Contribution to the study of dermatomycosis in Catalonia

We report the results of a study which aim was the mycological identification of specimens coming from patients included in a clinical trial. A total of 445 specimens from patients with clinical diagnosis of dermatomicosis were processed during 8 months (138 pityriasis versicolor, 28 cutaneous candidosis and 279 dermatophytosis). A 48% of pityriasis versicolor cultures were positive for Malassezia furfur, 50% of candidosis cultures were positive for yeasts and 67% of dermatophytosis cultures were positive for dermatophytes. According to our results Candida albicans was the principal causative agent for cutaneous candidosis and Trichophyton mentagrophytes and Trichophyton rubrum were the most frequent isolated species causing dermatophytosis.     

Protein profiles of Malassezia pachydermatis isolated from dogs

Chronic dermatophytosis was observed in 2276 (10.02%) of 22 692 patients with dermatophytosis during a period of 5.5 years. Males were affected at least 3 times more frequently than females. The age group most commonly affected was between 20 and 40 years of age. Females were affected more between the ages of 30 to 40 years. Tinea cruris and tinea corporis were the most common clinical types and tinea pedis was the least common type observed. The most frequent isolate was Trichophyton rubrum followed by T. mentagrophytes and T. violaceum. Ichthyosis vulgaris was the most common cutaneous association whereas atopy and diabetes mellitus were the most common systemic associations. This revised version was published online in August 2006 with corrections to the Cover Date.     

Genetic analysis of the BB/W diabetic rat

A large colony of BB/W diabetic rats has been developed as a research model for insulin dependent, type 1 diabetes mellitus. The foundation stock had 8% diabetics which appeared in a sporadic manner. The Worcester (W) colony was inbred by brother X sister matings for 11 generations and the proportion of diabetics increased to over 50%. The age of detection varies from 46 to 250 days. For selection purposes, classification was made at 120 days, which means that 15 to 20% potential diabetics were classified as normal. Evidence from different analyses indicates that the inheritance of diabetes is by a recessive gene or gene cluster with 50% penetrance at 120 days. The selection of breeding stock from diabetic parents raised the proportion of diabetics produced by two normal parents from 12 to 43%. Diallel tests show that diabetic and normal offspring of two diabetic parents have the same diabetic genotype. Outcrosses to other strains of rat indicate that the trait is transferred as a recessive with only 3% diabetics recovered in the F2 where noninbred BB stock was used as the diabetic source, and 36% where partially inbred BB/W was used as the diabetic parent. Since the proportion of diabetics produced by all types of crosses has changed, and may continue to change with changes in the genetic background, we have used the operational term penetrance to describe the frequency of diabetes in individuals homozygous for the diabetes gene cluster. At present the penetrance at 120 days is 59% in the BB/W colony.     

Use of arbitrarily primed polymerase chain reaction to differentiate Trichophyton dermatophytes

Abstract Dermatophytes such as Trichophyton species are common human pathogens, the infection of which results in dermatophytosis (also known as ringworm). Several laboratory tests are used routinely for the diagnosis of dermatophytosis, but they are either slow or lacking specificity. Through examination of genomic DNA from Trichophyton dermatophytes and other fungi in arbitrarily primed PCR, it was shown that a random primer 5'-ACCCGACCTG-3' produced bands of 4.3 kb, 1.9 kb, 1.7 kb and 0.7 kb in T. rubrum DNA, bands of 2.5 kb, 1.9 kb and 0.8 kb in T. mentagrophytes var. interdigitale and T. mentagrophytes var. mentagrophytes DNA, and bands of 2.5 kb, 1.9 kb, 1.5 kb and 0.9 kb in T. tonsurans DNA. This primer amplified bands of different sizes in other fungal DNA. Therefore, based on the distinct band patterns observed in arbitrarily primed PCR using this primer, T. rubrum , T. mentagrophytes and T. tonsurans dermatophytes could be rapidly differentiated.     

