Nitric oxide (NO) generated by gamma interferon (IFN-gamma) activation of macrophages mediates the killing of many intracellular pathogens. IFN-gamma is essential to innate resistance to Shigella flexneri infection. We demonstrate that NO is produced following S. flexneri infection both in mice and in activated cells in vitro and that while it is able to kill S. flexneri in a cell-free system, ...

A toxin extracted from heat-inactivated, alkaline-treated Shigella flexneri 2a showed biological properties similar to those of Shigella dysenteria 1 toxin. The S, flexneri 2a toxin was lethal to mice, enterotoxic for ileal loops of rabbits, and cytotoxic for HeLa cells. A serological relationship between S. flexneri 2a and S. dysenteriae 1 toxin was shown with cross neutralization tests.

Introduction: Raising antibiotic resistance has led the human community to more frequent application of herbal medicines. The tomato fruit, scientifically called Lycopersicon esculentum mill, is an important source of vitamins, minerals, and antioxidants, all with beneficial effects on human health. The present study aimed to evaluate the antibacterial effects of tomato aqueous extract on four ...

In 2006, 3,531 fecal samples were collected from patients with diarrhea in Henan Province, China. A total of 467 (13.2%) Shigella strains were isolated and serotyped. Seventy-one Shigella flexneri strains were characterized by MIC determination, pulsed-field gel electrophoresis (PFGE), and detection of genes encoding cephalosporin resistance. Most infections were caused by S. flexneri variant X...

PhoQ/PhoP is an important two-component system that regulates Shigella virulence. We explored whether the PhoQ/PhoP system is a promising target for new antibiotics against S. flexneri infection. By using a high-throughput screen and enzymatic activity coupled assay, four compounds were found as potential PhoQ inhibitors. These compounds not only inhibited the activity of SF-PhoQc autophosphory...

FORMAL, SAMUEL B. (Walter Reed Army Institute of Research, Washington, D.C.), T. H. KENT, H. C. MAY, A. PALMER, AND E. H. LABREC. Protection of monkeys against experimental challenge with a living attenuated oral polyvalent dysentery vaccine. J. Bacteriol. 91:17-22. 1966.-Virulent strains of Shigella flexneri lb, S. flexneri 3, and S. sonnei I were mated with an Hfr strain of Escherichia coli K...

The O-antigens of all Shigella flexneri serotypes, except serotype 6, share a linear tetrasaccharide repeat composed of one N-acetylglucosamine and three l-rhamnose residues, and differences between the serotypes are due to modification of various monosaccharide residues with glucosyl and/or O-acetyl and/or phosphoethanolamine (PEtN) groups. Plasmid-borne opt (formerly lpt-O) gene encoding a PE...

An early step governing Shigella flexneri pathogenesis is the invasion of the colonic epithelium from the basolateral surface followed by disruption of the colonic epithelial barrier. Despite recent insight into S. flexneri-host interactions, much remains to be determined regarding the nature of the initial contact between S. flexneri and the host epithelial basolateral membrane domain. Since t...

S. flexneri is the leading cause of bacillary dysentery in the developing countries. Several temperate phages originating from this host have been characterised. However, all S. flexneri phages known to date are lambdoid phages, which have the ability to confer the O-antigen modification of their host. In this study, we report the isolation and characterisation of a novel Mu-like phage from a s...

The Gram-negative enteroinvasive bacterium Shigella flexneri is responsible for the endemic form of bacillary dysentery, an acute rectocolitis in humans. S. flexneri uses a type III secretion system to inject effector proteins into host cells, thus diverting cellular functions to its own benefit. Protective immunity to reinfection requires several rounds of infection to be elicited and is short...