Phage therapy: a step forward in the treatment of Pseudomonas aeruginosa infections

Antimicrobial resistance constitutes one of the major worldwide public health concerns. Bacteria are becoming resistant to the vast majority of antibiotics and nowadays, a common infection can be fatal. To revert this situation, the use of phages for the treatment of bacterial infections has been extensively studied as an alternative therapeutic strategy. Since P. aeruginosa is one of the most common causes of healthcare-associated infections, many studies have reported the in vitro and in vivo antibacterial efficacy of phage therapy against this bacterium. This review collects data of all the P. aeruginosa phages sequenced to date, providing a better understanding about their biodiversity. This review will further address the in vitro and in vivo results obtained by using phages to treat or prevent P. aeruginosa infections as well as the major hurdles associated with this therapy.

Spontaneous healing of Mycobacterium ulcerans lesions in the guinea pig model

Buruli Ulcer (BU) is a necrotizing skin disease caused by Mycobacterium ulcerans infection. BU is characterized by a wide range of clinical forms, including non-ulcerative cutaneous lesions that can evolve into severe ulcers if left untreated. Nevertheless, spontaneous healing has been reported to occur, although knowledge on this process is scarce both in naturally infected humans and experimental models of infection. Animal models are useful since they mimic different spectrums of human BU disease and have the potential to elucidate the pathogenic/protective pathway(s) involved in disease/healing. In this time-lapsed study, we characterized the guinea pig, an animal model of resistance to M. ulcerans, focusing on the macroscopic, microbiological and histological evolution throughout the entire experimental infectious process. Subcutaneous infection of guinea pigs with a virulent strain of M. ulcerans led to early localized swelling, which evolved into small well defined ulcers. These macroscopic observations correlated with the presence of necrosis, acute inflammatory infiltrate and an abundant bacterial load. By the end of the infectious process when ulcerative lesions healed, M. ulcerans viability decreased and the subcutaneous tissue organization returned to its normal state after a process of continuous healing characterized by tissue granulation and reepethelialization. In conclusion, we show that the experimental M. ulcerans infection of the guinea pig mimics the process of spontaneous healing described in BU patients, displaying the potential to uncover correlates of protection against BU, which can ultimately contribute to the development of new prophylactic and therapeutic strategies.

Using polymers to improve the rutting resistance of asphalt concrete

This study assesses rutting on two types of modified asphalt mixtures containing: (i) amorphous polyolefin polymer and (ii) a particular polymer obtained by combining LDPE (low density polyethylene) and EVA (ethyl-vinyl-acetate). Rutting tests were performed by a wheel tracking device. Stiffness and fatigue tests were carried out to confirm the performance of the asphalt mixtures. The testing showed that polymer modification in this study improved rut resistance without compromising the stiffness and fatigue behavior. The rutting results were fit in the NCHRP 1-37A model and the in situ rutting performance of asphalt mixtures can be predicted.

Caracterização do microbioma e dos perfis de resistência nos afluentes e efluentes de ETAR

Dissertação de mestrado integrado em Engenharia Biomédica (área de especialização em Engenharia Clínica)

A novel small-caliber bacterial cellulose vascular prosthesis: production, characterization, and preliminary in vivo testing

Vascular grafts are used to bypass damaged or diseased blood vessels. Bacterial cellulose (BC) has been studied for use as an off-the-shelf graft. Herein, we present a novel, cost-effective, method for the production of small caliber BC grafts with minimal processing or requirements. The morphology of the graft wall produced a tensile strength above that of native vessels, performing similarly to the current commercial alternatives. As a result of the production method, the luminal surface of the graft presents similar topography to that of native vessels. We have also studied the in vivo behavior of these BC graft in order to further demonstrate their viability. In these preliminary studies, 1 month patency was achieved, with the presence of neo-vessels and endothelial cells on the luminal surface of the graft.

Introducing resistance genes against ToMV, TYLCV and TSWV infections in two tomato varieties (Muchamiel and De la Pera)

Dissertação de mestrado em Biologia Molecular, Biotecnologia e Bioempreendedorismo em Plantas

Prevalência e susceptibilidade de isolados clínicos de Pseudomonas aeruginosa numa unidade hospitalar de Portugal

Dissertação de mestrado em Bioquímica Aplicada (área de especialização em Biomedicina)

The relevance of bacterial interactions on oral health

Dissertação de mestrado integrado em Engenharia Biomédica (área de especialização em Engenharia Clínica)

Cost efficiency and resistance to chemical attack of a fly ash geopolymeric mortar versus epoxy resin and acrylic paint coatings

This article presents results of an experimental investigation on the resistance to chemical attack (with sulphuric, hydrochloric and nitric acid) of several materials: OPC concrete, high-performance concrete, epoxy resin, acrylic painting and a fly ash-based geopolymeric mortar). Three types of acids with three high concentrations (10, 20 and 30%) were used to simulate long-term degradation. A cost analysis was also performed. The results show that the epoxy resin has the best resistance to chemical attack independently of the acid type and the acid concentration. However, the cost analysis shows that the epoxy resin-based solution is the least cost-efficient solution being 70% above the cost efficiency of the fly ash-based geopolymeric mortar.

