Onychomycosis caused by Trichosporon mucoides

Health risk posed by direct ingestion of yeasts from polluted river water

River water is an essential human resource that may be contaminated with hazardous microorganisms. However, the risk of yeast infection through river water exposure is unclear because it is highly dependant on individual susceptibility and has therefore not been well-studied, to date. To evaluate this undefined risk, we analysed the fungal communities in less polluted (LP) and highly polluted (HP) river water, as determined using principal coordinate analysis of pollution indicators. We enumerated culturable yeasts using a thermally selective isolation procedure (37 °C) and thus promoted the growth of potentially opportunistic species. Yeast species identified as clinically relevant were then tested for antifungal resistance. In addition, we propose a quantitative microbial risk assessment (QMRA) framework to quantitatively assess the potential risk of yeast infection. Our results indicated that pollution levels significantly altered fungal communities (p = 0.007) and that genera representing opportunistic and pathogenic members were significantly more abundant in HP waters (p = 0.038). Additionally, the yeast species Candida glabrata and Clavispora lusitaniae positively correlated with other pollution indicators, demonstrating the species' indicator potential. Our QMRA results further indicate that higher risk of infection is associated with increased water pollution levels (considering both physicochemical and bacterial indicators). Furthermore, yeast species with higher pathogenic potential present an increased risk of infection despite lower observed concentrations in the river water. Interestingly, the bloom of Meyerozyma guilliermondii during the wet season suggests that other environmental factors, such as dissolved oxygen levels and water turbulence, might affect growth characteristics of yeasts in river water, which consequently affects the distribution of annual infection risks. The presence of antifungal resistant yeasts, observed in this study, could further contribute to variation in risk distribution. Research on the ecophysiology of yeasts in these environments is therefore necessary to ameliorate the uncertainty and sensitivity of the proposed QMRA model. In addition to the vital knowledge on opportunistic and pathogenic yeast occurrence in river water and their observed association with pollution, this study provides valuable methods and insights to initiate future QMRAs of yeast infections.

Onychomycosis in Patients with Diabetes Mellitus in Africa: A Global Scoping Review, 2000-2021

Onychomycosis is commonly studied in Africa but not in patients with diabetics despite having a significant number of her population living with diabetes mellitus (DM). Our review highlights a total of 15 studies with only two from Africa over the past two decades; 8 (53.3%) from Asia, 4 (26.7%) from Europe, 2 (13.3%) from Africa and 1 (6.7%) from North America. A total number of 4321 participants were involved with onychomycosis prevalence of 35.3% (1527/4321). Seven studies documented preponderance of onychomycosis in males, one showed preponderance in females, one showed no statistically significant difference in gender, while correlation with gender was unclear in the remainder. The risk factors identified were duration of diabetes, increasing age, occupation (agriculture), subclinical atherosclerosis, metabolic syndrome, obesity, triglyceride levels, and glycosylated haemoglobin. Three case control studies showed a statistically significant correlation between onychomycosis and individuals with DM. Diagnosis was mainly by microscopy and culture with Trichophyton (T) rubrum as the predominant isolate. Fungal nail infections are grossly underdiagnosed and/or underreported in Africa and hence the need for improved awareness and diagnosis especially in patients with DM. Although focused on Africa, this study also revealed paucity of data on onychomycosis in diabetic patients living in the Americas despite evidence from the literature showing a significant number of individuals from that region are living with diabetes. The need to evaluate this at-risk population for onychomycosis cannot be over emphasized.

Nail Changes in People Living with Human Immunodeficiency Virus: Observational and Cross-Sectional Study in a Third-Level Hospital

Introduction

Nail changes in people living with human immunodeficiency virus (HIV) have been scarcely reported. The aim of this study was to establish the frequency and characteristics of nail alterations observed in adults with HIV infection in a third-level hospital in Mexico.

Method

Observational and cross-sectional study carried out in 205 patients receiving care at the HIV/AIDS Clinic of the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (INCMNSZ) in Mexico City. We performed a nail and iconographic assessment of both hands and toenails. We collected information of demographic and clinical variables, as well as drugs use, and antiretroviral treatment used by the participants through a questionnaire and from medical records. We performed direct cytological examinations and nail mycological cultures in participants with symptoms of onychomycosis.

Results

The participants were predominantly male patients (91.2%), with a mean age of 41 (range 21-78) years, under antiretroviral therapy (91.2%), with a suppressed viral load (78.5%) and mean CD4+ lymphocyte count of 379.5 (range 20-1,162) cells/μL. Fitzpatrick's IV phototype was prevailing in the studied population (70%). Nail changes were documented in 72.2% of the patients; being pigmentary changes (37.1%) and trauma (30.7%) the most frequent. Onychomycosis was observed in 26.3%; with total dystrophic onychomycosis as the most frequent clinical variant (68.5%). We obtained fungal isolates in 59.3% of participants and Candida parapsilosis was the most frequent of these (37.5%).

