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Revista Iberoamericana de Micologia 2020
Topics: Agar; Culture Media; Lipid Metabolism; Malassezia
PubMed: 31879200
DOI: 10.1016/j.riam.2019.10.003 -
Journal of Fungi (Basel, Switzerland) Nov 2018The aim of this study was to establish a ketoconazole susceptibility test for using modified Leeming⁻Notman agar (mLNA). The susceptibilities of 33 isolates obtained...
The aim of this study was to establish a ketoconazole susceptibility test for using modified Leeming⁻Notman agar (mLNA). The susceptibilities of 33 isolates obtained by modified CLSI M27-A3 method were compared with the results by disk diffusion method, which used different concentrations of ketoconazole on 6 mm diameter paper disks. Results showed that 93.9% (31/33) of the minimum inhibitory concentration (MIC) values obtained from both methods were similar (consistent with two methods within 2 dilutions). BCRC 21676 and ATCC 22019 were used to verify the results obtained from the disk diffusion and modified CLSI M27-A3 tests, and they were found to be consistent. Therefore, the current study concludes that this new novel test-using different concentrations of reagents on cartridge disks to detect MIC values against ketoconazole-can be a cost-effective, time-efficient, and less technically demanding alternative to existing methods.
PubMed: 30453525
DOI: 10.3390/jof4040126 -
Veterinary Dermatology Apr 2020Tolerance of Malassezia pachydermatis to azole drugs has been reported worldwide, from strains isolated from dogs. Canine Malassezia dermatitis often is treated with...
BACKGROUND
Tolerance of Malassezia pachydermatis to azole drugs has been reported worldwide, from strains isolated from dogs. Canine Malassezia dermatitis often is treated with shampoos containing 2% miconazole (MCZ) or other topical MCZ products.
OBJECTIVES
In the in vitro study herein, it was investigated whether MCZ-induced amino acid substitutions in the lanosterol 14-alpha-demethylase (ERG11) gene 1 lead to azole tolerance in M. pachydermatis.
METHODS AND MATERIALS
Toleranced to MCZ was induced in an azole-susceptible strain of M. pachydermatis (CBS1879 ) by culture in medium containing MCZ. Antifungal susceptibility to MCZ, clotrimazole (CTZ) and itraconazole (ITZ) was assessed using the modified broth microdilution (BM) method. To assess the potential mechanism of tolerance in the three MCZ-resistant strains, ERG11 was sequenced. The interaction between the calcineurin inhibitor tacrolimus and MCZ in the azole-tolerant isolates also was examined.
RESULTS
Three strains (NUBS19001 to NUBS19003) from CBS1879 cultured in medium containing MCZ exhibited minimum inhibitory concentrations (MICs) of 40 mg/L to MCZ, 5 mg/L to ITZ and >32 mg/L to CTZ, meaning that the isolates were tolerant. The combination of MCZ and tacrolimus exerted an indifferent effect against the MCZ-tolerant strain. BLAST analysis using the NCBI database showed mutations in the cytochrome p450 encoded by ERG11 in the MCZ-tolerant strains.
CONCLUSIONS
In the present in vitro study, it was shown that MCZ exposure can induce amino acid substitutions in ERG11 and subsequent tolerance of M. pachydermatis to several azoles. Whether topical therapy with azole-containing products can exert a similar effect in vivo is a question that requires further research.
Topics: Amino Acid Substitution; Antifungal Agents; Azoles; Culture Media; Cytochrome P-450 Enzyme System; Drug Resistance, Fungal; Fungal Proteins; Malassezia; Miconazole; Microbial Sensitivity Tests; Mutation
PubMed: 31729813
DOI: 10.1111/vde.12805 -
Acta Veterinaria Hungarica Dec 2014Malassezia pachydermatis is a commonly isolated yeast in veterinary dermatology that can produce biofilms in vitro and in vivo, lowering its susceptibility to...
Malassezia pachydermatis is a commonly isolated yeast in veterinary dermatology that can produce biofilms in vitro and in vivo, lowering its susceptibility to antimicrobial drugs. The aim of this study was to determine and compare the in vitro susceptibility of planktonic cells and biofilms of M. pachydermatis isolates to ketoconazole and itraconazole. The presence of biofilm formation was confirmed by crystal violet staining and absorbance measurement at 595 nm wavelength, and by a scanning electron microscopy method. Cell viability was determined by the Celltiter 96 Aqueous One solution assay containing a water-soluble tetrazolium compound (MTS) with absorbance measurement at 490 nm. Planktonic cell minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) of ketoconazole and itraconazole were very low: MIC90 and MFC90 were 0.032 and 0.125 μg/ml for ketoconazole, while 0.063 and 0.25 μg/ml for itraconazole, respectively. Also, the half maximal effective concentrations (EC50) of itraconazole were higher for planktonic cells and biofilms compared to ketoconazole. The EC50 values of ketoconazole were 18-169 times higher and those of itraconazole 13-124 times higher for biofilms than for planktonic cells. Biofilm EC50 levels exceeded MICs 103-2060 times for ketoconazole and 84-1400 times for itraconazole. No significant difference was found between these values of the two substances. In conclusion, biofilms of all examined M. pachydermatis strains were much less susceptible to ketoconazole and itraconazole than their planktonic forms.
