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Medical Mycology Apr 2019In the case presented here, we describe the isolation of an azole-resistant strain of M. pachydermatis from a canine Malassezia dermatitis. The isolate (NUBS18001) from...
In the case presented here, we describe the isolation of an azole-resistant strain of M. pachydermatis from a canine Malassezia dermatitis. The isolate (NUBS18001) from this case exhibited a minimum inhibitory concentration (MIC) of 320 μg/ml to itraconazole (ITZ) by broth microdilution (BM) assay, >32 μg/ml to ITZ by E-test, and >32 μg/ml to KTZ by E-test. Synergistic effects between FK506 and ITZ in the azole-resistant strain was evaluated using the microdilution checker-board method. The ITZ-resistant strain exhibited MICs of 320 μg/mL of ITZ alone and 5 μg/ml of FK506 alone; the addition of FK506 attenuated the ITZ MIC to 2.5 μg/ml, yielding an ITZ FICI value of 0.507. This result suggested that the combination of ITZ and FK506 exerted an additive effect against the ITZ-resistant strain. To understand the other mechanism inferred to be present in our multi-azole-resistant strain, we sequenced the ERG11 gene from this isolate, and detected missense mutations (A412G and C905T) in the sequence of the ERG11 open reading frame (ORF). To the best of our knowledge, this work is the first report that a multi-azole-resistant M. pacydermatis strain contains mutations in ERG11.
Topics: Animals; Antifungal Agents; Azoles; Cytochrome P-450 Enzyme System; Dermatitis; Dermatomycoses; Dog Diseases; Dogs; Drug Resistance, Multiple, Fungal; Drug Synergism; Fluconazole; Ketoconazole; Malassezia; Microbial Sensitivity Tests; Mutation, Missense; Open Reading Frames; Voriconazole
PubMed: 29800467
DOI: 10.1093/mmy/myy035 -
Veterinary Dermatology Aug 2021Malassezia pachydermatis is a commensal organism of the skin, yet it may induce dermatitis and/or otitis. Lactoferricin (Lfcin) is an antimicrobial peptide obtained by...
BACKGROUND
Malassezia pachydermatis is a commensal organism of the skin, yet it may induce dermatitis and/or otitis. Lactoferricin (Lfcin) is an antimicrobial peptide obtained by the pepsin-mediated digestion of lactoferrin, a multifunctional innate-defence milk protein. The antibacterial activity of Lfcin is thought to cause alteration of bacterial membrane permeability, thus inducing cell death.
OBJECTIVES
The aim of this study was to evaluate in vitro antifungal activity of different dilutions of Lfcin solution against M. pachydermatis strains isolated from ears of dogs and cats with otitis externa.
METHODS AND MATERIALS
Fifty clinical Malassezia isolates from 40 dogs and 10 cats were tested. A dilution method in microtitre plates was used starting with a 20% Lfcin water solution. The different dilutions were 2:1 (13.3%), 1:1 (10%), 1:2 (6.7%), 1:5 (3.3%) and 1:10 (1.8%). Results were expressed as the value at which the growth of 50% (minimal fungicidal concentration MFC ) and 90% (MFC ) of yeast cells was inhibited.
RESULTS
All strains showed susceptibility to 20% Lfcin solution (100%). With 1:5 and 1:10 dilutions corresponding to 3.3% and 1.8% Lfcin solutions, all strains showed resistance. The MFC and MFC values were observed at 13.3% and 20% Lfcin solutions.
CONCLUSIONS AND CLINICAL RELEVANCE
The results indicated that Lfcin solution exhibits the antimicrobial activity specific to antimicrobial peptides. In particular, the 20% solution can be effective in killing M. pachydermatis isolated strains. Some susceptibilities also are evident at lower concentrations of ≤6.7% for four strains.
Topics: Animals; Cat Diseases; Cats; Dermatomycoses; Dog Diseases; Dogs; Lactoferrin; Malassezia; Otitis Externa
PubMed: 34009660
DOI: 10.1111/vde.12973 -
Medical Mycology Oct 2018The occurrence of Malassezia spp. bloodstream infections (BSIs) in neonatal intensive care unit was evaluated by using pediatric Isolator, BacT/Alert systems and central...
