Onychomycosis due to Onychocola canadensis: report of the first two Spanish cases

A revision of malbranchea-like fungi from clinical specimens in the United States of America reveals unexpected novelty

The fungi of the order Onygenales can cause important human infections; however, their taxonomy and worldwide occurrence is still little known. We have studied and identified a representative number of clinical fungi belonging to that order from a reference laboratory in the USA. A total of 22 strains isolated from respiratory tract (40%) and human skin and nails (27.2%) showed a malbranchea-like morphology. Six genera were phenotypically and molecularly identified, i.e. Auxarthron/Malbranchea (68.2%), Arachnomyces (9.1%), Spiromastigoides (9.1%), and Currahmyces (4.5%), and two newly proposed genera (4.5% each). Based on the results of the phylogenetic study, we synonymized Auxarthron with Malbranchea, and erected two new genera: Pseudoarthropsis and Pseudomalbranchea. New species proposed are: Arachnomyces bostrychodes, A. graciliformis, Currahmyces sparsispora, Malbranchea gymnoascoides, M. multiseptata, M. stricta, Pseudoarthropsis crassispora, Pseudomalbranchea gemmata, and Spiromastigoides geomycoides, along with a new combination for Malbranchea gypsea. The echinocandins showed the highest in vitro antifungal activity against the studied isolates, followed by terbinafine and posaconazole; in contrast, amphotericin B, fluconazole, itraconazole and 5-fluorocytosine were less active or lacked in vitro activity against these fungi.

[Onychocola canadensis Sigler in onychomycosis : A new dermatophyte-like mould in Germany]

Moulds or non-dermatophyte moulds (NDM) are being increasingly isolated as causative agent of onychomycoses. Known causes of a NDM-OM are Scopulariopsis brevicaulis, Fusarium, Aspergillus, Acremonium, Neoscytalidium dimidiatum, Arthrographis kalrae, and Chaetomium. In this article, 5 patients with suspected nail infection due to Onychocola canadensis are reported for the first time in Germany. Systemic antifungal agents are not considered to be effective in NDM onychomycosis. In individual cases, however, terbinafine seems to be effective in Onychocola canadensis infection of the nails. Treatment of choice represents, however, nontraumatic nail avulsion using 40 % urea ointment followed by antifungal nail lacquer with ciclopirox olamine or amorolfine.

Management of Onychomycosis in Canada in 2014

Background

Onychomycosis has several clinical presentations and is caused by various infectious organisms.

Objective

To provide guidance for selection of appropriate treatment.

Methods

The literature on onychomycosis management was reviewed to generate an evidence-based decision tree.

Results and Conclusion

Several options are available: terbinafine, itraconazole, fluconazole, ciclopirox 8% nail lacquer, efinaconazole 10% nail solution, and laser therapy. Further studies on lasers are needed before use can be recommended. Nondermatophyte molds or mixed infection can be managed with terbinafine or itraconazole with or without topicals. Itraconazole, fluconazole, and efinaconazole can be used for Candida infection. For dermatophytes, topicals can be considered for mild to moderate onychomycosis. For moderate to severe cases, any oral monotherapy can be used; however, we suggest terbinafine if there is a possibility of a drug interaction. These recommendations can be applied for all ages, immune function, or metabolic status, but proper monitoring and contraindications should be taken into consideration.

Onychomycosis caused by Onychocola canadensis: the first report in Estonia and lessons to learn

We report the first case of onychomycosis caused by Onychocola canadensis in Estonia. We believe that the number of nail infections caused by this fungus is underestimated due to the current diagnostic algorithm of non-dermatophytic onychomycosis. The need to define categories and criteria for 'proven' and 'probable' non-dermatophyte mold infections to promote more extensive studies in the future is also discussed.

[Onychomycoses due to molds]

