Influencia del grupo ecológico sobre la sensibilidad in vitro de los hongos dermatofitos a los antifúngicos

BackgroundDermatophytes can be divided into geophilic (soil), zoophilic (animals) and anthropophilic (humans) strains, depending on the source of the keratin that they use for nutritional purposes.AimsThe in vitro susceptibility of clinical isolates of dermatophyte fungi has been studied in the 3 ecological groups with several antifungal agents for the topical management of dermatophytoses in order to determine their relationship with the ecological group.MethodsA standardised dilution micromethod in a liquid medium was used for the determination of the in vitro antifungal activity of 9 topical antifungal drugs: amorolfine (AMR), bifonazole (BFZ), clotrimazole, econazole, ketoconazole, miconazole, oxiconazole, terbinafine (TRB) and tioconazole. The in vitro activity was obtained against 124 clinical isolates of dermatophyte moulds from the anthropophilic, zoophilic and geophilic ecological groups.ResultsThe in vitro antifungal activity was different depending on the ecological group, although a species-dependent profile was also observed.ConclusionsAzole derivatives showed a similar antifungal profile, being more active against anthropophilic dermatophytes > zoophilic > geophilic. Activity of TRB and AMR was different from that of azole derivatives (zoophilic > anthropophilic > geophilic). A higher in vitro antifungal activity against the 3 ecological groups was observed with TRB and AMR, whilst BFZ was the less active drug.     

Polyphasic Discrimination of Trichophyton tonsurans and T. equinum from Humans and Horses

Mycopathologia - The anthropophilic dermatophyte Trichophyton tonsurans and its zoophilic counterpart T. equinum are phylogenetically closely related. The barcoding marker rDNA internal transcribed...     

Controlling Malaria Using Livestock-Based Interventions: A One Health Approach

Where malaria is transmitted by zoophilic vectors, two types of malaria control strategies have been proposed based on animals: using livestock to divert vector biting from people (zooprophylaxis) or as baits to attract vectors to insecticide sources (insecticide-treated livestock). Opposing findings have been obtained on malaria zooprophylaxis, and despite the success of an insecticide-treated livestock trial in Pakistan, where malaria vectors are highly zoophilic, its effectiveness is yet to be formally tested in Africa where vectors are more anthropophilic. This study aims to clarify the different effects of livestock on malaria and to understand under what circumstances livestock-based interventions could play a role in malaria control programmes. This was explored by developing a mathematical model and combining it with data from Pakistan and Ethiopia. Consistent with previous work, a zooprophylactic effect of untreated livestock is predicted in two situations: if vector population density does not increase with livestock introduction, or if livestock numbers and availability to vectors are sufficiently high such that the increase in vector density is counteracted by the diversion of bites from humans to animals. Although, as expected, insecticide-treatment of livestock is predicted to be more beneficial in settings with highly zoophilic vectors, like South Asia, we find that the intervention could also considerably decrease malaria transmission in regions with more anthropophilic vectors, like Anopheles arabiensis in Africa, under specific circumstances: high treatment coverage of the livestock population, using a product with stronger or longer lasting insecticidal effect than in the Pakistan trial, and with small (ideally null) repellency effect, or if increasing the attractiveness of treated livestock to malaria vectors. The results suggest these are the most appropriate conditions for field testing insecticide-treated livestock in an Africa region with moderately zoophilic vectors, where this intervention could contribute to the integrated control of malaria and livestock diseases.     

The Clonal Population of Trichophyton equinum from Dermatophytoses of Japanese Racehorses

Mycopathologia - Trichophyton equinum is a zoophilic dermatophyte that is frequently isolated from horse dermatophytosis and rare infections in humans. In the present study, molecular and...     

Comparative Analysis of Putative Virulence-Associated Factors of Microsporum canis Isolates from Human and Animal Patients

Mycopathologia - Microsporum canis is a zoophilic dermatophyte and the most common fungus isolated from dogs and cats worldwide. To invade skin, this pathogen uses different enzymes, which may be...     

