Pathogenic A. salmonicida from human patients

The bacterium Aeromonas salmonicida is known since long time as a major fish pathogen unable to grow at 37 °C. However, some cases of human infection by putative mesophilic A. salmonicida have been reported. The goal of the present study is to examine two clinical cases of human infection by A. salmonicida in Spain and to investigate the pathogenicity in mammals of selected mesophilic A. salmonicida strains. An evaluation of the pathogenicity in a mouse model of clinical and environmental A. salmonicida strains was performed. The genomes of the strains were sequenced and analyzed in order to find the virulence determinants of these strains. The experimental infection in mice showed a gradient in the virulence of these strains and that some of them can cause necrotizing fasciitis and tissue damage in the liver. In addition to demonstrating significant genomic diversity among the strains studied, bioinformatics analyses permitted also to shed light on crucial elements for the virulence of the strains, like the presence of a type III secretion system in the one that caused the highest mortality in the experimental infection. Clinicians and microbiologists should consider these results for the inclusion of A. salmonicida in diagnosis tests since it is now clear that some mesophilic strains are also pathogens for humans

Histopatologia, sorologia e cultivo no diagnóstico da criptococose

Ten cases of cryptococcosis due to unusual microscopic forms of Cryptococcus sp. observed over a twenty-eight year period (1981-2009) are presented. The most important clinicopathological and laboratory data are tabulated. The uncommon forms of cryptococcal cells given are: structures resembling germ tube (one case), chains of budding yeasts (one case), pseudohyphae (two cases) and nonencapsulated yeast-like organisms (eight cases). The diagnosis was based on the histopathological findings. The causative organism was isolated and identified in seven cases; five were due to C. neoformans, and two to C. gattii. In addition, the importance of using staining histochemical techniques - Grocott's silver stain (GMS), Mayer's mucicarmine stain (MM) and Fontana-Masson stain (FM) - in the diagnosis of cryptococcosis is argued.A criptococose é a mais comum infecção fúngica oportunística observada em pacientes com síndrome da imunodeficiência adquirida (AIDS). Relatamos 13 casos da infecção baseados no diagnóstico histopatológico, sorológico e cultivo. Foram analisadas: a epidemiologia, as técnicas histoquímicas básicas de hematoxilina-eosina (HE) e coloração pela prata (GMS), bem como as técnicas histoquímicas especiais de mucicarmim de Mayer (MM) e Fontana-Masson (FM), o teste do antígeno criptocóccico (CrAg) e o isolamento em cultivos em ágar-Sabouraud (SAB), ágar infusão de cérebro-coração (BHI) e meio com canavanina azul de bromotimol (CGB). Em quatro casos, resultados tintoriais insatisfatórios pela coloração de MM associados a títulos negativos pelo teste do CrAg, a coloração de FM confirmou a infecção pelo Cryptococcus deficiente de cápsula. Oito isolados foram identificados: seis casos apresentaram a infecção por Cryptococcus neoformans e dois casos apresentaram a infecção por Cryptococcus gattii

Aspergillus fumigatus Fumagillin Contributes to Host Cell Damage

The activity of fumagillin, a mycotoxin produced by Aspergillus fumigatus, has not been studied in depth. In this study, we used a commercial fumagillin on cultures of two cell types (A549 pneumocytes and RAW 264.7 macrophages). This toxin joins its target, MetAP2 protein, inside cells and, as a result, significantly reduces the electron chain activity, the migration, and the proliferation ability on the A549 cells, or affects the viability and proliferation ability of the RAW 264.7 macrophages. However, the toxin stimulates the germination and double branch hypha production of fungal cultures, pointing out an intrinsic resistant mechanism to fumagillin of fungal strains. In this study, we also used a fumagillin non-producer A. fumigatus strain (∆fmaA) as well as its complemented strain (∆fmaA::fmaA) and we tested the fumagillin secretion of the fungal strains using an Ultra High-Performance Liquid Chromatography (UHPLC) method. Furthermore, fumagillin seems to protect the fungus against phagocytosis in vitro, and during in vivo studies using infection of immunosuppressed mice, a lower fungal burden in the lungs of mice infected with the ∆fmaA mutant was demonstrated.This research was funded by the Basque Government: grant number IT1362-19. X.G. and S.C.-S. received a Ph.D. fellowship from the Basque Government; and U.P.-C. from the University of the Basque Country

Efficacy of Micafungin in Combination with Other Drugs in a Murine Model of Disseminated Trichosporonosis

Using a murine model of disseminated infection caused by Trichosporon asahii, we have evaluated the efficacies of amphotericin B (AMB; 1 mg/kg of body weight/day), fluconazole (FLC; 20 mg/kg/twice a day), and micafungin (MFG; 5 mg/kg/twice a day). We tested these drugs alone and in combination (MFG with AMB and MFG with FLC). MFG with AMB showed a synergistic effect and demonstrated a higher degree of efficacy in prolonging survival and reducing the kidney fungal burden than either agent alone. The combination MFG with FLC was able to reduce significantly the kidney fungal burden in comparison to that achieved with either drug administered alone

Antifungal Therapy in an Athymic Murine Model of Chromoblastomycosis by Fonsecaea pedrosoi▿

We have compared the efficacy of terbinafine (TRB) and itraconazole (ITZ), the recommended drugs for the treatment of chromoblastomycosis, with that of posaconazole (PSC) and voriconazole (VRC) in athymic mice infected with the fungus Fonsecaea pedrosoi. Three weeks after challenge, mice were treated for 4 months with PSC at 10 or 20 mg/kg of body weight/day, with VRC at 10 or 20 mg/kg/day, with ITZ at 25 or 50 mg/kg/day, or with TRB at 150 or 250 mg/kg/day. The progress of the infection was evaluated by measuring the size of the lesions, by histopathological studies, and by cultures of the excised tissue. The two doses of PSC followed by the highest doses of ITZ and TRB showed the best results while VRC did not show efficacy. PSC could be an alternative in the treatment of chromoblastomycosis

In Vitro Activity and In Vivo Efficacy of Anidulafungin in Murine Infections by Aspergillus flavus ▿

Anidulafungin (AFG) showed high activity against 27 strains of Aspergillus flavus by use of broth microdilution and disk diffusion methods. This drug was effective in vivo in a murine model of disseminated infection with five isolates tested. AFG was able to prolong survival and reduce tissue burden of infected mice but not able to reduce galactomannan serum concentrations. The AFG serum levels were above the corresponding minimum effective concentrations (MEC) for all of the strains tested