Onychomycoses represent about 30% of superficial mycosis that are encountered in Dermatology consults. Fungi such as dermatophytes, which are mainly found on the feet nails, cause nearly 50% of these onychopathies. Yeasts are predominantly present on hands, whereas non-dermatophytic moulds are very seldom involved in both foot and hand nails infections. According to literature, these moulds are responsible for 2 to 17% of onychomycoses. Nevertheless, we have to differentiate between onychomycoses due to pseudodermatophytes such as Neoscytalidium (ex-Scytalidium) and Onychocola canadensis, which present a high affinity for keratin, and onychomycoses due to filamentous fungi such as Aspergillus, Fusarium, Scopulariopsis, Acremonium... These saprophytic moulds are indeed most of the time considered as colonizers rather than real pathogens agents. Mycology and histopathology laboratories play an important role. They allow to identify the species that is involved in nail infection, but also to confirm parasitism by the fungus in the infected nails. Indeed, before attributing any pathogenic role to non-dermatophytic moulds, it is essential to precisely evaluate their pathogenicity through samples and accurate mycological and/or histological analysis. The treatment of onychomycoses due to non-dermatophytic moulds is difficult, as there is today no consensus. The choice of an antifungal agent will first depend on the species that is involved in the infection, but also on the severity of nail lesions and on the patient himself. In most cases, the onychomycosis will be cured with chemical or mechanical removing of the infected tissues, followed by a local antifungal treatment. In some cases, a systemic therapy will be discussed.

Non-dermatophytic molds as agents of onychomycosis in Izmir, Turkey - a prospective study

The purpose of this study was to determine the prevalence of causative non-dermatophytic filamentous fungi in onychomycosis. Totally 1,222 (1,222 x 3 = 3,666) samples of nail scrapings from 1,146 patients (from 76 patients two specimens: both from finger- and toe-nails) with prediagnosis of onychomycosis sent to the Mycology Laboratory from the Clinic of Dermatology, Ege University Hospital, Izmir, Turkey, July 2001-December 2003, were prospectively studied with conventional mycological procedures. The set criteria for the diagnosis of onychomycosis due to non-dermatophytic molds were: (1) Observation of fungal elements in 15% KOH-preparations made from nail scrapings, (2) growth of the same mold in all three consecutive cultures of the specimens taken three times from the same patient with one-week intervals, (3) no growth of a dermatophyte or yeast in three consecutive cultures. As agents of onychomycosis molds were detected in 33 (9%), dermatophytes in 175 (48%), yeasts in 150 (41%), and mixed (two different fungi) in 8 (2%) patients. In cases of mold onychomycosis, 11 (33%) had finger-nail and 22 (67%) toe-nail infection; 25 (76%) were female and 8 (24%) male; and 27 (82%) were above 40 years of age. The agents of mold onychomycosis, in order of frequency, were Aspergillus niger (7), Acremonium spp. (6), Fusarium spp. (6), Ulocladium spp. (4), sterile mycelia (2), Alternaria sp. (1), Aspergillus flavus (1), Aspergillus fumigatus (1), Aspergillus terreus (1), Cladosporium sp. (1), Paecilomyces spp. (1), Scopulariopsis sp. (1) and Trichoderma sp. (1). In conclusion, this study showed that non-dermatophytic molds were responsible for nearly 10% of onychomycoses cases attending the dermatology outpatient clinic of a university hospital in Izmir, Turkey. Since molds are common contaminants in the laboratory, cultures from consecutively taken nail scrapings should be made and carefully evaluated in order to diagnose a "mold onychomycosis".

Isolation of Onychocola canadensis from four cases of onychomycosis in Belgium

Onychocola canadensis can cause onychomycosis of the toenails. Thirty-two cases have been described up to now. We report on the isolation of Onychocola canadensis from four patients with onychomycosis who acquired their infection in Belgium. Direct examination was positive. Onychocola canadensis was isolated in pure culture. According to the previously published cases, the patients affected were elderly and the preferential site of infection was the big toenail. In contrast to previous reports, we found a predominance in males. Treatment was started in all patients. Two out of the three patients about whom information was available, did not improve after treatment.

Arachnomyces kanei (anamorph Onychocola kanei) sp. nov., from human nails

Five isolates of a slow-growing cycloheximide resistant hyphomycetous fungus were obtained from nail specimens and investigated for their relationship to Onychocola canadensis (teleomorph Arachnomyces nodosetosus), a known agent of onychomycosis. In one patient diagnosed with superficial white onychomycosis, etiology was confirmed by a nail sample showing atypical filaments in direct microscopy, and by a follow-up specimen yielding cultures of the same fungus. A case of mixed infection with Aspergillus sydowii was also confirmed after examination of cultures grown from three successive microscopic-positive hallux nail specimens. For other isolates, etiological significance could not be confirmed by repeat sampling or results of direct microscopy were negative or unknown. Mating experiments yielded setose ascomata containing smooth oblate ascospores typical of Arachnomyces species. Phylogenetic analysis of ITS 2 region sequences support the conspecificity of the isolates and their placement within the genus. A. kanei sp. nov. (anamorph O. kanei sp. nov.) is described.