Mechanistic concepts involved in biofilm associated processes of Campylobacter jejuni: persistence and inhibition in poultry environments

Abstract

Campylobacter species, predominantly Campylobacter jejuni, remains a significant zoonotic pathogen worldwide, with the poultry sector being the primary vector for human transmission. In recent years. there has been a notable rise in the incidence of human campylobacteriosis, necessitating a deeper understanding of the pathogen's survival mechanisms and transmission dynamics. Biofilm presence significantly contributes to C. jejuni persistence in poultry and subsequent food product contamination, and this review describes the intricate processes involved in biofilm formation. The ability of Campylobacter to form biofilms on various surfaces, including stainless steel, plastic, and glass, is a critical survival strategy. Campylobacter biofilms, with their remarkable resilience, protect the pathogen from environmental stresses such as desiccation, pH extremes, biocides and sanitizing agents. This review explores the molecular and genetic mechanisms of C. jejuni biofilm formation, highlighting regulatory genes involved in motility, chemotaxis, and stress responses. Flagellar proteins, particularly flaA, flaB, flaG, and adhesins like cadF and flpA, are identified as the main molecular components in biofilm development. The role of mixed-species biofilms, where C. jejuni integrates into existing biofilms of other bacteria to enhance pathogen resilience, is also discussed. This review also considers alternative interventions to control C. jejuni in poultry production, in the context of increasing antibiotic resistance. It explores the effectiveness of prebiotics, probiotics, synbiotics, bacteriocins, bacteriophages, vaccines, and organic acids, with a focus on their mechanisms of action in reducing bacterial colonization and biofilm formation. Studies show that mixtures of organic acids and compounds like Carvacrol and Eugenol significantly downregulate genes linked with motility and adhesion, thereby disrupting biofilm integrity. It discusses the impact of environmental factors, such as temperature and oxygen levels on biofilm formation, providing insights into how industrial conditions can be manipulated to reduce contamination. This paper stresses the need for a multifaceted approach to control Campylobacter in poultry, integrating molecular and genetic insights with practical interventions. By advancing our understanding of biofilm dynamics and gene regulation, we aim to inform the development of more effective strategies to enhance food safety and protect public health.

Keywords: Campylobacter biofilm; Campylobacter persistence; biofilm inhibition; mechanistic concept; poultry environment.

Figure 1

Visual representation of biofilm formation and factors displaying impact on the developmental process of biofilm. Biofilm formation progresses through different phases: 1) Adhesion of free-swimming cells to a surface, followed by 2) formation of microcolonies encased within a self-produced polymeric matrix. 3) After intense microbial multiplication, biofilm matures, developing nutrient channels. 4) Lastly, bacterial cells detach and disperse to seed new biofilms. Created with Biorender.com.

Figure 2

C. jejuni contamination in poultry production. 1) Insects and flies originating from poultry farms, along with 2) reused litter within poultry facilities, contribute to the risk. 3) Poultry feces and environmental factors contaminate water sources, whereas 4) wild animals in proximity to farms can also introduce contaminants. Furthermore, 5) farm workers and equipment pose potential risks of contamination. 6) Additionally, rodents and livestock within the farm environment can lead to C. jejuni transmission. 7) Unclean transport crates at slaughterhouses, and 8) Cross-contamination during processing further exacerbates the risk of contamination. Created with Biorender.com.