Two cases of infectious spondylodiscitis, be­cause of their uncommon aetiorogies, are reported in this paper. Consideration of the theoretical aetiology of this entity, reinforces the necessity to value the clinico-epidemiological aspects pre­sent, in order to achieve a rapid resolution both in terms of diagnosis & therapy.

Chronic wounds, pressure sores, lesions, and infections of microbial origin in bedridden, paralyzed, or malnutrition patients remain the object of study of many researchers. A variety of factors behind the development of these disorders are related to the patient's immune system, making it unable to respond effectively to the treatment of the wound. These factors can be properly controlled, giving particular importance to the ethiology and stage of the wound, as well as the time periods corresponding to the replacement of the dressings. The present research reports a novel foam/soft material, L-Cys-g-PCL, with an application for decubitus/pressure ulcers, especially for wounds with a difficult healing process due to infections and constant oxidation of the soft tissues. During this work, the interactions between S. aureus and L-Cys-g-PCL foam were studied under conditions that simulate decubitus ulcers; namely, pH and exudate. The effects of duration of grafting (1 or 8 h) and pH (7.0 and 8.9) on wettability, surface energy, swelling, and porosity were also evaluated. Results showed an effective microbicidal activity exhibiting an inhibition ratio of 99.73% against S. aureus. This new L-Cys-g-PCL soft material showed saftey to contact skin, ability to be shaped to fill in sunken holes (craters) - pressure ulcers stage III - and to act as a smart material responsive to pH, which can be tailored to develop better swelling properties at alkaline pH where exudates are normally higher, so as to address exudate self-cleaning and prevention of desiccation..

O aparecimento de resistência a antimicrobianos utilizados na prática clínica é algo que preocupa a comunidade científica em geral. Diariamente são documentadas novas resistências e são descobertas novas estirpes possuidoras de genes de resistência anteriormente desconhecidos. Um dos casos mais preocupantes é o caso do Staphylococcus aureus resistente à Meticilina (MRSA). O MRSA, além de apresentar uma distribuição muito ampla a nível mundial possui, caracteristicamente, uma elevada resistência a diversos antimicrobianos. Adicionalmente, este agente infeccioso tem a possibilidade de ser portador de diversos genes de virulência. Assim, a diminuição das defesas imunológicas do hospedeiro causada pelos factores de virulência, juntamente com a reduzida susceptibilidade aos agentes quimioterapêuticos, torna o MRSA portador de genes de virulência um agente infeccioso muito temido. Neste contexto, no presente estudo procedeu-se à determinação da frequência de MRSA em isolados de duas unidades hospitalares do Norte de Portugal durante o período de 6 meses. Para tal, através da técnica Multiplex Polymerase Chain Reaction (mPCR) procedeu-se à detecção simultânea do gene que confere a resistência à Meticilina, o mecA, e dos genes que são responsáveis pelo factor de virulência Panton-Valentine Leukocidin, lukF-PVL e lukS-PVL (lukFS-PVL). O cluster lukFS-PVL foi amplificado num único produto de mPCR. Procedeu-se também ao estudo comparativo da susceptibilidade a vários antimicrobianos, de diferentes classes, entre os isolados não possuidores do gene mecA e os isolados possuidores do gene mecA e entre os isolados não possuidores do gene lukFS-PVL e os isolados possuidores do gene lukFS-PVL. Para tal, foi utilizado o método de difusão de disco Kirby-Bauer, comparando-se a frequência de isolados resistentes entre os vários isolados em estudo. Foram obtidos resultados que indicam uma frequência de aproximadamente 50% de isolados MRSA e uma frequência de 9% de isolados portadores do gene lukFS-PVL, na amostra. Relativamente aos perfis de susceptibilidade dos isolados em estudo, concluiu-se que para a maioria dos antimicrobianos utilizados os isolados portadores do gene mecA apresentavam mais resistências que os isolados não portadores do gene mecA. Esta situação não terá, certamente, uma única e fácil justificação. De facto, a explicação será complexa e multifactorial. Poderão estar envolvidos mecanismos bioquímicos e moleculares relativos a outros genes na vizinhança dos mecA cujas transcrição, recombinação e transferência poderão ocorrer simultaneamente. Poderão ser apontadas, também, razões de ordem clínica como, por exemplo, a grande pressão terapêutica com diversos fármacos que muitas vezes é complicada com a má utilização destes. No entanto, foram também observadas frequências de resistência baixas ou praticamente nulas para alguns antimicrobianos. A resistência a antimicrobianos tem várias implicações como, por exemplo, os custos a nível hospitalar e a incapacidade de tratar as infecções causadas pelos microrganismos resistentes. Assim, é necessário continuar e melhorar o esforço na prevenção da transmissão do MRSA com estratégias de controlo da infecção hospitalar, de políticas do medicamento, de educação para a saúde das populações e apostar em estudos de controlo epidemiológico e na investigação e desenvolvimento de novas moléculas terapêuticas de modo a abrandar a tendência de propagação destes microrganismos patogénicos por todo o mundo.

