The ability ofStaphylococcus aureusto invade and survive within host cells is believed to contribute to its propensity to cause persistent and metastatic infections. In addition,S. aureusinfections often are associated with atopic diseases such as dermatitis, rhinitis, and asthma. Mast cells, the key cells of allergic diseases, have a pivotal role in innate immunity and have the capacity of phagocytosis, and they can destroy some pathogenic bacteria. However, little is known about the ability of some other bacteria to survive and overcome mast cell phagocytosis. Therefore, we were interested in evaluating the interplay between mast cells andS. aureus. In this study, we show that human cord blood-derived mast cells (CBMC) can be infected by pathogenicS. aureus.S. aureusdisplayed a high adherence to mast cells as well as invasive and survival abilities within them. However, when infections were performed in the presence of cytochalasin D or when CBMC were preincubated with anti-Toll-like receptor 2 (TLR2) or anti-CD48 antibodies, the invasiveness and the inflammatory response were abrogated, respectively. Furthermore, we observed an increase of TLR2 and CD48 molecules on CBMC afterS. aureusinfection. The infection of CBMC withS. aureusalso caused the release of tumor necrosis factor alpha (TNF-α) and interleukin-8 (IL-8). Both live and killedS. aureusorganisms were found to trigger TNF-α and IL-8 release by CBMC in a time-dependent manner. Cumulatively, these findings suggest thatS. aureusinternalizes and survives in mast cells. This may play an important role in infections and in atopic diseases associated withS. aureus.

New Delhi metallo-β-lactamase (NDM)-producing bacteria have been identified at a worrying rate in Brazil since 2013. Owing to the need to understand the extent of their spread, this study reports the dissemination of bla _NDM in different species of Gram-negative bacilli in different regions and states of Brazil. A total of 81 isolates from nine states were studied, including 11 species. All isolates carried bla _NDM-1 variant and were considered multidrug resistant. Colistin and amikacin were the agents with higher activity compared with the other drugs tested. The findings indicate that the NDM-1 enzyme is already widespread in the country.