RESUMO Neste estudo foi avaliada a atividade antibacteriana de fibras têxteis contendo nanopartículas de poli(óxido de etileno-b-ácido lático) com óleos essenciais incorporados. O sistema desenvolvido demonstrou atividade antibacteriana contra Staphylococcus aureus, sugerindo seu potencial uso como agente antibacteriano. Foram utilizados copolímeros dibloco baseados em um bloco fixo de PEO (5kDa) e dois segmentos de PLA diferentes (4,5 e 10kDa). A morfologia, a eficiência do encapsulamento, a interação da blenda de óleos essenciais (incluindo, lavanda, melaleuca, tomilho, cravo, cedro e capim limão) e polímero e a cinética de liberação do agente ativo nas nanopartículas foram avaliadas. O raio hidrodinâmico das nanopartículas determinado pela dispersão da luz foi afetado pelo tamanho do bloco de poli(ácido lático). A liberação in vitro sugere que a barreira polimérica é capaz de controlar a liberação de óleo. A atividade antibacteriana foi mais eficaz em tecidos com fibras arranjadas aleatoriamente. De acordo com estudos da literatura, nanopartículas obtidas de copolímeros com menor massa molar de PLA favoreceram a liberação da mistura de óleos essenciais. O processo de incorporação dos óleos essenciais nas fibras têxteis mostrou-se eficiente sugerindo viabilidade quanto ao uso desse sistema no controle antibacteriano. Os sistemas desenvolvidos oferecem uma nova estratégia para a liberação controlada com atividade antibacteriana e apresentam potenciais aplicações na indústria calçadista.

ABSTRACT In this study was evaluated the antibacterial activity of textile fibers containing poly (ethylene oxide-b-lactic acid) nanoparticles with incorporated essential oils. The developed system demonstrated antibacterial activity against Staphylococcus aureus, suggesting its potential use as antibacterial agent. Diblock copolymers based on a fixed PEO block (5kDa) and two different PLA segments (4.5 or 10kDa) were used. The morphology, encapsulation efficiency, blending interaction of essential oils (including lavender, tea tree, thyme, cloves, cedar and lemon grass) and polymer and the release kinetics of the active agent in the nanoparticles. The hydrodynamic radius of the nanoparticles determined by light scattering was affected by the size of the poly(lactic acid) block. The in vitro release suggests that the polymeric barrier is able to control the oil release. Antibacterial activity was more effective in textiles with randomly arranged fibers. In agreement with studies from the literature, nanoparticles obtained from copolymers with lower PLA molar mass favored the release of the essential oil mixture. The incorporation process of the essential oils in the textile fibers proved to be efficient, suggesting viability regarding the use of this system in the antibacterial control. The developed systems offer a new strategy for controlled release with antibacterial activity and suggesting a potential application in the footwear industry.

ABSTRACT The global emergence of carbapenemases led to the need of developing new methods for their rapid detection. The aim of this study was to evaluate the performance of the rapid tests for carbapenemase-producing and non-producing Enterobacteriaceae. Carbapenem non-susceptible Enterobacteriaceae from a surveillance study submitted to a multiplex real time PCR for carbapenemase detection were included in this study. The isolates were subjected to the rapid phenotypic tests Carba NP, Blue-Carba and Carbapenem Inactivation Method (CIM). A total of 83 carbapenemase-producing (43) and non-producing (40) isolates were included in the study. The sensitivity/specificity were 62.7%/97.5%, 95.3%/100%, and 74.4%/97.5% for Carba NP, Blue-Carba and CIM, respectively. Both Carba NP and Blue-Carba presented their final results after 75 min of incubation; the final results for CIM were obtained only after 8 h. Failure to detect OXA-370 carbapenemase was the main problem for Carba NP and CIM assays. As the Blue-Carba presented the highest sensitivity, it can be considered the best screening test. Conversely, CIM might be the easiest to perform, as it does not require special reagents. The early detection of carbapenemases aids to establish infection control measures and prevent carbapenemases to spread reducing the risk of healthcare associated infections and therapeutic failure.

Nanoparticles comprised of the poly(ethylene oxide)-b-poly (lactic acid) diblock copolymer (PEO-b-PLA) with and without the incorporation of lavender oil were prepared by nanoprecipitation. Diblock copolymers based on a fixed PEO block (5KDa) and two different PLA segments (4.5 or 10KDa) were used. The morphology, encapsulation efficiency, essential oil-polymer interaction and the release kinetics of the active agent in the nanoparticles, were evaluated. The hydrodynamic radius of the nanoparticles determined by light scattering was affected by the size of the poly(lactic acid) (PLA) block. The lavender essential oil encapsulation efficiency (at a concentration of 0.4 µL mL-1) determined by UV-VIS spectroscopy was in the range of 70-75%. The in vitro release suggests that the polymeric barrier is able to control the oil release.