Shigella spp. are a major cause of bacillary dysentery, particularly among children in developing countries such as Iran. This study aimed to investigate the presence of two important Shigella ente...

/pdf/prevalence-of-enterotoxin-encoding-genes-among-diverse-56olu9ckm1.pdf

Prevalence of enterotoxin-encoding genes among diverse Shigella strains isolated from patients with diarrhea, southwest Iran

Shigella specie is a globally important intestinal pathogen disseminated all over the world. In this study we analyzed the genome and the proteomic component of two Shigella flexneri 2a clinical isolates, collected from pediatric patients with gastroenteritis of the Northwest region of Argentina (NWA) in two periods of time, with four years of difference. Our goal was to determine putative changes at molecular levels occurred during these four years, that could explain the presence of this Shigella`s serovar as the prevalent pathogen in the population under study.As previously reported, our findings support the idea of Shigella has a conserved "core" genome, since comparative studies of CI133 and CI172 genomes performed against 80 genomes obtained from the NCBI database, showed that there is a large number of genes shared among all of them. However, we observed that CI133 and CI172 harbors a small number of strain-specific genes, several of them present in mobile genetic elements, supporting the hypothesis that these isolates were established in the population by horizontal acquisition of genes. These differences were also observed at proteomic level, where it was possible to detect the presence of certain secreted proteins in a culture medium that simulates the host environment.Great similarities were observed between the CI133 and CI172 strains, confirming the high percentage of genes constituting the "core" genome of S. flexneri 2. However, numerous strain specific genes were also determined. The presence of the here identified molecular elements into other strain of our culture collation, is currently used to develop characteristic markers of local pathogens. In addition, the most outstanding result of this study was the first description of a S. flexneri 2 producing Colicin E, as one of the characteristics that allows S. flexneri 2 to persist in the microbial community. These findings could also contribute to clarify the mechanism and the evolution strategy used by this pathogen to specifically colonize, survive, and cause infection within the NWA population. 

/pdf/genomic-and-proteomic-characterization-of-two-strains-of-3ozublvp.pdf

Genomic and proteomic characterization of two strains of Shigella flexneri 2 isolated from infants’ stool samples in Argentina

Shigella flexneri is the main causative agent of shigellosis commonly distributed in developing countries with high morbidity and mortality rates. This study aimed to examine the presence of Shigella species in Sudanese currency notes using both traditional and molecular techniques. One hundred thirty-five currency notes were collected and their contaminants were isolated and identified conventionally and genetically using 16S rRNA gene amplification and sequencing. Eight isolates were identified as Shigella species in different notes, and 3 of them were resistant to penicillin, kanamycin, and nitrofurantoin. One S. flexneri isolate has insertion mutation of guanine nucleotide at position 730 of life essential gene 16S rRNA which known evolutionarily to be stable gene. Banknotes are highly circulating items and therefore, appropriate measures such as regular replacement of the dirty notes with new papers are necessary to protect peoples from being infected with drug-resistant pathogens.

/pdf/contamination-of-currency-notes-with-kanamycin-resistant-59lyqo8ctd.pdf

Contamination of Currency Notes with Kanamycin Resistant Shigella flexneri

/pdf/genomic-and-proteomic-characterization-of-two-strains-of-2mir1g15.pdf

ISSN Shigella sonnei, which has historically prevailed in industrialized countries, is currently undergoing an unprecedented expansion throughout the developing world. The harshness of shigellosis relies on certain virulence factors produced by the pathogen. Available information regarding virulence genes and epidemiological relatedness of S. sonnei strains in Iran is relatively scarce. In this study, 3540 stool specimens were obtained from children with diarrhoea in Tehran, Iran, from September 2016 through January 2018. PCR assays were performed to evaluate the presence of virulence genes among S. sonnei strains. The genetic relatedness of these strains was also assessed by multiple-locus variable number tandem repeat (VNTR) analysis (MLVA). A total of 50 S. sonnei strains were obtained, all of which harboured ipaH, sigA, and virA, whereas ial, invE, and sen were positive in 70% (n1⁄435), 62% (n1⁄431), and 54% (n1⁄427) of the strains, respectively. None of the S. sonnei strains carried set1A, set1B, and sat. The most frequent virulence profile was VP1 (positive for ipaH, ial, invE, sen, sigA, and virA), which was observed in 16 (32%) strains. Using MLVA, 12 genotypes were identified. According to the minimum spanning tree (MST) analysis, S. sonnei strains were grouped into three clonal complexes. CC1, which consisted of 44 (88%) isolates, was the largest clonal complex identified. No association was observed between virulence profiles and genotypes. Overall, it was shown that S. sonnei strains were virulent and clonally related. Furthermore, MLVA can be used as a helpful method for epidemiological investigations. Copyright 2019 Wolters Kluwer Health, Inc. All rights reserved.

Genotyping and diversity of virulence genes among Shigella sonnei isolated from children with diarrhoea.

Background Shigellosis is a serious problem in Guizhou and Shigella sonnei is an increasingly prevalent etiologic agent of local shigellosis cases. No data, however, are available about the molecular characterization of the local isolates of S. sonnei. We have conducted this study to molecularly characterize the clinical isolates of S. sonnei in Guizhou Province. Results 76 S. sonnei isolates, including four isolates from 1974–1982 and 72 isolates from 2008–2010, were used for analysis in this study. Pulsed-field gel electrophoresis (PFGE) based on XbaI digestion divided the 76 isolates into 38 PFGE patterns (PT) and 15 PTs were represented by more than one isolates with PT31 (N = 8) containing the most number of isolates, followed with PT2 (N = 6). Multiple-Locus Variable number tandem repeat (VNTR) Analysis (MLVA) based on seven VNTR loci discriminated them into 19 different MLVA types (MTs), and four MTs were represented by more than one isolate with MT4 (N = 39) containing the most number of isolates, followed with MT12 (N = 18). 15 Multilocus sequence typing (MLST) base on 15 loci differentiated the isolates into six sequence types (STs), among which four STs were novel. The most common STs are ST76 (N = 43) and ST116 (N = 25), accounting for 92.1%. Correlation between genetic relationships and geographical origins or isolation years was observed among the isolates studied. Majority of isolates were clustered in accordance with the origin of isolation years based on the genetic data, which were also from similar geographical origins. Conclusions Our results revealed the molecular characteristics including the specific genotypes such as four novel STs, clonal relationship, and genetic changes of local isolates from different years, which enhances our understanding of molecular characteristics of S. sonnei and contributes to the prevention and control of shigellosis in Guizhou Province.

/pdf/molecular-characterization-of-shigella-sonnei-an-4p2y3d4r6h.pdf

Molecular Characterization of Shigella sonnei: An Increasingly Prevalent Etiologic Agent of Shigellosis in Guizhou Province, Southwest of China.

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Molecular Characterization of Shigella sonnei: An Increasingly Prevalent Etiologic Agent of Shigellosis in Guizhou Province, Southwest of China.