Trichophyton mentagrophytes skin infections in laboratory animals as a cause of zoonosis

Recent sporadic distribution in Japan of Trichophyton mentagrophytes skin infections among laboratory rats or guinea pigs is reported. Six cases of laboratory infection by the fungus in humans who came in direct contact with the affected animals are also presented.Mating experiments with the causative fungi isolated from the animal and human skin lesions revealed that all but one sexually reactive strains belonged to the + mating type of Arthroderma vanbreuseghemii. A retrospective epidemiologic study ascertained that most of the affected rats were those derived from the same breeding colony of a certain experimental animal producing-co-operation in Saitama prefecture, where it had been produced by conventional methods of specific pathogen-free parental colony maintained in a barrier system.These two pieces of evidence suggest a possible transmission of the etiologic agent from some healthy carrier or infected hair-droppings in the environment to the breeding colony, during its breeding, or maintenance by the producer.     

Diagnosis of sialodacryoadenitis virus infection of rats in a virulent enzootic outbreak

In a natural outbreak of sialodacryoadenitis virus it was observed that the incidence of clinical signs in spontaneous-hypertensive rats was 100%, and that these signs were of a severity not observed before in other strains of rats. Rats free of the virus were introduced so that the progress of the disease could be studied under natural conditions of spontaneous spread from the enzootically-affected breeding colony. The pathogenesis of the infection in these Sprague-Dawley rats has been recorded over a period of 10 days after their introduction to the colony, and the results of extensive serological screening have shown that the antibody response of the spontaneous-hypertensive rats to the virus is lower than in other strains of rat.     

Rederivation of rat colonies seropositive for Bacillus piliformis and the subsequent screening for antibodies.

Latent infection of rats in a breeding colony with Bacillus piliformis detectable by antibodies to the agent in an immunofluorescence assay was eliminated by a combination of traditional rederivation techniques, using animal units not previously used for rat breeding, and the use of specific disinfection procedures. The success rate was apparently correlated with the use of peracetic acid instead of aldehyde products to decontaminate the animal unit.     

Immunology of dermatophytosis

By causing experimental lesions of dermatophytosis in rabbits inoculated and reinoculated with T. mentagrophytes var. granulosum and T. rubrum a study was carried out of the state of cellular immunity response, during infection, and also of the antigens responsible for the sensitization. Cellular immunity response was detected using the leucocyte migration test (L.M.T.) in the presence of antigenic compounds of the 'Keratinase' of Eleuterio et al.     

Antifungal therapy of dermatophytosis in guinea pigs and congenitally athymic rats

Guinea pigs and athymic nude (RNU/RNU) rats were used to assess the efficacy of three orally administered antifungal agents — Tolciclate, Tolnaftate, and Ketoconazole — against Trichophyton mentagrophytes dermatophytosis. All three antifungal agents inhibited the test strain of T. mentagrophytes in vitro. Antifungal agents were tested in intervention (oral therapy started 5 days after challenge) or prophylaxis (oral therapy started 5 days before challenge) protocols. Oral treatment of dermatophytosis on guinea pig skin demonstrated that Tolciclate and Tolnaftate alleviated clinical symptoms and shortened the duration of the dermatophytosis, in comparison to nontreated controls. Assessment of antifungal efficacy in the guinea pig model was time consuming (30–35 days) and variability in the duration and severity of clinical symptoms on guinea pig skin was common.Oral therapy of chronically infected athymic rats demonstrated that Tolciclate, Tolnaftate, and Ketoconazole were effective antifungal agents in vivo. Obvious improvement in clinical symptoms of dermatophytosis (i.e. less erythema and fewer lesions) was evident with all three antifungal agents within 10 days of starting oral therapy. By day 20, athymic rats that were treated with either Tolciclate or Ketoconazole showed marked clinical improvement of the chronic dermatophytosis.Chronically infected athymic rats, which lack thymus matured T-cells, are a promising new model to evaluate the efficacy of antifungal agents by culture, histology, and visual observations of clinical symptoms.     

