Chapter 2 - Interaction of microbial pathogens with plants: attachment to persistence

Abstract

Numerous foodborne outbreaks have been increasingly linked to consumption of contaminated fresh produce globally, which represents a considerable public health concern. It was traditionally thought that plants do not normally harbor enteric pathogens or that human enteric pathogens survive poorly in the harsh environment encountered by plants, their surfaces and tissues. However, recent studies have indicated that plants do play a role as a refuge or alternative host for effective survival of human enteric pathogens. Plant crops are generally cultivated in agricultural settings, near the ground or in open fields, where they are prone to constant exposure to microbial contamination through soil, manure or soil amendments, and irrigation water. Precise identification of potential contamination sources or transmission routes of pathogens is critical in the investigation of outbreaks and development of intervention strategies. In recent years, whole genome sequencing has been increasingly used for outbreak traceback and surveillance investigations, which has provided higher resolving power and reliability. This chapter discusses interactions of foodborne pathogens with plant surfaces, particularly concentrating on the molecular or genetic mechanisms of attachment, biofilm formation, internalization, and colonization used by pathogens during their survival and persistence. Factors influencing plant defense responses (i.e., plant host immunity) during colonization, survival, and persistence of pathogens are extensively discussed. Various produce decontamination methods, their applications and limitations are also addressed. In summary, a greater understanding of the interactions between enteric pathogens and their produce plant host will augment the development of effective mitigation strategies and control measures ultimately leading to safer foods for consumers.