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Master's Dissertation
DOI
10.11606/D.60.2017.tde-03052017-150659
Document
Author
Full name
Amanda Aparecida Seribelli
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Ribeirão Preto, 2016
Supervisor
Committee
Falcão, Juliana Pfrimer (President)
Elias Junior, Waldir Pereira
Nogueira, Mara Correa Lelles
Stehling, Eliana Guedes
Title in Portuguese
Análise do potencial patogênico, diversidade genotípica e perfil de resistência de linhagens de Shigella sonnei isoladas de 1983 a 2014 no Estado de São Paulo
Keywords in Portuguese
ERIC-PCR
Genes de virulência
MLST
MLVA
Perfil de resistência a antimicrobianos
PFGE
Shigella sonnei
Abstract in Portuguese
Shigella spp. está entre as quatro bactérias mais isoladas de fezes diarreicas no Brasil. No mundo cerca de 164,7 milhões de casos de shigelose ocorrem anualmente, sendo a maioria em países em desenvolvimento. O gênero Shigella spp. possui quatro espécies, sendo Shigella sonnei e Shigella flexneri as espécies mais frequentemente isoladas no Brasil e no mundo. O monitoramento de linhagens resistentes de Shigella spp. é essencial, pois este garante uma terapia eficiente quando necessária. Especificamente, a maioria dos estudos realizados com linhagens de S. sonnei no país verificaram apenas a ocorrência dessa e há poucos estudos que investigaram o potencial patogênico e a diversidade genotípica dessa espécie. Os objetivos desse projeto foram analisar o potencial patogênico, o perfil de resistência a antimicrobianos e a diversidade genotípica de linhagens de S. sonnei isoladas durante três décadas no Estado de São Paulo. No total foram caracterizadas 72 linhagens de S. sonnei isoladas de humanos, entre os anos de 1983 a 2014, quanto à presença de 12 genes de virulência por PCR, perfil de suscetibilidade frente a 16 antimicrobianos por disco difusão e tipagem molecular por Pulsed-field gel electrophoresis (PFGE), Enterobacterial repetitve intergenic consensus PCR (ERIC-PCR), Multiple-locus variable-number tandem-repeat analysis (MLVA) e 20 linhagens tipadas por Multi-locus sequence typing (MLST). Todas as linhagens apresentaram os genes de virulência ipaH, iuc e sigA. O gene ipaBCD foi encontrado em 14 (19%) linhagens, os genes ial e virF em 13 (18%) linhagens e o gene sen em sete (10%) linhagens. Os genes set1A, set1B, pic, sat e sepA não foram detectados. As mais altas taxas de resistência foram frente à sulfametoxazol-trimetoprim encontrada em 42 (58,3%) linhagens e frente à tetraciclina encontrada em 30 (41,6%) linhagens. Onze (15,5%) linhagens foram resistentes à ampicilina e piperacilina. Três (4,2%) linhagens foram resistentes à cefotaxima. Três (4,2%) linhagens foram resistentes ao cloranfenicol. Duas (2,8%) linhagens foram resistentes à ampicilina-sulbactam. Duas (2,8%) linhagens foram resistentes ao ácido nalidíxico. Uma (1,4%) linhagem foi resistente à amoxicilina-ácido clavulânico. Cinco (7%) linhagens foram multidroga resistentes (MDR). O dendrograma gerado pelo PFGE agrupou as 72 linhagens de S. sonnei em dois clusters designados PFGE-A e PFGE-B. O cluster PFGE-A agrupou 39 linhagens isoladas entre 1983-2014 com uma similaridade >=73,6% e mais especificamente 35 dessas linhagens apresentaram uma similaridade >=80,3%. O cluster PFGE-B agrupou 33 linhagens de S. sonnei isoladas entre 1984-2014 com uma similaridade >=74,7% e 27 dessas linhagens exibiram uma similaridade >=83,0%. Similarmente, o dendrograma gerado pelo ERIC-PCR agrupou as 72 linhagens de S. sonnei em dois clusters designados ERIC-A e ERIC-B. O cluster ERIC-A agrupou 37 linhagens isoladas entre 1983-2014 que exibiram uma similaridade >=78,8% e mais especificamente 36 dessas linhagens apresentaram uma similaridade >=82,3%. O cluster ERIC-B agrupou 34 linhagens de S. sonnei isoladas entre 1987-2014 que exibiram uma similaridade >=84,0%. Também por MLVA as linhagens foram agrupadas em dois clusters designados MLVA-A e MLVA-B. O cluster MLVA-A agrupou 31 linhagens isoladas entre 1983-2014 com uma similaridade >=40%. O cluster MLVA-B agrupou 41 linhagens isoladas entre 1983-2014 com uma similaridade >=21,6%. Todas as 20 S. sonnei foram tipadas por MLST como ST152. Conclui-se que o potencial patogênico das linhagens estudadas foi destacado pela presença de importantes genes de virulência. A alta porcentagem de resistência para alguns antimicrobianos testados, tais como, sulfametoxazol-trimetoprim e tetraciclina é preocupante e pode levar à falha terapêutica. Os resultados da tipagem molecular sugerem que existam dois subtipos prevalentes nas linhagens de S. sonnei estudadas que se diferenciaram pouco geneticamente e contaminaram humanos durante 31 anos na região metropolitana de Ribeirão Preto no Estado de São Paulo. O resultado do MLST indica que as linhagens estudadas de Shigella sonnei isoladas no Brasil descendem de um precursor comum