The occurrence of Malassezia spp. bloodstream infections (BSIs) in neonatal intensive care unit was evaluated by using pediatric Isolator, BacT/Alert systems and central venous catheter (CVC) culture. The efficacy of BacT/Alert system in detecting Malassezia was assessed by conventional procedures, culturing 1 ml of bottle content before incubation and by studying the survival of Malassezia spp. strains in BacT/Alert bottles. Of the 492 neonates enrolled, blood was collected by pediatric Isolator (290 patients; group I) or by BacT/Alert bottles (202 patients; group II). The survival of Malassezia furfur and Malassezia pachydermatis in BacT/Alert bottles was evaluated by culturing the inoculum suspension (from 106 to 10 colony-forming units, cfu/ml) and assessing the cfu/ml for 15 days. In total, 15 Malassezia BSIs were detected, of which six (2.1%) from both blood and CVC culture in Dixon agar (DixA) in patients belong to group I (blood collected by paediatric Isolator tube) and nine (4.4%) only from CVC culture in DixA in patients of group II (blood collected by BacT/Alert bottle). Only one patient (0.5%) from group II scored positive for M. furfur also by culturing in DixA 1 ml blood content of BacT/Alert bottle before incubation in BacT/Alert system.M. furfur population size in BacT/Alert bottles decreased during the incubation time, whereas that of M. pachydermatis increased. The BacT/Alert system detected M. pachydermatis even at very low concentration (i.e., 10 cfu/ml) but not any positive blood culture for M. furfur. For a correct diagnosis of Malassezia furfur BSI, the blood should be culture in lipid-enriched fungal medium, and the BacT/Alert system implemented by adding lipid substrates to increase the method sensibility. Finally, CVC cultures on lipid-supplemented media may be proposed as a routine procedure to diagnose the Malassezia fungemia.
Topics: Blood Culture; Fungemia; Humans; Infant; Infant, Newborn; Intensive Care Units, Neonatal; Malassezia; Microbial Viability; Microbiological Techniques; Sensitivity and Specificity; Specimen Handling
PubMed: 29294025
DOI: 10.1093/mmy/myx122 -
Mycoses Dec 2022Malassezia (M.) pachydermatis as a frequent reason for dermatological consultation in dogs and cats was recently shown to be lipid-dependent, too. Lipolytic activity is...
BACKGROUND
Malassezia (M.) pachydermatis as a frequent reason for dermatological consultation in dogs and cats was recently shown to be lipid-dependent, too. Lipolytic activity is a prerequisite for activating antimicrobial effectivity of fatty acid esters.
OBJECTIVES
It was therefore of interest whether it is possible to induce this mechanism in M. pachydermatis and to identify possible differences between minimal and strong lipid-dependent strains.
METHODS
In an agar dilution test, the minimal inhibitory concentrations of six fatty acid esters were determined for seventeen M. pachydermatis strains. GC analysis of parent compounds and liberated fatty acids was used to quantify ester cleavage.
RESULTS
Hydrolysis was observed in all test strains in a homogenous manner but was dependent on the chemical structure. Lowest MICs (500 ppm after 14 days of incubation) were obtained applying glyceryl monocaprylate and 3-hydroxylpropyl caprylate, while the corresponding esters of undecylenic acid showed nearly twice the value. As shown by GC analysis with the reference strains CBS 1879 and CBS 1892 and 3-hydroxypropyl caprylate, hydrolysis and caprylic acid formation starts immediately and was dependent on yeast density. Furthermore, nine azole-resistant strains isolated from dogs with treatment failures showed MIC values comparable to the other strains and no resistance to monohydric fatty acid esters.
CONCLUSIONS
Medium-chain fatty acid esters may represent a new therapeutic option for veterinary use even in azole-resistant strains. The in vivo verification in M. pachydermatis-associated dermatitis in dogs and cats will be the next step for the successful development of new therapeutics.
Topics: Dogs; Cats; Animals; Malassezia; Azoles; Caprylates; Esters; Cat Diseases; Antifungal Agents; Dog Diseases; Fatty Acids; Dermatomycoses
PubMed: 35923130
DOI: 10.1111/myc.13512 -
Veterinary Dermatology Oct 2021Otitis externa (OE) is a common disorder in dogs. Infection by the commensal yeast, Malassezia pachydermatis, may result in chronic disease that does not respond to...
BACKGROUND
Otitis externa (OE) is a common disorder in dogs. Infection by the commensal yeast, Malassezia pachydermatis, may result in chronic disease that does not respond to standard primary care. Chronic infectious OE may be associated with otitis media (OM).
HYPOTHESIS/OBJECTIVE
To report medical management, clinical outcomes and frequency of middle ear involvement, in dogs with Malassezia otitis unresponsive to primary care.
ANIMALS
Fifty-nine dogs from one referral veterinary hospital from January 2007 to September 2018.
METHODS AND MATERIALS
Retrospective analysis of medical records of dogs referred with chronic otitis and treated for Malassezia otitis at a referral veterinary hospital.
