engleski

Adhesion and invasion properties of Campylobacter jejuni in Caco-2 cells

Campylobacter is currently recognized as a leading cause of bacterial gastroenteritis worldwide. The species of Campylobacter which are responsible for food poisoning are classified as thermophilic as they grow at 42o but not at 25oC and microaerophilic, requiring a low oxygen content for growth. However, during transmission through the contamination cycle, Campylobacter is constantly exposed to stressful conditions such as changes in temperature, nutrient availability and oxygen saturation. In an in vitro model using Caco-2 cells, the cell adherence and invasion abilities of two Campylobacter jejuni isolates (poultry and clinical origin) were studied. Additionaly, the influence of environmental stress on adhesion and invasion properties was investigated. The present study showed that both C. jejuni strains adhered to and invaded Caco-2 cells. The human clinical isolate appeared to be more invasive than the animal isolate, but the difference did not reach statistical significance. The binding and invasion of C. jejuni in Caco-2 cells seemed to be enhanced by 5 hours exposure to atmospheric oxygen, especially when the human isolate was used. The growth pattern of oxygen stressed C. jejuni was characterized by a rapid intracellular replication in Caco-2 cells, reaching maximal values at 72h post infection. At the completition of the assay (5 days) a significant population of cells still remained viable, as confirmed by cultivation on blood agar plates. The consequence of C. jejuni exposure to environmental stresses and subsequent changes in physiological state and virulence properties of the bacteria will be discussed.

Campylobacter jejuni; environmental stress; virulence; Caco-2 cells

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