[Onychomycosis: multicentre epidemiological, clinical and mycological study]

Fractional modeling of flexural behavior of toenail plates: First step for clinical purposes

This work presents an identification procedure of flexural behavior of toenail plates in twenty subjects with no history of feet or nail injury as of in-vivo measurements. In particular, four different mechanical models are considered to describe such properties, ranging from the pure elastic to viscoelastic behavior, the latter from the classical and fractional points of view. The quality of the adjustment of each model is examined by a group of performance indices. Experimental data show that the best identification is achieved by the fractional order viscoelastic model for all subjects. These novel results in modeling flexural behavior of toenails are consistent with the published literature suggesting that viscoelastic materials may be successfully modeled with derivatives of fractional order. This could contribute, together with additional variables, to help health professionals, and more especially podiatrists, to have reliable and quantitative measures of the nail flexural behavior which can be susceptible of treatment or for prevention.

PAS stain based histological classification and severity grading of toenail onychomycosis

Onychomycosis is a common world-wide health issue. Accurate detection is essential for treatment. Multiple studies have shown that PAS-stain based histological visualization of fungal elements is superior to either direct microscopy with 20% potassium hydroxide, or fungal culture. However, PAS stain based histological classification and severity grading of onychomycosis are lacking in the literature. Here we reported a fungal detection rate of 47.87% based on an analysis of 13,805 toenails processed for H&E and PAS stains over a three year period. Based on the analysis of fungal density, distribution and infiltrating depth level in 858 PAS-positive toenails, we created a novel PAS stain based histological classification system to classify onychomycosis as occult onychomycosis (OO), focal or diffuse subungual onychomycosis (FSO or DSO), focal or diffuse plate onychomycosis (FPO or DPO), focal or diffuse subungual and plate onychomycosis (FSPO or DSPO) and superficial onychomycosis (SO). The severities of OO, FSO and FPO were graded as mild, DSO and DPO as moderate, FSPO and DSPO as severe infections, which revealed that more than 75% PAS positive toenails were severe infections. Evaluation of 97 paired toenails biopsied pre- and post-treatment from 47 patients demonstrated that the severity of infection was significantly reduced from severe to mild and moderate levels. These data indicate that the current histological classification evaluates not only the severity of the fungal infection but also the response to treatment. We further propose a guideline for treatment of onychomycosis based on the histological classification and severity.

[Evaluation of the usefulness of nail biopsy in the diagnosis of onychomycosis]

BACKGROUND

Onychomycosis affects between 2% to 30% of the world population. Nail biopsy may help in making a diagnosis and can distinguish between invasion and colonisation.

AIMS

To evaluate the diagnostic usefulness of nail biopsy with Periodic acid-Schiff (PAS) staining for onychomycosis, compared to direct KOH examination, culture and its combination in a reference laboratory in Colombia.

METHODS

The study included 66 patients in whom a blind and independent reading of the three tests was performed. The usefulness was defined based on the validity (sensitivity, specificity, Youden's index, likelihood ratios), performance (predictive values) efficiency (proportion of correctly diagnosed patients), and reproducibility (kappa coefficient).

RESULTS

The mean age of the patients was 55±16 years, and included 76% women. The direct tests with KOH were positive in 66.7% (n=44), 62.1% (n=41) were positive with culture, and 56.1% (n=37) with the biopsy. The main causal agents were non-dermatophytes moulds in 36.4% (n=24). The most frequent species were Neoscytalidium dimidiatum (n=11), Trichophyton rubrum (n=11), and Candida parapsilosis (n=13). The sensitivity of nail biopsy, when compared to the standard (KOH and/or culture), was 71%, specificity 83%, Youden's index 0.54, positive likelihood ratio 4.25, negative likelihood ratio 0.35, positive predictive value 92%, negative predictive value 52%, efficiency 74% and kappa coefficient 0.45. When biopsy was evaluated only in patients with onycholysis of the nail plate greater than 50%, all the parameters of diagnostic usefulness increased.

CONCLUSIONS

The overall usefulness of the biopsy was moderate for patients with more severe symptomatology, which makes its use advisable in cases of extensive onycholysis, and when discriminating colonisation from invasion is required.

