Onychomycosis in Ceará (Northeast Brazil): epidemiological and laboratory aspects

Global prevalence of onychomycosis in general and special populations: An updated perspective

BACKGROUND

Onychomycosis is a chronic nail disorder commonly seen by healthcare providers; toenail involvement in particular presents a treatment challenge.

OBJECTIVE

To provide an updated estimate on the prevalence of toenail onychomycosis.

METHODS

We conducted a literature search using PubMed, Embase and Web of Science. Studies reporting mycology-confirmed diagnoses were included and stratified into (a) populations-based studies, and studies that included (b) clinically un-suspected and (c) clinically suspected patients.

RESULTS

A total of 108 studies were included. Based on studies that examined clinically un-suspected patients (i.e., with or without clinical features suggestive of onychomycosis), the pooled prevalence rate of toenail onychomycosis caused by dermatophytes was 4% (95% CI: 3-5) among the general population; special populations with a heightened risk include knee osteoarthritis patients (RR: 14.6 [95% CI: 13.0-16.5]), chronic venous disease patients (RR: 5.6 [95% CI: 3.7-8.1]), renal transplant patients (RR: 4.7 [95% CI: 3.3-6.5]), geriatric patients (RR: 4.7 [95% CI: 4.4-4.9]), HIV-positive patients (RR: 3.7 [95% CI: 2.9-4.7]), lupus erythematosus patients (RR: 3.1 [95% CI: 1.2-6.3]), diabetic patients (RR: 2.8 [95% CI: 2.4-3.3]) and hemodialysis patients (RR: 2.8 [95% CI: 1.9-4.0]). The prevalence of onychomycosis in clinically suspected patients was significantly higher likely due to sampling bias. A high degree of variability was found in a limited number of population-based studies indicating that certain pockets of the population may be more predisposed to onychomycosis. The diagnosis of non-dermatophyte mould onychomycosis requires repeat sampling to rule out contaminants or commensal organisms; a significant difference was found between studies that performed single sampling versus repeat sampling. The advent of PCR diagnosis results in improved detection rates for dermatophytes compared to culture.

CONCLUSION

Onychomycosis is an underrecognized healthcare burden. Further population-based studies using standardized PCR methods are warranted.

Onychomycosis due to Fusarium species in different continents, literature review on diagnosis and treatment

Fusarium species are an emerging cause of onychomycosis, and the number of cases has dramatically increased in recent decades worldwide. This review presents an overview of the onychomycosis cases caused by Fusarium species and diagnosis and treatment that have been reported in the literature. The most common causative agent of onychomycosis is F. solani species complex, which accounts for 11.68% of the cases of Fusarium onychomycosis, followed by the F. oxysporum species complex (164 out of 1669), which is accounted for 9.83% of the total. F. fujikuroi species complex (42 out of 1669) and F. dimerum species complex (7 out of 1669) are responsible for 2.52% and 0.42 cases, respectively. Fusarium nail infections were reported in patients aged range 1-98, accounting for 5.55% (1669 out of 30082) of all cases. Asia has the highest species diversity of Fusarium onychomycosis (31.51%). South America accounts for 21.09%, and the most common causative agent is F. solani (19.32%), followed by F. oxysporum species complex (15.63%). Europe accounts for 4.90% of cases caused by F. oxysporum, followed by F. solani. Africa accounts for 23.87% of the cases due to the F. solani species complex, followed by F. oxysporum and F. fujikuroi. Distal and lateral subungual onychomycosis was the most common clinical symptom accounting for 58.7% (135 out of 230) of the cases. Data analysis relieved that terbinafine and itraconazole are active treatments for Fusarium onychomycosis. For a definitive diagnosis, combining of direct examination, culture and sequencing of the elongation factor of translation 1α are recommended. Accurate identification of the causative agents of onychomycosis due to Fusarium species and antifungal susceptibility testing is essential in patient management.

Non-Dermatophyte Mold Dominated Onychomycosis in Patients Attending a Rank Higher Specialized Dermatology Clinic in Addis Ababa, Ethiopia

Background

Onychomycosis is a common refractory fungal infection associated with significant morbidity. The objective of this study was to determine the prevalence of onychomycosis, and the diversity and species composition of fungal etiological agents.

Materials and Methods

A clinic-based, prospective, non-randomized cross-sectional study was carried out between October 2018 and June 2019 at Rank Higher Specialized Dermatology Clinic, Addis Ababa, Ethiopia. Nail scrapings were collected aseptically from 200 patients clinically identified with nail disorders of fungal origin by dermatologists. Fungal etiological agents were identified microscopically and by culture method following standard procedures.

Results

Among 200 nail scrapings, 161 (80.5%) samples were found out to be culture positive. Of these, 135 (83.9%) samples yielded single colonies while 26 (16.1%) mixed colonies gave a total of 190 isolates. Among the isolates, 25.8% were dermatophytes while 61.1% were non- dermatophytes molds, and 13.1% were yeasts. Females were more likely to present dystrophic nails than men. Patients in the middle age group were more affected. Trichophyton interdigitale, Aspergillus spp, and Candida albicans were the dominant species.

