Infection due to the mold Aspergillus fumigatus remains a common and life-threatening infection in many animals, especially birds. Animal models are still required to better understand the physiopathology of infection and evaluate diagnostic tools and treatment procedures. The aim of the present study was to assess the pathogenicity of A. fumigatus in two lineages of chicken (Gallus gallus): SPF White Leghorn PA12 layers and conventional JA657 broilers. Four-day-old birds were experimentally infected in an inhalation chamber in order to reproduce a "natural" contamination and to obtain a large repartition of conidia into the respiratory tract. Half of the chicks were injected subcutaneously with dexamethasone for 4 days before the infective challenge. At days 0 and 7, the effects of chicken lineage and immunosuppressive treatment on pulmonary fungal burden were analyzed using two linear mixed models. The pathogenicity of A. fumigatus varied according to the lineage: no clinical signs and no mortality were observed in layer chickens whereas more than 50% of mortality occurred in broilers. The effect of immunosuppressive treatment was also demonstrated, notably on animals weight but also on mortality.
AIMS:To describe a new molecular technique for the assessment of fungal diversity in the air.METHODS AND RESULTS:Air samples were collected every week in a henhouse in France during a 15-week period. After air sampling, the collecting membrane was diluted, and the liquid was used for subsequent cultivation and molecular analysis: PCR-temperature temporal gradient electrophoresis (TTGE), which has already been used for the identification of fungal species in air samples and PCR-denaturing high-performance liquid chromatography (D-HPLC), a new technique for the analysis of complex microbial populations. D-HPLC profiles were reproducible from run-to-run, and several fungal organisms could be identified at the species level by sequencing.CONCLUSIONS:PCR-D-HPLC enabled the identification of fungal species (both Ascomycota and Basidiomycota) that may be encountered in air. The new technique allowed the detection of more fungal species than did the PCR-TTGE technique. However, some fungal species were detected only by PCR-TTGE, suggesting that PCR-D-HPLC and PCR-TTGE are complementary.SIGNIFICANCE AND IMPACT OF THE STUDY:PCR-D-HPLC represents a considerable saving in time over currently available procedures for detection and identification of fungal organisms in air. However, the fungal diversity detected by PCR-D-HPLC or by PCR-TTGE was lower than that revealed by culture.
Parasites are increasingly used to complement the evolutionary and ecological adaptation history of their hosts. Pneumocystis pathogenic fungi, which are transmitted from host-to-host via an airborne route, have been shown to constitute genuine host markers of evolution. These parasites can also provide valuable information about their host ecology. Here, we suggest that parasites can be used as phylogeographic markers to understand the geographical distribution of intra-specific host genetic variants. To test our hypothesis, we characterised Pneumocystis isolates from wild bats living in different areas. Bats comprise a wide variety of species; some of them are able to migrate. Thus, bat chorology and migration behaviour can be approached using Pneumocystis as phylogeographic markers. In the present work, we find that the genetic polymorphisms of bat-derived Pneumocystis are structured by host chorology. Therefore, Pneumocystis intra-specific genetic diversity may constitute a useful and relevant phylogeographic tool.
Anti-Toxoplasma gondii antibodies were determined in serum and aqueous humor of two groups of cats in France: cats with uveitis (group 1, n=26) and cats with systemic disease (group 2, n=24) using an agglutination test. Titres above 1:64 were considered positive. IgG antibodies to T. gondii were detected in 10 serum samples from group 1 and in 10 serum samples from group 2, and in 2 aqueous humor samples from group 1 and in 1 aqueous humor samples from group 2. The distribution of ocular lesions according to the serological status of the animals indicated that lens luxation and buphthalmia were more frequent in T. gondii seropositive cats than in seronegative ones. The study reports a similar prevalence of anti-T. gondii antibodies in cats with uveitis and in cats without uveitis in France. Serological results must be analysed carefully and additional diagnostic tools is required.