THE PREVALENCE OF ONYCHOMYCOSIS IN THE ZAGREB AREA - THE ROLE OF SABOURAUD AGAR WITHOUT CYCLOHEXIMIDE IN DIAGNOSIS AND THERAPY

SUMMARY – Mycological analysis is considered the gold standard in the diagnosis of very common fungal diseases of nails. The purpose of the article is to present the prevalence of onychomycosis obtained by using direct microscopic examination (DME) and cultivation on Sabouraud media without cycloheximide. The quantitative retrospective research was conducted on 2706 patients of both sexes (mostly middle-aged to elderly) with various toenail lesions, who had undergone mycological analyses in the Mycological Laboratory of our Department of Dermatovenereology in 2013 and 2014. Analysis of the results obtained revealed that there were 35.4% of positive DME results; of these, there were 39.2% of dermatophytes, 59.1% of yeasts and 1.7% of molds. The percentage of dermatophytes (Trichophyton spp.) was twice as high in men as in women. A considerable percentage (12%) of mixed isolates was also observed. Particularly worrisome was the high percentage (one-third) of suppressed and insufficiently developed dermatophytes (a possible indicator of inappropriate preparation of patients for mycological analysis). Cultivation on culture media without cycloheximide requires frequent inspections because of the fast-growing molds while not allowing sporulation for a great number of dermatophytes. However, it has certain advantages, i.e. it offers an insight into the wide range of the present fungi. As part of the biofilm, they can be potentially pathogenic in dystrophic nails under certain circumstances because, according to our results, the percentage of dermatophytes does not change substantially with aging; however, what does change is the percentage of molds, yeasts and mixed isolates.

Meta-analysis of the utility of culture, biopsy, and direct KOH examination for the diagnosis of onychomycosis

Background

Onychomycosis is a highly prevalent disease worldwide. There is no standard test for its diagnosis, which remains costly, wasteful, and is sometimes delayed. The diagnostic tests for this disease are few and discordant. The objective was to evaluate the diagnostic validity, performance, and accuracy of culture, nail clipping with Periodic Acid-Schiff –PAS- staining (biopsy), and direct potassium hydroxide (KOH) examination for the study of onychomycosis.

Methods

A systematic review was conducted via meta-analysis using 5 databases and 21 search strategies. An ex ante protocol was applied with inclusion and exclusion criteria. Quality was assessed with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool, and the sensitivity, specificity, predictive values, likelihood ratios, diagnostic odds ratios, receiver operating characteristic (ROC) curves, and proportion of correctly diagnosed patients were evaluated with the meta-analysis of studies of evaluations of diagnostic and screening tests (Meta-DiSc) and Epidat using a random effects model.

Results

The efficiency or accuracy of the three tests is influenced by the methodological quality of the studies. These values are lower for KOH and culture and higher for biopsy in moderate quality studies.

Conclusion

The diagnostic tests evaluated in this meta-analysis independently showed acceptable validity, performance, and efficiency, with nail clipping with PAS staining outperforming the other two tests.

SIXTEEN YEARS OF DERMATOMYCOSIS CAUSED BY Candida spp. IN THE METROPOLITAN AREA OF PORTO ALEGRE, SOUTHERN BRAZIL

The yeasts of the genus Candida infect skin, nails, and mucous membranes of the gastrointestinal and the genitourinary tract. The aim of this study was to determine the prevalence of dermatomycoses caused by Candida spp., and their etiological aspects in the metropolitan area of Porto Alegre, Brazil. A retrospective study with data obtained from tertiary hospital patients, from 1996 to 2011, was performed. The analyzed parameters were date, age, gender, ethnicity, anatomical region of lesions, and the direct examination results. For all the statistical analyses, a = 0.05 was considered. Among positive results in the direct mycological examination, 12.5% of the total of 4,815 cases were positive for Candida spp. The angular coefficient (B) was -0.7%/ year, showing a decrease over the years. The genus Candida was more prevalent in women (15.9% of women versus 5.84% of men), and in addition, women were older than men (54 versus 47 years old, respectively). There was no difference between ethnic groups. The nails were more affected than the skin, with 80.37% of the infections in the nails (72.9% in fingernails and 7.47% in toenails). Our study corroborates the literature regarding the preference for gender, age, and place of injury. Moreover, we found a decrease in infection over the studied period.

Onycholysis and Chromonychia: A Case Caused by Trichosporon inkin

Yeasts cause only 5-10% of onychomycosis; the most common yeast is Candida albicans, and rarely Trichosporon spp. is found. Recently, it has become an important cause of fungemia with a high mortality rate in immunocompromised patients. Superficial infections caused by Trichosporon spp., including piedra and onychomycosis, occur in immunocompetent patients. Herein, we report a case of a fungal nail infection characterized by onycholysis and chromonychia caused by Trichosporon inkin.

The prevalence of onychomycosis in the global population: a literature study

BACKGROUND

Onychomycosis is a common disorder, and high prevalence figures are commonly cited in the literature.

OBJECTIVES

Evaluate the prevalence of onychomycosis based on published studies.

METHODS

Relevant studies were identified in Medline by using specific search criteria.

