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Veterinary Medicine and Science Nov 2023Fungal and yeast infections, including those caused by Malassezia spp., are becoming increasingly difficult to treat, likely due to the occurrence of drug resistance.
BACKGROUND
Fungal and yeast infections, including those caused by Malassezia spp., are becoming increasingly difficult to treat, likely due to the occurrence of drug resistance.
OBJECTIVES
This study aimed to evaluate the antifungal effects of omeprazole (OME), a proton pump inhibitor, against antifungal-resistant Malassezia pachydermatis and to investigate the potential synergistic effects between OME and other antifungal compounds.
METHODS
In total, 15 samples of M. pachydermatis isolated from the skin of dogs were tested. The susceptibility of M. pachydermatis to itraconazole, ketoconazole, miconazole, terbinafine and OME was assessed using a modified broth microdilution (BM) method. The in vitro efficacy of OME alone and in combination with other antifungal compounds was evaluated for all isolates using the BM chequerboard method. The data obtained were analysed using the fractional inhibitory concentration index (FICI).
RESULTS
The minimum inhibitory concentration (MIC) values of antifungal compounds and OME against quality control strain (M. pachydermatis CBS1879) were lower than the MIC values of same drugs against clinically collected strains. There was no significant difference in MIC values between drugs alone and combination. According to the analysis by the FICI method, no interaction was observed with OME and antifungal compounds.
CONCLUSIONS
Most M. pachydermatis strains were resistant to azole antifungal compounds. OME exerted antifungal effects against Malassezia spp. and even showed good effects on antifungal-resistant strains. No synergistic effects were observed between the antifungal compounds and OME.
Topics: Animals; Dogs; Antifungal Agents; Malassezia; Omeprazole; Drug Resistance, Fungal
PubMed: 37872836
DOI: 10.1002/vms3.1305 -
Veterinary Sciences Feb 2024This work describes the antimycotic activity of propolis from the stingless bees and , collected from two Mexican regions (Veracruz and Chiapas, respectively), against...
This work describes the antimycotic activity of propolis from the stingless bees and , collected from two Mexican regions (Veracruz and Chiapas, respectively), against three clinical isolates and the reference strain ATCC 14522 of , the causative agent of canine otitis. The chemical components of the ethanolic extracts of propolis were determined by gas chromatography coupled with mass spectrometry (GC-MS), and sesquiterpenes were the predominant compounds. The antimycotic activity was evaluated by plate microdilution. The induced changes in the yeasts were evaluated by fluorescence microscopy and staining with calcofluor white and propidium iodide. The minimum inhibitory concentration (MIC) was 7.11 mg/mL, and the minimum fungicidal concentration was 21.33 mg/mL for both extracts. The EPPs of and caused substantial damage to yeast morphology, where the propidium iodide staining of the yeasts treated with both EEPs revealed the penetration of this marker, which indicates the destruction of the cell wall and plasma membrane of the fungi. This result suggests that these types of propolis could be used as alternative treatments for canine external otitis. To the best of our knowledge, this seems to be the first scientific report that has demonstrated structural damage in by Mexican stingless bee propolis.
PubMed: 38535840
DOI: 10.3390/vetsci11030106 -
Frontiers in Veterinary Science 2023The purpose of this study was to characterize the variety and diversity of the oral mycobiome of domestic dogs and to identify the commensal and potentially pathogenic...
The purpose of this study was to characterize the variety and diversity of the oral mycobiome of domestic dogs and to identify the commensal and potentially pathogenic fungi present. Two hundred fifty-one buccal swabs from domestic dogs were obtained and struck onto a chromogenic fungal growth medium that distinguishes between fungal species based on colony color and morphology. After isolating and harvesting single colonies, genomic DNA was extracted from pure cultures. PCR was used to amplify a fungal-specific variable rDNA region of the genome, which was then sent for sequencing. Sequencing results were input into the NCBI BLAST database to identify individual components of the oral mycobiome of tested dogs. Of the 251 dogs swabbed, 73 had cultivable fungi present and 10 dogs had multiple fungal species isolated. Although the dogs did not show signs of oral infections at the time, we did find fungal species that cause pathogenicity in animals and humans. Among fungal isolates, and species from the genus were predominant. Following fungal isolate identification, antifungal drug susceptibility tests were performed on each isolate toward the medically important antifungal drugs including fluconazole, ketoconazole, and terbinafine. Drug susceptibility test results indicated that a large number of isolates had high MIC values for all three drugs. Exploring the oral mycobiome of dogs, as well as the corresponding drug susceptibility profiles, can have important implications for canine dental hygiene, health, and medical treatment. Identifying the microorganisms within the canine mouth can illustrate a common pathway for fungal pathogens of One Health concern to spread from our canine companions to humans.
