Iron, copper, and zinc are essential for all living organisms. Moreover, the homeostasis of these metals is vital to microorganisms during pathogenic interactions with a host. Most pathogens have developed specific mechanisms for the uptake of micronutrients from their hosts in order to counteract the low availability of essential ions in infected tissues. We report here an analysis of genes potentially involved in iron, copper, and zinc uptake and homeostasis in the fungal pathogens Paracoccidioides brasiliensis, Cryptococcus neoformans var. grubii, and Cryptococcus gattii. Although prior studies have identified certain aspects of metal regulation in Cryptococcus species, little is known regarding the regulation of these elements in P. brasiliensis. We also present amino acid sequences analyses of deduced proteins in order to examine possible conserved domains. The genomic data reveals, for the first time, genes associated to iron, copper, and zinc assimilation and homeostasis in P. brasiliensis. Furthermore, analyses of the three fungal species identified homologs to genes associated with high-affinity uptake systems, vacuolar and mitochondrial iron storage, copper uptake and reduction, and zinc assimilation. However, homologs to genes involved in siderophore production were only found in P. brasiliensis. Interestingly, in silico analysis of the genomes of P. brasiliensis Pb01, Pb03, and Pb18 revealed significant differences in the presence and/or number of genes involved in metal homeostasis, such as in genes related to iron reduction and oxidation. The broad analyses of the genomes of P. brasiliensis, C. neoformans var. grubii, and C. gattii for genes involved in metal homeostasis provide important groundwork for numerous interesting future areas of investigation that are required in order to validate and explore the function of the identified genes and gene pathways.

The presence of bats in caves, attics, ceilings, and roofs is important epidemiologically as they can increase the chance of human acquisition of pathogens, including Histoplasma capsulatum. Brazilian urban areas contain many species of bats, especially insectivorous bats, that are attracted by a wide range of readily available food and shelter. From August 2003 to December 2008, we analysed 2427 bats in the São Paulo State region. Homogenates of the livers and spleens of the bats were plated on specific medium to identify animals infected with H. capsulatum. The fungus was isolated from 87 bats (3·6%). The infected bats were identified as Molossus molossus (74), Nyctinomops macrotis (10), Tadarida brasiliensis (1), Molossus rufus (1) and Eumops glaucinus (1), all insectivorous species. The data presented are a relevant contribution to the epidemiology of H. capsulatum in densely populated urban areas such as in São Paulo State, especially since histoplasmosis is not included in the mandatory disease notification system.

Since 1998 a cat-transmitted epidemic of sporotrichosis has been observed in Rio de Janeiro (RJ), Brazil. Besides the lymphocutaneous and fixed forms, other presentations, such as disseminated cutaneous and mucosal involvement, as well as for the first time, erythema nodosum and erythema multiforme have been reported associated with sporotrichosis. This study investigates the phenotypes and genotypes of Sporothrix schenckii isolates recovered from different clinical forms of the disease noted as part of this epidemic. A total of 88 isolates recovered from 59 cases associated with the epidemic and 29 controls (from cases in other Brazilian regions and Spain) were included in this study. In vitro susceptibility testing was conducted as part of the phenotypic analysis, while the genotypic analysis involved a DNA fingerprinting method with primer M13 and ribosomal DNA sequencing of the internal transcribed spacer (ITS). MIC values of amphotericin B, itraconazole, posaconazole, ravuconazole, and terbinafine were found to be significantly lower (P<0.01) for isolates associated with the epidemic than for control strains. No differences in MIC values were observed related to clinical forms of the infection. Fingerprinting analysis showed that RJ epidemic strains were genetically related. Although nine subtypes were found, they were not associated with specific clinical forms. Similar results were obtained with the ITS sequence analysis. These data suggest that the strains isolated from the epidemic cases of sporotrichosis in RJ all originated from a common source.

No abstract

No abstract