In vitro susceptibility of Sporothrix spp. to complexes coordinated with Co(II) and cobalt chloride hexahydrate

Abstract Sporothrix spp. are the major dimorphic fungus associated with a type of subcutaneous mycosis, sporotrichosis. The limitation of antifungal availability and the past reports of in vitro resistance of Sporothrix spp. clinical isolates makes it important to search for new compounds with antifungal activities. In this study, we therefore evaluate the in vitro activities of complexes coordinated with Co(II) and cobalt chloride hexahydrate against clinical isolates of Sporothrix spp. Broth microdilution test was performed as per M38-A2 from CLSI (2008) in duplicate for 31 clinical isolates of Sporothrix spp. (27 S. brasiliensis e 04 S. schenckii stricto sensu). The antifungal activities of the complexes coordinated with Co(II) and cobalt chloride hexahydrate were detected at a concentration range of 32-128 µg/mL for all isolates. None of the compounds demonstrated any cytotoxicity (to macrophage cells) at the concentration of 200 µg/mL. The activity against Sporothrix spp. recorded in this study instigate the continuity of experimental studies with Co(II) to search for the mechanisms of antifungal action as well as to evaluate its interaction with the commercial antifungal drugs.

Can Aspergillus fumigatus conidia cause false-positive results in the galactomannan enzyme immunoassay test?

Abstract INTRODUCTION: Several factors can cause false-positive results in the galactomannan (GM) test; however, others remain unknown. Presently, the impact of airborne contamination by Aspergillus conidia during enzyme-linked immunosorbent assay (ELISA) remains uninvestigated. METHODS: We studied 12 A. fumigatus isolates. Fungal conidia were serially diluted and tested for GM detection using the Platelia® Aspergillus enzyme immunoassay (EIA). RESULTS: The conidia concentration required for an EIA-positive result was 4.8 × 103 (median). CONCLUSIONS: This is the first study to evaluate the impact of environmental contamination on the Platelia® Aspergillus EIA assay. Only massive contamination can interfere with GM optical readings, suggesting that environmental contamination does not cause false-positive test results.

Prevalence of Candida spp. in cervical-vaginal samples and the in vitro susceptibility of isolates

Abstract Vulvovaginal candidiasis (VVC) is an infection of the genital mucosa caused by different species of the genus Candida. Considering the lack of data on this topic in the south of Brazil, this study aimed to assess the prevalence of Candida spp. in the cervical-vaginal mucosa of patients treated at a university hospital in southern Rio Grande do Sul, as well as the etiology and the susceptibility of the isolates against fluconazole, itraconazole, miconazole and nystatin. Samples were collected at the gynecology clinic of the Federal Hospital of the University of Rio Grande, and the isolates were identified using phenotypic and biochemical tests. The susceptibility analysis was performed according to the CLSI M27-A2 protocol. Of the 263 patients included, Candida spp. was isolated in 27%, corresponding to a prevalence of approximately 15% for both VVC and colonization. More than 60% of the isolates were identified as Candida albicans; C. non-albicans was isolated at a rate of 8.6% in symptomatic patients and 14.3% in asymptomatic patients. The prevalence of resistance against fluconazole and itraconazole was 42% and 48%, respectively; the minimal inhibitory concentration of miconazole ranged from 0.031 to 8 µg/mL, and that of nystatin ranged from 2 to >16 µg/mL. The high rate of resistance to triazoles observed in our study suggests the necessity of the association of laboratory exams to clinical diagnosis to minimize the practice of empirical treatments that can contribute to the development of resistance in the isolates.

Seroepidemiology of Paracoccidioides brasiliensis infection in horses from Rio Grande do Sul, Brazil

Paracoccidioides brasiliensis is the etiological agent of the major systemic mycosis in Brazil, called paracoccidioidomycosis. Although the Rio Grande do Sul is considered an endemic area of the disease, there are few studies on the ecology of P. brasiliensis in the state. Therefore, this study aimed to evaluate the infection of P. brasiliensis in horses from the mesoregion of Southwest Riograndense, using these animals as sentinels. Serological techniques, such as double immunodiffusion in agar gel (AGID) and indirect ELISA, were performed to detect the anti-gp43 P. brasiliensis antibody in horses from five different farms in the region of Bagé, RS, Brazil. Serology was performed in 200 Pure Blood English horses up to two years of age that were born and raised exclusively at the farms. Of these horses, 12% had anti-gp43 antibodies according to the ELISA results, with rates ranging from 0 to 30% according to the farm of origin (p < 0.001). Based on the immunodiffusion results, all equine serum samples were negative. These results indicate the presence of the fungus P. brasiliensis in the middle region of the southwestern state of Rio Grande do Sul, Brazil.