RESULTS
Chronic Malassezia OE was treated successfully in 91% of ears, in 87% of these cases with one ear flush intervention. Median time-to-resolution was 27 days after ear flush intervention. Neither duration of otitis, presence of neutrophils in aural discharge nor administration of oral itraconazole affected clinical outcome. Malassezia OM occurred concurrently in 17% of ears.
CONCLUSIONS AND CLINICAL RELEVANCE
These findings assist clinicians and carers of affected dogs in decision-making, by documenting that most cases of canine Malassezia otitis that have not resolved with standard primary care, can be treated successfully with a well-staged and intense medical treatment plan. Malassezia OM should be suspected to occur concurrently in around a fifth of affected ears.
Topics: Animals; Dermatomycoses; Dog Diseases; Dogs; Malassezia; Otitis Externa; Primary Health Care; Retrospective Studies
PubMed: 34189776
DOI: 10.1111/vde.12995 -
Mycoses Dec 2017Previous studies have evaluated the action of gentamicin against Malassezia pachydermatis. The aim of this study was to evaluate in vitro susceptibility of...
Previous studies have evaluated the action of gentamicin against Malassezia pachydermatis. The aim of this study was to evaluate in vitro susceptibility of M. pachydermatis to the aminoglycosides- gentamicin, tobramycin, netilmicin and framycetin. The minimum inhibitory concentration (MIC) of gentamicin was determined following methods M27-A3 microdilution and Etest . The Etest was used to determine the minimum inhibitory concentration (MIC) of the tobramycin and netilmicin. The Kirby-Bauer test was used to determine the antibiotic susceptibility to the framycetin. The MIC50 and MIC90 were 8.12 μg/mL and 32.5 μg/mL by microdilution method for gentamicin. The MIC50, determined by the Etest , was 8 μg/mL for gentamicin and netilmicin and 64 μg/mL for tobramycin. The MIC90 was 16 and 32 μg/mL for gentamicin and netilmicin respectively. The MIC90 was outside of the detectable limits for tobramycin. To framycetin, 28 strains (40%) of the 70 M. pachydermatis isolates tested showed a diameter of 22 mm, 22 strains (31.42%) showed a diameter of 20 mm, 16 strains showed a diameter of ≤ 18 mm, and only 5.71% of the isolates showed a diameter of ≥ 22 mm. This study provides evidence of high in vitro activity of the aminoglycosides-gentamicin, tobramycin, netilmicin and framycetin against M. pachydermatis. For gentamicin Etest showed similar values of MIC50 y MIC90 that the obtained by microdilution method. We considered Etest method could be a good method for these calculations with aminoglycosides.
Topics: Amikacin; Aminoglycosides; Antifungal Agents; Gentamicins; Malassezia; Microbial Sensitivity Tests; Netilmicin; Tobramycin
PubMed: 28925032
DOI: 10.1111/myc.12665 -
Natural Product Research Dec 2021Antibiotic resistance is a global problem, searching for new antimicrobial agents is an urgent need. In this study, antibacterial and antimicrobial effects of...
Antibiotic resistance is a global problem, searching for new antimicrobial agents is an urgent need. In this study, antibacterial and antimicrobial effects of milk-derived antimicrobial agents, lactoferrin-derived peptides, lactoferricin (Lfc) and lactoferrampin (Lfa) (alone or in combination) and their association with natural extracts have been explored. The assessment of antimicrobial activity was based on two measurements: Minimum Inhibitory Concentration and Fractional Inhibitory Concentration indexes. Lfc alone is more suitable for inhibiting and while Lfa against , a synergistic effect of the two peptides against all the three pathogens has been detected. A strong synergy of all the natural extracts with Lfc and Lfa solution against selected microorganisms was pointed out. Our results suggest that natural-derived compounds, such as milk peptides and vegetal extracts could be promising tools to treat moderate fungal and bacterial infections.
Topics: Animals; Anti-Infective Agents; Antimicrobial Peptides; Lactoferrin; Microbial Sensitivity Tests; Milk
PubMed: 32927978
DOI: 10.1080/14786419.2020.1821017 -
Journal of Enzyme Inhibition and... Dec 2022Warm-blooded animals may have on healthy skin, but changes in the skin microenvironment or host defences induce this opportunistic commensal to become pathogenic....