The diagnostic and prognostic role of liquid-based cytology: are we ready to monitor therapy and resistance?

Here, we evaluate the diagnostic and prognostic role of liquid-based cytology (LBC) in different body lesions, including thyroid, lung, effusions and malignant breast lesions. LBC has gained consensus after being applied to both non-gynecologic and fine-needle aspiration cytology. Although some remain sceptical regarding the diagnostic efficacy of LBC, mainly when used alone, in recent years, good results have been obtained as long as it showed a high diagnostic accuracy. Here, we discuss the additional possibility of storing material for the application of ancillary techniques (immunocytochemistry–molecular analysis) with several diagnostic and prognostic advantages, which may pave the way for the challenging evaluation of both monitoring responses to treatment and resistance to targeted therapies in thyroid, lung, breast carcinoma or malignant effusions. Furthermore, it provides the use of several molecular spots as specific targets for personalized therapy.

Development of multifunctional coatings deposited on polymers based sensors for biomedical applications

Tese de Doutoramento (Programa Doutoral em Engenharia de Materiais)

A spin-offs journey into achieving marketable products from bacterial cellulose

[Excerpt] Academic spin-offs, technological ventures born inside Universities, have increasingly strengthen the connections between the scholarship and the economy, by fostering the role of technology transfer and knowledge commercialization. This presentation will outline the major steps in taking an idea or a technology to market, growing the venture and aiming at securing a successful exit. Also, it will present BCTechnologies (Bacterial Cellulose Technologies), a spin-off from the University of Minho (Portugal). (...)

Structural and enzymatic characterization of ABgp46, a novel phage endolysin with broad anti-Gram-negative bacterial activity

The present study demonstrates the antibacterial potential of a phage endolysin against Gram-negative pathogens, particularly against multidrug resistant strains of Acinetobacter baumannii. We have cloned, heterologously expressed and characterized a novel endolysin (ABgp46) from Acinetobacter phage vb_AbaP_CEB1 and tested its antibacterial activity against several multidrug-resistant A. baumannii strains. LC-MS revealed that ABgp46 is an N-acetylmuramidase, that is also active over a broad pH range (4.0-10.0) and temperatures up to 50°C. Interestingly, ABgp46 has intrinsic and specific anti-A. baumannii activity, reducing multidrug resistant strains by up to 2 logs within 2 hours. By combining ABgp46 with several organic acids that act as outer membrane permeabilizing agents, it is possible to increase and broaden antibacterial activity to include other Gram-negative bacterial pathogens. In the presence of citric and malic acid, ABgp46 reduces A. baumannii below the detection limit (> 5 log) and more than 4 logs P. aeruginosa and Salmonella Typhimurium strains. Overall, this globular endolysin exhibits a broad and high activity against Gram-negative pathogens, that can be enhanced in presence of citric and malic acid, and be used in human and veterinary medicine.

Chlamydia pneumoniae and atherosclerosis. Identification of bacterial DNA in the arterial wall

OBJECTIVE: The intracellular Gram-negative bacterium Chlamydia pneumoniae has been associated with atherosclerosis. The presence of Chlamydia pneumoniae has been investigated in fragments of the arterial wall with a technique for DNA identification. METHODS: Arterial fragments obtained from vascular surgical procedures in 58 patients were analyzed. From these patients, 39 were males and the mean age was 65±6 years. The polymerase chain reaction was used to identify the bacterial DNA with a pair of primers that codify the major outer membrane protein (MOMP) of Chlamydia pneumoniae. The amplified product was visualized by electrophoresis in the 2% agarose gel stained with ethidium bromide, and it was considered positive when migrating in the band of molecular weight of the positive controls. RESULTS: Seven (12%) out of the 58 patients showed positive results for Chlamydia pneumoniae. CONCLUSION: DNA from Chlamydia pneumoniae was identified in the arterial wall of a substantial number of patients with atherosclerosis. This association, which has already been described in other countries, corroborates the evidence favoring a role played by Chlamydia pneumoniae in atherogenesis.