China
Africa
Explore chapters and articles related to this topic
Yersinia
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Y. enterocolitica can produce heat-stable enterotoxin (Yst), which has the same pathogenic characteristics of enterotoxin as other intestinal pathogenic bacteria. The growth period, temperature, osmotic pressure, pH value, and host factors affect the expression of the yst gene.1 Murine toxin exists only in Y. pestis, being a kind of soluble protein exotoxin, which has severe toxicity in rodents. Murine toxin and phospholipase D protein superfamily share homology and are found in the bacterial cytoplasm. The bacterial cell lysis causes inflammation, necrosis, hemorrhage, shock, sepsis, and severe pathogenic liver, kidney, and myocardial damage.80
Introductory Remarks
Published in Dongyou Liu, Laboratory Models for Foodborne Infections, 2017
Apart from infections with foodborne viruses, bacteria, fungi, and parasites, another important cause of foodborne diseases is toxins or toxic chemicals produced by foodborne bacteria and fungi as well as those associated with shellfish and plants [6]. Toxins originated from foodborne bacteria can be separated into exotoxins (which remain part of the bacteria, and are secreted, or, similar to endotoxins, released during bacterial lysis) and endotoxins (which form part of the bacterial outer membrane, and are released during bacterial lysis). Some well-known foodborne bacterial exotoxins include superantigens from S. aureus and Streptococcus pyogenes; pore-forming toxins (PFTs) from E. coli, L. monocytogenes, and Streptococcus pneumoniae; heat-stable enterotoxins (ST, exotoxins targeting the intestine) from pathogenic strains of E. coli; and botulinum neurotoxin (BoNT) from C. botulinum. A notable foodborne bacterial endotoxin is lipopolysaccharide (LPS, which is made up of O antigen, core oligosaccharide, and lipid A) from Gram-negative bacteria. As water-soluble proteins, PFTs induce host membrane damages as amphiphilic surfactants and phospholipases. On the other hand, endotoxins (e.g., LPS) cause severe inflammation, endotoxemia (septic shock), and autoimmune disease. Being the by-products of foodborne fungi, mycotoxins are responsible for alimentary mycotoxicoses in humans through food consumption. The most common foodborne mycotoxins consist of aflatoxins (from Aspergillus parasiticus and Aspergillus flavus), altertoxins (from Alternaria), fumonisins (from Fusarium moniliforme), ochratoxins (from Aspergillus ochraceus, Aspergillus carbonarius, Penicillium verrucosum), patulin (from Aspergillus, Penicillium), and trichothecenes (from Fusarium).
Phosphodiesterase 5 (PDE5) restricts intracellular cGMP accumulation during enterotoxigenic Escherichia coli infection
Published in Gut Microbes, 2020
Jennifer Foulke-Abel, Huimin Yu, Laxmi Sunuwar, Ruxian Lin, James M. Fleckenstein, James B. Kaper, Mark Donowitz
The Global Enteric Multi-Center Study (GEMS) identified enterotoxigenic Escherichia coli (ETEC) infection as one of the four leading causes of acute diarrhea and associated mortalities in developing countries.1 As the leading cause of traveler’s diarrhea, ETEC is also a recognized burden on deployed U.S. military personnel.2 The host diarrheal response is initiated by the secreted peptide heat-stable enterotoxin (ST) and/or the multi-subunit protein heat-labile enterotoxin (LT) via induction of second messenger cGMP and cAMP synthesis, respectively. ETEC strain H10407, originally isolated from a patient in Bangladesh with severe cholera-like diarrhea,3 employs additional factors to facilitate host interaction, including but not limited to the secreted mucinase EatA4 and surface adhesins EtpA5,6 and CfaE.7 Strains expressing ST, alone or in combination with LT, were more highly associated with diarrhea than LT-only expressing strains,8 confirming the importance of ST in disease pathogenesis. As such, recent renewed efforts to employ ST antigens for vaccine development are under way.9,10
Linaclotide for the treatment of chronic constipation
Published in Expert Opinion on Pharmacotherapy, 2018
Gabrio Bassotti, Paolo Usai-Satta, Massimo Bellini
The investigation of the pathophysiologic causes of cholera led to the isolation of the Escherichia coli heat-stable enterotoxin (STa) as the cause of traveler’s diarrhea. STa binds to the guanylate cyclase-C (GC-C) receptor in the mucosa of the small bowel, activating fluid secretion through GC-C conversion of guanosine triphosphate to cyclic guanosine monophosphate (cGMP) [18,19]. As a consequence of the above studies, the search for the natural ligand to the GC-C receptor led to the discovery of uroguanylin and identified the GC-C receptor. Linaclotide (see below) is a potent GC-C agonist. In vivo animal studies and in vitro studies in human colon carcinoma T84 cells have shown the binding of linaclotide to GC-C receptors with consequent stimulation of intracellular cGMP [20,21].
Efficacy and safety of plecanatide in treating constipation predominant irritable bowel syndrome
Published in Expert Opinion on Pharmacotherapy, 2018
Investigation of the pathophysiologic cause of cholera led to the discovery of enterotoxigenic Escherichia coli and subsequent isolation of the E. coli heat-stable enterotoxin (STa) as the cause of Traveler’s diarrhea [14]. STa binds to the guanylate cyclase C receptor in the mucosa of the small bowel [15] activating small bowel fluid secretion through guanylate cyclase-C conversion of guanosine triphosphate (GTP) to cyclic guanosine monophosphate (cGMP) [16,17]. The search for the natural ligand to the receptor led to the discovery of uroguanylin [18] and identified the guanylate cyclase C receptor. Recognizing the potential for drug development, two development pathways emerged, one (linaclotide) captured the potential of the ST-peptide and the other developed a natural analog to native uroguanylin (plecanatide). Although both are agonists for the GC-C receptor, they are pharmacophysiologically distinctly different with plecanatide retaining the pH-dependent receptor binding characteristics of uroguanylin.