PubMed: 38033632
DOI: 10.3389/fvets.2023.1281712 -
Veterinary World Nov 2023Fungal infections are a growing problem for both humans and animals due to the emergence of pathogenic strains resistant to modern antifungal treatments. To evaluate the...
BACKGROUND AND AIM
Fungal infections are a growing problem for both humans and animals due to the emergence of pathogenic strains resistant to modern antifungal treatments. To evaluate the efficacy of new antifungal drugs, it is essential to develop animal models that demonstrate typical responses to both the infection (pathogenesis and clinical course) and to the treatment, including adverse effects. In this study, we established a rabbit otitis model by infection of an aggressive multidrug-resistant strain from dogs, C23, with no need for concomitant immunosuppression.
MATERIALS AND METHODS
Twenty healthy adult male gray giant rabbits (1 year old, 5.5 kg) were inoculated once with C23 at 10 colony-forming units/mL. We observed the clinical signs of the disease and collected ear smears and blood samples every 5 days.
RESULTS
The infection progressed rapidly and exhibited characteristic clinical signs without spontaneous recovery for at least 1 month. In fact, substantial deterioration was observed as evidenced by blood parameters.
CONCLUSION
This rabbit otitis model established using an aggressive drug-resistant fungus strain without immunosuppression could prove valuable for testing novel antifungal agents.
PubMed: 38152255
DOI: 10.14202/vetworld.2023.2192-2199 -
Research in Veterinary Science Mar 2024Despite the increasing interest in studying the gut mycobiota of dogs, the association between fungal colonization and the development of digestive disorders in this...
Despite the increasing interest in studying the gut mycobiota of dogs, the association between fungal colonization and the development of digestive disorders in this species remains largely understudied. On the other hand, the high prevalence of antifungal-resistant yeasts detected in previous studies in samples from animals represents a major threat to public health. We analyzed the presence of culturable yeasts in 112 rectal swab samples obtained from dogs with digestive disorders attended in a veterinary teaching hospital. Our results revealed that Malassezia pachydermatis was frequently isolated from the studied dog population (33.9% of samples), and that the isolation of this yeast was significantly associated to the age of animals, but not to their sex, disease group, or the presence of vomits and/or diarrhea. In contrast, other yeast species were less prevalent (17.9% of samples in total), and their isolation was not significantly associated to any variable included in the analysis. Additionally, we observed that 97.5% of the studied M. pachydermatis isolates (n = 158, 1-6 per positive episode) displayed a minimum inhibitory concentration (MIC) value >4 μg/ml to nystatin, 31.6% had a MIC ≥32 μg/ml to fluconazole, and 27.2% had a MIC >4 μg/ml to amphotericin B. The antifungal susceptibility profiles of non-Malassezia (n = 43, 1-7 per episode) were more variable and included elevated MIC values for some antifungal-species combinations. These results confirm that the intestine of dogs is a reservoir of opportunistic pathogenic yeasts and suggest that the prevalence of M. pachydermatis colonization depends more on the age of animals than on any specific digestive disorder.
Topics: Dogs; Animals; Antifungal Agents; Hospitals, Animal; Dermatomycoses; Hospitals, Teaching; Microbiota; Dog Diseases; Microbial Sensitivity Tests
PubMed: 38219470
DOI: 10.1016/j.rvsc.2024.105153 -
Veterinary World Mar 2024Catnip essential oils have antimicrobial effects against bacteria, yeast, and fungi; however, there is limited information regarding their antimicrobial activity against...
BACKGROUND AND AIM
Catnip essential oils have antimicrobial effects against bacteria, yeast, and fungi; however, there is limited information regarding their antimicrobial activity against pathogens that cause canine skin infections. This study aimed to identify the phytochemical constituents of catnip essential oil and assay its antimicrobial activity against , , , , , and .
