noted in the number of free cells after 2 h of incubation at pH 2 and 8, when compared to decreases of about 2 logs in the all microencapsulated S. cerevisiae under similar conditions.

CONCLUSION

It is concluded that microencapsulation process was significantly able to increase the survival rate of Saccharomyces in a simulated gastrointestinal condition (p<0.05)..

Fungal flora of the combs and wattles of Iranian native chickens

BACKGROUND AND OBJECTIVES

Poultry are more susceptible to receiving and spreading of fungal infections in exact conditions. The goal of this study was to identify the normal fungal flora and dermatophytes agent of the combs and wattles of adult native chickens in Tehran, Iran.

MATERIALS AND METHODS

A total of 150 combs and wattles samples were collected by skin scraping or brushing of the margin of the suspected lesion and skin of organ. The mycological analyses were performed by direct microscopy and culture media.

RESULTS

One hundred and ninety fungi were isolated from the combs of 150 native chickens' samples that including non-dermatophytes isolates 165 (86.8%), dermatophytes 6 (3.2%) and yeast 19 (10%). Among different fungal isolates, Aspergillus was the predominant species.

CONCLUSION

Our results showed that human in contact with poultry, both at the household and the industrial level, have a clear risk factor for exposure to fungal pathogens, especially dermatophytes.