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- Prevalence of shigatoxigenic Escherichia coli in bovine cattle: a survey in the North Region of PortugalPublication . Ballem, Andressa; Gonçalves, Soraia; Ferreira, A.I.; Fernandes, Conceição; Saavedra, Maria José; Pinto, C.; Oliveira, H.; Almeida, Gonçalo; Almeida, CarinaShiga toxin-producing Escherichia coli (STEC) strains are food-borne pathogens that can be transmitted to humans through many different routes, but mainly through consumption of contaminated foods. STEC strains are characterized by the production of Shiga toxins (Stx) that are encoded by two genes stx1 and/or stx2. Each toxin can be subdivided into subtypes and, currently, there are three known subtypes for stx1 (stx1a, stx1c, and stx1d) and seven for stx2 (stx2a, stx2b, stx2c, stx2d, stx2e, stx2f, and stx2g). Others virulence factors, such the production of intimin protein, encoded by eae gene, are associated with severe outcomes of STEC-associated diseases. The most common STEC serotype implicated worldwide is E. coli O157:H7, but many other STEC strains are associated with severe human diseases. Ruminants, especially cattle, are a major reservoir for O157 and non-O157 STEC. Information on STEC prevalence in Portuguese dairy cattle is limited, so we analysed for the presence of STEC 329 faecal specimens collected from the rectum of healthy dairy cattle. The samples were collected from adult lactating cows (n=194) and from heifers (n=135) with ages among 6 to 18 months, between March and June 2019, at milk farms (n=17) in the North region of Portugal. After enrichment, in modified TSB with novobiocin, samples were analysed by real time PCR to detect the presence of stx1, stx2 and eae in accordance to ISO/TS 13136:2012(E). In addition, conventional PCR for the detection of sxt1 and stx2 gene subtypes was performed according to the guidelines of the VTEC European Union Reference
- Biofilmes em superfícies industriaisPublication . Simões, Lúcia Chaves; Gomes, Inês B.; Fernandes, Conceição; Saavedra, Maria José; Simões, ManuelA sobrevivência dos mais aptos é um princípio biológico aplicável a todos os seres vivos e, embora organismos diferentes tenham desenvolvido mecanismos próprios para maximizar as suas hipóteses de sobrevivência, todos possuem um fator comum — a sobrevivência está diretamente relacionada com a capacidade de adaptação às variações das características do meio ambiente. As bactérias são particularmente adaptáveis a tais variações, em virtude da sua taxa de reprodução extremamente elevada, o que lhes permite a transferência de características de sobrevivência para gerações futuras em períodos de tempo muito curtos. Adicionalmente, muitas espécies bacterianas têm uma tendência natural para se fixar a superfícies, multiplicar e incorporar numa matriz viscosa produzida pelos microrganismos colonizadores, formando biofilmes1
- Alterações morfológicas da brânquia de Mugil causadas pela exposição de metais pesados na lagoa de Esmoriz-Paramos, PortugalPublication . Fernandes, Conceição; Fontaínhas-Fernandes, A.; Monteiro, Sandra Mariza; Salgado, Maria Antónia
- Searching for olive mill waste water (OMWW) solutions: is there a potential on microalgae treatment?Publication . Silva, Olinda; Vasconcelos, Vítor; Aires, Alfredo; Fernandes, ConceiçãoOlive Mill Waste Water (OMWW) is the principal industry extraction residue of olive oil and still one of the most serious environmental problems. Toxicity of this effluent is mainly due to high levels of phenolic compounds and low pH, thus OMWW direct disposal may pollute both. land and aquatic environments (1). A variety of biological processes have been tested to reduce OMWW phenolic compounds. Several studies were carried out with different bacteria (2,3) yeasts (4 ,5) and fungi (6,7) but in general their effectiveness in reducing OMWW toxicity varies greatly.