Conclusion

The prevalence rate of onychomycosis in the present study was high. The isolation rate of non-dermatophyte molds was higher than dermatophytes and yeasts. Trichophyton interdigitale, Aspergillus spp, and Candida albicans were the dominant etiological agents. Females and patients in the middle age group were more affected. An increase in the prevalence of non-dermatophyte molds in nail infections dictates further investigation demonstrating how this group of fungi causes onychomycosis.

Polishing the Therapy of Onychomycosis Induced by Candida spp.: Amphotericin B-Loaded Nail Lacquer

Onychomycosis induced by Candida spp. has several limitations regarding its treatment. Nail lacquers display the potential to overcome these drawbacks by providing therapeutic compliance and increasing local drug bioavailability. Thus, this work aimed to produce a nail lacquer loaded with Amphotericin B (AmB) and evaluate its performance. The AmB-loaded nail lacquer was produced and preliminarily characterized. An AmB quantification method was developed. Stability, drug release, permeability and anti-Candida activity assays were conducted. The analytical method validation met the acceptance criteria. The drug loading efficiency was 100% (0.02 mg/g of total product), whereas the AmB stability was limited to ≅7 days (≅90% remaining). The nail lacquer displayed a drying time of 187 s, non-volatile content of around 20%_w/w, water-resistance of approximately 2%_w/w of weight loss and satisfactory in vitro adhesion. Moreover, the in vitro antifungal activity against different Candida spp. strains was confirmed. The AmB release and the ex vivo permeability studies revealed that AmB leaves the lacquer and permeates the nail matrix in 47.76 ± 0.07% over 24 h. In conclusion, AmB-loaded nail lacquer shows itself as a promising extemporaneous dosage form with remarkable anti-Candida activity related to onychomycosis.

Antifungal Properties of Essential Oils and Their Compounds for Application in Skin Fungal Infections: Conventional and Nonconventional Approaches

Essential oils (EOs) are known to have varying degrees of antimicrobial properties that are mainly due to the presence of bioactive compounds. These include antiviral, nematicidal, antifungal, insecticidal and antioxidant properties. This review highlights the potential of EOs and their compounds for application as antifungal agents for the treatment of skin diseases via conventional and nonconventional approaches. A search was conducted using three databases (Scopus, Web of Science, Google Scholar), and all relevant articles from the period of 2010-2020 that are freely available in English were extracted. In our findings, EOs with a high percentage of monoterpenes showed strong ability as potential antifungal agents. Lavandula sp., Salvia sp., Thymus sp., Citrus sp., and Cymbopogon sp. were among the various species found to show excellent antifungal properties against various skin diseases. Some researchers developed advanced formulations such as gel, semi-solid, and ointment bases to further evaluate the effectiveness of EOs as antifungal agents. To date, most studies on the application of EOs as antifungal agents were performed using in vitro techniques, and only a limited number pursued in vivo and intervention-based research.

The change of causative pathogens in toenail onychomycosis

BACKGROUND

Toenail dystrophies are among the most common diseases in adulthood. Onychomycosis is one of the most frequently observed infectious diseases of the nail.

AIM

The aim of this study was to determine the prevalence of fungal agents in the etiology of nail dystrophies such as discoloration, thickening, subungual hyperkeratosis, and onycholysis in toenails and to emphasize the importance of diagnosis by other laboratory confirmation tests since various nail diseases may mimic onychomycosis.

SUBJECTS AND METHODS

Nail samples taken from 53 patients who were admitted to the dermatology clinic with the complaint of toenail disorders were examined by using potassium hydroxide mount, fungal culture, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry methods. Each nail was photographed, and descriptive analysis of the data was performed.

RESULTS

Of 53 patients included in the study, 39 were female (73.6%) and 14 were male (26.4%). The ages of the patients ranged from 14 to 70 years, and the mean age was 37.8 years. No fungi could be isolated in 17 (32%) patients with nail dystrophy, while fungal pathogens were observed in 36 (68%) patients on potassium hydroxide mount, culture, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry examinations. Among nondermatophyte molds, Aspergillus species (52.7%) were identified as the most common fungal pathogen causing onychomycosis.

CONCLUSION

Although fungal pathogenic agents are mostly detected among the diseases causing color changes and deformities in the nails, it should be kept in mind that nail findings of systemic or other skin diseases may mimic onychomycosis and the diagnosis should be confirmed by laboratory tests in addition to clinical manifestations for accurate treatment.

STUDY LIMITATIONS

Other systemic diseases causing nail dystrophy were not questioned in the study.

Activity of Metal-Azole Complexes Against Biofilms of Candida albicans and Candida glabrata

Background:

Onychomycosis is a chronic nail infection caused by fungi frequently resistant to antifungal treatments. Recalcitrance in nail infections is a result of reduced antifungal penetration due to biofilm formation, combined with poor patient compliance with the treatment, which can be as long as 18 months.