A naturally occurring epizootic caused by Sendai virus in breeding and aging rodent colonies. II. Infection in the rat.

Sendai virus infected a hysterectomy derived, barrier maintained breeding colony and a conventional aging rat colony. The virus produced seroconversion in the colonies followed by a 7-month period of decreasing titers. Clinical signs were absent during the months when titers were highest, and there was no increase in mortality, but multifocal interstitial pneumonia with perivascular and peribronchial cuffing by lymphocytes and plasma cells was present in rat lungs examined histologically. Such lesions were absent before the period of seroconversion. During the months of declining titers, the interstitial and perivascular lesions decreased in frequency and severity. The peribronchial lesions did not decrease, however, and were still present in many rats 7 months after the acute infection. Attempts to isolate the virus from weanling rats were unsuccessful.     

Animal dermatophytosis. Recent advances

The proportion of positive samples in relation to the number of samples examined from cases of dog and cat dermatophytosis varies considerably from one investigation to another. In dogs, it ranges between 4% and 10% and few studies show higher prevalences. On the other hand, the percentages of positive cultures cited in the reviewed literature from dogs with or without suspected dermatophytosis are quite similar. In dogs with suspected lesions of dermatophytosis, with few exceptions, Microsporum canis is the most common species isolated. Trichophyton mentagrophytes and Microsporum gypseum are less frequently isolated. In cats the prevalence of dermatophytes is usually higher than in dogs, and it is usually higher than 20%. However the frequency of positive findings is higher in cats with suspected dermatophytosis than in cats without visible lesions, with the exception of asymptomatic infected cats and transient carrier cats. Cats are accepted as the principal reservoir for M. canis. Griseofulvin is the drug of choice in canine and feline dermatophytosis.     

Inapparent Streptococcus pneumoniae type 35 infections in commercial rats and mice

Streptococcus pneumoniae was isolated from specific-pathogen-free rodents in two rooms at a commercial breeding facility during vendor surveillance testing. In a survey of 274 animals from the two rooms over a period of 7 months, capsular serotype 35 S. pneumoniae was isolated from the upper respiratory tracts of 11% (9 of 82) of C57BL/6 mice in room A and 14% (10 of 72) of F344 rats in room B, but not from WKY rats, BALB/c mice or DBA/2 mice from room A. In both C57BL/6 mice and F344 rats, older rodents had higher colonization frequencies. Nasal lavage cultures gave the best results in identifying colonized rodents. No clinical illness or microscopic lesions were associated with pneumococcal colonization in rats or mice, and no other evidence of potential pathogen infection was found except for positive serologic tests for mouse rotavirus in mice. This is the first report of natural pneumococcal infection in mice, and the first report of type 35 S. pneumoniae infection in rodents. The findings support an earlier observation that pneumococcal infections in rat colonies tend to be monotypic and suggest that the same may be true in mice.     

An alternative method for the decontamination of rats carrying Mycoplasma pulmonis without the use of germfree isolators

Two strains of Lewis rat were successfully freed from Mycoplasma pulmonis infection by using a combination of oral treatment with oxytetracycline hydrochloride and obtaining young by hysterectomy. Laminar flow cabinets were used to perform hysterectomies on donor animals and for rearing hysterectomy-derived animals. After thorough microbiological examination the rats were brought to the breeding colony of the Laboratory Animal Centre. Periodic laboratory tests using both cultural and enzyme-linked immunosorbent assay methods showed that the animals have remained free from M. pulmonis for the last 3 years.     