Conclusions

We observed a high prevalence of nail changes with very diverse etiology, as well as a variety of nondermatophytic yeasts and molds isolates associated with cases with onychomycosis. These findings reinforce and confirm the need for routine nail examination and stress the importance of medical personnel working with people living with HIV to have broad knowledge of nail pathology.

Molecular identification of yeasts from the order Trichosporonales causing superficial infections

BACKGROUND

The molecular reclassification of the order Trichosporonales placed the medically relevant Trichosporon species into three genera of the family Trichosporonaceae: Cutaneotrichosporon, Trichosporon, and Apiotrichum. From the clinical and epidemiological standpoint, it is important to identify any species of the family Trichosporonaceae because they present different antifungal susceptibility profiles. In Mexico, little is known about trichosporonosis etiology because the fungi are identified through phenotypic methods.

AIMS

To identify at a molecular level 12 yeast isolates morfologically compatible with Trichosporon, obtained from patients with superficial infections.

METHODS

The yeast isolates were obtained from patients with white piedra, onychomycosis, and hand and foot dermatomycosis, and were identified morphologically and genotypically (sequencing of the IGS1 region and phylogenetic analysis using the Maximum Likelihood Method). The phylogenetic analysis included 40 yeast sequences from the order Trichosporonales and one from Cryptococcus neoformans as outgroup.

RESULTS

Based on the molecular analysis, we identified three (25%) Trichosporon inkin isolates, two (16.7%) Trichosporon asteroides, two (16.7%) Cutaneotrichosporon mucoides, and one each (8.3%) of Trichosporon aquatile, Trichosporon asahii, Apiotrichum montevideense, Cutaneotrichosporon cutaneum, and Cutaneotrichosporon jirovecii.

CONCLUSIONS

The molecular characterization of the isolates showed a broad diversity of species within the order Trichosporonales, particularly among onychomycosis. It is essential to identify these yeasts at the species level to delve into their epidemiology.

Combinatory Effect of ALA-PDT and Itraconazole Treatment for Trichosporon asahii

BACKGROUND AND OBJECTIVES

Trichosporiosis is an opportunistic infection that includes superficial infections, white piedra, hypersensitivity pneumonitis, and invasive trichosporonosis. The effect of antifungal agents against these infections is largely weakened by drug resistance and biofilms-related virulence. Photodynamic therapy (PDT) is a new therapeutic approach developed not only to combat cancerous lesions but also to treat infectious diseases such as fungal infections. However, there are few studies on the antimicrobial mechanism of 5-aminolevulinic acid PDT (ALA-PDT) in treating Trichosporon. In this work, we explored the possibility of combining ALA-PDT with an antifungal agent to enhance the therapeutic efficacy of Trichosporon asahii (T. asahii) in a clinical setting and in vitro.

STUDY DESIGN/MATERIALS AND METHODS

The biofilms of T. asahii were constructed by a 96-well plate-based method in vitro. The planktonic and adherent T. asahii were exposed to different concentrations of photosensitizers and different light doses. After PDT treatment, counting colony-forming units and tetrazolium (XTT) reduction assay were used to estimate the antifungal efficacy. The minimal inhibitory concentration of itraconazole before and after PDT treatment was determined by the broth dilution method, and XTT viability assay was used to detect and evaluate the synergistic potential of ALA-PDT and itraconazole combinations in inhibiting biofilms. Scanning electron microscopy (SEM) was performed to assess the disruption of biofilms.

RESULTS

Using combination therapy, we have successfully treated a patient who had a T. asahii skin infection. Further in vitro studies showed that the antifungal effect of ALA-PDT on planktonic and adherent T. asahii was dependent on the concentration of ALA and light dosages used. We also found that the sensitivity of both planktonic and biofilm cells to itraconazole were increased after ALA-PDT. Synergistic effect were observed for biofilms in ALA-PDT and itraconazole-combined treatment. The disruption of biofilms was confirmed by SEM, suggesting that ALA-PDT effectively damaged the biofilms and the destruction was further enhanced by ALA-PDT combination of antifungal agents.

CONCLUSIONS

In conclusion, these data suggest that ALA-PDT could be an alternative strategy for controlling infections caused by Trichosporon. The combination therapy of ALA-PDT with itraconazole could result in increased elimination of planktonic cells and biofilms compared with single therapy. All these findings indicate that it could be a promising treatment against trichosporonosis. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

The first report of onychomycosis caused by Cryptococcus friedmannii (Naganishia friedmannii) a basidiomycetous yeast

Yeasts are common etiologic agents of onychomycosis. This study reported a case of onychomycosis due to Cryptococcus friedmannii (Naganishia friedmannii). This yeast was isolated of the right great toenail of 57-year-old man. Microscopic examination of nail scrapings showed budding cells with thin capsule. Sequence analyzes of the internal transcribed spacer regions was closely related to Cryptococcus friedmannii. The results of susceptibility testing showed the Cryptococcus friedmannii to be sensitive to fluconazole, itraconazole and amphotericin B.