Publications by authors named "Graciela V Lopes"

This study investigated the formation of fibers and capsules using rice starch as a wall material to encapsulate orange peel essential oil (OPEO) by electrospinning for antimicrobial applications. Rice starch at a concentration of 20 % (w/v) and varying OPEO concentrations (30 %, 40 %, and 50 %, w/w) were used to produce materials. Free OPEO was analyzed for its chemical profile and antimicrobial activity.

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Geranium (Pelargonium graveolens) is known for being an aromatic plant rich in bioactive compounds with antibacterial properties. In this study, geranium essential oil (GEO) was extracted and encapsulated in ultrafine bean starch fibers produced by electrospinning as an antibacterial agent. GEO revealed a composition rich in volatile compounds, including citronellol, cis-geraniol, β-linalool, citronellyl formate, and linalool formate.

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Unlabelled: This study aimed to investigate the occurrence and the genetic diversity of subsp. in sausages from Southern Brazil, evaluate virulence genes and determine the phenotypic and genotypic basis of antimicrobial and sanitizer resistance. was detected in sausage samples with an overall prevalence of 5.

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The growing number of Listeria monocytogenes strains displaying increased tolerance to sanitizers widely applied in the food industry is becoming a problem. The aims of this study were to evaluate the susceptibility of L. monocytogenes isolates from food and food industry environments to sanitizers (benzalkonium chloride, sodium hypochlorite, peracetic acid, and chlorhexidine) and heavy metals (cadmium chloride), as well as to investigate the presence of the main genes related to efflux pumps.

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The aim of this study was to evaluate 140 Salmonella Derby isolates collected over a 10-year period from porcine origins (environment, pig carcass, lymph nodes, intestinal content, and pork) for their phenotypic and genotypic antimicrobial resistance, their ability to produce biofilm, and their genetic relatedness. The minimum inhibitory concentration (MIC) was determined using microdilution broth method and antimicrobial resistance genes were investigated by PCR. The quantification of biofilm formation was performed in sterile polystyrene microtiter plates.

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Article Synopsis
  • * Results showed that isolates were categorized into two main lineages, with lineage I displaying higher invasion capabilities in human cells and expressing a specific virulence factor called InlA.
  • * isolates from lineage II exhibited lower invasion rates due to a lack of InlA expression or mutations that caused malfunction, indicating differences in virulence potential linked to the isolates' genetic backgrounds.
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Campylobacter jejuni is a highly frequent cause of gastrointestinal foodborne disease in humans throughout the world. Disease outcomes vary from mild to severe diarrhea, and in rare cases the Guillain-Barré syndrome or reactive arthritis can develop as a post-infection complication. Transmission to humans usually occurs via the consumption of a range of foods, especially those associated with the consumption of raw or undercooked poultry meat, unpasteurized milk, and water-based environmental sources.

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Staphylococcus aureus is one of the most common pathogens associated with food poisoning, which is caused by the ingestion of food contaminated with staphylococcal enterotoxins (SE). Our study aims at evaluating the occurrence and expression of five SE genes (sea, seb, sec, sed, and see) in S. aureus previously isolated from broiler carcasses.

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Ozone application has been suggested as an additional measure to the slaughter animals under hygiene programs. In this study, we determined the efficacy of gaseous ozone applied to pig carcasses during chilling (16 h at 2-5°C). Forty carcasses were allocated to each treatment: control, without ozone application (T1) and 5 ppm gaseous ozone application (T2), divided in two 4-h periods.

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This study investigated the ability of isolates from milk to form biofilm, through detection of adhesion genes, investigating exopolysaccharide (EPS) production and biofilm formation on polystyrene (PS) and stainless steel (SS) surfaces, and by quantifying the expression of and genes under different temperatures and culture media. Among the 31 isolates, the adhesion genes and were found in 81% and 61% of the isolates, respectively. The screening tests for phenotype revealed that 58% of the isolates were EPS producers, and 45% showed the ability to produce biofilm on PS.

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Article Synopsis
  • - The study assessed the biofilm formation ability of poultry isolates under various conditions, including different surfaces (stainless steel, polystyrene), temperatures (7, 25, and 42 °C), and oxygen levels (microaerophilic and aerobic).
  • - All isolates successfully formed biofilm on both surfaces across the tested conditions, particularly thriving in dual-species scenarios where biofilm formation increased significantly at lower temperatures (7 °C).
  • - Ten genes related to biofilm formation were identified in the isolates, with some detected across all samples, raising concerns about the ability of these poultry isolates to form resilient biofilms under diverse environments.
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  • The study aimed to assess the prevalence of thermophilic Campylobacter in broiler farms and slaughterhouses in southern Brazil, revealing that 53.6% of samples tested positive for C. jejuni.
  • Resistance to certain antibiotics was significant, with 74% of isolates resistant to nalidixic acid and 67.3% to enrofloxacin, but no resistance was found to macrolides recommended for treating human infections.
  • Genetic analysis identified eight distinct patterns of C. jejuni, all carrying major virulence genes, indicating that the pathogen poses a risk to consumers by contaminating chicken products and potentially causing illness.
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The aims of this study were to evaluate the occurrence of Listeria monocytogenes and Salmonella spp. in sliced cheese and ham from retail markets in southern Brazil, as well as to perform molecular characterization and to assess the antimicrobial resistance profile of the isolates. Samples (n = 160) of sliced cheese and ham were collected at retail level from the city of Pelotas, Brazil.