Objective:

Metal-drug complexation is a widely used strategy to increase drug efficacy. Therefore, the aim of this work was to evaluate the antifungal and anti-biofilm activity of several metal-azole complexes against Candida albicans and Candida glabrata.

Methods:

Susceptibility assays and scanning electron microscopy were performed to determine the anti-biofilm activity of eight metal-azole complexes in vitro and ex-vivo, using human nail fragments.

Results:

In vitro susceptibility assays showed that complexation of both Au(I) and Zn(II) to clotrimazole and ketoconazole improved the anti-biofilm activity compared to the azole alone. Using an ex-vivo model of biofilm formation on fragments of human nails, we also demonstrate the improved efficacy of metal-azole complexes against biofilms of C. albicans and C. glabrata that resembles the onychomycosis structure. Noteworthy, biofilms of C. glabrata were more susceptible to the optimized complexes than those of C. albicans.

Conclusion:

In conclusion, metal-azole complexes used in this work show promising anti-biofilm activity and further clinical studies should confirm its potential for the treatment of Candida-associated onychomycosis.

Prevalence, Risk Factors, and Spectrum of Fungi in Patients with Onychomycosis in Addis Ababa, Ethiopia: A Prospective Study

BACKGROUND

Onychomycosis is a common refractory infection deleteriously affecting quality of life via social stigma and upsetting day-to-day activities.

OBJECTIVE

To study the prevalence of onychomycosis, spectrum of fungal etiological agents, and associated risk factors.

METHODS

A prospective nonrandomized study on the prevalence of onychomycosis was carried out from September 2017 to April 2018 at a dermatology center in Addis Ababa. Nail scrapings were collected from 303 patients clinically identified with nail disorders of fungal origin by dermatologists. Fungal etiological agents were identified microscopically and by culture method following standard procedures.

RESULTS

The prevalence of onychomycosis was 60.4%. Fungi neither were detected nor showed visible fungal growth in 39.6% of the cases. Females were more likely to present dystrophic nails than men. Patients in the middle age group were more affected. The isolation rates of dermatophytes, yeasts, and nondermatophyte molds were 44.7%, 33.3%, and 32.3%, respectively. Trichophyton rubrum, Scytalidium dimidiatum, and Candida albicans were the dominant species of dermatophytes, nondermatophyte molds, and yeasts, respectively. There was no statistically significant association between onychomycosis and risk factors.

CONCLUSIONS

The prevalence rate of onychomycosis in the present study was high. The isolation rate of nondermatophyte molds was comparable with that of dermatophytes. Further studies on the prevalence of onychomycosis, fungal etiological agents, and changes in species distribution of the etiological agents of nail infection in Ethiopia are important.

Mycoses in northeastern Brazil: epidemiology and prevalence of fungal species in 8 years of retrospective analysis in Alagoas

Superficial and cutaneous mycoses are common in tropical countries, caused by dermatophytes, yeast, and non-dermatophyte molds in different clinical specimens. In order to define the epidemiology of mycoses and the profile of their etiological agents in Alagoas (northeastern Brazil) between 2009 and 2016, we obtained data of patients from the main laboratories of Alagoas, by examining clinical samples with direct microscopy and culture on Sabouraud dextrose agar and Chromagar^®Candida. A total of 3316 patients were confirmed with mycoses (595 men/2716 women) and 40.25 of average age. Positive samples totaled 3776, mainly vaginal secretion (1593/42.2%), toenails (876/23.2%), and fingernails (589/15.6%). Yeasts were the most isolated (3129/82.9%), including 3012 Candida spp. (79.8%), 57 Malassezia spp. (1.5%), 42 Trichosporon sp. (1.1%), 10 Geotrichum spp. (0.3%), and 8 Rhodotorula spp. (0.2%). Candida albicans was the most frequent species (715/18.9%), followed by C. krusei (194/5.1%), C. tropicalis (24/0.6%), and 2079 unspecified species (55.1%). Among 17.1% filamentous fungi, 14.8% dermatophytes were distributed as 211 Trichophyton sp. (5.6%), 125 T. rubrum (3.3%), 106 T. tonsurans (2.8%), 72 T. mentagrophytes (1.9%), 2 Microsporum sp. (0.1%), 15 M. canis (0.4%), and 26 Epidermophyton sp. (0.7%). Other fungi represented the minority: Fusarium sp. and Aspergillus sp. These are the first clinical data on the Alagoas population affected by fungi pathogens, confirming a higher incidence of candidiasis (mainly vulvovaginal and onychomycosis) and dermatophytes, providing a better understanding of different mycoses in northeastern Brazil.

Factors associated with onychomycosis in nail psoriasis: a multicenter study in Pakistan

BACKGROUND

Treatment of psoriatic nail disease is challenging, and dystrophic psoriatic nails can get secondarily infected with fungi.

METHODS

This 2-year, matched case-control study was conducted at three tertiary care centers of Karachi, Pakistan. Data were collected from patients with nail psoriasis as cases with age- and gender-matched controls. A detailed questionnaire was filled for all study participants. Nail Psoriasis Severity Index (NAPSI) scoring tool was used to assess dystrophy. Fungal infection was inferred by nail clippings for fungal hyphae and culture.

