Pesquisa de integron classe 1 e cassete gênico em Escherichia coli recuperadas de indivíduos sadios e infectados e em DNA de sedimento contaminado por arsênio

• Ano de defesa: 2013
• Autor(a) principal: Clarisse Oliveira Pinto
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Genética
• Link de acesso: http://hdl.handle.net/1843/BUOS-96LHTS

Integrons are genetic elements that incorporate gene cassettes, conver ting them into functional genes. These elements have been highlighted as an important reservoir of antimicrobial resistance genes. However, the high diversity of these genes suggests that the integron cassette system also plays an important role in the adaptation of the bacteria. This study investigated the frequency of class 1 integron and diversity of gene cassettes into two distinct populations of Escherichia coli from healthy children of the Amazon and women with UTI - women with urinary tract infection and stream sediment samples from the stream Mina, contaminated by arsenic collected during dry and rainy seasons. Most women with UTI E. coli isolates harbored intI 1 genes (67%) and gene cassettes (38%) unlike isolates from healthy children (12% and 12%, respectively). Most gene cassettes found in E. coli isolates are determinants of resistance to aminoglycosides (aadA5, aadA22 and aadA1) and to a lesser frequency, determinants of trimethoprim resistance (dfr1, dfr17 and dfrA17). The most representative E. coli phylogenetic group among clinical isolates was group B2, while group A was more represented among the healthy children isolates. The minimum inhibitory concentration assay revealed that frequency of resistance was higher among women with UTI isolates than healthy children isolates. Moreover, multidrug resistance occurred in all women with UTI isolates but in 52,4% the healthy children isolates. The investigation of the sediment samples from the Mina stream revealed a diversity of ORFs of gene cassettes that were not related to antimicrobial resistance and that, in its majority, did not have homology to database sequences. This suggests that bacterial communities in natural environments show a range of ORFs not yet characterized. Quantitative PCR indicated that the frequency of bacteria harboring the intI1 gene was almost five times greater in the dry season samples than those collected in the rainy season. Therefore, data from this study suggest that integrons are widespread in both clinical and natural environments.