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Beef jerky is a ready-to-eat product that does not require refrigeration at the point of sale. Here, we evaluated the occurrence of in the production process of beef jerky, the presence of virulence genes and the genomic relatedness of the isolates, to assess the safety of the final product. The raw material, surfaces with and without contact with the product and the final product were evaluated along the beef jerky processing line.

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Salmonellosis, caused by the consumption of contaminated foods, is a major health problem worldwide. The aims of this study were to assess the susceptibility of Salmonella spp. isolates to benzalkonium chloride (BC) disinfectant and the antimicrobial activity of Butia odorata Barb.

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The aims of this study were to evaluate the presence of genes associated with adhesion (cadF), invasion (ciaB), and cytotoxin production (cdtA, cdtB, and cdtC) among Campylobacter jejuni isolates from a poultry slaughterhouse and to investigate the effect of different temperatures on the expression of these virulence-associated genes. A total of 88 C. jejuni isolates from cecum, liver, chicken carcasses, chilled water, and scalding water were submitted to PCR assay for detection of virulence genes.

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This study aimed to evaluate the presence of pathogens in, and the hygienic-sanitary quality of, commercialized foods of animal origin at the international border region of Rio Grande do Sul, Brazil. In total, 270 samples of raw and processed foods of animal origin were collected in Paso de los Libres, Argentina (n = 65 raw meat, n = 47 dairy products, n = 28 processed meat) and Rivera, Uruguay (n = 60 raw meat, n = 31 dairy products, n = 29 processed meat), or were seized by the Brazilian International Agricultural Surveillance System (Brazil-Argentina border) (n = 9 raw meat, n = 1 bush meat). The samples were subjected to the enumeration of aerobic mesophilic bacteria, enterobacteria, and coagulase-positive staphylococci, and were tested for Salmonella spp.

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Staphylococcus aureus is a common causative agent of bovine mastitis in dairy cows and commonly associated with foodborne disease outbreaks. The aim of this study was to evaluate the presence of enterotoxin genes, agr typing, antimicrobial resistance, and genetic diversity of S. aureus isolated from milk of cows with mastitis in dairy farms from southern Brazil.

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The genetic basis of tetracycline resistance in a food isolate Listeria monocytogenes (Lm16) was evaluated. Resistance to tetracycline was associated with the presence of the tetM gene in plasmid DNA. The sequence of tetM showed 100% of similarity with the Enterococcus faecalis sequences found in the EMBL database, suggesting that Lm16 received this gene from E.

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Staphylococcus aureus is an important pathogen of foodborne origin. The pathogen produces a variety of toxins that include the staphylococcal enterotoxins (SE). The present study aimed to evaluate the prevalence and expression of 5 SE genes (sea, seb, sec, sed, and see) in S.

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Forty-five multi-resistant Salmonella enterica subsp. enterica serovar (S.) Typhimurium isolates obtained at five pig abattoirs in Southern Brazil were characterized.

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In the light of frequent discussions about the correct performance of in vitro susceptibility testing and the interpretation of the results obtained, the aim of the present report is to summarize basic facts that may facilitate the understanding of this complex topic. For this, the terms "antimicrobial resistance", "ESBL", and "MRSA" are defined. Besides the statements on antimicrobial resistance, information on intrinsic and acquired resistance properties as well as basic rules for the correct performance of antimicrobial susceptibility testing in routine diagnostics are presented.

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During the last decade, antimicrobial resistance in bacteria from food-producing animals has become a major research topic. In this review, different emerging resistance properties related to bacteria of food-producing animals are highlighted. These include: extended-spectrum β-lactamase-producing Enterobacteriaceae; carbapenemase-producing bacteria; bovine respiratory tract pathogens, such as Pasteurella multocida and Mannheimia haemolytica, which harbor the multiresistance mediating integrative and conjugative element ICEPmu1; Gram-positive and Gram-negative bacteria that carry the multiresistance gene cfr; and the occurrence of numerous novel antimicrobial resistance genes in livestock-associated methicillin-resistant Staphylococcus aureus.

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Salmonella enterica subsp. enterica plays a role as a foodborne pathogen worldwide. The consumption of contaminated pork has been associated with human salmonellosis and the increase in antimicrobial resistance among Salmonella from pigs and pork products is a concern.

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