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INTRODUCTION: Malassezia is a major component of the skin microbiome, a lipophilic symbiotic organism of the mammalian skin, which can switch to opportunistic pathogens triggering multiple dermatological disorders in humans and animals. This phenomenon is favored by endogenous and exogenous host predisposing factors, which may switch Malassezia from a commensal to a pathogenic phenotype. AREA COVERED: This review summarizes and discusses the most recent literature on the pathogenesis of Malassezia yeasts, which ultimately results in skin disorders with different clinical presentation. A literature search of Malassezia pathogenesis was performed via PubMed and Google scholar (up to May 2023), using the following keywords: Pathogenesis and Malassezia;host risk factors and Malassezia, Malassezia and skin disorders; Malassezia and virulence factors: Malassezia and metabolite production; Immunology and Malassezia. EXPERT OPINION: Malassezia yeasts can maintain skin homeostasis being part of the cutaneous mycobiota; however, when the environmental or host conditions change, these yeasts are endowed with a remarkable plasticity and adaptation by modifying their metabolism and thus contributing to the appearance or aggravation of human and animal skin disorders.
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Malassezia , Dermatopatias Infecciosas , Animais , Humanos , Malassezia/genética , Malassezia/metabolismo , Pele , Fatores de Risco , Fenótipo , MamíferosRESUMO
INTRODUCTION: Malassezia spp. are a group of lipid-dependent basidiomycetes yeasts acting as commensal organisms of the human and animal skin. However, under some not well-defined circumstances, these yeasts may switch to opportunistic pathogens triggering a number of skin disorders with different clinical presentations. The genus comprises of 18 lipid-dependent species with a variable distribution in the hosts and pathologies thus suggesting a host- and microbe-specific interactions. AREA COVERED: This review highlighted and discussed the most recent literature regarding the genus Malassezia as a commensal or pathogenic organisms highlighting Malassezia-associated skin disorders in humans and animals and their antifungal susceptibility profile. A literature search of Malassezia associated skin disorders was performed via PubMed and Google scholar (up to May 2023), using the different keywords mainly associated with Malassezia skin disorders and Malassezia antifungal resistance. EXPERT OPINION: Malassezia yeasts are part of the skin mycobiota and their life cycle is strictly associated with the environment in which they live. The biochemical, physiological, or immunological condition of the host skin selects Malassezia spp. or genotypes able to survive in a specific environment by changing their metabolisms, thus producing virulence factors or metabolites which can cause skin disorders with different clinical presentations.
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Dermatite Seborreica , Dermatomicoses , Malassezia , Tinha Versicolor , Humanos , Animais , Tinha Versicolor/tratamento farmacológico , Tinha Versicolor/microbiologia , Tinha Versicolor/patologia , Dermatomicoses/tratamento farmacológico , Dermatomicoses/microbiologia , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico , Dermatite Seborreica/tratamento farmacológico , Dermatite Seborreica/microbiologia , Pele/microbiologia , Pele/patologia , LipídeosRESUMO
Cladosporium infections have a poor prognosis in animals, most likely due to a lack of knowledge about diagnosis and treatment. In this study, we described a case of a lethal Cladosporium allicinum infection in a captive bullfrog (Pyxicephalus adspersus) in Europe. One adult male bullfrog was referred with clinical signs of lethargy and a cutaneous nodule. Fungal infection was suspected on cytology and confirmed by histology and cultural isolation. The mold was identified by molecular methods using partial sequencing of the TEF1α gene and the ITS region of rDNA. Climbazole antifungal treatment was started but the frog died after 30 days, and necropsy was done. Pigmented hyphae and structures consistent with muriform bodies were found on a background of diffuse granulomatous inflammation at cytological and histopathological examinations. Fungal culture revealed the presence of pigmented fungi identified as Cladosporium allicinum only by partial sequencing of the TEF1α gene. A focally extensive granuloma with intralesional hyphae and muriform bodies effacing the architecture of head, liver, kidneys, lungs, and large intestine were retrieved after necropsy. This study is the first Italian report of the occurrence of lethal C. allicinum infection in a frog and highlights the role of this Cladosporium sp. in chromoblastomycosis.