ABSTRACT We report a case of eumycetoma due to Cladophialophora bantiana in a 3-year-old male Siberian Husky living in France. The dog presented a tumefaction on the thorax and deformity of the second and third subjacent ribs, which were surgically removed. Macroscopic black granules were visible on the ribs, and direct microscopic examination revealed their fungal origin. Cultures yielded pure colonies of C. bantiana . The identification of the causative agent was confirmed after amplification and sequence analysis of fungal internal transcribed spacers 1 and 2 and 5.8S ribosomal DNA regions. Surgery and antifungal treatment with oral itraconazole associated with flucytosine allowed apparent cure after a 10-month follow-up. Envenomation with pine processionary caterpillars ( Thaumetopoea pityocampa ) and subsequently intensive corticotherapy were considered as possible predisposing factors. This is, to the best of our knowledge, the first case in which C. bantiana is identified as the causative agent of eumycetoma.
Cytological examination using the tape-strip technique and fungal culture using contact plates with modified Dixon's medium were compared to evaluate the carriage of Malassezia yeasts on four cutaneous sites (left pinna, umbilical region, axilla and perianal area) in adult Basset Hounds. Twenty animals were included in the study. High numbers of Malassezia were isolated from at least one area in 100% of the animals. The frequencies of isolation and population sizes differed significantly according to anatomical location. They were greater on the pinna, followed by the umbilical area, axilla and perianal area. Fungal culture was more sensitive than cytology for the isolation of Malassezia yeasts. Frequencies of isolation were greater using this method, but population sizes were constantly smaller than with cytology.
The performance of the dermatophyte test medium (DTM) RapidVet-D was assessed using hair samples collected from experimentally infected guinea pigs. Three dermatophyte species were included in the study: Microsporum canis, Trichophyton mentagrophytes and Trichophyton equinum. DTM substrates were inoculated with infected hairs and scales, incubated at 18, 21, 24, 27 or 37 degreesC and examined daily for 15 days. The rapidity of colour change was clearly related to the incubation temperature and to the number of infected hairs deposited on the reactive substrates. With the optimum incubation temperature 27 degreesC, a systematic colour change could be observed only a few days post-inoculation: 3 days with M. canis infected hairs, 4 days with T. equinum and 5 days with T. mentagrophytes.
Aims: The present study describes a system based on PCR and restriction endonuclease analysis (REA) to distinguish the seven currently recognized Malassezia species.Methods and Results: Fifty-five representative yeast isolates were examined. A single primer pair was designed to amplify the large subunit ribosomal RNA (LSU rRNA) gene of the seven Malassezia species, and identification was achieved by digestion of the PCR products with three restriction endonucleases: BanI, HaeII and MspI. A specific restriction endonuclease analysis pattern was determined for each species investigated. Moreover, PCR-REA allowed the detection and characterization of mixtures of several Malassezia species.Conclusion: PCR-REA of only the LSU rRNA gene is a reliable and rapid method to distinguish all Malassezia species.Significance and impact of the study: PCR-REA represents a considerable saving in time over currently available identification procedures. This method should be evaluated on clinical material directly.
The aim of this study was to improve our knowledge about the taxonomy and phylogeny of the family Saprolegniaceae, a group of water molds including several pathogens of plants, fish and crustacea. ITS and LSU rDNA were sequenced for representatives of forty species corresponding to ten genera (Achlya, Aphanomyces, Brevilegnia, Dictyuchus, Leptolegenia, Plectospira, Pythiopsis, Saprolegnia, Thraustotheca). Phenetic and cladistic analyses were then carried out. The species Brevilegnia bispora does not appear to belong to the family Saprolegniaceae. Plectospira myrianda clusters with Aphanomyces spp. and they constitute an ancestral group. (Thraustotheca clavata is closely related to the eccentric species of the genus Achlya. The genus Achlya appears polyphyletic, corroborating more or less the three known subgroups, defined by their sexual spore type (eccentric, centric and subcentric). The achlyoid type of spore dehiscence, shared by Aphanomyces and Achlya genera, is shown to be an ancestral character. The saprolegnioid, dictyoid and thraustothecoid types of spore dehiscence are derived characters but their relative evolutionary positions are not resolved.