Application of molecular techniques to monitor the genetic diversity of Staphylococcus aureus in dairy production environments

Autor: Soares, Bianca da Silva
Přispěvatelé: Souza, Miliane Moreira Soares de, Coelho, Shana de Matos de Oliveira, Coelho, Irene da Silva, Rossi, Ciro C?sar, Giambiagi, M?rcia, Penna, Bruno de Ara?jo
Jazyk: portugalština
Rok vydání: 2017
Předmět:
Zdroj: Biblioteca Digital de Teses e Dissertações da UFRRJ
Universidade Federal Rural do Rio de Janeiro (UFRRJ)
instacron:UFRRJ
Popis: Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2019-02-26T16:16:57Z No. of bitstreams: 1 2017 - Bianca da Silva Soares.pdf: 1297969 bytes, checksum: e2e00aad3edae556b42af19d7e0c2f97 (MD5) Made available in DSpace on 2019-02-26T16:16:57Z (GMT). No. of bitstreams: 1 2017 - Bianca da Silva Soares.pdf: 1297969 bytes, checksum: e2e00aad3edae556b42af19d7e0c2f97 (MD5) Previous issue date: 2017-02-17 Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES Brazilian dairy production is constantly growing and is predominantly supplied through family production. Bovine mastitis is common in dairy herds, causing high economic losses for the dairy industry. Mastitis is caused by inflammation of the mammary tissue by physical, chemical or pathogens. Mastitis is caused by inflammation of the mammary tissue by physical, chemical or pathogens. Staphylococcus aureus acts as an important pathogen causing subclinical bovine mastitis. Success of this pathogen persistence in the host occurs due to a series of factors of colonization and virulence that this bacterium has.This bacterial species carries genetic heterogeneity and a population characterized by genetically diverse strains. The analysis of the genetic variation appear as an important tool for epidemiological studies. For the realization of this thesis, were selected 53 S. aureus strains originated from cows with subclinical mastitis six farms in different cities of the State of Rio de Janeiro. The 53 strains of S. aureus were submitted to detection of the virulence profiles, agr and spa gene typing. From the 53 strains of S. aureus, 17 strains were selected through the virulence profiles (previously established) to be submitted to Pulsed Field Gel Electrophoresis (PFGE), Multilocus Sequence Typing (MLST), phenotypic production of Biofilm, antimicrobial susceptibility, and genotypic detection of methicillin resistance.It was possible to detected 58.5% (31/53) positive isolates for icaA gene; 83% (44/53) for icaD gene; 66% (35/53) for fbnA gene; 26.4% (14/53) positive for fbnB gene; 3.7% (2/53) for cap8 gene; 92.4% (49/53) for the hlA gene and 84.9% (45/53) for hlB gene. No isolate showed positive for the gene cap5. These results enabled to establish 18 different profiles. Phenotypic analysis of biofilm production, demonstrated a prevalence of strains with a low phenotypic expression. Most isolates (67.9% - 36/53) classified as Group II of agr system. Typing of spa gene showed 12 different types in 53 isolates tested, been prevalent the spa type 605 (54.7% - 29/53). These isolates underwent PFGE with analysis of the profiles generated was observed extensive genetic heterogeneity of the selected isolates and no clones. The typing technique MLST generated five different types of ST/CC, been ST/CC 126 the most prevalent (64.7% - 11/17). The strains tested were resistant to ciprofloxacin, erythromycin and penicillin. It was not possible to detect the presence of any MRSA strain in this study A produ??o leiteira bovina no Brasil est? em constante crescimento sendo predominante abastecida atrav?s da produ??o familiar. A mastite bovina ? frequente nos rebanhos leiteiros ocasionando grandes perdas econ?micas para a ind?stria leiteira. A mastite ? ocasionada pela inflama??o do tecido mam?rio por agentes f?sicos, qu?micos ou por patog?nos. Staphylococcus aureus ? um importante pat?geno causador de mastite bovina subcl?nica cronica. O sucesso da persist?ncia deste patog?no no hospedeiro ocorre devido a uma s?rie de fatores de coloniza??o e virul?ncia que esta bact?ria possui. Est? esp?cie bacteriana possui heterogeneidade gen?tica e uma popula??o caracterizada por cepas geneticamente diversificadas. A an?lise da varia??o gen?tica ? uma importante ferramenta para fins de estudos epidemiol?gicos. Para a realiza??o da presente tese, foram estudadas 53 cepas de S.aureus oriundos do leite de vacas com mastite subcl?nica de seis fazendas em diferentes munic?pios do Estado do Rio de Janeiro. As 53 cepas de S. aureus foram submetidos a detec??o dos perfis de virul?ncia, tipagem do gene agr e do spa. Das 53 cepas de S. aureus, 17 cepas foram selecionadas atrav?s dos perfis de virul?ncia (previamente estabelecidos) para serem submetidas ?s t?cnicas de Eletroforese em Gel de Campo Pulsado (PFGE), Tipagem da Sequ?ncia Multilocus (MLST), avalia??o fenot?pica da produ??o de biofilme, suscetibilidade a antimicrobianos e a detec??o genot?pica de resist?ncia a meticilina. Foi poss?vel detectar 58,5% (31/53) de isolados positivos para o gene icaA; 83% (44/53) para o gene icaD; 66% (35/53) para o gene fbnA; 26,4% (14/53) positivos para o gene fbnB; 3,7% (2/53) para o gene cap8; 92,4% (49/53) para o gene hlA e 84,9% (45/53) para o gene hlB. Nenhum isolado foi positivo para o gene cap5. A partir destes resultados foi poss?vel estabelecer 18 diferentes perfis. Atrav?s da t?cnica de PFGE foi poss?vel observar grande heterogeneidade gen?tica e aus?ncia de cepas clonais.A an?lise fenot?pica da produ??o de biofilme, demostrou a preval?ncia de cepas com baixa express?o fenot?pica. A maioria dos isolados (67,9%- 36/53) foi classificada como grupo II do sistema agr. A tipagem do gene spa evidenciou 12 diferentes tipos nos 53 isolados testados, sendo prevalente o spa tipo 605 (54,7%- 29/53). A t?cnica de tipagem MLST gerou cinco tipos diferentes de ST/CC, sendo prevalente o ST/CC 126 (64,7%-11/17). As cepas testadas foram resistentes aos antibi?ticos ciprofloxacina, eritromicina e penicilina. N?o foi poss?vel detectar a presen?a de nenhuma cepa MRSA no presente estudo.
Databáze: OpenAIRE
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