Clinical and epidemiological survey of dermatophytoses in Jaen (Spain)

Prevalence of dermatophytosis, with respect to age and sex and dermatophyte species, in Jaen was investigated during a period of three years (1996-1999). The prevalence of dermatophytosis over three years was 4.48 cases / 1000 inhabitants. The isolated species were: Microsporum canis (48.6%), Trichophyton mentagrophytes (27.1%), Epidermophyton floccosum (10%), Trichophyton rubrum (8.6%), Trichophyton violaceum (4.3%), and Microsporum gypseum (1.4%). The most frequently observed dermatophytoses were tinea corporis (62.8%), followed by tinea capitis (12.8%); other clinical forms encountered were, in decreasing order of frequency, tinea cruris, tinea pedis and tinea unguium, tinea faciei and tinea barbae. Men were more affected than women.     

Mycoplasma pulmonis-host relationships in a breeding colony of Sprague-Dawley rats with enzootic murine respiratory mycoplasmosis

The longitudinal Mycoplasma pulmonis-host relationships in rats 1 to 72 weeks of age were investigated in a conventional breeding colony of Sprague-Dawley rats with enzootic murine respiratory mycoplasmosis (MRM). Mean intracage ammonia (NH3) concentrations of 52 +/- 21 micrograms/1 and active Sendai virus infections during the first month of life were associated with important early events in MRM. There was rapid colonization of proximal airways by large numbers of M. pulmonis in most rats by 2 weeks of age and the lungs by 6 weeks. The prevalence of lesions of MRM peaked by 3 weeks in nasal passages, later in middle ears, larynx and trachea, and not until 8 weeks in lungs. Approximately 10% of rats 8 weeks of age and older had bronchiectasis and/or bronchiolectasis, usually restricted to a few airways. Despite continued high NH3 concentrations (42 +/- 14 micrograms/1 in cages of weanlings and 86 +/- 45 micrograms/1 in cages of adults), M. pulmonis populations declined dramatically by 8 weeks of age. Nevertheless, in older rats lesions continued to be extremely prevalent in proximal airways. Mycoplasma pulmonis infection and disease persisted in respiratory tracts of most rats through 72 weeks of age, despite high serum concentrations of mycoplasma-specific IgM and IgG antibodies. These interrelationships of M. pulmonis, host, and environment may be representative of many breeding colonies of rats that have enzootic MRM.     

Keratinolysis by poultry farm soil fungi

Two hundred and eleven dogs (including strictly house and stray dogs) and 170 cattle in and around the city of Madras, India were screened for the presence of dermatophytosis. 106 strains of dermatophytes (89 strains from dogs and 17 strains from bovines) were isolated. 57/106 strains were Trichophyton mentagrophytes var. mentagrophytes and 42/106 strains were of the Microsporum gypseum complex. 5 strains of T. rubrum and 2 strains of T. simii were also obtained in culture. A predominance of M. gypseum complex isolates was recorded in stray dogs and cattle and T. mentagrophytes var. mentagrophytes and T. rubrum in strictly house dogs. The family history of the owners of the most of the dogs had clear records of dermatophytosis. Further, the owners of the 11 dogs that yielded T. mentagrophytes var. mentagrophytes had either tinea corporis or tinea pedis. The etiological agent of all the 11 human cases was T. mentagrophytes var. interdigitale. Similarly the owners of 4 of the 5 dogs that yielded T. rubrum were known T. rubrum patients. All these patients responded to oral griseofulvin or ketaconozole, but the recurrence of lesions was noted with the cessation of treatment. None of the patients had onychomycosis and the family history of all the patients revealed no reports of T. rubrum infections. The pet dogs were presumed to be the source of re-infection. Reversed transmission of dermatophytes from humans to animals may be the reason for the selective predominance of these organisms in strictly house dogs. They also may act as sources of reinfection. Most of the animals had small, occult, scattered lesions. These lesions may either go unnoticed or are ignored by the owners of the animals. The taxonomic status of T. mentagrophytes var. mentagrophytes and T. mentagrophytes var. interdigitale was aligned to their teleomorph Arthroderma vanbreuseghemii. Our study suggests that the periodic screening and medication of all live-stock are essential for the prevention and management of the public health problem caused by dermatophytes. This revised version was published online in August 2006 with corrections to the Cover Date.     

