[Presence of virulence factors and pathovars in strains of Campylobacter jejuni isolated from patients with diarrhea and healthy children].

Background: To study the prevalence of virulence factors (adhesion, invasion, cytotoxicity and hemolytic activity) and to establish the presence of pathovars (virulence phenotype) in C. jejuni strains isolated in pediatric patients with inflammatory and secretory diarrhea and asymptomatic carriers.
Methods: We analyzed 95 strains of 48 patients with inflammatory diarrhea (blood and mucus in feces), 30 patients with secretory diarrhea (watery) and 17 strains isolated in asymptomatic children (control group). The study of adherence capacity, invasion and cytotoxicity was made in the Hep-2 cell line, and the analysis of hemolytic activity in blood agar plates with a 5% sheep's blood. The pathovars were defined by the cellular adhesion (phenotypes A and a) and the cytotoxicity (phenotypes E and e).
Results: 29.1% of inflammatory strains presented adherence capacity, 66.6% were invasive, 64.5% cytotoxic and 52.1% hemolytic. In the secretory strains the values were 70, 20, 10 and 6.6% respectively; in the control group the 11.7% presented adherence capacity and 5.8% were invasive. We obtained difference statistically significative for the secretory strains in the adherence capacity, and in inflammatory strains in the adherence capacity, cytotoxicity and hemolysis. The phenotype Ae predominate in the secretory strains, and the phenotype ae in the strains belonging to the control group. No pathovar predominates in the inflammatory strains.
Conclusions: The analysis of virulence markers permit us to establish the pathogenic behaviour of the C. jejuni strains isolated in patients with diarrhea. The study of the adherence capacity and cytotoxicity (pathovars) would be used as a virulence markers and to predict the inflammatory or secretory nature of the diarrhea caused by C. jejuni strains.