RESULTS

Among 477 participants, 159 cases and 318 controls completed the study. Their mean age was 44 years, and one-third were female. Fungal culture positivity was statistically significant in cases as compared to the control group (P < 0.001). The most frequent species identified was Candida parapsilosis in both cases and controls. Body mass index, NAPSI scoring, socioeconomic status, elevated diastolic blood pressure, smoking status psoriasis among first-degree relatives, and longstanding disease of more than 10 years were significant factors in univariable analysis. Multivariable logistic regression identified independent factors like low to middle socioeconomic status, history of psoriasis in first-degree relative, current smoker, and obesity.

CONCLUSION

We found nearly one-third of the psoriatic patients with nail involvement having concomitant fungal infection. We emphasize that nail clipping for fungal smear and culture should be advised to those patients with coexisting factors found significant in our study results. This opinion can be incorporated in psoriasis management guidelines for improving treatment of psoriatic nails.

A Study of Onychomycosis at a Tertiary Care Hospital in Eastern Bihar

Background:

Onychomycosis (OM) is a major public health problem which is increasing worldwide. It is associated with high morbidity and causes physical, psychological, and occupational problems in patients.

Aims:

This study aims to study the pattern of etiological agents, clinical features, and severity assessment of OM in this part of India.

Materials and Methods:

Sixty eight clinically suspected patients with positive potassium hydroxide and fungal culture were studied.

Results:

Males were infected more often than females (1.61:1). The most common age group affected was 21–40 years. Finger nails were affected more frequently than toe nails. Distal and lateral subungual OM was the most common (48 cases, 70.59%) clinical pattern. For most of the patients (66.18%), nail involvement was severe. Discoloration was the most common (67 cases, 98.53%) change, followed by subungual hyperkeratosis (51 cases, 75%). Principal causative agents were dermatophytes (55 cases, 80.88%) with Trichophyton rubrum being the most common one (35 cases, 51.47%). In 9 (13.23%) cases, Candida albicans, in 6 (8.82%) Aspergillus niger and in 1 (1.47%) case Acremonium sp. (AC) have been isolated as the sole causative agent. In 2 (2.94%) cases, mixed infection with dermatophyte and Aspergillus and in 1 (1.47%) case dermatophyte and Candida were noted.

Conclusion:

Although dermatophytes were the most common causative agent of OM, nondermatophytic molds, and yeasts were also encountered. The genus and species identification helps in the proper diagnosis and management. Morphological changes in nail may help in presumptive diagnosis of OM.

Epidemiology and fungal species distribution of superficial mycoses in Northeast Brazil

OBJECTIVE

Dermatomycoses are superficial fungal infections which affect the skin, hair and nails of humans and animals. Male and female patients of all ages are affected by this condition. The main etiological agents of dermatomycoses are the dermatophytes fungi of the genera Trichophyton, Microsporum and Epidermophyton, while the main yeasts belong to the genera Candida, Malassezia and Trichosporon. The variation in the distribution of dermatomycoses worldwide justify the conduction of epidemiological studies in order to contribute for the better understanding of patterns of mycological cutaneous infections. This study was conducted from April 2013 to December 2014.

MATERIAL AND METHODS

A total of 205 patients were evaluated, while 235 clinical specimens were obtained. From our positive cases of mycological examination, 73 (64.6%) patients were female, while 40 (35.4%) were male. Scales from the skin and nails were collected and observed at optical microscopy after potassium hydroxide clarification. Cultures were performed on Sabouraud Dextrose Agar added chloramphenicol. Identification was performed by classic methodology.

RESULTS

We found that the glabrous skin was the largest source of dermatomycoses (30.11%), followed by toenails (27.4%) and fingernails (17.7%). Regarding onychomycosis, the most affected population was over 50 years old. Trichophyton rubrum was the dermatophyte fungal species more commonly found. Most of the patients with pityriasis versicolor were adults and female. Another important fact observed is that Candida parapsilosis was the most prevalent species. Finally, a high incidence of T. tonsurans in cases of superficial mycoses was observed.

CONCLUSION

Our results clearly demonstrate peculiarities in terms of etiological agents of dermatophytoses distribution in a specific region of Brazil.

Prevalence of Candida tropicalis and Candida krusei in onychomycosis in João Pessoa, Paraiba, Brazil from 1999 to 2010

Over time, as the etiology of onychomycosis has developed, yeasts from the genus Candida have emerged as important etiological agents. This study aimed to determine the frequency of yeast caused onychomycosis in Joao Pessoa, Paraíba, Brazil from 1999 to 2010. A retrospective study from January 1999 to December 2010 evaluated the results of onychomycosis positive direct mycological exams (DME) - for yeast and realized in the Hemato(r) Clinical Laboratory. Women were the most affected by onychomycosis which occur preferentially in adults, and the toenails are the favorite yeast targets. The prevalent yeasts were Candida tropicalis and C. krusei.