Strain differences in the induction of mono-oxygenase activity in mouse skin by topical clobetasol propionate: evidence of a role for the hr locus

The effect of the topical application of clobetasol propionate on cutaneous ethoxycoumarin O'dealkylation (EOD) has been studied in various strains of mice. Clobetasol propionate markedly increased cutaneous EOD activity in adult hairless mice only. Similar treatment of adult haired C57BL/6J mice, or adult haired DBA/2J mice had no significant effect on cutaneous EOD activity. In contrast 3 methylcholanthrene induced cutaneous EOD activity in both hairless and C57 strains to a far greater extent than in the DBA strain. EOD activity in hairless mice non-responsive to polycyclic hydrocarbons, derived by selective breeding of hairless and DBA strains was induced by clobetasol propionate to a similar extent to that observed in responsive hairless strains. Hepatic EOD activity was not induced by clobetasol propionate in any of the strains tested. Strain differences in the induction of EOD by clobetasol propionate were not related to differences in either the concentration of cytosolic glucocorticoid receptor in the skin, the dissociation constant of the cytosolic receptor, or differences in percutaneous absorption. Polycyclic hydrocarbons did not compete with triaminolone acetonide for binding to the cytosolic glucocorticoid receptor. Strain differences in the induction of EOD activity by clobetasol propionate appear therefore not to be related to strain differences in either the Ah receptor of the glucocorticoid receptor, but to be regulated by the hr locus.     

Insular bird populations can be saved from rats: a long-term experimental study of white-chinned petrels<Emphasis Type="Italic"> Procellaria aequinoctialis</Emphasis> on Ile de la Possession (Crozet archipelago)

The white-chinned petrel is a subantarctic seabird that requires urgent implementation of conservation measures for the species. At sea, adults suffer heavy mortality due to fisheries' practices. On land, introduced rats prey on chicks at several localities, and we test here if and how rats can be efficiently controlled. Since 1994, we have conducted an intensive rat-control program during each breeding season in a white-chinned petrel colony on Ile de la Possession (150 km²; Crozet archipelago, southern Indian Ocean), which had been monitored since 1986. On the same island, a control white-chinned petrel colony, where no poisoning occurred, was also monitored, and we assessed the seasonal variations of rat abundance. We compared three situations: high rat-poisoning, low rat-poisoning and control conditions without poisoning. Low-poisoning trials performed in our experimental colony between 1988 and 1991 did not lead to higher chick production than for the previous two control years. However, petrel-breeding success was significantly higher when intensive poisoning occurred (50%) than for the previous years (16%). The duration of our study (8 years before intensive poisoning, plus 8 years afterwards), combined with a comparison of petrel annual breeding success between our experimental and control colonies, allowed us to assess more effectively the impact of rats. Forty-one per cent of breeding failures occurring in non-poisoned areas were attributed to rats. We conclude that threatened insular bird populations can be conserved and restored in localities even where total rat eradication is not possible. However, only intensive and repeated (long-term) poisoning will control rats sufficiently.     

Reproductive characteristics of a captive colony of big-eared climbing rats (Ototylomys phyllotis)

The authors analyzed the breeding characteristics of a colony of Ototylomys phyllotis (big-eared climbing rat) from Campeche, México, that was bred in captivity for 6 y. The big-eared climbing rat is a reservoir of Leishmania (Leishmania) mexicana, a causal agent of localized cutaneous leishmaniasis on the Yucatán Peninsula. The colony had been established to facilitate studies analyzing the effectiveness of O. phyllotis as an experimental model for L. (L.) mexicana. The authors describe the housing and husbandry of the colony, the procedures used for mating the animals and the behavior of the animals during mating. They report that the animals showed social behavior and could be bred successfully. Most breeding pairs successfully produced litters; some pairs produced more than one litter. The authors also report data for other parameters, such as the interval between pairing and birth or between births of consecutive litters, litter size, survival to weaning, the timing of sexual maturity and the effects of breeder age on breeding success.