Research Publications (Food Safety)

Background Azithromycin is frequently used to treat shigellosis; however, clinical outcomes are uncertain. Methods We performed an observational cohort study in Bangladesh of patients with invasive diarrhea treated empirically with azithromycin. Susceptibility testing was performed by broth microdilution and disk diffusion post hoc on all Shigella isolates and clinical response was correlated with in vitro susceptibility.

Shigella is a leading cause of moderate-to-severe diarrhea globally and the causative agent of shigellosis and bacillary dysentery. Associated with 80 to 165 million cases of diarrhea and >13% of diarrheal deaths, in many regions, Shigella exposure is ubiquitous while infection is heterogenous.

by Nirupama Shivakumar, Ambily Sivadas, Sarita Devi, Farook Jahoor, John McLaughlin, Craig P. Smith, Anura V. Kurpad, Arpita Mukhopadhyay

The foodborne pathogen Yersinia enterocolitica causes gastrointestinal infections worldwide. In the spring of 2019, the Swedish Public Health Agency and Statens Serum Institut in Denmark independently identified an outbreak caused by Yersinia enterocolitica 4/O:3 that after sequence comparison turned out to be a cross-border outbreak. A trace-back investigation suggested shipments of fresh prewashed spinach from Italy as a common source for the outbreak.

The ocular surface possesses its own bacterial microbiota. Once given a chance, opportunistic pathogens within ocular microbiota may lead to corneal infection like bacterial keratitis (BK). To reveal the possible factor that makes people vulnerable to BK from the perspective of ocular bacterial microbiota, as well as to compare diagnostic information provided by high-throughput 16S rDNA sequencing and bacterial culture, 20 patients with BK and 42 healthy volunteers were included.

ABSTRACT Many cytosolic bacterial pathogens hijack the host actin polymerization machinery to form actin tails that promote direct cell-to-cell spread, enabling these pathogens to avoid extracellular immune defenses. However, these pathogens are still susceptible to intracellular cell-autonomous immune responses that restrict bacterial actin-based motility.

Increasing antimicrobial resistance and limited alternative treatments have led to fluoroquinolone-resistant Shigella strain inclusion on the WHO global priority pathogens list.

Developing effective therapeutics or preventive interventions for important health threats is greatly enhanced whenever accessible models can enable the assessment of clinically important outcomes. While no non-human model is ever perfect, inexpensive in vivo small animal models in such as mice are often of great help in assessing the relevant efficacy of potential interventions.

Background and Aims

Women with severe intrahepatic cholestasis of pregnancy (ICP) are at higher risks of fetal complications and without effective treatments. Changes in gut microbiota in pregnancy were found to be related to the altered intestinal bile acid composition, so we aimed to explore the alterations of microbiota in the gut of ICP patients.

Methods

Bacterial Type III Secretion Systems (T3SSs) are specialized multicomponent nanomachines that mediate the transport of proteins either to extracellular locations or deliver Type III Secretion effectors directly into eukaryotic host cell cytoplasm. Shigella, the causing agent of bacillary dysentery or shigellosis, bears a set of T3SS proteins termed translocators that form a pore in the host cell membrane.

ABSTRACT

Intestinal microecology plays an important role in the development and progression of hematological malignancies. However, characteristics of gut microbiota in diffuse large B cell lymphoma (DLBCL) have not been reported. The microbiota composition of fecal samples from 25 untreated DLBCL patients and 26 healthy volunteers was examined by 16S rRNA gene sequencing. On α-diversity analysis, there was no significant difference in species diversity and abundance between the two groups.

Shigella are pathogens originating within the Escherichia lineage but frequently classified as a separate genus. Shigella genomes contain numerous insertion sequences (ISs) that lead to pseudogenisation of affected genes and an increase of non-homologous recombination. Here, we study 414 genomes of E. coli and Shigella strains to assess the contribution of genomic rearrangements to Shigella evolution.

The study aimed to evaluate qualitatively and quantitatively the antimicrobial capacity of 10 potential probiotic Lactobacillus strains against model enteropathogens and spoilage microorganisms. The probiotic strains (live and heat-killed forms) were also assessed for their ability to inhibit adhesion of selected pathogens to Caco-2 cells.

In Vibrio parahaemolyticus, type III secretion system 1 (T3SS1) is a major virulence factor that delivers effectors into the host eukaryotic cytoplasm; however, studies on its infection mechanism are currently limited. To determine the function of the vscF gene, we constructed the vscF deletion mutant ΔvscF and complementation strain CΔvscF.

We report the complete genome sequence of selenate [Se(VI)]-reducing Shigella sonnei SE6-1, which was isolated from stream sediment from an industrial complex in Jeonju, South Korea. The genome sequence is 4,762,774 bp long, with a G+C content of 50.7% and 4,548 genes, including 4,440 coding sequences, 22 rRNA genes, and 86 tRNA genes.

SF2a-TT15 was safe and well tolerated and induced high titres of anti-SF2a LPS IgG antibodies. These results support further evaluation of this original synthetic oligosaccharide-protein conjugate vaccine candidate for safety, immunogenicity, and protective efficacy in target populations.

Controversy surrounds the ranking by clinical importance of diarrhoeal disease pathogens.

The instability of Shigella genomes has been described, but how this instability causes phenotypic differences within the Shigella flexneri species is largely unknown and likely variable. We describe herein the genome of S. flexneri strain PE577, originally a clinical isolate, which exhibits several phenotypic differences compared to the model strain 2457T. Like many previously described strains of S. flexneri, PE577 lacks discernible, functional CRISPR and restriction-modification systems.

Infections caused by multidrug-resistant shigellae resistant to broad-spectrum cephalosporins are becoming more prevalent in the Middle East. We report a case of severe diarrhea due to a multiresistant Shigella flexneri 1 strain carrying four different ß-lactamase genes.

The pathogenesis of type 2 diabetes mellitus (T2DM) is commonly associated with altered gut bacteria. However, whether the microbial dysbiosis that exists in human diabetic patients with or without retinopathy is different remains largely unknown. Here, we collected clinical information and fecal samples from 75 participants, including 25 diabetic patients without retinopathy (DM), 25 diabetic patients with retinopathy (DR), and 25 healthy controls (HC).

Author(s): Khashayar Shahin, Lili Zhang, Abbas Soleimani Delfan, Majid Komijani, Abolghasem Hedayatkhah, Hongduo Bao, Mohadeseh Barazandeh, Mojtaba Mansoorianfar, Maoda Pang, Tao He, Majid Bouzari, Ran Wang

Shiga toxins (Stxs) are classic bacterial toxins and major virulence factors of toxigenic Shigella dysenteriae and enterohemorrhagic Escherichia coli (EHEC). These toxins recognize a glycosphingolipid globotriaosylceramide (Gb3/CD77) as their receptor and inhibit protein synthesis in cells by cleaving 28S ribosomal RNA.

VirB is a key regulator of genes located on the large virulence plasmid (pINV) in the bacterial pathogen Shigella flexneri. VirB is unusual; it is not related to other transcriptional regulators, instead, it belongs to a family of proteins that primarily function in plasmid and chromosome partitioning; exemplified by ParB. Despite this, VirB does not function to segregate DNA, but rather counters transcriptional silencing mediated by the nucleoid structuring protein, H-NS.