Introduction: Could changes in Staphylococcus aureus cellular walls, which are commonly associated with multidrug resistance phenotype, influence their immune evasion mechanisms? Objective: To evaluate the microbicide response and survival of alveolar macrophages after in vitro infection with methicillin-sensitive and methicillin-resistant Staphylococcus aureus. Material and methods: We used 20 adult, male, albino, Wistar rats. The alveolar macrophage samples were obtained after tracheostomy and bronchoalveolar lavage. The alveolar macrophages were cultured in the proportion of 1:1 cells/ml Roswell Park Memorial Institute (RPMI) medium/well and isolated by plate adhesion. For the assessment of immunological parameters, four systems were established: negative control, positive control, methicillin sensitive S. aureus (MSSA) and methicillin resistant S. aureus (MRSA). Results: When comparing MRSA and MSSA systems, there was no significant difference as to adhesion and phagocytosis rates, superoxide anion production and macrophage viability. By analyzing the kinetics of nitric oxide production, after 4 to 10 hours of cellular culture incubation, there was lower average production of this radical in the MRSA system when compared to MSSA. However, after 12 hours, no differences were detected between both systems. Conclusion: It is claimed that methicillin resistance may be a factor that influences the bacteria's ability to escape from macrophage microbicide response. Although the results of some immunological parameters were similar in the surveyed systems, the oscillations occurred during the production of nitric oxide may contribute significantly to the survival of Staphylococcus aureus.

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The tests demonstrate nutritional restriction during critical periods of development, although nutritional supplementation may compromise defense patterns in adulthood in a timely manner, preserving distinct signaling mechanism, so that the individual does not become widely vulnerable to infections by opportunistic pathogens.

Suplementação de antioxidantes no tratamento da lesão pulmonar aguda: meta-análise OriginAl Article intrODUctiOn Antioxidant supplementation (1-3) may prolong the initial phase or inhibit the propagation phase of reactive oxygen species (ROS) and reactive nitrogen species (RNS). (4) Disrupted oxidant-antioxidant balance has a major role in the genesis of inflammatory diseases, such as acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). (5,6) Antioxidants have been traditionally administered via oral, (3) intraperitoneal (1) or intravenous (2) routes. Patients with ARDS have a significant decrease when compared to healthy subjects at concentrations of reduced glutathione (138 ± 25 vs. 7 ± 4 μM), ascorbic acid (85 ± 21 vs. 27 ± 10 μM) concentrations in the bronchoalveolar lavage fluid (BALF), α-tocopherol (11.46 ± 0.55 vs. 7.73 ± 0.54 mg/L), β-carotene and selenium. (7,8) The plasma concentrations of lipid peroxides are also significantly increased versus controls [e.g., malondialdehyde (MDA), 2.2 vs. 1.3 nM]. (9,10) Additionally, patients with ARDS or patients who are at risk of ARDS show significantly reduced plasma polyunsaturated fatty acid concentrations

Rev. Nutr., Campinas, 25 (5) R E S U M O ObjetivoAvaliar a influência da desnutrição neonatal sobre a produção de Interferon gama, Interleucina-12 e Interleucina-10 em cultura de macrófagos alveolares e linfócitos infectados, in vitro, com Staphylococcus aureus sensível/resistente à meticilina.

Neonatal malnutrition focusing on critical periods of development promoted lower expression of iNOS, nitric oxide production, cell viability, and exacerbated reactive oxygen species production. The high levels of reactive oxygen species may favor the onset of serious and systemic infections with fatal outcome if associated with methicillin-resistant Staphylococcus aureus.