An increasing incidence of nosocomial infections caused by non-multiresistant methicillin-resistant Staphylococcus aureus (nMMRSA) has been reported worldwide. The present study genotyped nMMRSA isolates obtained from hospitals in two cities in Brazil. The hospital isolates displayed pulsed-field gel electrophoresis (PFGE) patterns that were similar to those of the USA100 (ST5-SCCmecII) and USA 800 (ST5-SCCmecIV) strains, which are related to the New York/Japan and paediatric clones, respectively. Carriage of SCCmecIV and the classification by multilocus sequence typing (MLST) of a representative of this PFGE pattern in clonal complex 5 (CC5) confirmed the genetic relationship of the Brazilian isolates with USA800. The USA800-related Brazilian isolates were responsible for severe nosocomial infections in compromised adults and elderly patients in Brazil. A higher growth rate, an ability to form biofilm on inert polystyrene surfaces and the presence of the egc locus may have contributed, at least in part, to the fitness of these organisms as global nosocomial pathogens.

No abstract

Trichosporon species have been considered important agents of opportunistic systemic infections, mainly among immunocompromised patients. Infections by Trichosporon spp. are generally associated with biofilm formation in invasive medical devices. These communities are resistant to therapeutic antifungals, and therefore the search for anti-biofilm molecules is necessary. This study evaluated the inhibitory effect of farnesol against planktonic and sessile cells of clinical Trichosporon asahii (n = 3) andTrichosporon inkin (n = 7) strains. Biofilms were evaluated during adhesion, development stages and after maturation for metabolic activity, biomass and protease activity, as well as regarding morphology and ultrastructure by optical microscopy, confocal laser scanning microscopy, and scanning electron microscopy. Farnesol inhibited Trichosporon planktonic growth by 80% at concentrations ranging from 600 to 1200 μM for T. asahii and from 75 to 600 μM for T. inkin. Farnesol was able to reduce cell adhesion by 80% at 300 μM for T. asahii and T. inkin at 600 μM, while biofilm development of both species was inhibited by 80% at concentration of 150 μM, altering their structure. After biofilm maturation, farnesol decreased T. asahii biofilm formation by 50% at 600 μM concentration and T. inkin formation at 300 μM. Farnesol inhibited gradual filamentation in a concentration range between 600 and 1200 μM. Farnesol caused reduction of filament structures of Trichosporon spp. at every stage of biofilm development analyzed. These data show the potential of farnesol as an anti-biofilm molecule.

Persister cells are metabolically inactive dormant cells that lie within microbial biofilms. They are phenotypic variants highly tolerant to antimicrobials and, therefore, associated with recalcitrant infections. In the present study, we investigated if Trichosporon asahii and T. inkin are able to produce persister cells. Trichosporon spp. are ubiquitous fungi, commonly found as commensals of the human skin and gut microbiota, and have been increasingly reported as agents of fungemia in immunocompromised patients. Biofilms derived from clinical strains of T asahii (n=5) and T. inkin (n=7) were formed in flat-bottomed microtiter plates and incubated at 35°C for 48 h, treated with 100 μg/ml amphotericin B (AMB) and incubated at 35°C for additional 24 h. Biofilms were scraped from the wells and persister cells were assayed for susceptibility to AMB. Additionally, we investigated if these persister cells were able to generate new biofilms and studied their ultrastructure and AMB susceptibility. Persister cells were detected in both T asahii and T. inkin biofilms and showed tolerance to high doses of AMB (up to 256 times higher than the minimum inhibitory concentration). Persister cells were able to generate biofilms, however they presented reduced biomass and metabolic activity, and reduced tolerance to AMB, in comparison to biofilm growth control. The present study describes the occurrence of persister cells in Trichosporon spp. and suggests their role in the reduced AMB susceptibility of T. asahii and T. inkin biofilms.

Niemann-Pick disease (NPD) is a rare lysosomal storage disorder that is generalized and severe, as well as being characterized by intracellular sphingomyelin accumulation caused by deficiency of sphingomyelinase activity.(1)From a respiratory standpoint, the various types of NPD, including type B, can cause progressive loss of pulmonary function, with suggestive radiological findings. We report the case of a 27-year-old female patient with type B NPD. The patient was initially referred for outpatient treatment in 2003, presenting with a history of hepatosplenomegaly and delayed psychomotor development since childhood. The diagnosis of NPD was confirmed by measuring peripheral leukocyte sphingomyelinase activity, which was found to be decreased (0.009 nmol • h −1• mg −1 of protein; reference value, 0.745of protein). Serology for HIV, hepatitis B, and hepatitis C was negative, as was serology for syphilis (venereal disease research laboratory test). In addition, ANF was negative. Gaucher's disease was ruled out because beta-glucosidase levels were normal. The patient developed ascites and complained of mild dyspnea, being referred to the pulmonology clinic. She underwent a six-minute walk test (six-minute walk distance [6MWD] = 396 m; predicted 6MWD = 724 m), showing intense dyspnea at the end of the test (modified Borg scale score = 9) but no oxygen desaturation (SpO 2 = 97%). Spirometry results were suggestive of restrictive lung disease (FEV 1 = 1.77 L [61% of predicted]; FVC = 2.07 L [57% of predicted]; and FEV 1 /FVC ratio = 85%). A chest X-ray revealed no pulmonary changes. An HRCT scan revealed interlobular septal thickening in the bases and apices, together with right pleural effusion (Figures 1a and 1b). A rare entity, NPD is an autosomal recessive disorder characterized by abnormal accumulation of sphingomyelin in the reticuloendothelial system. Type B NPD has heterogeneous clinical manifestations and is mainly characterized by hepatosplenomegaly and progressive hypersplenism. Neurological involvement is rare; when it does occur, it is mild. The diagnosis is made by careful history taking and physical examination, as well as by determination of sphingomyelinase activity (which is decreased in peripheral leukocytes), together with fibroblast cell culture or analysis of bone marrow biopsy specimens revealing characteristic sea-blue histiocytes. There can be respiratory impairment secondary to macrophage and sphingomyelin accumulation in the distal airways and the alveoli, which leads to gradual deterioration of pulmonary function, reducing exercise tolerance. The clinical manifestations are heterogeneous, ranging from absence of symptoms to respiratory failure, and lung disease can progress to hypoxemia requiring oxygen therapy. (2,3)