Descriptive study of onychomycosis in a hospital in São Paulo

Onychomychosis, a nail fungus infection is the most frequent nail ailment, constituting about half of all nail disorders. It can be caused by dermatophytes, non-dermatophytes, yeasts and Prothoteca spp. Methods include 5407 samples of patients with suspected onychomycosis, studied from January 2002 to December 2006, by direct mycological examination and fungi culture. The diagnosis of onychomycosis was confirmed in samples from 3822 direct mycological and/or culture positive. The diagnosis was established by culture for fungi. Among the 1.428 identified agents, the dermatophytes were responsible for 68.6% (N = 980) of cases, followed by yeasts with 27.6% (N = 394), non-dermatophytes fungi with 2.2% (N = 31), Prothoteca spp with 0.1% (N = 2), and associations with 1.5% (N = 22). Females were more affected, with 66% (N = 2527) of cases, and the most affected age group ranged from 31 to 60 years of age (median 47 years). Fungal microbiota is often changed in the world, both quantitatively and qualitatively, and is affected by several environmental factors. Thus, the periodic review of the composition of this microbiota is important to evaluate the epidemiology and thus proportion a better therapeutic response.

Lipopeptide biosurfactant from Bacillus thuringiensis pak2310: A potential antagonist against Fusarium oxysporum

OBJECTIVES

The aims of the study were to evaluate the effects of a biosurfactant obtained from a novel Bacillus thuringiensis on Fusarium oxysporum to determine the morphological changes in the structure of the fungi and its biofilm in the presence of the biosurfactant and to evaluate the toxicity of the biosurfactant on HEp-2 human epithelial cell lines.

MATERIALS AND METHODS

The strain was screened and isolated from petroleum contaminated soil based on the E24 emulsification index. The biosurfactant was produced on glycerol, extracted using chloroform:methanol system and purified using HPLC. The purified fraction showing both surface activity (emulsification and oil-spread activity) and anti-fusarial activity (agar well diffusion method) was studied using FT-IR and MALDI-TOF MS, respectively. The minimum inhibitory concentration (MIC) and the biofilm inhibitory concentration (BIC) were determined using dilution method. The effect of biosurfactant on the morphology of Fusarium oxysporum was monitored using light microscopy and confocal laser scanning microscopy (for biofilm).

RESULTS

The purified surfactant showed the presence of functional groups like that of surfactin in the FT-IR spectra and MALDI-TOF MS estimated the molecular weight as 700Da. The MIC and BIC were estimated to be 0.05 and 0.5mg/mL, respectively. The molecule was also non-toxic to HEp-2 cell lines at 10× MIC.

CONCLUSION

A non-toxic and effective anti-Fusarium biosurfactant, that is both safe for human use and to the environment, has been characterized. The growth and metabolite production using glycerol (major byproduct of biodiesel and soap industries) also adds up to the efficiency and ecofriendly nature of this biosurfactant.

Etiology of foot mycosis and onychomycosis

The article presents data from Russian and foreign sources related to the etiology of foot mycosis and onychomycosis. In spite of the substantial spread of data by countries and regions of the world, dermatophytes play a leading part in the etiology of foot mycosis and onychomycosis, and Trichophyton rubrum is found in most studies in more than one half of all cases. Yeast-like fungi of the Candida genus as well as mold fungi belong to less frequent pathogens of foot mycosis. However, they play a greater role in countries with hot and humid climate such as Brazil, Indonesia, Columbia and India. These data are important for the determination of organizational measures aimed at the early diagnostics of patients, timely treatment and implementation of anti-epidemic and disinfectant measures.

A 7-year survey of superficial and cutaneous mycoses in a public hospital in Natal, Northeast Brazil

In the present study, we determined the frequency of superficial and cutaneous mycoses and their etiologic agents during a 7-year period (2002–2008) in Natal, Brazil. A total of 1,717 specimens of skin, nail, and hair were collected from 1,382 patients with suspected mycoses lesions and were then subjected to direct microscopy and culture.

Antifungal susceptibility patterns of yeasts and filamentous fungi isolated from nail infection

BACKGROUND

Onychomycosis is the nail infection caused by a wide spectrum of fungi species, including yeasts, dermatophytes and filamentous fungi non-dermatophytes (FFND). This fungal infection represents an important medical problem because it involves the patient's life quality.

OBJECTIVE

The aim was to isolate and identify the fungal agents of onychomycosis, and to determine the in vitro susceptibility to antifungal agents.

METHODS

During the period of March 2008 to March 2009, 114 patients clinically suspected of having onychomycosis were examined. Demographic data, mainly age and gender were obtained from each patient. The nail samples collected (136) were submitted to direct examination with potassium hydroxide 20% and grown on Sabouraud dextrose agar. The in vitro antifungal susceptibility testing was performed according to the method of broth microdilution, recommended by the Clinical Laboratory Standards Institute (CLSI).