Natural products have been presented as possible food preservatives due to their antimicrobial properties with some of these already being used in the food industry. However, it is known that microorganisms are able to adapt to antimicrobial agents, even if from natural sources, and some stresses. In this study, the influence of subinhibitory concentrations of resveratrol on Staphylococcus aureus ATCC 25923 and Listeria monocytogenes LMG 16779 was studied by evaluating the development of homologous- or cross-resistance to the antibiotics (ampicillin, erythromycin, vancomycin) commonly used to treat infections caused by these bacteria, as well as to one disinfectant (benzalkonium chloride) often used in the food sector. The development of tolerance against adverse conditions, acid (pH 2.4) and heat (55 °C) stresses, after the bacterial adaptation to resveratrol (¼ and ½ × MIC) was also assessed. The results suggest that resveratrol does not lead to homologous- or cross-resistance development for both strains studied, nonetheless it was observed a significant increase in tolerance to acid and heat stress in the case of L. monocytogenes and heat stress for S. aureus. These results, thus, indicate that resveratrol has potential to be used as a food preservative depending on the food processing conditions.

The main purpose of this work is to obtain a cotton-based textile material functionalized with l-cysteine (l-cys) to achieve an antimicrobial effect with potential application in biomedical, geriatric or pediatric textiles. The binding capacity of l-cys to cotton fibres was assessed through different functionalization strategies—surface activation and exhaustion processes. A subsequent analysis of the possible antibacterial action against Staphylococcus aureus and Klebsiella pneumoniae was performed according with the Japanese International standard (JISL, 2008). To determine the mechanism of action of l-cys on the selected strains, flow cytometry was used. The results revealed that the exhaustion process was performed with success to confer bioactivity to the treated fabric, as assessed by an effective antibacterial effect against both Gram-positive and Gram-negative bacteria, and successfully linkage of l-cys was observed via FTIR with a durable effect demonstrated after the washing tests (fastness to washing). It was also observed that l-cys exerts a bacteriostatic effect against both bacterial strains, since there were alterations in the metabolic activity ofthe microorganisms after the application of the bioactive textile which was shown by the CTC (cyanoditolyl tetrazolium chloride) staining used in flow cytometry. This study shows a new and successful biotechnological process to develop antibacterial textiles through the functionalization of cotton fibres with l-cys which presents a broad range of applications in healthcare, since l-cys is a natural antibacterial compound, non-toxic and affects pathogenic bacteria related to hospital infections.

