BACKGROUND Behavioral and neurochemical alterations associated with toxoplasmosis may be influenced by the persistence of tissue cysts and activation of an immune response in the brain of Toxoplasma gondii-infected hosts. The cerebral extracellular matrix is organised as perineuronal nets (PNNs) that are both released and ensheath by some neurons and glial cells. There is evidences to suggest that PNNs impairment is a pathophysiological mechanism associated with neuropsychiatric conditions. However, there is a lack of information regarding the impact of parasitic infections on the PNNs integrity and how this could affect the host’s behavior. OBJECTIVES In this context, we aimed to analyse the impact of T. gondii infection on cyst burden, PNNs integrity, and possible effects in the locomotor activity of chronically infected mice. METHODS We infected mice with T. gondii ME-49 strain. After thirty days, we assessed locomotor performance of animals using the open field test, followed by evaluation of cysts burden and PNNs integrity in four brain regions (primary and secondary motor cortices, prefrontal and somesthetic cortex) to assess the PNNs integrity using Wisteria floribunda agglutinin (WFA) labeling by immunohistochemical analyses. FINDINGS AND MAIN CONCLUSIONS Our findings revealed a random distribution of cysts in the brain, the disruption of PNNs surrounding neurons in four areas of the cerebral cortex and hyperlocomotor behavior in T. gondii-infected mice. These results can contribute to elucidate the link toxoplasmosis with the establishment of neuroinflammatory response in neuropsychiatric disorders and to raise a discussion about the mechanisms related to changes in brain connectivity, with possible behavioral repercussions during chronic T. gondii infection.

INTRODUÇÃO: As espécies de Klebsiella spp. podem causar vários tipos de infecções, principalmente hospitalares, e têm merecido destaque pelos seus variados e emergentes mecanismos de resistência. OBJETIVOS: Determinar a frequência de isolamento e a caracterização do perfil de resistência de Klebsiella spp. em um hospital universitário durante um período de 10 anos e, ainda, avaliar a tendência para o crescimento dessa resistência. Material e método: Fez-se um estudo descritivo e retrospectivo a partir de dados coletados nos livros de registro do Laboratório de Microbiologia Clínica do hospital investigado, correspondentes ao período de janeiro de 1999 a dezembro de 2008. RESULTADO: A frequência de isolamento de Klebsiella spp. foi de 13,4% com predominância em uroculturas (56,4%). Houve aumento significativo na resistência para a maioria dos antimicrobianos testados ao longo do período analisado com tendência para o crescimento da mesma. Nesse período, isolou-se 23% de Klebsiella spp. com fenótipo produtor de betalactamases de amplo espectro (ESBL). DISCUSSÃO: O isolamento de Klebsiella spp. resistente a antimicrobianos em amostras de origem clínica e a detecção da tendência do crescimento da resistência, inclusive às drogas de reserva terapêutica, são motivos de grande preocupação. Nesse hospital, a implantação de métodos de triagem e de confirmatórios para os mecanismos de resistência de Klebsiella spp. poderiam auxiliar no diagnóstico e no tratamento das infecções causadas por esse microrganismo. CONCLUSÃO: A tendência de crescimento na resistência aos antibióticos detectada neste estudo reforça a importância de monitoramentos contínuos. Estes elucidam características locais, orientando para melhores medidas de controle.

INTRODUCTION: Klebsiella spp. species can cause several infections, particularly nosocomial ones. Furthermore, its multiple emerging resistance mechanisms have been widely described. OBJECTIVES: To determine the isolation frequency and resistance profile of Klebsiella spp. at a university hospital during a ten-year period as well as to assess the increase in its resistance. Material and method: A retrospective and descriptive study was carried out based on data collected from the record books of the Laboratory of Clinical Microbiology of the investigated Hospital from January 1999 to December 2008. RESULTS: The isolation frequency of Klebsiella spp. was 13.4%, predominantly in urine cultures (56.4%). There was a significant increase in resistance to most antimicrobials tested over the analyzed period; 23% of Klebsiella spp. with ESBL phenotype was isolated over this period. DISCUSSION: Multi-resistant Klebsiella spp. isolates from clinical samples as well as its growing trend in resistance mechanisms, including to reserve drugs, are cause for great concern. The implementation of screening and confirmatory methods of bacterial resistance could aid in the diagnosis and treatment of infections caused by this microorganism. CONCLUSION: The increase in resistance to antibiotics reinforces the importance of continuous monitoring, which elucidates local characteristics and allows more suitable control measures.