Race and ethnicity: Risk factors for fungal infections?

Racial and ethnic identities, largely understood as social rather than biologic constructs, may impact risk for acquiring infectious diseases, including fungal infections. Risk factors may include genetic and immunologic differences such as aberrations in host immune response, host polymorphisms, and epigenomic factors stemming from environmental exposures and underlying social determinants of health. In addition, certain racial and ethnic groups may be predisposed to diseases that increase risk for fungal infections, as well as disparities in healthcare access and health insurance. In this review, we analyzed racial and ethnic identities as risk factors for acquiring fungal infections, as well as race and ethnicity as they relate to risk for severe disease from fungal infections. Risk factors for invasive mold infections such as aspergillosis largely appear related to environmental differences and underlying social determinants of health, although immunologic aberrations and genetic polymorphisms may contribute in some circumstances. Although black and African American individuals appear to be at high risk for superficial and invasive Candida infections and cryptococcosis, the reasons for this are unclear and may be related to underling social determinants of health, disparities in access to healthcare, and other socioeconomic disparities. Risk factors for all the endemic fungi are likely largely related to underlying social determinants of health, socioeconomic, and health disparities, although immunologic mechanisms likely play a role as well, particularly in disseminated coccidioidomycosis.

Important Mycoses of Wildlife: Emphasis on Etiology, Epidemiology, Diagnosis, and Pathology-A Review: PART 1.

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.

Important Mycosis of Wildlife: Emphasis on Etiology, Epidemiology, Diagnosis, and Pathology-A Review: PART 2.

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.

Role of lizards as reservoirs of pathogenic yeasts of zoonotic concern.

Reptiles have become popular exotic pets and in some parts of the world, they are used as important source of food, medicines, and materials. Synanthropic lizards are recognized as reservoirs of viruses, bacteria, and parasites but their role in dissemination of zoonotic pathogenic yeasts in the environment was never investigated. Therefore, fecal samples (n=177) from Podarcis siculus (Italian wall lizard), Chalcides ocellatus (Ocellated skink) and Tarentola mauritanica (Moorish gecko) were collected and yeasts were isolated and identified biochemically and molecularly by sequencing the rDNA internal transcribed spacer region (ITS). The phylogenetical relationship of isolated yeast species and their antifungal susceptibility profiles to ten antifungal agents were also assessed. Sixty samples (n=60/177; 33.9%) scored positive for yeasts, with the highest occurrence in C. ocellatus (n=11/17; 64.7%) and the highest variety of species in P. siculus (n=11/12; 91.6%). A total of 364 isolates belonging to Candida, Trichosporon, Saccharomyces and Geotrichum genera were molecularly identified. In particular, Candida albicans (n=160; 44%) followed by Trichosporon coremiiforme (n=44; 12.1%), Pichia kudriavzevii (n=32; 8.8%) and Trichosporon asahii (n=28; 7.7%) were the most frequently isolated species. The phylogenetic tree grouped all representative sequence types within the clade including Candida spp. strains from different geographical areas and from animal species, including human. All tested strains showed high susceptibility to the assayed antifungal drugs. This study suggests the role of lizards as reservoirs and spreaders of zoonotic pathogenic yeasts in the environment. The absence of resistance phenomena in the isolated yeasts might reflect an environment free of azole antifungal pollution or chemicals, suggesting the usefulness of these animals as bio indicators of environment quality.

Wild Boar (Sus scrofa) as Reservoir of Zoonotic Yeasts: Bioindicator of Environmental Quality.