PubMed: 25410389
DOI: 10.1556/AVet.2014.019 -
Veterinary Microbiology Dec 2015Antimicrobial therapy using a combination of polymyxin B and miconazole is effective against the main bacterial pathogens associated with otitis externa in dogs, and a...
Is transmission electron microscopy (TEM) a promising approach for qualitative and quantitative investigations of polymyxin B and miconazole interactions with cellular and subcellular structures of Staphylococcus pseudintermedius, Escherichia coli, Pseudomonas aeruginosa and Malassezia...
Antimicrobial therapy using a combination of polymyxin B and miconazole is effective against the main bacterial pathogens associated with otitis externa in dogs, and a synergistic effect of both drugs has been shown previously. The objective of the present investigation was to visualize ultrastructural changes after exposure of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus pseudintermedius and Malassezia pachydermatis to polymyxin B and miconazole by transmission electron microscopic (TEM). For this, cultures of E. coli, P. aeruginosa, S. pseudintermedius and M. pachydermatis were exposed to polymyxin B and miconazole, alone or in combination for 24 h. Ultrastructural changes were observed most frequently in the cell envelope of the four microorganisms. Exposure to polymyxin B seemed to cause more damage than miconazole within the range of concentrations applied. Treatment resulted in changes of the cell size: in E. coli, cell size increased significantly after treatment with either compound alone; in P. aeruginosa, cell size decreased significantly after treatment with polymyxin B and with miconazole; exposure of S. pseudintermedius to miconazole caused a decrease in cell size; in M. pachydermatis, cell size increased significantly after treatment with polymyxin B.; in E.coli, S. pseudintermedius and M. pachydermatis, cell size changed highly significant, in P. aeruginosa significantly after exposure to the combination of both compounds. In conclusion, by using a different approach than previous investigations, this study confirmed a clear combinatory effect of polymyxin B and miconazole against the tested microorganisms involved in canine otitis externa. It is the first time that visualization technologies were applied to compare the effect of single drugs to their combinatory effects on cellular and subcellular entities of selected bacterial and yeast species.
Topics: Animals; Anti-Bacterial Agents; Antifungal Agents; Dog Diseases; Dogs; Drug Synergism; Escherichia coli; Linear Models; Malassezia; Miconazole; Microbial Sensitivity Tests; Microscopy, Electron, Transmission; Otitis Externa; Polymyxin B; Pseudomonas aeruginosa; Staphylococcus
PubMed: 26527257
DOI: 10.1016/j.vetmic.2015.10.002 -
Microbiology Resource Announcements May 2021We have assembled the genome sequence of Malassezia pachydermatis isolated from a canine otitis sample with Nanopore-only long reads. With 99× coverage and 8.23 Mbp,...
We have assembled the genome sequence of Malassezia pachydermatis isolated from a canine otitis sample with Nanopore-only long reads. With 99× coverage and 8.23 Mbp, the genome sequence was assembled in 10 contigs, with 6 of them corresponding to chromosomes, improving the scaffolding of previous genome assemblies for the species.
PubMed: 34042482
DOI: 10.1128/MRA.00205-21 -
Mycoses Oct 2017Otitis caused by Malassezia pachydermatis is generally a common and recurrent disease in canine clinical pathology. The increased incidence of fungal resistant to... (Comparative Study)
Comparative Study
Otitis caused by Malassezia pachydermatis is generally a common and recurrent disease in canine clinical pathology. The increased incidence of fungal resistant to antifungal in both humans and pets is a cause for concern and is associated with the indiscriminate use of antifungals. Finding the most effective disinfectants and antifungals has become essential. To evaluate the in vitro inhibitory activity of hydrogen peroxide on the growth of M. pachydermatis and compare its efficacy with commercial ear cleaners. The test for sensitivity to antimicrobials was carried out following the indications of the CLSI document M44-A2. The comparative results demonstrated that hydrogen peroxide 1.5% showed excellent results for growth inhibition of M. pachydermatis, followed by Epiotic and MalAcetic , the lowest result was for Otoclean .