RESULTS

Eleven population-based and 21 hospital-based studies were identified. The mean prevalence in Europe and North America was 4.3% [95% Confidence Interval (CI): 1.9-6.8] in the population-based studies, but it was 8.9% (95% CI: 4.3-13.6) for the hospital-based studies. Both population-based and hospital-based studies showed that onychomycosis is more common in toenails and is seen more frequently in males. The main causative agent was a dermatophyte in 65.0% (95% CI: 51.9-78.1) of the cases. Trichophyton rubrum was the single most common fungus and was cultured on average in 44.9% of the cases (95% CI: 33.8-56.0). Moulds were found on average in 13.3% (95% CI: 4.6-22.1) and yeasts in 21.1% (95% CI: 11.0-31.3).

LIMITATIONS

We may not have been able to locate all studies.

CONCLUSIONS

Onychomycosis is a common disorder, but it may not be as common as cited in the literature, because hospital-based studies might overestimate the prevalence of onychomycosis. It is more frequent in males, and toenails are more commonly affected. Dermatophytes, particularly T. rubrum, are the main causative agents.

Non-dermatophyte mould onychomycosis: a clinical and epidemiological study at a dermatology referral centre in Bogota, Colombia

Worldwide prevalence of non-dermatophyte mould onychomycosis has increased in recent years; however, available information on the topic is confusing and oftentimes contradictory, probably due to the small number of reported cases. The aim of this study was to determine and describe the aetiological agents, as well as the epidemiological and clinical characteristics of non-dermatophyte mould onychomycosis in a dermatology referral centre in Bogota, Colombia. A cross-sectional descriptive study was conducted between January 2001 and December 2011 among patients who attend the National Institute of Dermatology with a confirmed diagnosis of onychomycosis by non-dermatophytes moulds. There were 317 confirmed cases of non-dermatophyte mould onychomycosis in 196 women and 121 men whose average age was 43 years. Twenty-seven per cent of them had a history of systemic disease. The habit of walking and showering barefoot was the major infection-related factor. Distal and lateral subungual presentation was the most common pattern of clinical presentation. The most frequent non-dermatophyte mould was Neoscytalidium dimidiatum followed by Fusarium spp. No relationship was observed with predisposing factors previously reported in the literature. Clinical features found in this population are indistinguishable from onychomycosis caused by dermatophytes. High prevalence of N. dimidiatum found here was in contrast to a large number of studies where other types of moulds predominate.

Sertaconazole: an antifungal agent for the topical treatment of superficial candidiasis

Sertaconazole is a useful antifungal agent against mycoses of the skin and mucosa, such as cutaneous, genital and oral candidiasis and tinea pedis. Its antifungal activity is due to inhibition of the ergosterol biosynthesis and disruption of the cell wall. At higher concentrations, sertaconazole is able to bind to nonsterol lipids of the fungal cell wall, increasing the permeability and the subsequent death of fungal cells. Fungistatic and fungicidal activities on Candida are dose-dependent. The antifungal spectrum of sertaconazole includes deramophytes, Candida, Cryptococcus, Malassezia and also Aspergillus, Scedosporium and Scopulariopsis. Sertaconazole also shows an antimicrobial activity against streptococci, staphylococci and protozoa (Trichomonas). In clinical trials including patients with vulvovaginal candidiasis, a single dose of sertaconazole produced a higher cure rate compared with other topical azoles such as econazole and clotrimazole, in shorter periods. Sertaconazole has shown an anti-inflammatory effect that is very useful for the relief of unpleasant symptoms.

Aspergillus terreus complex: an emergent opportunistic agent of Onychomycosis

The incidence of onychomycosis due to non-dermatophyte moulds (NDM) is increasing. Aspergillus terreus is relatively undocumented as an agent of this fungal infection. The aim of this work is to show the prevalence of onychomycosis caused by A. terreus and to describe its clinical features. Nail samples were collected for microscopic examination and culturing in selective media. All cases of onychomycosis due to NDM were confirmed by a second sample. Aspergillus terreus isolates were identified through their morphological characteristics and using molecular methods. A total of 2485 samples were obtained. Positive cultures were obtained in 1639 samples. From 124 NDM confirmed cultures, 23 were identified as A. terreus (18.5%). Superficial white onychomycosis was the most frequent clinical pattern. A high percentage was found in fingernails. The prevalence of A. terreus in this study considerably exceeded the percentages reported by other authors. Onychomycosis due to A. terreus presents similar clinical patterns to those caused by dermatophytes, but is difficult to eradicate and is associated with less predictable treatment outcomes. Better knowledge of the aetiology of A. terreus may be important for accomplishing more accurate and effective treatment.