Species Identification of Dermatophytes by MALDI-TOF MS

MALDI-TOF (matrix-assisted laser desorption/ionization time-of-flight) mass spectrometry (MS) is a new tool for the identification of microorganisms, inclusive of dermatophytes. The technique is faster, more straightforward, and powerful when compared to conventional dermatophyte identification methods (culture and microscopy). Accurate species identification in dermatophytes is not only essential to survey epidemiologic situations, but also for an appropriate medical treatment and to locate the source of infection (zoophilic or anthropophilic). Multiple platforms from a number of well-established commercial manufacturers (Andromas SAS, Bruker Daltonics, bioMérieux) have been used for dermatophyte identification with different success. Independent from the platform used, all of the studies reviewed here report on problems with the identification of phylogenetically closely related anthropophilic and zoophilic dermatophyte species. Thus, supplementation of the databases/libraries as well as standardized extraction protocols and cultivation methods are the precondition required for optimal species identification.     

Chicory extracts from Cichorium intybus L. as potential antifungals

In this work extracts from roots of the common vegetable Cichorium intybus L., highly appreciated for its bitter taste, were studied to investigate their possible biological activity on fungi from a variety of ecological environments: some are parasites on plants (phytopathogens) or of animals and humans (zoophilic and anthropophilic dermatophytes), others live on the soil and only seldom parasitize animals (geophilic dermatophytes). The extracts were ineffective on geophilic species and on tested phytopathogens, with the exception of Pythium ultimum, whereas they inhibited the growth of zoophilic and anthropophilic dermatophytes, in particular Trichophyton tonsurans var. sulfureum, whose treatment caused morphological anomalies, here observed by scanning electron microscopy. This behaviour is discussed on the basis of the presence in the chicory extract of the two main sesquiterpene lactones, 8-deoxylactucin and 11β,13-dihydrolactucin.     

Zoophagia and alternative host selection of the marlaia vectors in Senegal]

Blood-engorged females of An. gambiae s.l., An. funestus, An. pharoensis and An. rufipes caught resting indoors were tested (precipitin or enzyme-linked immunosorbent assay) to determine the source of bloodmeal. The species of the An. gambiae complex fed mainly on human hosts in all prospected areas, except in those of the mid Senegal river valley where an important zoophily was observed within and near the irrigation zone. Among 4,597 blood-engorged females of An. gambiae s.l., 29% fed on cattle with 7.5% of mixed boodmeals, mainly human-bovine or human-equine. The presence of cattle, culicid population densities and individual mosquito safety devices were the most determinant factors of animal deviation. Blood of most domestic animals was found in the stomach of collected females, but according to areas, bovines and equines were the main hosts for zoophilic females of An. gambiae s.l. Females of An. funestus collected in the middle-west were more anthropophilic than those collected in south-eastern areas. An. pharoensis was most prevalent in the Senegal river delta where it was found to be very anthropophilic. An. rufipes was strongly endophilic but exclusively zoophilic in all prospected areas.     

Phylogeny of anopheline (Diptera: Culicidae) species in southern Africa,based on nuclear and mitochondrial genes

A phylogeny of anthropophilic and zoophilic anopheline mosquito species was constructed, using the nuclear internal transcribed spacer 2 (ITS2) and mitochondrial cytochrome oxidase subunit I (COI) genes. The ITS2 alignment, typically difficult due to its noncoding nature and large size variations, was aided by using predicted secondary structure, making this phylogenetically useful gene more amenable to investigation. This phylogeny is unique in explicitly including zoophilic, non‐vector anopheline species in order to illustrate their relationships to malaria vectors. Two new, cryptic species, Anopheles funestus‐like and Anopheles rivulorum‐like, were found to be present in Zambia for the first time. Sequences from the D3 region of the 28S rDNA suggest that the Zambian An. funestus‐like may be a hybrid or geographical variant of An. funestus‐like, previously reported in Malawi. This is the first report of An. rivulorum‐like sympatric with An. rivulorum (Leeson), suggesting that these are separate species rather than geographic variants.     

Olfactory sensitivities of mosquitoes with different host preferences (Anopheles gambiae s.s., An. arabiensis,An. quadriannulatus,An. m. atroparvus) to synthetic host odours