Title in English
Analysis of the potential pathogenic, genotypic diversity and resistance profile of Shigella sonnei strains isolated from 1983 to 2014 in the State of São Paulo
Keywords in English
Antimicrobials resistance profile
ERIC-PCR
MLST
MLVA
PFGE
Shigella sonnei
Virulence genes
Abstract in English
Shigella spp. is among the four most isolated bacteria from diarrheal faeces in Brazil. In the world about 164.7 million cases of shigellosis occur annually, mostly in developing countries. The genus Shigella spp. comprises four species, being Shigella sonnei and Shigella flexneri the most frequently isolated species in Brazil and worldwide. The monitoring of resistant strains of Shigella spp. is essential and ensures an effective therapy when necessary. Specifically, the majority of the studies with S. sonnei performed in the country verified only the occurrence of this bacterium and there are few studies that investigated the pathogenic potential and genotypic diversity of this species. The aims of this project were to analyze the pathogenic potential, antimicrobial resistance profile and genotypic diversity of S. sonnei strains isolated during three decades in the State of São Paulo. In total, 72 of S. sonnei strains isolated from humans, between the years 1983-2014, were characterized for the presence of 12 virulence genes by PCR, resistance profile against 16 antimicrobials by disk diffusion and molecular typing by Pulsed-field gel electrophoresis (PFGE), Enterobacterial repetitve intergenic consensus PCR (ERIC-PCR), Multiple-locus variable-number tandem-repeat analysis (MLVA) and 20 strains typed by Multi-locus sequence typing (MLST). All the strains contained the ipaH, iuc and sigA genes. The ipaBCD gene was detected in 14 (19%) strains, the ial and virF genes in 13 (18%) strains and the sen gene in seven (10%) strains. The set1A, set1B, pic, sepA and sat genes were not detected. The highest resistance rates were against trimethoprim-sulfamethoxazole found in 42 (58.3%) strains and against tetracycline found in 30 (41.6%) strains. Eleven (15.5%) strains were resistant to ampicillin and piperacillin. Three (4.2%) strains were resistant to cefotaxime. Three (4.2%) strains were resistant to chloramphenicol. Two (2.8%) strains were resistant to ampicillin-sulbactam. Two (2.8%) strains were resistant to nalidixic acid. One (1.4%) strain was resistant to amoxicillin-clavulanic acid. Five (7%) strains were multidrug resistant (MDR). The dendrogram generated by PFGE grouped the 72 S. sonnei strains into two clusters designated PFGE-A and PFGE-B. The PFGE-A cluster comprised, 39 S. sonnei strains isolated between 1983 and 2014 with a similarity above 73.6% and more specifically 35 of those strains exhibited a similarity >= 80.3%. The PFGE-B cluster grouped, 33 S. sonnei strains isolated between 1984 and 2014 with a similarity above 74.7%, and 27 of those strains exhibited a similarity above 83.0.Similarly, the dendrogram generated by ERIC-PCR grouped the 72 S. sonnei strains into two clusters designated ERIC-A and ERIC-B. The ERIC-A cluster comprised, 37 S. sonnei strains isolated between 1983 and 2014 that exhibited a similarity above 78.8% and specifically 36 strains of those exhibited a similarity >= 82.3%. The ERIC-B cluster grouped, 34 S. sonnei strains isolated between 1987 and 2014 that exhibited a similarity above 84.0%. Also, by MLVA strains were grouped into two clusters designated MLVA-A and MLVA-B. The MLVA-A cluster comprised 31 strains isolated between 1983 and 2014 with a similarity >=40%. The MLVA-B cluster comprised 41 strains isolated between 1983 and 2014 with a similarity >=21.6%. All the 20 S. sonnei were typed by MLST as ST152. In conclusion, the possible pathogenic potential of the strains studied was highlighted by the presence of important virulence genes. The high percentage of resistance to some of the antimicrobials tested such as trimethoprim-sulfamethoxazole and tetracycline is worrying and may lead to therapeutic failure. Molecular typing results may suggest that there are two prevalent subtypes of S. sonnei strains studied that differed little genetically and have been contaminating humans over 31 years in the metropolitan region of Ribeirão Preto in the São Paulo State in Brazil. The result of MLST indicates that the Shigella sonnei strains studied isolated in Brazil descended from a common precursor
 
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Release Date
2019-05-03
Publishing Date
2017-07-21
 
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