Identification of cytotoxin-producing Klebsiella oxytoca strains isolated from clinical samples with cell culture assays

Klebsiella oxytoca is an opportunistic pathogen which damages intestinal epithelium through producing cytotoxin tilivalline. This toxin plays a role in the pathogenesis of bacteria and is the main virulence factor which leads to antibiotic-associated hemorrhagic colitis progress. In this study, we collected a total of 75 K. oxytoca strains isolated from the stool, urine, blood, wounds, and sputum and evaluated them in terms of the production of toxins; we detected their cytotoxic effects on HEp-2 cells. Of all the isolates, five K. oxytoca strains isolated from the stool cultures, two strains isolated from the blood cultures, one strains isolated from the wound cultures, and one strains isolated from the urine cultures had cytotoxic effects on HEp-2 cells. The strains isolated from sputum cultures had no cytotoxic effects on HEp-2 cells. In the current study, the majority of strains isolated from the stool of the patients included cytopathic effects on HEp-2 cells. •Five K. oxytoca strains isolated from the stool culture.•Two strains isolated from the blood cultures.•One strains isolated from the wound cultures.•One strains isolated from the urine cultures had cytotoxic effects on HEp-2 cells.•The strains isolated from sputum cultures had no cytotoxic effects on HEp-2 cells.