- Potencial de biorremediação de Chlorella vulgaris (Chlorophyceae) em águas residuais do processamento da mandioca, Capítulo 9Publication . Medeiros, Verónica de; Loures, Carla Cristina Almeida; Fernandes, ConceiçãoMost cassava processing industry generates a large volume of wastewater effluent with high contaminating load of COD and BOD and cyanide concentration, posing to a serious threat to the environment. A variety of processes has been tested to treat this wastewater effluent, where the effectiveness in reducing the toxicity varies greatly. Microalgae are photosynthetic microorganisms that can rapidly generate biomass from solar energy, CO2 and nutrients in water, namely those present in wastewater effluents. Also, algal biomass and algae-derived compounds are potentially useful in industrial applications, as well as for biodiesel production. Taking this into account, the aim of this work was evaluated the ability of Chlorella vulgaris to growth on cassava-processing effluent and assess the bioremediation potential by evaluating toxicity of effluent. Batch cultures, with C. vulgaris in suspended and in immobilized-cell systems, under different dilutions (20-50%) of cassava effluent were tested. The effectiveness of the process has been assessed by phytotoxicity, in germination trials of Lactuca sativa. Best results were obtained with C. vulgaris in immobilizedsystems and carried out with higher initial cell concentrations. Regarding the phytotoxicity, after biotreatment we can conclude that microalgae can reduce the toxicity of cassava effluent, leading to Germination Increase index (GI) range of 88-100%.
- Heavy metal contamination in a mugil wild population of a coastal lagoonPublication . Fernandes, Conceição; Fontaínhas-Fernandes, A.; Cabral, David; Carrola, João; Salgado, Maria AntóniaPolluted sediments usualy contain complex chemical mistures that may have synergistic and/or antagonistic effects on target organisms. Establishing causality in the 1ieId, is thus, particularly difficulty and the biomarker responses recorded in whole sediment toxicity assays are o correlactive nature only
- Escherichia coli phylogenetic and antimicrobial pattern as an indicator of anthropogenic impact on threatened freshwater musselsPublication . Varandas, Simone; Fernandes, Conceição; Cabecinha, Edna; Gomes, Sónia; Silva, Gabriela Jorge da; Saavedra, Maria JoséFreshwater bivalves are widely used as accumulation indicators and monitoring tools for assessing contaminant effects on different levels of biological integration. This pilot study aimed to explore the phylogenetic diversity of Escherichia coli isolated from freshwater mussels (Margaritifera margaritifera and Potomida littoralis) and characterize their phenotypes and antibiotic resistance profiles. Samples were collected in the Rabaçal and Tua Rivers, in the Douro basin, Portugal—two sites representing different levels of anthropogenic contamination. Antimicrobial susceptibility testing was performed via the disk diffusion method with 21 antibiotics. Results showed that 31% of isolates were multidrug-resistant (MDR). Thus, freshwater mussels provide an effective and time-integrated approach for identifying/quantifying fecal indicators, including MDR bacteria. PCR-based assays were designed for assessing phylogenetic E. coli groups. Among the E. coli isolates, the highest prevalence (44%) was observed in group D or E, followed by group E or Clade I (25%), group A (19%), and group B1 (13%). E. coli isolated from M. margaritifera predominantly exhibited a higher prevalence of phylogroups D or E, whereas E. coli from P. littoralis showed associations with phylogroups E or clade I, B1, A, and D or E. Our results provide new insights into the phylogenetic diversity of E. coli in freshwater bivalves. Additionally, the findings highlight the possible linkage of phylogroups with the host species, the geographical location in the water stream, and human activity. Using E. coli as a bioindicator isolated from freshwater mussels helps us grasp how human activities affect the environment. This study has important implications for those interested in safeguarding water resources, especially in tackling antibiotic resistance in aquatic ecosystems.
