Browsing by Author "Almeida, Carina"
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- 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.
- 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.
- Prevalence and serotypes of Shiga toxinproducing Escherichia coli (STEC) in dairy cattle from Northern PortugalPublication . Ballem, Andressa; Gonçalves, Soraia; Garcia-Meniño, Isidro; Flament-Simon, Saskia C.; Blanco, Jesús E.; Fernandes, Conceição; Saavedra, Maria José; Pinto, Carlos; Oliveira, Hugo; Blanco, Jorge; Almeida, Gonçalo; Almeida, CarinaThis is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The prevalence of Shiga toxin (Stx)-producing Escherichia coli (STEC) was determined by evaluating its presence in faecal samples from 155 heifers, and 254 dairy cows in 21 farms at North of Portugal sampled between December 2017 and June 2019. The prevalence of STEC in heifers (45%) was significantly higher than in lactating cows (16%) (p 0.05, Fisher exact test statistic value is 0.00001). A total of 133 STEC were isolated, 24 (13.8%) carried Shiga-toxin 1 (stx1) genes, 69 (39.7%) carried Shiga-toxin 2 (stx2) genes, and 40 (23%) carried both stx1 and stx2. Intimin (eae) virulence gene was detected in 29 (21.8%) of the isolates. STEC isolates belonged to 72 different O:H serotypes, comprising 40 O serogroups and 23 H types. The most frequent serotypes were O29:H12 (15%) and O113:H21 (5.2%), found in a large number of farms. Two isolates belonged to the highly virulent serotypes associated with human disease O157:H7 and O26:H11. Many other bovine STEC serotypes founded in this work belonged to serotypes previously described as pathogenic to humans. Thus, this study highlights the need for control strategies that can reduce STEC prevalence at the farm level and, thus, prevent food and environmental contamination.
- 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
- 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, CarinaTo assess the prevalence of STEC in dairy cattle faeces in the North of Portugal and to determine the genetic pool of STEC virulence genes: stx1 and stx2 and eae.