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Publications

2022

Bacteriophages in the Control of Aeromonas sp. in Aquaculture Systems: An Integrative View

Authors
Pereira, C; Duarte, J; Costa, P; Braz, M; Almeida, A;

Publication
ANTIBIOTICS-BASEL

Abstract
Aeromonas species often cause disease in farmed fish and are responsible for causing significant economic losses worldwide. Although vaccination is the ideal method to prevent infectious diseases, there are still very few vaccines commercially available in the aquaculture field. Currently, aquaculture production relies heavily on antibiotics, contributing to the global issue of the emergence of antimicrobial-resistant bacteria and resistance genes. Therefore, it is essential to develop effective alternatives to antibiotics to reduce their use in aquaculture systems. Bacteriophage (or phage) therapy is a promising approach to control pathogenic bacteria in farmed fish that requires a heavy understanding of certain factors such as the selection of phages, the multiplicity of infection that produces the best bacterial inactivation, bacterial resistance, safety, the host's immune response, administration route, phage stability and influence. This review focuses on the need to advance phage therapy research in aquaculture, its efficiency as an antimicrobial strategy and the critical aspects to successfully apply this therapy to control Aeromonas infection in fish.

2022

Combined Effect of Phage phT4A and Pressure-Based Strategies in the Inhibition of Escherichia coli

Authors
Pereira, C; Marques, JF; Reis, S; Costa, P; Martins, AP; Pinto, CA; Saraiva, JA; Almeida, A;

Publication
ANTIBIOTICS-BASEL

Abstract
The major concern regarding the bacteriophage (or phage) therapy approach is the regrowth of bacteria after treatment, a consequence of the emergence of phage-resistant mutants. However, this limitation can be overcome by combining different therapies. In this study, the potential of combining phage phT4A with pressure storage (HS) to enhance the control of Escherichia coli and bacterial regrowth after treatment was evaluated. For that, the combining effect of phage phT4A and HS was studied and compared with storage at atmospheric pressure (AP) under refrigeration (4 degrees C, RF) and room temperature (RT). Initially, the effect of high hydrostatic pressure (200, 300 and 400 MPa) and HS (75 MPa), as well as refrigeration in phage phT4A viability, was determined. However, a considerable phage inactivation was verified at 200 MPa and so only HS at 75 MPa was further studied for combined treatment. The combined treatment with phage phT4A and HS was more efficient (reduction of 2.5 log CFU/mL after 7 days of storage) than phage phT4A (E. coli concentration was similar to that of the bacterial control after 7 days of storage) and HS (reduction of 1.8 log CFU/mL after 7 days of storage) applied individually. The combination of phage phT4A with refrigerated storage did not decrease E. coli levels. However, both the combination of phage with HS and the treatment with HS at 75 MPa effectively reduced E. coli concentration and prevented its regrowth. Phage phT4A viability was slightly affected during HS; however, the efficiency of the combined treatment phage-HS was not compromised. Further studies are needed to validate these findings in food products.

2022

Evaluation of UV-C Radiation Efficiency in the Decontamination of Inanimate Surfaces and Personal Protective Equipment Contaminated with Phage phi 6

Authors
Bartolomeu, M; Braz, M; Costa, P; Duarte, J; Pereira, C; Almeida, A;

Publication
MICROORGANISMS

Abstract
To help halt the global spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), appropriate disinfection techniques are required. Over the last years, the interest in Ultraviolet-C (UV-C) radiation as a method to disinfect inanimate surfaces and personal protective equipment (PPE) has increased, mainly to efficiently disinfect and prevent SARS-CoV-2 from spreading and allow for the safe reuse of said equipment. The bacteriophage phi 6 (or simply phage phi 6) is an RNA virus with a phospholipid envelope and is commonly used in environmental studies as a surrogate for human RNA-enveloped viruses, including SARS-CoV-2. The present study investigated the use of two new UV irradiation systems ((2)2.4W and (8)5.5W)) constituted by conventional mercury UV-C lamps with a strong emission peak at similar to 254 nm to potentially inactivate phage phi 6 on different surfaces (glass, plastic, stainless steel, and wood) and personal protective equipment, PPE, (surgical and filtering facepiece 2, FFP2, masks, a clear acetate visor, and disposable protective clothing). The results showed that both UV-C systems were effective in inactivating phage phi 6, but the UV-C sterilizing chamber (8)5.5W had the best disinfection performance on the tested surfaces. The inactivation effectiveness is material-dependent on all surfaces, reaching the detection limit of the method at different times (between 60 and 240 s of irradiation). The glass surface needed less time to reduce the virus (30 s) when compared with plastic, stainless, and wood surfaces (60 s). The virus inactivation was more effective in the disposable surgical and FFP2 masks (60 and 120 s, respectively) than in the disposable vest and clear acetate visor (240 s). Overall, this study suggests that UV-C lamps with peak emission at similar to 254 nm could provide rapid, efficient, and sustainable sanitization procedures to different materials and surfaces. However, dosage and irradiation time are important parameters to be considered during their implementation as a tool in the fight against human coronaviruses, namely against SARS-CoV-2.

2021

Boosting E-Auditing Process Through E-Files Semantic Enrichment

Authors
Sousa, C; Carvalho, M; Pereira, C;

Publication
Trends and Applications in Information Systems and Technologies - Volume 2, WorldCIST 2021, Terceira Island, Azores, Portugal, 30 March - 2 April, 2021.

Abstract

2020

How Knowledge Acquisition Diversity Affects Innovation Performance during the Technological Catch-Up in Emerging Economies: A Moderated Inverse U-Shape Relationship

Authors
Li, Q; Guo, JJ; Liu, W; Yue, XG; Duarte, N; Pereira, C;

Publication
SUSTAINABILITY

Abstract
Many domestic enterprises in emerging economies are concerned with the question of how to better utilize the portfolio of technology sourcing channels to achieve rapid economic growth by technological innovation. This paper looks at this issue by exploring the impacts of knowledge acquisition diversity (KAD) on innovation performance of domestic enterprises in China and the technological contexts (in terms of technology gap and technology development speed) under which KAD is most likely to contribute. Using panel data of the manufacturing industry in China over the 2001-2009 period, the results show that KAD has an inverse U-shaped relationship with innovation performance in terms of both product-related innovation performance (NPS) and knowledge-related innovation performance (PAT). Specifically, it reveals that the capability to generate technological innovation over time is dependent on how domestic enterprises manage their portfolio of knowledge sourcing channels to learn from foreign enterprises. Moreover, it is shown that the technology gap significantly moderates the inverted U-shaped relationship between KAD and both NPS and PAT. Technology development speed has a moderating effect on the inverted U-shaped relationship between KAD and innovation only in terms of NPS. The results of this study can help us to understand the relationships among technological contexts, KAD and innovation performance of domestic enterprises in emerging countries.

Supervised
thesis

2019

Utilização de técnicas de recomendação para suportar processos de negociação conceptual

Author
Anabela Pereira Esteves

Institution
IPP-ESTG