RESULTS

Onychomycosis was observed in 95 (83.3%) patients, including 16 men (16.8%) and 79 women (83.2%), with mean age of 48.1 years. Candida parapsilosis, Trichophyton rubrum and Fusarium spp were the fungi most frequently isolated. The most of the isolated yeasts showed susceptibility to antifungal agents studied. Among filamentous fungi, high MIC values to itraconazole were found for T. rubrum and T. mentagrophytes, while Fusarium spp showed decreased susceptibility to itraconazole and voriconazole.

CONCLUSION

C. parapsilosis was the most common fungal species isolated from patients with onychomycosis. The different response obtained by in vitro susceptibility testing to drugs shows the importance of these methods to assist clinicians in choosing the best therapeutic option.

Dermatophytes: host-pathogen interaction and antifungal resistance

Cutaneous mycoses are among the most common infections in humans and have become an important public health issue because they cause invasive infections in immunocompromised patients. During the infectious process, dermatophyte-host interactions trigger specific metabolic adaptations that allow the pathogen to adhere to and penetrate the host tissue, scavenge nutrients, and overcome the host defense mechanisms. This metabolic shift and the interplay between metabolism, morphogenesis and stress response are important factors that have been extensively studied in several pathogens. Host cells also respond to the pathogen stimuli by activating intracellular signaling pathways that trigger the immune response against the infectious agent. The comprehension of the molecular aspects of these responses may help to establish new therapeutical strategies. In this review, different aspects of the biology of dermatophytes are addressed, with emphasis on the dermatophyte-host interaction and the mechanisms of antifungal resistance.

A study on the etiological agent and clinico-mycological correlation of fingernail onychomycosis in eastern India

Background:

Onychomycosis manifests itself in various forms, notably onychodystrophy, onycholysis, subungual hyperkeratosis, or nail-plate discoloration. Not necessarily nail changes mentioned here should always be of fungal origin.

Objective:

The present study is planned to get an idea about etiological agent and clinical correlation in fingernail onychomycosis.

Materials and Methods:

Nail-clipping and subungual debris of patients with above mentioned nail changes were subjected to KOH preparation. Culture was done on SDA and SDCCA media. Species identification was done by colony character, pigment production, LCB staining, and some special tests like germ tube test, etc.

Results:

Out of 85 cases, 44 cases showed the growth of fungus, amounting to 51.76% positivity. Among those 44 cases, the infective fungal agents were predominantly dermatophytes (50%), and the rest were due to yeasts (27.27%) and moulds (22.72%). Among the different species, Trichophyton rubrum (29.54%) accounted for the majority of dermatophytes; Candida albicans (11.78%) was the predominant yeast; and Aspergillus niger (18.18%) the commonest mold. No significant association could be established between the different fungal species and various clinical manifestations. Positive results were found more with fungal culture (95.45%) than KOH preparation (63.64%).

Conclusion:

The results show that nail changes are not always a reliable marker for predicting the causative organism, and relying only on the clinical manifestation (i.e., pattern of nail changes) in the diagnosis of onychomycosis is often misleading. The present study highlights the need for microbiological confirmation in case of onychomycosis.

Haemolytic and proteinase activities in clinical isolates of Candida parapsilosis and Candida tropicalis with reference to the isolation anatomic site

The aim of this study was to determine in vitro haemolytic and protease activities of Candida parapsilosis and Candida tropicalis isolates, obtained from anatomically distinct sites. Analysis of haemolytic activity of C. parapsilosis and C. tropicalis isolates obtained from the same anatomic site revealed that C. tropicalis isolates from blood had statistically higher activity (P < 0.05) than C. parapsilosis. On comparison of haemolytic activities of Candida isolates obtained from different anatomic sites, C. parapsilosis isolates from tracheal secretion were found to have higher activity than blood isolates. Protease activity was detected in the majority of the isolates analysed. Analysis of proteinase activity of C. parapsilosis and C. tropicalis isolates obtained from the same anatomic site revealed that C. parapsilosis isolates from tracheal secretion had statistically higher activity than C. tropicalis isolates. On comparison of proteinase activities of Candida isolates obtained from different anatomic sites, C. parapsilosis isolates from tracheal secretion were found to have higher activity than blood and superficial lesions isolates. Furthermore, C. tropicalis isolates from superficial lesions had higher activity than tracheal secretion isolates. Our results show the potential of C. parapsilosis and C. tropicalis isolates, obtained from distinct anatomic sites, to produce haemolytic factor and proteinases. Anatomic sites of isolation seem to be correlated with these activities, particularly for C. parapsilosis isolates.

Candida parapsilosis: a review of its epidemiology, pathogenesis, clinical aspects, typing and antimicrobial susceptibility

The Candida parapsilosis family has emerged as a major opportunistic and nosocomial pathogen. It causes multifaceted pathology in immuno-compromised and normal hosts, notably low birth weight neonates. Its emergence may relate to an ability to colonize the skin, proliferate in glucose-containing solutions, and adhere to plastic. When clusters appear, determination of genetic relatedness among strains and identification of a common source are important. Its virulence appears associated with a capacity to produce biofilm and production of phospholipase and aspartyl protease. Further investigations of the host-pathogen interactions are needed. This review summarizes basic science, clinical and experimental information about C. parapsilosis.