MATERIALS AND METHODS
Catnip essential oil was extracted by hydrodistillation, and its chemical constituents were analyzed by gas chromatography-mass spectrometry (GC-MS). antimicrobial activity was investigated using broth microdilution and time-kill tests. To evaluate the effect of catnip essential oil on microbial morphology and cell membrane integrity, scanning electron microscopy (SEM) and leakage studies were conducted.
RESULTS
GC-MS analysis revealed that the principal components of catnip essential oil were - and -nepetalactone (57.09% of peak area), --nepetalactone (39.69% of peak area), -caryophyllene (1.88% of peak area), and caryophyllene oxide (1.34% of peak area). The minimum inhibitory concentration, minimum bactericidal concentration, and minimum fungicidal concentration values determined by broth microdilution ranged from 0.0625 mg/mL to 4.0 mg/mL. Time-kill testing showed that the germicidal effects of catnip essential oil were time and concentration-dependent, respectively. Environmental SEM and cell leakage analysis indicated that catnip essential oil disrupted the integrity of cell membranes in the tested microorganisms.
CONCLUSION
Catnip essential oil has potential as an alternative antimicrobial against a wide range of canine skin infection pathogens, including , and .
PubMed: 38680153
DOI: 10.14202/vetworld.2024.585-592 -
Journal of Fungi (Basel, Switzerland) Nov 2023Most fungal species are commensals and non-pathogenic to plants, humans, or animals. However, several species of the , , , and genera are common causes of disease, even...
Most fungal species are commensals and non-pathogenic to plants, humans, or animals. However, several species of the , , , and genera are common causes of disease, even for immunocompetent individuals. Besides mucosal damage, fungi may contribute to a skin barrier impairment, favoring sensitization and allergy development. A total of 68 allergic dogs were selected from a veterinary dermatology and allergy outpatient consultation for conditions related to both overgrowth and other fungal complications. The allergy diagnosis was made through anamnesis and current clinical criteria, with the involved allergenic species being identified by intradermal tests (IDTs) and allergen-specific immunoglobulin E (sIgE) determination in serum. , , and showed as the higher sensitization species from house dust mites, grass pollen, and fungi, respectively. Significant correlations at < 0.05 were found between sensitization to and grass pollens, and , , , and dust/storage mites, and between fungi like mix and or . A significant correlation was also found between sensitization to the mix and , , or . Rather severe dermatitis was observed when a positive IDT to was found, regardless of the detection of circulating sIgE, allowing us to consider the usefulness of both the IDT and the sIgE for a systematic diagnosis of allergy to fungi.
PubMed: 37998880
DOI: 10.3390/jof9111075 -
Animals : An Open Access Journal From... Feb 2024A retrospective study of microbiological laboratory results from 2020 to 2022, obtained from a veterinary diagnostic laboratory of the island of Gran Canaria, Spain,...
Microbiological Survey and Evaluation of Antimicrobial Susceptibility Patterns of Microorganisms Obtained from Suspect Cases of Canine Otitis Externa in Gran Canaria, Spain.
A retrospective study of microbiological laboratory results from 2020 to 2022, obtained from a veterinary diagnostic laboratory of the island of Gran Canaria, Spain, focused on canine otitis cases, was performed. The objective of this study was to analyze the pathogen distribution, antimicrobial susceptibility, prevalence of multidrug resistant phenotypes and the role of coinfections in otitis cases in order to provide up-to-date evidence that could support effective control strategies for this prevalent pathology. A total of 604 submissions were processed for the diagnosis of canine external otitis. Of the samples analyzed, 472 were positive for bacterial or fungal growth (78.1%; 95% CI: 74.8-81.4%). A total of 558 microbiological diagnoses were obtained, divided in 421 bacterial (75.4%; 95% CI: 71.8-79.0%) and 137 fungal (24.6%; 95% CI: 20.9-28.1%) identifications. , and were the most prevalent microorganisms detected in clinical cases of otitis. High level antimicrobial resistance was found for (30.7%), (29.4%), (25.1%) and (19%). Multidrug-resistant phenotypes were observed in 47% of the bacteria isolated. In addition, a 26.4% prevalence of methicillin-resistant was detected. The high prevalence of antimicrobial resistant phenotypes in these bacteria highlights the current necessity for constant up-to-date prevalence and antimicrobial susceptibility data that can support evidence-based strategies to effectively tackle this animal and public health concern.
PubMed: 38473127
DOI: 10.3390/ani14050742