Wildlife animals are recognized as reservoirs for zoonotic fungi and their faeces might play an important role in introducing pathogens into the environment. Thought wild boar (Sus scrofa) population has dramatically increased across Europe, information about their possible role in dissemination of zoonotic pathogenic yeasts in the environment is scant. Therefore, fecal samples (n = 124) from wild boars from Campania region (Southern Italy) were collected and yeasts identified biochemically and molecularly by sequencing of the internal transcribed spacer region and their phylogenetical relationship assessed. The antifungal susceptibility profiles of yeasts were also investigated using AFST-EUCAST method. Yeasts were isolated from 50.1% of the samples with the highest occurrence in samples from the province of Salerno (61.1%). A total of 368 Candida strains belonging to nine species were identified, with Candida albicans (45.7%), followed by Candida krusei (15.2%), Kazachstania slooffiae (9.8%) and Candida parapsilosis (7.6%) as the most prevalent identified species. Among C. albicans four sequence types (i.e., ST1-ST4) were identified with an intraspecific nucleotide difference up to 0.21%. The ML tree grouped all representative sequence types as paraphyletic clades with those of the references yeast species, respectively and supported by high bootstrap values. Fluconazole was the less active drug whereas, posaconazole, voriconazole, and isavuconazole the most active one. No resistance phenomena were observed for C. albicans and high MICs values for 5FC, azoles and echinocandines were registered in non-albicans Candida spp. This study showed, for the first time, the important role of wild boars in dissemination of pathogenic fungi in the environment. The absence of resistance phenomena in the Candida spp. might reflect environmental free from residues of azoles antifungals pollution or chemicals and suggests the role of wild boar as bio indicators of environment quality.

Virulence and Antifungal Susceptibility of Microsporum canis Strains from Animals and Humans.

The enzymatic and antifungal profiles of dermatophytes play an important role in causing infections in humans and animals. This study aimed to assess the virulence factors produced by Microsporum canis strains, in vitro antifungal profile and the relationship between virulence, antifungal profile and occurrence of lesions in animals and humans. A total of 100 M. canis strains from humans with tinea corporis (n = 10) and from animals presenting (n = 64) or not (n = 26) skin lesions was employed to evaluate phospholipase (Pz), hemolytic (Hz), lipase (Lz), catalase (Ca), and thermotolerance (GI) activities. In addition, in vitro antifungal profile was conducted using the CLSI broth microdilution method. A statistically significant difference (p < 0.05) in Lz and Ca values was revealed among strains from hosts with and without lesions. Voriconazole, terbinafine, and posaconazole were the most active drugs followed by ketoconazole, griseofulvin, itraconazole, and fluconazole in decreasing activity order. The significant positive correlation between azole susceptibility profile of M. canis and virulence factors (i.e., hemolysin and catalase) suggest that both enzyme patterns and antifungal susceptibility play a role in the appearance of skin lesions in animals and humans.

Subtyping Options for Microsporum canis Using Microsatellites and MLST: A Case Study from Southern Italy.

Microsporum canis is considered one of the most common zoophilic dermatophyte species causing infections in animals and humans worldwide. However, molecular epidemiological studies on this dermatophyte are still rare. In this study, we aimed to analyse the population structure and relationships between M. canis strains (n = 66) collected in southern Italy and those isolated from symptomatic and asymptomatic animals (cats, dogs and rabbits) and humans. For subtyping purposes, using multilocus sequence typing (MLST) and multilocus microsatellite typing (MLMT), we first used a limited set of strains to screen for variability. No intraspecies variability was detected in six out of the eight reference genes tested and only the ITS and IGS regions showed two and three sequence genotypes, respectively, resulting in five MLST genotypes. All of eight genes were, however, useful for discrimination among M. canis, M. audouinii and M. ferrugineum. In total, eighteen microsatellite genotypes (A-R) were recognized using MLMT based on six loci, allowing a subdivision of strains into two clusters based on the Bayesian iterative algorithm. Six MLMT genotypes were from multiple host species, while 12 genotypes were found only in one host. There were no statistically significant differences between clusters in terms of host spectrum and the presence or absence of lesions. Our results confirmed that the MLST approach is not useful for detailed subtyping and examining the population structure of M. canis, while microsatellite analysis is a powerful tool for conducting surveillance studies and gaining insight into the epidemiology of infections due to this pathogen.

Conventional therapy and new antifungal drugs against Malassezia infections.

Malassezia yeasts are commensal microorganisms occurring on the skin of humans and animals causing dermatological disorders or systemic infections in severely immunocompromised hosts. Despite attempts to control such yeast infections with topical and systemic antifungals, recurrence of clinical signs of skin infections as well as treatment failure in preventing or treating Malassezia furfur fungemia have been reported most likely due to wrong management of these infections (e.g., due to early termination of treatment) or due to the occurrence of resistant phenomena. Standardized methods for in vitro antifungal susceptibility tests of these yeasts are still lacking, thus resulting in variable susceptibility profiles to azoles among Malassezia spp. and a lack of clinical breakpoints. The inherent limitations to the current pharmacological treatments for Malassezia infections both in humans and animals, stimulated the interest of the scientific community to discover new, effective antifungal drugs or substances to treat these infections. In this review, data about the in vivo and in vitro antifungal activity of the most commonly employed drugs (i.e., azoles, polyenes, allylamines, and echinocandins) against Malassezia yeasts, with a focus on human bloodstream infections, are summarized and their clinical implications are discussed. In addition, the usefulness of alternative compounds is discussed.

