Título:	Caracterização biológica de isolados clínicos de Klebsiella spp do Hospital Universitário de Brasília (HUB/UnB) durante o período de junho de 2014 a dezembro de 2016
Autor(es):	Cardoso, Ana Paula
Orientador(es):	Campos, Tatiana Amabilis de
Assunto:	Epidemiologia Patogenicidade Hipervirulência Klebsiella pneumoniae
Data de publicação:	16-Dez-2019
Data de defesa:	18-Fev-2019
Referência:	CARDOSO, Ana Paula. Caracterização biológica de isolados clínicos de Klebsiella spp do Hospital Universitário de Brasília (HUB/UnB) durante o período de junho de 2014 a dezembro de 2016. 2019. 92 f., il. Dissertação (Mestrado em Biologia Microbiana)—Universidade de Brasília, Brasília, 2019.
Abstract:	Klebsiella spp is one of the genera of the Enterobactereaceae family most associated with community-acquired nosocomial infections, Klebsiella pneumoniae and Klebsiella variicola being the most commonly associated with infections of the urinary tract (UTI's), pulmonary, blood and septicemia. In addition to the pathogenicity inherent in both microorganisms, and primarily to infect immunocompromised patients, the emergence of resistant (R) and multiresistant (MDR) lineages with hypermucosal phenotype (hmKP) and hypervirulent strains capable of infecting healthy patients and spreading metastatically, being to date identified in species of K. pneumoniae; have hindered the therapeutic treatment of patients. In addition, clinical isolates of K. variicola were mistakenly identified as K. pneumoniae due to genetic and phenotypic similarity between them, further hindering intervention and therapeutic success in patients affected by this strain. Thus, the correct identification of these strains, the biological characterization of their virulence mechanisms and factors, and the epidemiological characterization make it possible to differentiate and understand them, and these peculiarities may be associated with the severity of the pathologies caused by them. Therefore, the objective of this work is to perform the biological characterization of Klebsiella spp isolated by the Hospital Universitário de Brasília (HUB) during the period from September 2013 to January 2017. Our results show that both isolates K. pneumoniae and K. variicola present virulence mechanisms that demonstrate the pathogenicity of the isolates, such as survival and growth in blood and human serum after 30 minutes of infection; the production of a strong or moderate biofilm on the abiotic surface, giving the isolates a greater resistance to the action of antimicrobials besides presenting profiles of resistance or multiresistance being the majority of the isolates originated outside the hospital indicating that the isolates came from the community, and use their hosts as reservoirs. In addition, the isolates presented genotypic characteristics that characterize them as hmKP strains, since the capsule expression in these strains is greater, due to the presence of the regulator gene rmpA already described in the literature, but in some of our isolates of K. pneumoniae although presented the phenotype, the presence of the rmpA gene was not detected in them, suggesting the presence of another gene (s) responsible for the phenotype. We obtained in our collection of K. pneumoniae isolated with K1 capsular type, highly associated with hypervirulent strains capable of infect healthy patients. We also observed that the mechanisms and factors of K. pneumoniae studied in this study were not associated with a single clone, suggesting that K. pneumoniae strains with a high pathogenic potential are widely disseminated in the hospital environment and in the Brasília-DF community. Furthermore, K. variicola strains have the ability to infect and survive in HEp-2 epithelial cells, although they are not cytotoxic to them, and may be another mechanism used by the pathogen to successfully evade the immune system of the host. Finally, our results show a worrying scenario, since isolates of K. pneumoniae and K. variicola present virulence mechanisms that make them more pathogenic, in addition to K. variicola strains have been erroneously identified, impairing the correct and effective treatment, these strains have been increasingly associated with nosocomial infections and have a higher virulence than those isolated from K. pneumoniae.
Unidade Acadêmica:	Instituto de Ciências Biológicas (IB) Departamento de Biologia Celular (IB CEL)
Informações adicionais:	Dissertação (mestrado)—Universidade de Brasília, Instituto de Biologia, Pós-Graduação em Biologia Microbiana, 2019.
Programa de pós-graduação:	Programa de Pós-Graduação em Biologia Microbiana
Licença:	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.bce.unb.br, www.ibict.br, http://hercules.vtls.com/cgi-bin/ndltd/chameleon?lng=pt&skin=ndltd sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra disponibilizada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
Agência financiadora:	Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Fundação de Apoio à Pesquisa do Distrito Federal (FAP/DF) e Fundação de Apoio ao Desenvolvimento Científico e Tecnológico do Hospital da Universidade de Brasília (FAHUB).
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