Author(s):
Ferreira Cavalcanti, Adriene Maria ; Hernandes, Rodrigo Tavanelli [UNESP] ; Takagi, Elizabeth Harummyy ; Cabilio Guth, Beatriz Ernestina ; Ori, Erica de Lima ; Schicariol Pinheiro, Sandra Regina ; Andrade, Tania Sueli de ; Oliveira, Samara Louzada [UNESP] ; Cergole-Novella, Maria Cecilia ; Francisco, Gabriela Rodrigues ; Santos, Luis Fernando dos
Date: 2020
Persistent ID: http://hdl.handle.net/11449/196681
Origin: Oasisbr
Subject(s): STEC; serotypes; virulence markers; molecular typing; MLST
Description
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Since no recent data characterizing Shiga toxin-producing E. coli (STEC) from human infections in Brazil are available, the present study aimed to investigate serotypes, stx genotypes, and accessory virulence genes, and also to perform pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) of 43 STEC strains recovered from 2007 to 2017. Twenty-one distinct serotypes were found, with serotype O111:H8 being the most common. However, serotypes less frequently reported in human diseases were also found and included a hybrid STEC/ETEC O100:H25 clone. The majority of the strains carried stxla as the sole stx genotype and were positive for the eae gene. Regarding the occurrence of 28 additional virulence genes associated with plasmids and pathogenicity islands, a diversity of profiles was found especially among the eae-harboring strains, which had combinations of markers composed of up to 12 distinct genes. Although PFGE analysis demonstrated genetic diversity between serotypes such as O157:H7, O111:H8, O26:H11, O118:H16, and O123:H2, high genetic relatedness was found for strains of serotypes O24:H4 and O145:H34. MLST allowed the identification of 17 distinct sequence types (STs) with ST 16 and 21 being the most common ones. Thirty-five percent of the strains studied were not typeable by the currently used MLST approach, suggesting new STs. Although STEC 0111:H8 remains the leading serotype in Brazil, a diversity of other serotypes, some carrying virulence genes and belonging to STs incriminated as causing severe disease, were found in this study. Further studies are needed to determine whether they have any epidemiological relevance.
Adolfo Lutz Inst, Ctr Bacteriol, Natl Reference Lab STEC Infect & HUS, BR-01246000 Sao Paulo, SP, Brazil
Univ Estadual Paulista, Dept Microbiol & Imunol, Inst Biociencias, BR-18618970 Botucatu, SP, Brazil
Univ Fed Sao Paulo, Dept Microbiol, Imunol, Parasitol,Escola Paulista Med, BR-04023062 Sao Paulo, SP, Brazil
Univ Estadual Paulista, Dept Microbiol & Imunol, Inst Biociencias, BR-18618970 Botucatu, SP, Brazil
FAPESP: 2017/00411-1
FAPESP: 2014/20354-4