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In the past few years, there has been a spurred tripling in the figures of fungal diseases leading to one of the most alarming rates of extinction ever reported in wild species. Some of these fungal diseases are capable of virulent infections and are now considered emerging diseases due to the extremely high number of cases diagnosed with fungal infections in the last few decades. Most of these mycotic diseases in wildlife are zoonotic, and with the emergence and re-emergence of viral and bacterial zoonotic diseases originating from wildlife, which are causing devastating effects on the human population, it is important to pay attention to these wildlife-borne mycotic diseases with zoonotic capabilities. Several diagnostic techniques such as fungal isolation, gross pathology, histopathology, histochemistry, cytology, immunohistochemistry, radiography, CT, and molecular methods such as PCR or ELISA have been invaluable in the diagnosis of wildlife mycoses. The most important data used in the diagnosis of these wildlife mycoses with a zoonotic potential have been re-emphasized. This will have implications for forestalling future epidemics of these potential zoonotic mycotic diseases originating from wildlife. In conclusion, this review will highlight the etiology, epidemiology, diagnosis, pathogenesis, pathogenicity, pathology, and hematological/serum biochemical findings of five important mycoses found in wild animals.
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Wild animals are an important component of the ecosystem, and play a major role in it. However, in recent years, there has been an astronomical increase in the incidence of wildlife mycotic diseases leading to wildlife extermination. It is important to note that most of these mycotic diseases are zoonotic, and since there is a lot of attention given to zoonosis of a bacterial or viral origin in recent times, it is important to look into the mycotic diseases which may have zoonotic potential. Previously, the authors expatiated on some major wildlife mycotic diseases. In this review, we shed light on the etiology, epidemiology, diagnosis, pathogenesis, pathogenicity, macroscopic and microscopic pathology, and hematological and serum biochemical findings of dermatophytosis, coccidioidomycosis, blastomycosis, and sporotrichosis, which are very important mycoses of wildlife.
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Middle East respiratory syndrome (MERS) is a serious emerging zoonosis. It is characterized by severe infection of the respiratory tract in humans. Dromedary camels are considered to be the most probable origin of the pathogenic Middle East respiratory syndrome coronavirus (MERS-CoV). This cross-sectional survey was carried out to ascertain the seroprevalence of MERS-CoV in dromedary camels at Illela border and human patients in a secondary care hospital in Illela, Sokoto State, Nigeria from November 2016 to January 2017. Serum samples from 74 camels and 39 human patients were collected while a data form was administered to the camel handlers (40) and human patients to obtain information on zoographic characteristics of dromedary camels, demographic characteristics of camel handlers and human patients and some practices of both groups which are likely to predispose to MERS-CoV infection. The serum samples were analyzed for antibodies against MERS-CoV using the indirect Enzyme-Linked Immuno-Sorbent Assay (ELISA). All the camels sampled were seropositive against MERS-CoV and 74% of the human patients had antibodies against MERS. All handlers treated their camels without consulting veterinarians and there was little or no biosecurity measures undertaken. Age, sex, and occupation were not significant determinants for the presence of MERS-CoV antibody in human patients sampled. This study serves as a baseline for similar researches and due to the high seroprevalence obtained in this study for both camels and humans, there is need for trained personnel, surveillance and diagnostic tools at our border posts and animal markets. Supplementary information: The online version contains supplementary material available at 10.1007/s00580-022-03351-3.
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In spite of the increasing medical interest in Malassezia yeasts, the virulence factors of Malassezia furfur causing bloodstream infections (BSI) were never investigated. Therefore, phospholipase (Pz), lipase (Lz), hemolysin (Hz), biofilm production, and in vitro antifungal susceptibility profiles were evaluated in M. furfur strains, isolated from both pityriasis versicolor (PV) patients (n = 18; Group 1) or from preterm infants BSI (n = 21; Group 2). All the test stains exhibited Pz activity, whereas 92.3% and 97.4% of strains exhibited Lz and Hz activities, respectively. Pz, Lz, and Hz activities were higher (i.e., lower values) within Group 1 strains (i.e., 0.48, 0.40, and 0.77) than those within Group 2 (i.e., 0.54, 0.54, and 0.81). The biofilm production was higher within Malassezia isolates from Group 2 (0.95 ± 0.3) than from Group 1 (0.72 ± 0.4). Itraconazole and posaconazole were the most active drugs against M. furfur, followed by amphotericin B and fluconazole. The minimum inhibitory concentrations (MIC) values varied according to the origin of M. furfur strains being statistically lower in M. furfur from Group 1 than from Group 2. This study suggests that M. furfur strains produce hydrolytic enzymes and biofilm when causing PV and BSI. Data show that the phospholipase activity, biofilm production, and a reduced antifungal susceptibility profile might favor M. furfur BSI, whereas lipase and hemolytic activities might display a synergic role in skin infection.