For centuries, plants have been used for a wide variety of purposes, such as treating diseases, food flavouring and preservation and perfumery. The essential oils (EOs) are aromatic, oil-like volatile substances present in different plant materials that have a wide range of biological activities and can be used in different areas, such as chemical, cosmetic, food, perfumery, and pharmaceutical industries and have been used as therapeutic agents since ancient times. Thymus zygis is a widespread plant, mainly used as a culinary flavouring agent, which EO has demonstrated bioactive properties, such as antioxidant and antimicrobial, and that may even enhance the effect of certain antimicrobial agents. Furthermore, the potential application as a food preservative has been described on different matrixes mainly due to its antimicrobial activity against pathogenic and spoilage microorganisms in food. Considering the different applications of EOs, this work aimed to study the composition, antioxidant, and antimicrobial properties and also the cytotoxicity of the EOs of Foeniculum vulgare, Helichrysum stoechas, Mentha pulegium, Pinus pinaster, Ruta graveolens, and Thymus mastichina. The chemical composition, and the bioactive properties of the T. zygis EO were also evaluated with a focus on antimicrobial activity against Staphylococcus aureus and Listeria monocytogenes, and application of the EO in food. The F. vulgare, H. stoechas, M. pulegium, P. pinaster, R. graveolens, T. mastichina and T. zygis EOs showed antioxidant activity acting through inhibition of lipid peroxidation, while only the H. stoechas, M. pulegium and T. zygis EOs scavenged the free radicals of DPPH. M. pulegium and T. zygis EOs showed the strongest antimicrobial activity and only volatiles compounds from these EOs demonstrated inhibitory activity. Regarding the EO cytotoxicity on a fibroblasts cell line, it was observed that the effect was directly proportional to the EOs concentration, in which the highest cytotoxic effect was obtained with the R. graveolens EO. Considering the antimicrobial potential of the EO from T. zygis and since it showed the greater activity among the tested EOs, it was decided to proceed with further evaluation of this EO, thus deepening its bioactive activities, mainly the antibacterial activity against S. aureus and L. monocytogenes. Taking into account that S. aureus is a Gram-positive bacterium that causes a wide variety of clinical infections, from less severe to serious and life-threatening infections and because these are aggravated by antibiotic resistance, the antibacterial activity of T. zygis EO against strains of S. aureus was evaluated. The T. zygis EO demonstrated antimicrobial activity against S. aureus strains with bactericidal effect. The EO of T. zygis also revealed a synergistic or additive effect in combination with the antibiotic’s ampicillin, ciprofloxacin, or vancomycin against S. aureus strains and, in some cases, changed the antibiotic-resistance phenotype from resistant to susceptible. The T. zygis EO inhibit the formation of biofilms by S. aureus and partially eliminate the preformed biofilms even at subinhibitory concentrations. The EO reduced the haemolytic activity of S. aureus SA 03/10 (the only strain tested that causes haemolysis) as well the quorum-sensing in Chromobacterium violaceum biosensor. Therefore, these results demonstrate the good bioactive properties of the T. zygis EO, mainly the antimicrobial activity against S. aureus, revealing its potential to be used as an antibacterial agent and/or as an enhancer of the effect of antibiotics. Since L. monocytogenes is a foodborne Gram-positive bacterium with a high mortality rate and has the ability to survive and replicate in adverse conditions, allowing the wide distribution of this bacterium in different environments and matrices, such as water, soil, and food products, the antimicrobial activity of T. zygis EO against strains of L. monocytogenes was evaluated. The T. zygis EO presented good antibacterial activity against L. monocytogenes with MIC value of 0.05% while showing a bactericidal effect. The EO significantly reduced the biofilm formation with inhibition percentages from 16.85 to 89.86% and also the motility, while not inducing cross-resistance to antibiotics. The concentration of 2× MIC of T. zygis EO reduced the L. monocytogenes counts (initial inoculum of ~106 CFU/mL) in the chicken juice (1.53 log CFU/mL) and the lettuce model (to below the detection limit) after two days of storage. Regarding the sanitizing of fresh vegetables, the use of 0.2% (v/v) of EO for 5 min of immersion, reduce L. monocytogenes and natural microbiota counts for values below the detection limit of the method for iceberg lettuce. For the spinach leaves, L. monocytogenes and the natural microbiota counts were reduced to 4.35 log CFU/mL and in a range of 4.47 to 5.94 log CFU/mL, respectively, when compared with the washing with water. Thus, the T. zygis EO has demonstrated promising antibacterial activity against L. monocytogenes and these results point to the potential use of the T. zygis EO as a natural food preservative or sanitiser for controlling L. monocytogenes and the natural microbiota in food products. Overall, the present study revealed significant bioactive properties of different EOs, highlighting T. zygis EO to be considered in further studies for potential use in food preservation, due to their antioxidant and antimicrobial properties as well as in the control and reduction of the pathogenicity of the L. monocytogenes and S. aureus.

