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Previous issue date: 2013-04-30 / Salmonella Enteritidis is the most prevalent serotype isolated in Brazil, mainly associated with poultry products, which have been primarily involved in foodborne disease outbreaks. The high prevalence of reduced susceptibility to antimicrobial agents in various Salmonella serotypes isolated from samples related to livestock animal, animal foods and human has been reported worldwide. Therefore, has increased the interest in investigating the genetic mechanisms involved in resistance to antimicrobial agents, especially genetic elements capable of carrying resistance genes cassettes, which could be the origin of multi-resistant strains. Besides the genetically determined antimicrobial resistance, bacteria can also exhibit resistance by the ability to form biofilm, which protects bacteria from environmental stresses, favoring the colonization and persistence of these microorganisms in the environment. Thus, the aim of this study was to determine the antimicrobial susceptibility of S. Enteritidis strains and investigate the genes involved in the main resistance determined, as well as evaluate the ability of these strains in to produce biofilm. Forty-seven S. Enteritidis strains isolated from human, poultry, swine, and food were analyzed. Sixteen isolates (34%) were phenotypically resistant to at least one antibiotic tested. Of these, four isolates harbored class 1 integron. All strains resistant to sulfonamide had concomitantly genes sul1 and sul2. The genes strA, strB, aadA and aadB were identified in the majority of the aminoglycosides resistant isolates, whereas 92.9% showed strA, 71.4% strB, 7.1% aadA and 50% aadB. The tetB gene was detected in two of the three strains resistant to tetracycline, and tetC in one. In the three strains resistant to ampicillin the blaTEM gene was detected. Overall, among the 47 S. Enteritidis tested, 89.4% strains were able to form biofilm on polystyrene plates. Among these, 42.4% were considered weak biofilm producers, 14.9% moderate producers and 34% strong producers. It has been demonstrated that the majority of the S. Enteritidis strains that showed resistance to at least one antimicrobial agent were able to form biofilm, which increases concerns about food contamination, especially by the possibility of persistence of bacteria resistant to antibiotics on the environment and the subsequently dissemination of these strains to human. / A Salmonella Enteritidis tem sido o sorotipo mais prevalente no Brasil, principalmente associado a produtos de origem av?cola, que t?m sido prioritariamente envolvidos em surtos de doen?as transmitidas por alimentos. A alta preval?ncia de suscetibilidade reduzida a antimicrobianos em diversos sorotipos de Salmonella isolados de amostras relacionadas a animais de produ??o, a humanos e a alimentos de origem animal vem sendo relatada no mundo inteiro. Com isto, tem aumentado o interesse em investigar os mecanismos gen?ticos envolvidos na resist?ncia a antimicrobianos, especialmente elementos gen?ticos capazes de carrear cassetes de genes de resist?ncia, o que pode constituir a origem de cepas multi-resistentes. Al?m da resist?ncia a antimicrobianos determinada geneticamente, as bact?rias tamb?m podem apresentar resist?ncia pela habilidade de formar biofilme, protegendo-as de estresses ambientais, favorecendo a coloniza??o e persist?ncia desses microrganismos no ambiente. Deste modo, o objetivo deste estudo foi determinar a suscetibilidade a antimicrobianos de cepas de S. Enteritidis e investigar os genes envolvidos nas principais resist?ncias determinadas, bem como avaliar a capacidade de forma??o de biofilme destas cepas. Para tanto, foram analisadas 47 cepas de S. Enteritidis isoladas de humanos, aves, su?nos e alimentos. Dezesseis isolados (34%) se mostraram fenotipicamente resistentes a pelo menos um antimicrobiano testado. Destes, quatro apresentaram integron de classe 1. Todas as cepas resistentes ? sulfonamida apresentaram concomitantemente os genes sul1 e sul2. Os genes strA, strB, aadA e aadB foram identificados na maioria dos isolados que apresentaram resist?ncia a aminoglicos?deos, sendo que 92,9% apresentaram o gene strA, 71,4% strB, 7,1% aadA e 50% aadB. O gene tetB foi detectado em duas das tr?s cepas resistentes ? tetraciclina e o tetC em uma. J? as tr?s cepas resistentes ? ampicilina apresentaram o gene blaTEM. No total, dentre as 47 cepas de S. Enteritidis testadas, 89,4% foram capazes de formar biofilme em placas de poliestireno. Dentre estas, 42,4% foram consideradas fracas produtoras de biofilme, 14,9% produtoras moderadas e 34% fortes produtoras. Foi demonstrado que a maioria das cepas que mostraram resist?ncia a pelo menos um antimicrobiano foram capazes de formar biofilme, o que aumenta a preocupa??o a respeito da contamina??o de alimentos, especialmente pela possibilidade de persist?ncia de microrganismos resistentes a antimicrobianos no ambiente e a subsequente dissemina??o destas cepas para humanos.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/5468 |
| Date | 30 April 2013 |
| Creators | Puffal, J?lia |
| Contributors | Oliveira, Silvia Dias de |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Biologia Celular e Molecular, PUCRS, BR, Faculdade de Bioci?ncias |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 8198246930096637360, 600, 600, 36528317262667714 |
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