Warm-blooded animals may have on healthy skin, but changes in the skin microenvironment or host defences induce this opportunistic commensal to become pathogenic. Malassezia infections in humans and animals are commonly treated with azole antifungals. Fungistatic treatments, together with their long-term use, contribute to the selection and the establishment of drug-resistant fungi. To counteract this rising problem, researchers must find new antifungal drugs and enhance drug resistance management strategies. Cyclic adenosine monophosphate, adenylyl cyclase, and bicarbonate have been found to promote fungal virulence, adhesion, hydrolase synthesis, and host cell death. The CO/HCO/pH-sensing in fungi is triggered by HCO produced by metalloenzymes carbonic anhydrases (CAs, EC 4.2.1.1). It has been demonstrated that the growth of can be inhibited by primary sulphonamides, which are the typical CA inhibitors. Here, we report the cloning, purification, and characterisation of the -CA (MpaCA) from the pathogenic fungus , which is homologous to the enzyme encoded in the genome of and , that are responsible for dandruff and seborrhoeic dermatitis. Fungal CAs could be thus considered a new pharmacological target for combating fungal infections and drug resistance developed by most fungi to the already used drugs.
Topics: Carbonic Anhydrase Inhibitors; Carbonic Anhydrases; Dose-Response Relationship, Drug; Malassezia; Molecular Structure; Recombinant Proteins; Structure-Activity Relationship
PubMed: 34894958
DOI: 10.1080/14756366.2021.1994559 -
Open Veterinary Journal 2022External otitis is common in dogs, and one of the main agents involved is , a yeast belonging to the otic microbiota. Empirical treatment can fail; therefore, it is...
BACKGROUND
External otitis is common in dogs, and one of the main agents involved is , a yeast belonging to the otic microbiota. Empirical treatment can fail; therefore, it is essential to know the antifungal susceptibility profile to prescribe appropriate treatment, a fact scarcely reported in Chile.
AIM
This study aimed to determine the antifungal sensitivity of isolated from the external auditory canal of dogs in central Chile.
METHODS
Ear swabs from 30 dogs (15 healthy and 15 with external otitis) were used. Samples were subjected to cytology and fungal culture. The antifungal susceptibility was determined according to clinical and laboratory standards institute (CLSI) document M44A-2 using the disk diffusion test from amphotericin B, Caspofungin, fluconazole, nystatin, clotrimazole, and voriconazole were used.
RESULTS
The prevalence of was 66.7% from 8 healthy dogs and 12 with otitis. While fungal culture was not associated with the patient's clinical condition ( = 0.24), the yeast count by cytology was significantly higher in dogs with otitis ( = 0.003). The strains were sensitive to all antifungals except for Caspofungin, where 55% of the strains were resistant.
CONCLUSION
is isolated more frequently in dogs with otitis, and the ear cytological examination is useful to differentiate colonized dogs versus dogs with otitis. In addition, most antifungals are active against this yeast, except Caspofungin, an antifungal used in human medicine. This situation should be further monitored in epidemiological programs to evaluate the possible impact on Chilean public health.
Topics: Animals; Antifungal Agents; Caspofungin; Chile; Dermatomycoses; Dog Diseases; Dogs; Malassezia; Otitis Externa; Saccharomyces cerevisiae
PubMed: 35342729
DOI: 10.5455/OVJ.2022.v12.i1.12 -
Medical Mycology Journal 2022Azole resistance in Malassezia pachydermatis has been reported in isolates from canine skin worldwide. Decreased susceptibility of M. pachydermatis to azoles has been...
Azole resistance in Malassezia pachydermatis has been reported in isolates from canine skin worldwide. Decreased susceptibility of M. pachydermatis to azoles has been hypothesized to potentially result from mutations in the ERG11 gene, which encodes lanosterol 14α-demethylase. To sequence the mutation hotspots of ERG11 in the isolates, we prepared primers (MPERG11hot2S and MPERG11hot2R) based on the conserved sequences of M. pachydermatis ERG11. DNA samples from azole-resistant and -susceptible strains were amplified by PCR using the primer pair. PCR amplicons were sequenced and analyzed for single-nucleotide polymorphisms (SNPs) in the target gene. Seven of the tested azole-resistant strains (16 strains) harbored ERG11 SNPs at nucleotide 904 (G→A) or 905 (C→T), resulting in the replacement of Ala 302 with Thr or Val (Ala302Thr or Val). None of the tested azole-susceptible strains had a mutation at either of those residues. Our PCR method detected SNPs at the nucleotide-905 (C→T) hotspot mutation site in M. pachydermatis ERG11. Moreover, we discovered an additional hot spot site at nucleotide 904 (G→A).
Topics: Animals; Dogs; Antifungal Agents; Azoles; Drug Resistance, Fungal; Malassezia; Microbial Sensitivity Tests; Polymorphism, Single Nucleotide
PubMed: 35650071
DOI: 10.3314/mmj.21-00013