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Master's Dissertation
DOI
https://doi.org/10.11606/D.42.2016.tde-16082016-141428
Document
Author
Full name
Kamila Oliveira Nunes
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2016
Supervisor
Committee
Elias Junior, Waldir Pereira (President)
Ferreira, Rita de Cassia Cafe
Takahara, Silvia Yumi Bando
Title in Portuguese
Relações filogenéticas entre Escherichia coli enteroagregativa e uropatogênica.
Keywords in Portuguese
Escherichia coli
Filogenia
Infecção bacteriana
Abstract in Portuguese
Escherichia coli isoladas de infecções do trato urinário (ITU) são conhecidas como E. coli uropatogênicas (UPEC). Dentre as E. coli diarreiogênicas, o patótipo denominado E. coli enteroagregativa (EAEC) é definido pela produção do padrão de adesão agregativa em células epiteliais cultivadas. Estudos recentes mostraram que algumas cepas de UPEC albergam propriedades de virulência de EAEC, indicando que cepas de EAEC podem causar ITU. Assim sendo, o objetivo deste estudo foi analisar as relações filogenéticas entre cepas de EAEC que apresentam marcadores genéticos de E. coli extraintestinais (ExPEC) e cepas de UPEC com e sem marcadores genéticos de EAEC. Para tal, foram selecionadas 92 EAEC, 8 UPEC com e 10 sem marcadores de EAEC. As 92 EAEC foram analisadas quanto à presença dos genes considerados como marcadores de cepas de ExPEC (papA/papC, sfa/foc, afa/dra, iutA, kpsMT II), detectando 30 (32,6%) cepas com esse perfil. Estas 30 cepas foram selecionadas para análises de filogrupos e multilocus sequence type (MLST) junto às cepas de UPEC. Foi observado que 17 (54,4%) cepas de EAEC e 3 (16,6%) de UPEC pertenceram ao filogrupo A, 2 (6,45%) EAEC e 1 (5,5%) UPEC ao filogrupo B1, 3 (9,68%) EAEC e 8 (44,4%) UPEC ao filogrupo B2, 6 (19,35%) EAEC e 2 (11,1%) UPEC ao filogrupo D, 1 (3,2%) EAEC e 4 (22,2%) UPEC ao filogrupo E, 1 (3,2%) EAEC ao filogrupo F e 1 EAEC (3,2%) não pôde ser classificada de acordo com esta metodologia. Comparando os dois grupos de UPEC notou-se que dentre as cepas com marcadores de EAEC 3 (37,5%) pertenceram ao filogrupo E, 2 (25%) aos filogrupos A e D e 1 (12,5%) ao filogrupo B1. Dentre as cepas sem marcadores de EAEC 1 (10%) pertenceu ao filogrupo A, 1 (10%) ao filogrupo E e 8 (80%) ao filogrupo B2. As análises de MLST através do sequenciamento dos genes recA, fumC, icd, mdh, purA, adk e gyrB permitiram determinar 42 sequence types (ST) distintos, dos quais 22 foram descritos neste estudo. Os mais comuns foram o ST 10 (5 cepas) e ST 95 e ST 746 (ambos com 2 cepas cada). A árvore filogenética gerada confirmou esses dados, mostrando o grupamento das cepas de EAEC com marcadores de ExPEC com as cepas de UPEC com marcadores de EAEC. Em resumo, o presente estudo mostrou que um subgrupo de cepas de EAEC está inserido nos mesmos grupos filogenéticos de cepas de UPEC com marcadores de EAEC apresentando, portanto, correlação filogenética. Houve diferenças de distribuição filogenética entre cepas de UPEC com e sem marcador de EAEC. Concui-se que cepas de EAEC podem apresentar potencial uropatogênico, tanto no curso de uma infecção diarreica, quanto em carreadores assintomáticos.
Title in English
Phylogenetic relationship among enteroaggregative and uropathogenic Escherichia coli strains.
Keywords in English
Escherichia coli
Bacterial infection
Phylogeny
Abstract in English
Escherichia coli isolated from urinary tract infections (UTI) are known as uropathogenic E. coli (UPEC). Among the diarrheagenic E. coli, the enteroaggregative E. coli (EAEC) pathotype is defined by the production of the aggregative adherence on cultured epithelial cells. Recent studies have shown that some UPEC strains harbor virulence properties of EAEC, indicating that EAEC strains can cause UTI. Therefore, the aim of this study was to analyze the phylogenetic relationships among EAEC strains that have genetic markers of extraintestinal E. coli (ExPEC) and UPEC strains, with and without genetic markers of EAEC. For that reason, we selected 92 EAEC, 8 UPEC with and 10 without EAEC markers. The 92 EAEC were analyzed for the presence of genes considered as markers for ExPEC strains (papA/papC, sfa/foc, afa/dra, iutA, kpsMT II), detecting 30 (32.6%) strains with that profile. These 30 strains were selected for phylogroup and multilocus sequence type (MLST) analysis with the UPEC strains. It was observed that 17 (54.4%) EAEC and 3 (16.6%) UPEC belonged to the phylogroup A, 2 (6.45%) EAEC and 1 (5.5%) UPEC to the phylogroup B1, 3 (9.68%) EAEC and 8 (44.4%) UPEC to the phylogroup B2, 6 (19.35%) EAEC and 2 (11.1%) UPEC to the phylogroup D, 1 (3.2%) EAEC and 4 (22.2%) UPEC to the phylogroup E, 1 (3.2%) EAEC to the phylogroup F and 1 (3.2%) EAEC could not be classified according to this methodology. Comparing the two groups of UPEC it was observed that among the UPEC strains with EAEC markers, 3 (37.5%) belonged to the phylogroup E, 2 (25%) to the phylogroups A and D and 1 (12.5%) to the phylogroup B1. Among the UPEC strains without EAEC markers, 1 (10%) belonged to the phylogroup A, 1 (10%) to the phylogroup E and 8 (80%) to the phylogroup B2. The MLST analysis by sequencing of recA, fumC, icd, mdh, purA, adk and gyrB genes allowed to determine 42 distinct sequence types (ST), of whom, 22 were described in this study. The most common were ST 10 (5 strains), and ST 95 and ST 746 (both with two strains each). The phylogenetic tree generated confirmed that data, showing the clustering of EAEC strains (harboring ExPEC markers) with the UPEC strains (harboring EAEC markers). In summary, the current study showed that a subgroup of EAEC strains are clustered in the same phylogenetic groups of UPEC strains with EAEC markers and, thus, present phylogenetic correlation. Also, there were differences in phylogenetic distribution among UPEC strains with and without EAEC markers. In conclusion, EAEC strains may have uropathogenic potential, either in the course of a diarrheal infection or in asymptomatic carriers.
 
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Publishing Date
2016-08-16
 
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