Cryptococcus spp. em excretas de Columba livia (pombos domésticos) provenientes de um hospital universitário no Sul do Brasil / Cryptococcus spp. in excreta of Columba livia (domestic pigeons) from a university hospital in southern Brazil

A criptococose é uma micose primariamente pulmonar, sendo adquirida por meio de inalação de propágulos fúngicos infectantes encontrados no ambiente. Um dos principais agentes etiológicos da criptococose é a espécie Cryptococcus neoformans , que apresenta distribuição mundial. O objetivo desse trabalho foi pesquisar a ocorrência de Cryptococcus spp. em excretas de Columba livia (pombos domésticos) encontradas na área externa do prédio do Hospital Universitário Dr. Miguel Riet Correa Junior, centro de referência para o tratamento da Síndrome da Imunodeficiência Adquirida na região sul do estado do Rio Grande do Sul, Brasil. Durante um período de dez meses, foi coletado um total de 40 amostras de excretas secas da área acadêmica e da área hospitalar do Hospital Universitário. As excretas foram adicionadas de solução salina com cloranfenicol, homogeneizados em vórtex, semeados em ágar Níger e incubados a 25ºC com observações diárias até sete dias. A identificação do micro-organismo foi realizada por provas fenotípicas e bioquímicas. Das 40 amostras processadas e analisadas, 13 (32,5%) foram positivas para o isolamento de Cryptococcus spp., variando de 20.000 a 3.000.000 UFC/g de fezes. O isolamento desse fungo em um ambiente hospitalar é relevante em saúde pública, pois evidencia a exposição dos indivíduos que frequentam esse local a propágulos infectantes.(AU)

Cryptococcosis is primarily a pulmonary mycosis, being acquired by inhalation of infective fungal propagules found in the environment. One of the main etiological agents of cryptococcosis is the yeast Cryptococcus neoformans , which has worldwide distribution and whose natural habitat is the feces of birds. The aim of this study was to investigate the occurrence of Cryptococcus spp. in excreta of Columba livia (domestic pigeon) found in the outer area of the building of Hospital Universitário Dr. Miguel Riet Correa Junior, a reference center for the treatment of Acquired Immunodeficiency Syndrome in southern state of Rio Grande do Sul, Brazil. During a period of ten months, a total of 40 samples of dried excreta was collected from the site's academic area and hospital. To the excreta, were added saline solution with chloramphenicol, homogenized in a vortex, cultivated in Niger seed agar and incubated at 25°C with daily observations up to seven days. The identification of the microorganism was performed by phenotypical and biochemical tests. From the 40 samples processed and analyzed, 13 (32.5%) were positive for the isolation of Cryptococcus spp., with the quantity of yeasts ranging from 20.000 to 3.000.000 CFU/g of feces. Isolation of the opportunistic fungus Cryptococcus spp. at a university hospital is relevant in public health for demonstrating the exposure of individuals who frequent this site to infectant propagules.(AU)

Onychomycosis: clinical, mycological and in vitro susceptibility testing of isolates of Trichophyton rubrum

BACKGROUND: Onychomycosis or nail fungal infection is the most common nail disease. Despite the wide range of studies on this condition, it remains difficult to establish the correct diagnosis and effective treatment. OBJECTIVES: To evaluate the efficacy of classical laboratory methods for the diagnosis of onychomycosis, and the in vitro susceptibility of the its main etiological agent to antifungals used in routine. METHODS: Nail samples of 100 patients with clinically suspected feet onychomycosis were collected to confirm the diagnosis by direct mycological examination and fungal culture. In vitro antifungal susceptibility testing was performed against strains of the main dermatophyte isolated by microdilution, according to the standardized protocol (M38-A2 - CLSI) RESULTS: Clinical diagnosis of onychomycosis was confirmed by laboratory analysis in 59% of patients. Of these, 54.2% were positive only in direct mycological examination, 44.1% in direct mycological examination and culture, and one case (1.7%) was positive only in culture, resulting in weak agreement between these tests (Kappa = 0.385; p <0.001) High minimum inhibitory concentration values of fluconazole and itraconazole were observed in 66.7% and 25.0% of isolates of T. rubrum tested. Additionally, high MIC values of terbinafine and ciclopirox was detected in only one isolate, and this was one of the strains in which in vitro activity of itraconazole and fluconazole has not been proven. CONCLUSIONS: Poor agreement was observed between direct mycological examination and culture for the diagnosis of onychomycosis, with direct mycological examination being significantly more sensitive. Except for fluconazole, the other three antifungals tested showed good in vitro activity against clinical isolates of T. rubrum. .