Abstract
All organisms belong to one of the three domains of life: Bacteria, Archaea, and Eukarya. As foodborne pathogens, general properties such as the morphological and structural characteristics of bacteria, viruses, molds, parasites, and algae are reviewed in this chapter. The cell walls of Gram-positive bacteria contain a thick peptidoglycan (PGN), which is highly complex and dynamic containing a disaccharide N-acetyl-d-glucosamine (NAG) and N-acetylmuramic acid (NAM) and linked by β-1,4-glycosidic linkage (GlcNAc-(β1–4)-MurNAc) and pentapeptide. The PGN not only protects the bacterial cells against mechanical or physical damages but also hosts numerous structural and functional proteins for rigid exoskeleton and for functional attributes such as bacterial pathogenesis and induction of host immune response. The Gram-negative cell envelope consists of the outer membrane (OM) which carries LPS (an endotoxin), a thin PGN layer, and a cytoplasmic membrane. Due to the presence of OM, the protein secretion system in Gram-negative bacteria is mediated by several secretory pathways designated as type I–VI secretory pathways, of which type III secretion system is known as the molecular syringe that delivers bacterial virulence proteins directly to the interior of the host cell. Some bacteria produce endospores, which are essentially a long-term survival strategy for the bacteria.
Most foodborne viruses cause severe gastroenteritis and affect a large number of people every year. Foodborne enteric viruses are shed in large numbers (109 particles per gram) from infected patients through feces or vomitus. Person-to-person or fecal–oral transmission is a common mechanism for the spread of such viral infection. Since viruses are highly infectious, only a small dose of 10–100 particles is required to infect a person. Protozoan parasites are increasingly becoming a major concern due to their spread through fresh vegetables and fruits. Immunocompromised people are highly susceptible to the intracellular protozoan parasites. Water and soil tainted with feces generally serve as the major contamination sources, and the presence of these pathogens indicates breaches in the hygienic or sanitary practices during food production and harvest. Mycotoxins are small molecules produced as secondary metabolites by the toxigenic molds. Mycotoxins may exert carcinogenic, mutagenic, or teratogenic activities. Seafood toxins are generally associated with fish and shellfish that acquire toxins from ingested algae or are due to the bacterial enzymatic activities on fish proteins.
Keywords
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Further Readings
Beveridge, T.J. (1999) Structures of Gram-negative cell walls and their derived membrane vesicles. J Bacteriol 181, 4725-4733.
Boneca, I.G. (2005) The role of peptidoglycan in pathogenesis. Curr Opin Microbiol 8, 46-53.
Conlan, J.V., Sripa, B., Attwood, S. and Newton, P.N. (2011) A review of parasitic zoonoses in a changing Southeast Asia. Vet Parasitol 182, 22-40.
Costa, T.R.D., Felisberto-Rodrigues, C., Meir, A., Prevost, M.S., Redzej, A., Trokter, M. and Waksman, G. (2015) Secretion systems in Gram-negative bacteria: structural and mechanistic insights. Nat Rev Microbiol 13, 343-359.
Dawson, D. (2005) Foodborne protozoan parasites. Int J Food Microbiol 103, 207.
Dorny, P., Praet, N., Deckers, N. and Gabriel, S. (2009) Emerging food-borne parasites. Vet Parasitol 163, 196-206.
Eckburg, P.B., Lepp, P.W. and Relman, D.A. (2003) Archaea and their potential role in human disease. Infect Immun 71, 591-596.
Feltcher, M.E. and Braunstein, M. (2012) Emerging themes in SecA2-mediated protein export. Nat Rev Microbiol 10, 779-789.
Foster, S.J. (1994) The role and regulation of cell wall structural dynamics during differentiation of endospore-forming bacteria. J Appl Bacteriol 76, S25-S39.
Galdiero, S., Falanga, A., Cantisani, M., Tarallo, R., Pepa, M.E.D., D’Oriano, V. and Galdiero, M. (2012) Microbe-Host Interactions: Structure and Role of Gram-Negative Bacterial Porins. Curr Protein & Peptide Sci 13, 843-854.
Kalaitzis, J.A., Chau, R., Kohli, G.S., Murray, S.A. and Neilan, B.A. (2010) Biosynthesis of toxic naturally-occurring seafood contaminants. Toxicon 56, 244-258.
Keates, S., Hitti, Y.S., Upton, M. and Kelly, C.P. (1997) Helicobacter pylori infection activates NF-kappa B in gastric epithelial cells. Gastroenterology 113, 1099-1109.
Murphy, P.A., Hendrich, S., Landgren, C. and Bryant, C.M. (2006) Food mycotoxins: An update. J Food Sci 71, R51-R65.
Navarre, W.W. and Schneewind, O. (1999) Surface Proteins of Gram-Positive Bacteria and Mechanisms of Their Targeting to the Cell Wall Envelope. Microbiol Mol Biol Rev 63, 174-229.
Rodriguez-Lazaro, D., Cook, N., Ruggeri, F.M., Sellwood, J., Nasser, A., Nascimento, M.S., D’Agostino, M., Santos, R., Saiz, J.C., Rzezutka, A., Bosch, A., Girones, R., Carducci, A., Muscillo, M., Kovac, K., Diez-Valcarce, M., Vantarakis, A., von Bonsdorff, C.H., Husman, A.M.D., Hernandez, M. and van der Poel, W.H.M. (2012) Virus hazards from food, water and other contaminated environments. FEMS Microbiol Rev 36, 786-814.
Schneewind, O. and Missiakas, D. (2014) Sec-secretion and sortase-mediated anchoring of proteins in Gram-positive bacteria. Biochem Biophys Acta - Mol Cell Res 1843, 1687-1697.
Setlow, P. (2014) Germination of spores of Bacillus species: What we know and do not know. J Bacteriol 196, 1297-1305.
Weidenmaier, C. and Peschel, A. (2008) Teichoic acids and related cell-wall glycopolymers in Gram-positive physiology and host interactions. Nat Rev Microbiol 6 (4), 276-287.
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 2018 Springer Science+Business Media, LLC, part of Springer Nature
About this chapter
Cite this chapter
Bhunia, A.K. (2018). Biology of Microbial Pathogens. In: Foodborne Microbial Pathogens. Food Science Text Series. Springer, New York, NY. https://doi.org/10.1007/978-1-4939-7349-1_2
Download citation
DOI: https://doi.org/10.1007/978-1-4939-7349-1_2
Published:
Publisher Name: Springer, New York, NY
Print ISBN: 978-1-4939-7347-7
Online ISBN: 978-1-4939-7349-1
eBook Packages: Chemistry and Materials ScienceChemistry and Material Science (R0)