Virulence and in vitro antifungal susceptibility of Candida albicans and Candida catenulata from laying hens.

In spite of evidence that domestic and wild birds may act as carriers of human pathogenic fungi, data on the role of laying hens as reservoirs of drug resistant and virulent yeasts is lacking. Here, we assess several virulence factors (phospholipase and haemolysin activity) and the antifungal susceptibility profiles of 84 Candida albicans and 17 Candida catenulata strains isolated from cloacae (group A), faeces (group B) and eggs (group C) of laying hens. Of these strains, 95% C. albicans and 23% C. catenulata strains displayed phospholipase and haemolytic activities. For C. albicans, the highest values of phospholipase (Pz = 0.62) and haemolytic activities (Hz = 0.49) were recorded among the strains from group C whilst for C. catenulata (Pz = 0.54; Hz = 0.49) among those from group A. High minimum inhibitory concentration (MIC) values for azoles and amphotericin B (AmB) were recorded irrespective of their sources in all C. albicans strains. A total of 22 C. albicans strains were multidrug resistant, displaying resistance to fluconazole, itraconazole (ITZ), voriconazole (VOR) and posaconazole (POS). All C. catenulata strains from group C were resistant to ITZ, POS, micafungin and anidulafungin and susceptible to AmB. In this study, C. albicans and C. catenulata isolated from the cloacae, faeces and eggs of laying hens produced phospholipase and haemolysin and might be multidrug resistant. In the environment (faeces) or in eggs, C. albicans and C. catenulata strains might acquire pathogenic virulence traits and/or show multidrug resistance profiles. Based on these results, breeding and handling of laying hens and/or eggs may have implications for human and animal health.

Comparative evaluation of E-test and CLSI methods for Itraconazole, Fluconazole and Ketoconazole susceptibilities of Microsporum canis strains.

The incidence of resistance to antifungal agents for dermatophytes is increasing, but most of the methods currently available to test the antifungal susceptibility of Microsporum canis still require standardization. The aims of this study were: (i) to evaluate the antifungal susceptibility of M. canis strains recovered from animals to ketoconazole (KTZ), fluconazole (FLZ) and itraconazole (ITZ) using a modified CLSI broth microdilution (CLSI M38-A2-BMD) and the E-test® protocols and (ii) to estimate the agreement between the methods. Tentative azole epidemiological cutoff values (ECVs) were also proposed in order to interpret the results of in vitro susceptibility tests and to establish the agreement between the E-test and CLSI BMD methods. A total of forty clinical M. canis strains from animals with skin lesions were tested, and the essential (EA) and categorical agreement (CA) between the two methods were determined. KTZ displayed the lowest MIC values, while ITZ and FLZ the highest. The ECV for KTZ and ITZ were 4 µg/ml, while those of FLZ was 64 µg/ml. Based on ECVs, about 88% of M. canis strains were susceptible to all azoles being a cross-resistance with ITZ-FLZ registered for one strain. A total of five M. canis strains showed MIC > ECV for FLZ using CLSI, while one strain showed MIC > ECV for ITZ using both tests. KTZ, ITZ and FLZ showed EA ranging from 92.5 to 95%, for all azoles and CA > 97% except for FLZ (87.5%). The good CA between the E-test and the CLSI BMD provides evidence of the reliability of the former method to test the antifungal susceptibility of M. canis for ITZ and KTZ and not for FLZ.

The best type of inoculum for testing the antifungal drug susceptibility of Microsporum canis: In vivo and in vitro results.

