Demonstration of a cytotoxin from Campylobacter jejuni.

A 48-hour culture filtrate of Campylobacter jejuni was found to produce cytopathic effects on three human cell lines--that is, HeLa, MRC-5 and Hep-2. The cytopathic effects observed include cell rounding, loss of adherence and cell death after 24-48 h of incubation. Such morphological changes were observed with eight of the eleven strains of Campylobacter jejuni isolated from the blood/stools of patients who suffered from either acute gastroenteritis or septicaemia. The toxic factor did not retain its activity after treatment at 100 degrees C for 30 min. Trypsinisation of the filtrate totally abolished its toxic activity thus indicating that it was probably protein in nature. It is most probably an extracellular toxin as bacterial sonicates did not produce any toxic effect. This study reports the finding of toxic factor(s) in the culture filtrate of Campylobacter jejuni which is cytotoxic to human tissue culture cells.