Identification, antifungal susceptibility and scanning electron microscopy of a keratinolytic strain of Rhodotorula mucilaginosa: a primary causative agent of onychomycosis

Onychomycosis is a dermatological problem of high prevalence that mainly affects the hallux toenail. Onychomycosis caused by the yeast Rhodotorula mucilaginosa was identified using colony morphology, light microscopy, urease and carbohydrate metabolism in a 57-year-old immunocompetent patient from Rio de Janeiro, Brazil. High-resolution scanning electron microscopy of nail fragments, processed by a noncoating method, led to the observation with fine detail of the structures of both nail and fungus involved in the infection. Yeasts were mainly found inside grooves in the nail. Budding yeasts presented a spiral pattern of growth and blastoconidia were found in the nail groove region. Keratinase assays and keratin enzymography revealed that this isolate was highly capable of degrading keratin. Antifungal susceptibility tests showed that the fungus was susceptible to low concentrations of amphotericin B and 5-flucytosine and resistant to high concentrations of fluconazole, itraconazole, voriconazole and terbinafine. These findings showed data for the first time concerning the interaction of R. mucilaginosa in toenail infection and suggest that this emerging yeast should also be considered an opportunistic primary causative agent of onychomycosis.

The anatomical distribution and antimicrobial susceptibility of yeast species isolated from healthy dogs

The aim of this work was to identify the predominant yeast species present at different anatomical sites in healthy dogs and to determine their in vitro antimicrobial susceptibility using a broth microdilution assay. Samples were collected from the preputial, vaginal, oral and perianal mucosae and the isolates cultured were identified according to their morphological characteristics and biochemical profile. Malassezia pachydermatis was the most commonly isolated yeast, followed by Candida parapsilosis, Candida tropicalis, Candida albicans, Saccharomyces cerevisiae and Rhodotorula spp. Minimum inhibitory concentrations of the azole derivatives ketoconazole, itraconazole and fluconazole against Candida spp. were 0.03-16 microg/mL, 0.06 to >16 microg/mL and 0.5-64 microg/mL, respectively and Candida isolates were sensitive to caspofungin and amphotericin B. Although all isolates of M. pachydermatis were sensitive to itraconazole, fluconazole, ketoconazole and amphotericin B, they were found to be resistant to caspofungin. The study has highlighted that Candida spp., M. pachydermatis, S. cerevisiae and Rhodotorula spp. are part of the normal canine surface microbiota and some of these organisms exhibit in vitro resistance to commonly used antimicrobials.

Geographic and temporal trends in isolation and antifungal susceptibility of Candida parapsilosis: a global assessment from the ARTEMIS DISK Antifungal Surveillance Program, 2001 to 2005

We examined data from the ARTEMIS DISK Antifungal Surveillance Program to describe geographic and temporal trends in the isolation of Candida parapsilosis from clinical specimens and the in vitro susceptibilities of 9,371 isolates to fluconazole and voriconazole. We also report the in vitro susceptibility of bloodstream infection (BSI) isolates of C. parapsilosis to the echinocandins, anidulafungin, caspofungin, and micafungin. C. parapsilosis represented 6.6% of the 141,383 isolates of Candida collected from 2001 to 2005 and was most common among isolates from North America (14.3%) and Latin America (9.9%). High levels of susceptibility to both fluconazole (90.8 to 95.8%) and voriconazole (95.3 to 98.1%) were observed in all geographic regions with the exception of the Africa and Middle East region (79.3 and 85.8% susceptible to fluconazole and voriconazole, respectively). C. parapsilosis was most often isolated from blood and skin and/or soft tissue specimens and from patients hospitalized in the medical, surgical, intensive care unit (ICU) and dermatology services. Notably, isolates from the surgical ICU were the least susceptible to fluconazole (86.3%). There was no evidence of increasing azole resistance over time among C. parapsilosis isolates tested from 2001 to 2005. Of BSI isolates tested against the three echinocandins, 92, 99, and 100% were inhibited by concentrations of < or = 2 microg/ml of anidulafungin (621 isolates tested), caspofungin (1,447 isolates tested), and micafungin (539 isolates tested), respectively. C. parapsilosis is a ubiquitous pathogen that remains susceptible to the azoles and echinocandins; however, both the frequency of isolation and the resistance of C. parapsilosis to fluconazole and voriconazole may vary by geographic region and clinical service.