There is no information on the virulence factors of M. furfur involved in invasive infections. Our data suggest that the phospholipase activity, biofilm production, and a reduced antifungal susceptibility profile might favor M. furfur blood-stream infections.
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Malassezia , Sepse , Tinha Versicolor , Fatores de Virulência , Animais , Humanos , Recém-Nascido , Antifúngicos/farmacologia , Recém-Nascido Prematuro , Lipase , Malassezia/isolamento & purificação , Malassezia/metabolismo , Malassezia/patogenicidade , Fosfolipases , Sepse/etiologia , Tinha Versicolor/epidemiologia , Tinha Versicolor/microbiologia , Tinha Versicolor/veterináriaRESUMO
This cross-sectional study evaluated kidney function and urinary analytes in cattle presented for slaughter at Nsukka abattoir, Enugu State, Nigeria. A total of 133 cattle were evaluated; they were physically examined at the lairage before slaughter and after slaughter, blood for hematology and serum biochemistry were collected from the jugular vein, and urine samples for urinalysis was also collected from the urinary bladder. Standard procedures were followed in all the laboratory determinations. Results showed that, out of 133 sample population of cattle evaluated, 74 (55.6%) were apparently healthy, while 59 (44.4%) were unhealthy with observable clinical signs of diseases or disorders. Serum creatinine evaluation of the 133 cattle showed that 7.5% (10 cattle out of 133) had renal impairment (serum creatinine above 2 mg/dl). There was no significant association (p > 0.05) between renal impairment and age or sex. Out of the sampled cattle, 11 (8.3%) had positive urine bilirubin levels, while none (0%) had urobilinogen in urine, and 5 (3.8%) were positive for ketonuria. Only 6 (4.5%) were positive for urine glucose, but 113 (92.5%) were positive for urine proteins. The cattle sampled had urine pH ranging from 6 to 9, and specific gravity ranging from 1.000 to 1.030 and of all the sampled cattle, 6 (4.5%) were positive for nitrite. Based on the results, it is suggestive that based on the serum creatinine level which is a known marker of kidney function, 7.5% of cattle sampled had renal impairment.
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Testes de Função Renal/veterinária , Rim/fisiologia , Urina/química , Animais , Bovinos , Estudos Transversais , Feminino , Masculino , NigériaRESUMO
Prevalence and distribution of Shiga toxin-producing Escherichia coli (STEC) serogroups from the faecal samples of cattle and camels slaughter in Maiduguri abattoir and their antibiotic resistance profile of the isolates were determined. The highest prevalence (24%) was recorded in the month of September and more STEC isolates came from cattle than the camels. There was significant (P < 0.05) seasonal trend in the prevalence of STEC among cattle and camel with more cases recorded during the wet season. Although, the study did not demonstrate significant influence of sex from the various sources. The serogroups recorded in this study were O157, O26, O91, O103 and O111. There was no significant difference (P < 0.05) between the detection rates of serogroups. The serogroup O26 was significantly (P < 0.05) the most observed serogroup in both camels and cattle. None of the STEC isolates tested positive for the O45 serogroup. PCR assays shows that 50 (63.3%) of the 86 STEC isolates carried the stx2 gene, 34 (43%) possessed the stx1 gene, and 14 (16.3%) carried both stx1 and stx2 genes. Other genes detected include eae and ehlyA. The antimicrobial resistance among the STEC O157 and non-O157 isolates from cattle and camels in Maiduguri abattoir were very high and the STEC isolates were resistant to at least one or more of the antimicrobial agents tested. There was also multidrug resistance with the most frequent occurring patterns been ampicillin/nalidixic acid and tetracycline/trimethoprim. However, all the 79 isolates were sensitive to chloramphenicol, ceftazidime and ceftriaxone; therefore, these drugs could be drugs of choice in the treatment of STEC infections.