BACKGROUND: Data correlating in vitro drug susceptibility of Microsporum canis with clinical outcomes of its infections are lacking as well as the most suitable inoculum and incubation time in broth microdilution assays. OBJECTIVES AND METHODS: Microsporum canis strains were collected from animal hosts that tested positive (Group I; n = 13) and negative (Group II; n = 14) to this pathogen following itraconazole (ITC) therapy. In vitro ITC susceptibility was assessed according to the Clinical Laboratory Standards Institute (CLSI M38-A2) methodology using conidia, hypha-conidia and arthroconidia at 3 and 7 days of incubation in order to assess the most suitable inoculum and incubation time. Successively, ketoconazole (KTC), voriconazole (VRC), terbinafine (TRB), posaconazole (PSZ), fluconazole (FLC) and griseofulvin (GRI) susceptibilities were assessed using the chosen inoculum. RESULTS: The MIC values of ITC after three-day incubation were equal than those recorded after 7-day incubation. Itraconazole MICs were ≤1 µg/mL for strains from Group II and >1 µg/mL for those of Group II only when conidia were used. All strains showed high susceptibility to VRC, POS, TEB and low susceptibility to ITC, KTC, GRI and FLC regardless of the source and incubation time. CONCLUSIONS AND CLINICAL IMPORTANCE: Results suggest that correlation between the in vitro results and clinical outcome was observed only by incubating conidia for 3 days at 30 ± 2°C. These conditions might be most suitable to assess in vitro susceptibility of M. canis and assist in determining the occurrence of drug resistance and cross-resistance phenomena.

Effect of chlorogenic and gallic acids combined with azoles on antifungal susceptibility and virulence of multidrug-resistant Candida spp. and Malassezia furfur isolates.

Chlorogenic acid (CHA) and gallic acid (GA) are safe natural phenolic compounds that are used as enhancers of some drugs in influencing antioxidant, anticancer, and antibacterial activities. Among fungi, Candida spp. and Malassezia spp. are characterized by an increasing prevalence of multidrug resistance phenomena and by a high morbidity and mortality of their infections. No data are available about the efficacy of CHA and GA combined with azoles on the antifungal susceptibility and on the virulence of both fungi. Therefore, their antifungal and antivirulence effects have been tested in combination with fluconazole (FLZ) or ketoconazole (KTZ) on 23 Candida spp. and 8 M. furfur isolates. Broth microdilution chequerboard, time-kill studies, and extracellular enzymes (phospholipase and hemolytic) activities were evaluated, displaying a synergistic antifungal action between CHA or GA and FLZ or KTZ on C. albicans, C. bovina, and C. parapsilosis, and antagonistic antifungal effects on M. furfur and Pichia kudriavzevii (Candida krusei) isolates. The time-kill studies confirmed the chequerboard findings, showing fungicidal inhibitory effect only when the GA was combined with azoles on Candida strains. However, the combination of phenolics with azoles had no effect on the virulence of the tested isolates. Our study indicates that the combination between natural products and conventional drugs could be an efficient strategy for combating azole resistance and for controlling fungistatic effects of azole drugs.

Synergistic Effects of Efflux Pump Modulators on the Azole Antifungal Susceptibility of Microsporum canis.

The microbiologic and clinical resistance of dermatophytes is seldom reported, and the mechanisms associated with resistance are not well known. This study investigated the effect of efflux pump modulators (EPMs) (i.e., haloperidol HAL and promethazine PTZ) and their inhibiting activity on the minimum inhibitory concentrations of itraconazole (ITZ) and fluconazole (FLZ) against selected M. canis strains. M. canis strains with low (≤ 1 µg/ml itraconazole and < 64 µg/ml fluconazole) and high (> 1 µg/ml itraconazole and ≥ 64 µg/ml fluconazole) azole MIC values were tested using Checkerboard microdilution assay. The disk diffusion assay, the minimum fungicidal concentration and the time-kill assay were also performed in order to confirm the results of checkerboard microdilution assay. The MIC values of ITZ and FLZ of M. canis decreased in the presence of subinhibitory concentrations of HAL and PTZ, the latter being more effective with a greater increased susceptibility. Synergism was observed in all strains with high azole MICs (FICI < 0.5) and no synergism in the strains with low azole MICs. A fungicidal activity was observed after 48 h of incubation when ITZ and FLZ were tested in combination with HAL or PTZ. These results suggest that the drug efflux pumps are involved in the defense mechanisms to azole drugs in M. canis strains. The synergism might be related to an increased expression of efflux pump genes, eventually resulting in azole resistance phenomena. Complementary studies on M. canis resistance are advocated in order to investigate the molecular mechanisms of this phenomenon.