Fusarium infections in immunocompromised patients

Fusarium species cause a broad spectrum of infections in humans, including superficial, locally invasive, and disseminated infections. The clinical form of fusariosis depends largely on the immune status of the host and the portal of entry, with superficial and localized disease occurring mostly in immunocompetent patients and invasive and disseminated disease affecting immunocompromised patients. Risk factors for severe fusariosis include prolonged neutropenia and T-cell immunodeficiency, especially in hematopoietic stem cell transplant recipients with severe graft-versus-host disease. The most frequent presentation of disseminated fusariosis is a combination of characteristic cutaneous lesions and positive blood cultures, with or without lung or sinus involvement. The prognosis is poor and is determined largely by degree of immunosuppression and extent of infection, with virtually a 100% death rate among persistently neutropenic patients with disseminated disease. These infections may be clinically suspected on the basis of a constellation of clinical and laboratory findings, which should lead to prompt therapy. Treatment options include the lipid formulations of amphotericin B, voriconazole, and posaconazole. Prevention of fusarial infection among high-risk patients should be considered.

Medically important fungi found in hallux nails of university students from Cali, Colombia

The presence of medically important fungi was studied in hallux nails scrapings obtained from 504 students (204 males, 300 females) of three universities in Cali. Specimens were examined by direct microscopic examination and fungal culture. Medically important fungi were found in 49 (9.7%) students, 24 (4.8%) had onychomycosis while the rest did not have nail lesions. Trichophyton rubrum was the most commonly isolated fungi in students with lesions, where as T. mentagrophytes predominated in healthy nails. Most of the students with fungi were males. The prevalence of fungi was higher in individuals between 26 and 35 years. No association was observed between fungi and practicing sports or undergoing pedicures. These results suggest that dermatophytes can be found in healthy hallux nails, which can be reservoirs of pathogenic fungi.

Antifungal activity of propolis extract against yeasts isolated from onychomycosis lesions

The aim of this study was to determine the in vitro activity of propolis extract against 67 yeasts isolated from onychomycosis in patients attending at the Teaching and Research Laboratory of Clinical Analysis of the State University of Maringá. The method used was an adaptation made from the protocol approved by the National Committee for Clinical Laboratory Standards. The yeasts tested were: Candida parapsilosis 35%, C. tropicalis 23%, C. albicans 13%, and other species 29%. The propolis extract showed excellent performance regarding its antifungal activity: the concentration capable of inhibiting the all of the yeasts was 5 x 10(-2) mg/ml of flavonoids and 2 x 10(-2) mg/ml of flavonoids stimulated their cellular death. Trichosporon sp. were the most sensitive species, showing MIC50 and MIC90 of 1.25 x 10(-2) mg/ml of flavonoids, and C. tropicalis was the most resistant, with CFM50 of 5 x 10(-2) mg/ml of flavonoids and MFC90 of 10 x 10(-2) mg/ml. In view of the fact that propolis is a natural, low cost, nontoxic product with proven antifungal activity, it should be considered as another option in the onychomycosis treatment.

[Causative agents of onychomycosis--a retrospective study]

BACKGROUND

Dermatophytes, yeasts and moulds all are potential causative agents of onychomycosis. The aim of this study was to determine the percentage of cases of onychomycoses caused by each group. In addition, the responsible genus and species was identified for each nail infection.

PATIENTS AND METHODS

In a retrospective study performed at the Department of Dermatology of the Leipzig University, 5,077 nail samples from 4,177 patients--2,240 women and 1,937 men--with a variety of nail changes--not just onychomycosis--were investigated. 75% were toenails, 23% fingernails, and 2% from both sites.

RESULTS

Both microscopic and/or cultural detection of fungi (dermatophytes, yeasts and moulds) were successful in 54% of samples. Causative fungal agents were: 68% dermatophytes, 29% yeast, and 3% moulds. The most frequently detected dermatophyte species were T. rubrum (91%), and T. mentagrophytes (7.7%). Among yeasts, C. parapsilosis (42%) was most common,followed by C. guilliermondii (20.1%), C. albicans (14.2%), and Trichosporon spp. (10%). Scopulariopsis brevicaularis (43%) was the most frequent mould. The percentage of mixed fungal infections was 22%.

CONCLUSIONS

Dermatophytes, in particular T.rubrum, but also T. mentagrophytes, are the most frequently isolated causative agents in onychomycosis. In addition, yeasts may be isolated relatively frequently, while moulds are uncommon.

Candidemia in a Brazilian hospital: the importance of Candida parapsilosis

The aim of this study was to perform a retrospective analysis of cases of candidemia in a Brazilian hospital in the city of Fortaleza, Ceará. A total of 50 blood cultures were analyzed from 40 candidemic patients. The mycological diagnosis was based on the phenotypical analysis and the patients' data were recorded in appropriate files. The most frequent species were Candida parapsilosis (n = 18), followed by C. albicans (n = 14), C. tropicalis (n = 8), C. guillermondii (n = 6), C. glabrata (n = 2), and Candida spp. (n = 2). A detailed descriptive study was undertaken with 21 patients whose medical records were complete. The candidemia episodes occurred in eight male patients and 13 female patients. The most representative risk factors implicated in candidemia were prior antibiotic therapy, central venous catheters, parenteral nutrition, gastric probes and mechanical ventilation. Death occurred in 13 of the 21-candidemic patients. This study demonstrated the emergence of candidemia caused by C. parapsilosis in a Brazilian hospital in the city of Fortaleza, Ceará.