Responses of antennal olfactory cells associated with sensilla trichodea were recorded in females of four Anopheles species (Diptera, Culicidae) with different host preferences: the anthropophilic An. gambiae s.s., the opportunistic An. arabiensis, and the zoophilic An. quadriannulatus and An. maculipennis atroparvus. Stimuli were vapours of synthetic host-odours: ethanoic, propanoic, butanoic, 3-methyl propanoic, 4-methyl butanoic acid, 1-octen-3-ol, and 3- and 4-methyl phenol. On stimulation with fatty acids and phenols either excitation or inhibition of spike activity was found, whereas responses to 1-octen-3-ol were invariably excitatory. The odour spectra of the cells could include activating as well as inhibiting substances. Differences in host preferences may be reflected in the numbers of olfactory cells responding to different odours and/or in the sensitivities of these cells. In An. gambiae more cells were excited by fatty acids than in An. arabiensis and An. m. atroparvus, whereas inhibition occurred more often in the latter two species. In addition, the fatty acid-excited cells in An. gambiae were more sensitive to these substances than in An. m. atroparvus and An. quadriannulatus. On the contrary, in the latter two species cells were more responsive to 1-octen-3-ol. In An. arabiensis, responses of stimulus-excited cells were intermediate between those in the anthropophilic and zoophilic species.     

Trichophyton simii infection in man and animals

Nine human infections due toT. simii comprising of tinea corporis (6), tinea cruris (2) and tinea capitis (1) have been reported. Human cases were having lesions typically of zoophilic contracted infections. Lesions in dogs were on nose and upper lip and were circular. All the strains showed typical and identical macro and microscopie morphology. Three isolates studied by Stockdale were negative (2) and positive (1) strains. One studied here was negative. Possible epidemiology is discussed.     

Genetical investigations on zoophilic and exophilic Anopheles arabiensis from Antananarivo area (Madagascar)

The presence of markedly zoophilic and exophilic Anopheles arabiensis at Alasora, near Antananarivo, Madagascar, is confirmed. This population of An. arabiensis appears clearly different in its feeding and resting behaviour when compared to those from Continental Africa, which, especially in West Africa, show rather high degrees of anthropophily and endophily. Genetical observations were carried out on material from Alasora including polytene chromosome studies, multilocus genetic analysis and crossing experiments with a West African strain of An. arabiensis. The results support the hypothesis of a conspecific status of An. arabiensis from Madagascar and Continental Africa.     

伏立康唑联合光动力治疗难治性脓癣一例

脓癣是人体皮肤对亲动物性或亲土性皮肤癣菌发生的严重炎症反应,多见于儿童,感染早期常无典型临床表现,因而容易扩散传染。炎症反应明显,可快速发展为隆起性斑块或脓肿,易误诊为单纯细菌感染,延误治疗。目前尚无确切的治疗方案或共识,现报告1例特比奈芬联合伊曲康唑治疗后效果不佳、采用伏立康唑联合光动力治疗后达到完全治愈的儿童难治性脓癣病例。     

Clinical Forms of Dermatophytosis (Ringworm Infection)

Dermatophytic infections of the skin, hairs and nails are very common and are very variable in aspect. In skin, inflammatory symptoms are often absent, but in other cases they may be very pronounced, in particular when caused by zoophilic dermatophytes. In onychomycosis, it is very difficult to make the differential diagnosis with other causes of onychodystrophy on purely clinical grounds; indeed, even in case of fungal infection, the causative agent can be suspected on clinical grounds only in a minority of cases. The clinical presentation of skin infections, infections of the scalp and beard, and the nails are presented more in detail.     

Relationship Between Phenotypic and Genotypic Characteristics of <Emphasis Type="Italic">Trichophyton mentagrophytes</Emphasis> Strains Isolated from Patients with Dermatophytosis

According to epidemiological, clinical and mycological criteria, it has long been admitted that the Trichophyton mentagrophytes species includes two varieties: a zoophilic variety (var. mentagrophytes) and an anthropophilic variety (var. interdigitale) that involve the upper and the lower part of the body, respectively. The further application of molecular techniques to the characterization of dermatophyte strains showed that this classification is unreliable. The aim of our study was to assess the usefulness of PCR–RFLP (restriction fragment length polymorphism) and sequencing in the characterization of T. mentagrophytes strains taken from Tunisian patients. The study was carried out in 2008 in the laboratory of Parasitology–Mycology of Farhat Hached University Hospital, Sousse, Tunisia. A total of 133 strains were isolated from 133 patients addressed to the laboratory for dermatological lesions very evocative of dermatomycosis. Eighty strains were isolated from lesions located on the lower part of the body (onychomycosis, tinea pedis) and 53 strains from the upper part of the body (tinea capitis, tinea corporis). All strains were submitted to mycological examination (direct microscopic examination and culture on Sabouraud medium) and further investigated by using RFLP analysis of the PCR-amplified ITS1-5.8 s-ITS2 region of the ribosomal DNA and the MvaI restriction enzyme. In addition, 62 strains were further submitted to a sequencing of the ITS1-5.8 s-ITS2 region. On the basis of mycological criteria, all strains were diagnosed as T. mentagrophytes. All strains produced the same RFLP pattern and were identified as T. mentagrophytes interdigitale regardless of the location of lesions. Out of the 62 sequenced strains, 16 were found anthropophilic and 46 were zoophilic. In conclusion, all strains provisionally diagnosed as T. mentagrophytes on the basis of mycological criteria were shown to belong to T. interdigitale by using PCR–RFLP and sequencing irrespective of the site of lesions. The predominance of zoophilic strains needs further investigation.     

