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Made available in DSpace on 2020-12-12T01:24:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-10-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa e Inovação do Estado de Santa Catarina Brazil is the number one exporter of chicken meat, and this industry maintains constant microbiological vigilance. The objective of this study was to characterize the pathogenicity, antimicrobial resistance (AMR) and the profile of biofilm production of Escherchia coli strains isolated from raw refrigerated cuts of chicken meat sold in retail markets of the four largest poultry companies in Brazil. We collected 150 samples of chicken meat, in order to isolate E. coli and performed susceptibility tests (to amoxicillin associated with clavulanic acid, ceftiofur, enrofloxacin, gentamicin, and trimethoprim + sulfamethoxazole). In addition, the disc approximation test to detect extended spectrum beta-lactamases enzymes (ESBLs) producers was performed. E. coli ability to form biofilm was checked using polystyrene microplates. We also searched for ESBLs genes (blaCTY-M2, blaSHV-1, blaTEM-1, blaCTX-M2, blaOXA-1, blaPSE-1 and AmpC) and adhesion genes (sfa/foc, afa/draB, iha, hrla, fimC, tsh, papC, mat, cr1, felA, fimH and papG) in ESBL-E. coli producers and in those E. coli classified as strongly biofilm formers, respectively. The overall percentage of E. coli isolation was 58.66%, with brand A having the highest percentage (70%), followed by brands D, B and C (60, 53.3 and 50%, respectively). The highest resistance profile was observed for beta-lactams (39.5%), followed by sulfonamide associated to trimethoprim (36.9%) and polymyxin (33.4%). Of the isolates obtained, 77% were non-susceptible to at least one antimicrobial. Brand A showed the highest overall percentage of resistance with 95.23%, followed by brands C (80%), B (75%) and D (69.44%). Overall, 73.86% of the isolates were non susceptible to at least one antibiotic and 36.3% were multiresistants. A total of 17.04% of E. coli strains were identified as ESBLs producers and 70.44% were able to form biofilms (moderate-to-strong). The blaTEM-1 gene was the most prevalent (73.33%), followed by blaSHV-1 (46.66%) and blaCMY-2 (6%). Of the 31 strongly biofilm-forming strains, 26 (83.87%), 24 (77.41%) and 20 (64.51%) expressed fimC, papG and crl genes, respectively. Taken together, our results show that Brazilian chicken meat can be contaminated with E. coli that are non-susceptible to multiple antibiotics, able to form biofilm and showing a diverse repertoire of adhesins linked to pathogenicity depending on the brand evaluated. Graduate Program in Animal Science Universidade do Estado de Santa Catarina (UDESC-Oeste) Universidade Federal do Rio Grande do Sul (UFRGS) Laboratory of Applied Statistics Department of Mathematics São Paulo State University (Unesp) School of Engineering Laboratory of Applied Statistics Department of Mathematics São Paulo State University (Unesp) School of Engineering

This study aimed to assess the antimicrobial activity of various honeys against strains of gram-negative and -positive bacteria, as well as to determine the physicochemical parameters of these honeys. Seven honeys from various species of stingless bees were evaluated. The physical-chemical parameters evaluated were pH, moisture, water activity, acidity, ash, electrical conductivity and color. Antimicrobial activity was determined using disc diffusion agar tests and minimum inhibitory concentrations. We found that there was a relationship between the physical-chemical parameters and the antimicrobial activity. The minimum inhibitory concentration of 25% honey was able to inhibit the growth of both gram-positive and -negative bacteria; the greatest efficacy was verified for the species of bees Melipona mondury, M. quadrifasciata, Scaptotrigona bipunctata and Tetragona clavipes. Regarding synergism, Escherichia coli maintained its sensitivity profile in relation to all studied honeys combined with antimicrobials. An important factor to consider is the concentration of honey capable of sensitizing the microorganism, as it has been shown to be dependent on the species of the stingless bee. Nevertheless, all honeys showed antimicrobial activity in various methods of analysis. These data suggest that honey is a promising alternative to sensitize resistant microorganisms, for the health of humans and animals alike. Este estudio tuvo como objetivo evaluar la actividad antimicrobiana de diversas mieles frente a cepas de bacterias gram negativas y positivas, así como determinar los parámetros físico-químicos de estas mieles. Se evaluaron siete mieles de varias especies de abejas sin aguijón. Los parámetros físico-químicos evaluados fueron pH, humedad, actividad del agua, acidez, ceniza, conductividad eléctrica y color. La actividad antimicrobiana se determinó mediante pruebas de agar de difusión en disco y concentraciones inhibitorias mínimas. Encontramos que existe una relación entre los parámetros físico-químicos y la actividad antimicrobiana. La concentración mínima inhibitoria del 25% de miel fue capaz de inhibir el crecimiento de bacterias tanto grampositivas como negativas; la mayor eficacia se verificó para las especies de abejas Melipona mondury, M. quadrifasciata, Scaptotrigona bipunctata y Tetragona clavipes. En cuanto al sinergismo, Escherichia coli mantuvo su perfil de sensibilidad en relación a todas las mieles estudiadas combinadas con antimicrobianos. Un factor importante a considerar es la concentración de miel capaz de sensibilizar al microorganismo, ya que se ha demostrado que depende de la especie de abeja sin aguijón. Sin embargo, todas las mieles mostraron actividad antimicrobiana en varios métodos de análisis. Estos datos sugieren que la miel es una alternativa prometedora para sensibilizar a los microorganismos resistentes, tanto para la salud de los seres humanos como de los animales. Este estudo teve como objetivo avaliar a atividade antimicrobiana de mel de abelhas frente a cepas de bactérias gram-negativas e positivas, bem como determinar os parâmetros físico-químicos desse mel. Foram avaliadas sete amostras mel de espécies de abelhas sem ferrão. Os parâmetros físico-químicos avaliados foram pH, umidade, atividade de água, acidez, cinzas, condutividade elétrica e cor. A atividade antimicrobiana foi determinada por meio de testes de ágar de difusão em disco e concentrações inibitórias mínimas. Verificamos que existe uma relação entre os parâmetros físico-químicos e a atividade antimicrobiana. A concentração inibitória mínima de 25% de mel foi capaz de inibir o crescimento de bactérias gram-positivas e-negativas; a maior eficácia foi verificada para as espécies de abelhas Melipona mondury, M. quadrifasciata, Scaptotrigona bipunctata e Tetragona clavipes. Em relação ao sinergismo, Escherichia coli manteve seu perfil de sensibilidade em relação a todos os méis estudados associados a antimicrobianos. Um fator importante a se considerar é a concentração de mel capaz de sensibilizar o microrganismo, pois tem se mostrado dependente da espécie de abelha sem ferrão. No entanto, todas as amostras de mel apresentaram atividade antimicrobiana em diferentes métodos de análise. Esses dados sugerem que o mel é uma alternativa promissora para sensibilizar microrganismos resistentes, para a saúde de humanos e animais.