This study aimed to evaluate the antibacterial activity of L. and (L.) DC extracts against , including methicillin-resistant (MRSA) strains. To this end, assays were conducted to assess killing kinetics, antibiotic combination effects, modulatory effects on ethidium bromide, inhibition of quorum sensing, and biofilm formation. extract demonstrated the strongest activity, with MIC values ranging from 7.8 to 62.5 µg/mL. When combined with antibiotics such as ampicillin, ciprofloxacin, or vancomycin, the extracts of and predominantly exhibited synergistic (FICI value ≤ 0.5) or additive effects (0.5 < FICI ≤ 1), with some combinations resensitizing resistant strains. The aerial parts of displayed modulatory effects on ethidium bromide MIC, reducing the concentration from 32 to 8 µg/mL, suggesting efflux pump inhibitory activity. In addition, this extract displayed slight quorum-sensing inhibition at a concentration of 125 µg/mL. Moreover, and extracts inhibit the formation of biofilm by strains, even at subinhibitory concentrations (0.5× and 0.25× MIC). The presence of compounds such as myricetin 3 -galactoside, catechin derivatives, gallic acid, kaempferol, and chlorogenic acid in the extracts may contribute to their anti- activity. These results demonstrated the dual antimicrobial and antivirulence potential of and extracts, highlighting their promise as therapeutic agents or adjuvants against These extracts can be promising candidates for further studies on the development of novel strategies targeting multiple pathogenic pathways.

Bacteremia por Staphylococcus aureus causa morbidade e mortalidade significativas, principalmente causadas por S.aureus resistente à meticilina (MRSA). Atualmente, a vancomicina é uma das principais drogas de escolha para o tratamento das infecções por MRSA. A microdiluição em caldo (MDC) continua sendo a metodologia considerada padrão-ouro para determinar a concentração inibitória mínima (CIM) para a vancomicina. A maioria dos laboratórios clínicos empregam métodos mais práticos nas rotinas, porém esses métodos podem não determinar os valores de CIM para a vancomicina com precisão. Este estudo teve como objetivo avaliar a acurácia dos valores de CIM obtidos através dos sistemas automatizados Vitek System® 2 e BD Phoenix 100®, bem como do teste de fita gradiente Etest®, frente aos valores obtidos por MDC. Um total de 78 amostras (n=27 de S. aureus sensível à meticilina e n=51 de MRSA) foram isoladas de infecções da corrente sanguínea de pacientes internados em um Hospital Universitário, na cidade do Rio de Janeiro. A CIM para a vancomicina foi determinada seguindo as recomendações do Clinical and Laboratory Standards Institute (CLSI) e dos fabricantes dos sistemas comerciais analisados. Também realizamos a tipagem SCCmec a fim de estabelecer uma possível correlação dos tipos encontrados com os valores de CIMs verificados na análise. A maioria dos isolados apresentou valores de CIM de 1μg/mL por MDC e através do BD Phoenix100®. Etest® e VITEK System®2 determinaram para a maior parte dos isolados CIM de 1,5 e 0,5 μg/mL para a vancomicina, respectivamente. Assim, Etest® e VITEK System®2 tenderam a superestimar e subestimar, respectivamente, os valores de CIM. Três isolados MRSA, sensíveis à vancomicina pela MDC, eram intermediários à vancomicina pelo Etest®. Os tipos SCCmec II (39%) e IV (51%) foram os mais frequentes, não havendo relação entre o tipo de SCCmec e os valores de CIM. Os resultados mostraram que as CIMs para a vancomicina variam de acordo com o método utilizado. É essencial que os médicos considerem que os valores das CIMs podem ser diferentes, dependendo do método utilizado, uma vez que o valor da CIM é geralmente um dos parâmetros laboratoriais mais empregados pelos médicos para selecionar a terapia mais apropriada.