Isolation and characterization of microsatellite loci in the mosquito Anopheles stephensi Liston (Diptera: Culicidae)

The mosquito Anopheles stephensi is an important malaria vector in India, Pakistan, Iran and Afghanistan. Differences in egg morphology and chromosomal characters have been described between urban and rural forms of this mosquito but the population genetic structure remains unclear. In India this species is mainly urban, rural populations are largely zoophilic and not thought to transmit malaria. In eastern Afghanistan and the Punjab and Northwest Frontier Province, Pakistan, it is the major malaria vector. We have developed primers for 16 microsatellite loci to assist in defining the population structure and epidemiological importance of this mosquito.     

On the estimation of the influence of the character of insect pollinators movements on the pollen transfer dynamics

The pattern of pollinator movements determines the dynamics of the pollen transfer between zoophilic plants. The structure of plant populations depends on this aspect of the pollinator foraging behavior. A new method for the estimation of the rate of moving away from an object was used for a more precise determination of the distance at which pollinators transfer pollen. The method is based on the measuring of distances covered by pollinators per several flights. The highest rate was found in hoverflies (Diptera, Syrphidae). Butterflies (Pieris brassicae) play an insignificant role in long-distance pollen transfers due to their circular movements.     

Eastern Cottontail (<Emphasis Type="Italic">Sylvilagus Floridanus)</Emphasis> as Carrier of Dermatophyte Fungi

Eastern cottontail (Sylvilagus floridanus, fam. Leporidae), introduced into Piedmont (Italy) in the 1960s, was studied as carrier of dermatophyte fungi. Of 216 hair samples collected from animals culled between September 1999 and July 2000 in the Province of Alessandria (Piedmont, Italy) during a pest control project, 57 (26.4%) yielded dermatophyte colonies. As two different species of dermatophytes grew from two samples, a total of 59 fungal isolates (26.5%) were obtained. Six dermatophyte species both geophilic (M. gypseum, M. cookei, Trichophyton ajelloi, T. terrestre) and zoophilic (M. canis, T. mentagrophytes) were identified. No sex-related differences were found but season-related differences were observed. The highest prevalence of dermatophyte-positive samples was recorded in May–September, due to the geophilic fungi whose prevalence decreased during colder and increased during warmer months ( p < 0.001). The presence of zoophilic dermatophytes, T. mentagrophytes, commonly associated with rodents, small mammals and lagomorphs and M. canis, usually correlated with domestic environment, did not change the whole year round. As Eastern cottontail has been showed to be a carrier of dermatophytes transmissible to man (M. canis, T. mentagrophytes and M. gypseum), it may represent a source of infection for gamekeepers, hunters and veterinarians.     

A reevaluation of the genus Malassezia by means of genome comparison

Results of a study of the genus Malassezia on the basis of genome characters confirm that two species should be maintained, M. furfur and M. pachydermatis. The two forms associated with skin disease, frequently referred to as Pityrosporum orbiculare and P. ovale, were found to be synonymous, the name M. furfur having priority. Malassezia pachydermatis, hitherto regarded as a strictly zoophilic species, may also be found on humans.     

Deep Dermatophytosis Caused by Zoophilic Strain of <Emphasis Type="Italic">Trichophyton interdigitale</Emphasis> with Successful Treatment of Itraconazole

We report a 66-year-old female patient with deep dermatophytosis caused by zoophilic strain of Trichophyton interdigitale, a rare granulomatous presentation of Trichophyton species infection in patients with underlying systemic diseases, and she was successfully cured by itraconazole. Since the identification of Trichophyton mentagrophytes complex had been misused for years, a brief discussion of molecular diagnosis and taxonomy of T. mentagrophytes complex is given. The pathogenesis and comparison with cases reported in the literature are also discussed.