- Bioaccumulation of heavy metals in Liza saliens from the Esmoriz-Paramos coastal lagoon, PortugalPublication . Fernandes, Conceição; Fontaínhas-Fernandes, A.; Peixoto, Francisco P.; Salgado, Maria AntóniaHeavy metal (Cu and Zn) concentrations in liver, gills, and muscle of leaping grey mullet, Liza saliens, from the Portuguese Esmoriz–Paramos coastal lagoon were measured to evaluate their bioaccumulation as a function of sediment contamination. The highest metal concentrations were observed in the liver (254mg Cu kg 1) and gills (114 mgZn kg 1). Bioaccumulation factors (BAFs) were found to follow the order: Cu-liver4Cu-gills4Cu-muscle and Zn-gills4Zn-liver4Zn-muscle. The highest BAFs were observed in the organs mainly implicated in metal metabolism and a significant positive relationship was found between BAFs and fish age. These results suggest the loss of homeostatic capacity of L. saliens under chronic metal exposure leading to bioaccumulation. Furthermore, Cu-liver and Zngills accumulation can be good environmental indicators of metal stress in L. saliens
- An assessment of the processing and physicochemical factors contributing to the microbial contamination of salpicão, a naturally-fermented Portuguese sausagePublication . Cadavez, Vasco; Gonzales-Barron, Ursula; Pires, P.; Fernandes, E.; Pereira, Ana Paula; Gomes, Aline; Araújo, José Pedro; Lopes-da-Silva, M.F.; Rodrigues, Paula; Fernandes, Conceição; Saavedra, Maria José; Butler, Francis; Dias, TeresaComplete microbiological, physicochemical and environmental longitudinal data were obtained from factory surveys in order to elucidate risk factors leading to the survival of Enterobacteriaceae, Staphylococcus aureus and Listeria monocytogenes in salpicão sausage. A total of six batches were surveyed from two factories; one added nitrite and polyphosphates in their formulation (Factory II). The addition of polyphosphates slowed down fermentation, which favoured the increase in Enterobacteriaceae (∼0.5 log CFU/g), S. aureus (∼0.5 log CFU/g) and L. monocytogenes (∼70 CFU/g) until maceration. Maceration should be regarded as a critical stage in the control of S. aureus in salpicão, as longer maceration (p = 0.033), higher temperatures of maceration (p = 0.018) and pH of macerated meat (p = 0.079) led to higher S. aureus counts in the final product. The main hurdle controlling S. aureus in salpicão is the pH. For L. monocytogenes and Enterobacteriaceae, at least three hurdles hinder their viability: low Aw (p = 0.010; 0.012), smoking (p < 0.0001; 0.020) and nitrite (p = 0.158; 0.105). Cross-contamination, especially during mixing, should be avoided as it is an important factor explaining the increase in Enterobacteriaceae (p = 0.041), S. aureus (p = 0.015) and L. monocytogenes (p = 0.082) on a batch basis. There is a need to optimise the acidification process and reinforce good hygiene practices
- Antibiotic resistance profile among Shiga toxin-producing Escherichia coli isolated from dairy cattlePublication . Ballem, Andressa; Almeida, Gonçalo; Almeida, Carina; Fernandes, Conceição; Saavedra, Maria JoséShiga toxin-producing Escherichia coli (STEC) are foodborne pathogens that can cause serious diseases in humans, including bloody diarrhoea and kidney failure. Ruminants, such as cattle, are considered the main reservoirs and source of STEC. Human infection can occur through contaminated food and water, or direct contact with infected animals. STEC antimicrobialresistance (AMR) is increasingly frequent in patients with serious disease. It is necessary to understand the epidemiology, the emergence, and the prevalence of AMR in STEC isolated from cattle to investigate how resistance spreads from ruminants to humans. Thus, susceptibility tests were performed on 55 STEC strains belonging to 29 serogroups. The strains were isolated from healthy dairy cattle faeces (cows and heifers) in the North of Portugal. Antibiotic susceptibility testing (AST) was performed by disc diffusion method following European Committee on Antimicrobial Susceptibility Testing (EUCAST, 2020) and Clinical and Laboratory Standards Institute (CLSI, 2020). The antibiotics used included penicillins (ampicillin; amoxicillin-clavulanic acid), cephalosporins (ceftazidime; cefotaxime; cefoxitin; cephalothin), carbapenems (imipenem; meropenem), aminoglycosides (kanamycin), phenicol (chloramphenicol), sulphonamides/ trimethoprim (trimethoprim-sulfamethoxazole), fluoroquinolones (moxifloxacin; levofloxacin) and tetracyclines (tetracycline; tigecycline). Results reveal low level of resistance among the isolates tested. However, five (9%) STEC isolates were resistant to one antibiotic, and three (5,5%) to three or more antibiotic classes (multidrug resistance-MDR). The MDR strains were resistant to trimethoprim-sulfamethoxazole, tetracycline and other antibiotics commonly used to treat gastroenteritis. Two strains MDR belonged to O91 serogroup and were founded in heifers in the same farm. O91 is an important serogroup to public health surveillance, as it is commonly associated with contamination of products from animal origin, and it has been isolated from patients with severe gastrointestinal disease. Overall, the AMR did not seem to be widely spread in STEC isolates from cattle; but serotype O91 might be of special concern as two O91-multidrug resistance profiles have been identified.