Topics: Animals; Antifungal Agents; Dermatomycoses; Dog Diseases; Dogs; Hydrogen Peroxide; Malassezia; Microbial Sensitivity Tests; Otitis Externa
PubMed: 28557001
DOI: 10.1111/myc.12637 -
Veterinary Dermatology Aug 2015Wipes containing chlorhexidine and azole derivates have been recommended for veterinary use. No study has been published about their activity against Malassezia...
BACKGROUND
Wipes containing chlorhexidine and azole derivates have been recommended for veterinary use. No study has been published about their activity against Malassezia pachydermatis.
HYPOTHESIS/OBJECTIVES
To evaluate the in vivo and in vitro activity of wipes soaked in a chlorhexidine, climbazole and Tris-EDTA solution against Malassezia pachydermatis.
ANIMALS
Five research colony shar-pei dogs.
METHODS
Wipes were applied once daily onto the left axilla, left groin and perianal area (protocol A), and twice daily on the right axilla, right groin and umbilical region (protocol B) for 3 days. In vivo activity was evaluated by quantifying Malassezia colonies through contact plates on the selected body areas before and after wipe application. The activity of the solution in which the wipes were soaked was assessed in vitro by contact tests following the European Standard UNI EN 1275 guidelines.
RESULTS
Samples collected after wipe application showed a significant and rapid reduction of Malassezia yeast CFU. No significant difference in the Malassezia reduction was found between protocols A and B. In vitro assay showed 100% activity against Malassezia yeasts after a 15 min contact time with the wipe solution.
CONCLUSIONS AND CLINICAL IMPORTANCE
Wipes containing chlorhexidine, climbazole and Tris-EDTA substantially reduced the M. pachydermatis population on the skin of dogs. The results, although this was an uncontrolled study performed on a small number of dogs, suggest that these wipes may be useful for topical therapy of Malassezia dermatitis involving the lips, paws, perianal area and skin folds.
Topics: Administration, Cutaneous; Animals; Antifungal Agents; Chlorhexidine; Dermatomycoses; Dog Diseases; Dogs; Drug Therapy, Combination; Edetic Acid; Female; Imidazoles; Malassezia; Male; Pilot Projects
PubMed: 26083147
DOI: 10.1111/vde.12220 -
Animals : An Open Access Journal From... Apr 2023Chronic otitis externa of dogs is a significant problem due to the prevalence and complexity of the treatment of such animals. There is evidence that in 60-80% of cases...
Chronic otitis externa of dogs is a significant problem due to the prevalence and complexity of the treatment of such animals. There is evidence that in 60-80% of cases of infectious diseases microorganisms located in the biofilm phenotype play the main role. Microorganisms in the biofilm phenotype have a number of advantages, the most significant of which is considered to be increased resistance to various external factors. Among them, a special place is occupied by resistance to antibiotics. In recent decades, research has been conducted at an increasing scale on the role of biofilm infections in various pathologies in veterinary medicine. The etiology and therapy of dog otitis externa caused by biofilm has not been fully studied. This is why we consider relevant the scientific and practical aspects of research on the etiology and therapy of dog otitis externa from the position of biofilm infection. In this work, it has been statistically proven that there is a relationship between the optical density of biofilms and their sensitivity to drugs, and this relationship is statistically significant. In addition, we have demonstrated that Farnesol has a good antibiofilm effect at a concentration of more 1.6 μM/mL (24% OD decrease of biofilm), and its highest antibiofilm effect (71-55%-more than a half) was observed at a concentration of 200-12.5 μM/mL.
PubMed: 37048514
DOI: 10.3390/ani13071259 -
Mycoses Dec 2018We report a malasseziosis model in immunocompromised Swiss mice. For this model, the mice were immunosuppressed with a combination of cyclophosphamide at 150 mg/kg and...
We report a malasseziosis model in immunocompromised Swiss mice. For this model, the mice were immunosuppressed with a combination of cyclophosphamide at 150 mg/kg and hydrocortisone acetate at 250 mg/kg. Two groups were formed according to the site of inoculation. Dermatitis group received an intradermal injection of 5 × 10 cell/mouse at a shaved dorsal region, while the otitis group received the same inoculum in the middle ear. Five animals/group were euthanised at different times, and the skin and ear were histopathologically analysed. During the first euthanasia, which occurred after inoculation, microscopic examination showed that all mice presented budding yeast-like in a tissue sample. The presence of yeasts decreased over time being undetected on the 17th day (dermatitis group) and the 21st day (otitis group) after inoculation. This is the first murine model for malasseziosis that can be useful for evaluating new treatment approaches.
Topics: Animals; Cyclophosphamide; Dermatomycoses; Disease Models, Animal; Female; Histocytochemistry; Hydrocortisone; Immunocompromised Host; Immunosuppressive Agents; Injections, Intradermal; Malassezia; Mice; Otitis Media
PubMed: 30106183
DOI: 10.1111/myc.12839