Staphylococcus aureus is an important agent of health care and community infections. Environmental surfaces, especially those in frequent contact with the hands, can serve as reservoirs of microorganisms, working as fomites in microbial spread. In the public transportation system, contact surfaces with hands can act as transmission vehicles, assisting the dispersion of S. aureus in the community. The aim of this study was to determine the prevalence of S. aureus and methicillin resistant S. aureus (MRSA) in buses, terminals and platforms of a larger route of the public transportation system in the city of Goiânia-GO, to determine the susceptibility and virulence profiles and assess the genetic similarity among S. aureus isolates. We collected 852 swabs fromhandrails of buses and ratchets of platforms and terminals that compose the East-West line. The isolation of staphylococci was done by standard techniques and species identification by detection of the femA gene. S. aureus identified were submitted to antimicrobial susceptibility testing, conventional PCR for detection of mecA and lukS-Fgenes, multiplex PCR to detect virulence factors genes, SCCmec typing and PFGE to assess the genetic similarity among strains. The contamination prevalence of handrails and ratchets by S. aureus was 17.7% (151/852). MRSA was detected in 0,5% of samples. The phenotype known as iMLSB was detected in 41.0% (62/151) of the isolates. Several virulence profiles were detected in 43 (28.5%)isolates, PFGE analysis revealed extensive genetic diversity of circulating strains, including MRSA strains similar to USA300 and USA800. The results suggest that S. aureus and MRSA strains, showing different susceptibility and virulence profiles are circulating in the community. They may be transmitted between individuals through fomites, putting the user population of the service at risk.

Staphylococcus aureus can produce a wide variety of virulence factors secreted or associated with bacterial wall, among them the exotoxins. The pathogenicity of S. aureus to the bovine udder is not quite clarified, but the staphylococcal exotoxins and their combinations may play a role in the pathogenic potential of the microorganism. Considering that knowing the virulence factors of S. aureus provides an important information of the establishment of effective control strategies of intramammary infections we aimed to detect the DNA of S. aureus isolates from milk of cows with clinical or subclinical mastitis and identify genes encoding bacterial exotoxins and superantigens. For this purpose, in the present study were used 55 isolates of S. aureus, obtained from milk samples from cows with clinical or subclinical mastitis. The isolates were electronically identified using the methodology described by Vitek 2® device manual. Genomic DNA extrac ted using the High Pure PCR Template Preparation Kit. The laboratory analysis for detection of species and genes encoding the exotoxins were performed at the Laboratório de Especialidades Biológicas of Centro de Pesquisa em Alimentos of Escola de Veterinária e Zootecnia da Universidade Federal de Goiás (LEB/CPA/EVZ/UFG). The gene eta was detected in 85,5% of the isolates, the pvl gene in 63,6% and the tst gene in 14,5%. The etb gene was not isolated. It was verified that the Real Time PCR technique for detection of sodA gene proved to be effective in identifying the species S. aureus, and may become an important tool in the diagnosis of the bovine mastits causing microorganisms. The isolates of S. aureus mastitis harbor genes exotoxins, such as pvl, tst and eta, which the last one may play an important role in the pathogenesis of bovine mastitis since the majority of the isolates showed to be positive for its presence.