Invasion of HEp-2 cells by Shigella spp. isolated from acute pediatric diarrhea

Aim: infection is an important global health problem in developing countries where hygiene is poor and hence shigellosis is a main cause of diarrhoea-associated mortality and morbidity, particularly in children under the age of five. The bacterial entry into colon and rectal epithelial cells has been named ‘bacterium-directed phagocytosis’. This term highlights that the bacteria actively stimulate their own uptake into non-professional phagocytes. The aim of this study was to demonstrate the invasion of HEp-2 cells by spp. isolated from acute pediatric diarrhea in Tehran, Iran.Methods: Three-hundred and ten non-duplicative diarrheal stool samples were collected from the children admitted to Children’s Medical Center in Tehran, Iran. Samples were cultured and suspected colonies were identified by routine microbiological and biochemical tests. The invasion of the two isolated spp. to HEp-2 cells was studied.Results: Of 310 stool samples, 16 (5.2%) spp. were isolated, including seven (43.7%) and nine (56.3%) . Four (44.4%) and seven (42.8%) showed invasive phenotype to HEp-2.Conclusion: and are reported as the most prevalent spp. in nature which infect humans. Invasion of various cell lines gives the chance of survival to spp. This ability causes more virulent infections in the host. Despite costly and time consuming cell culture techniques, the current method described in this paper is reliable for detecting invasive behavior of spp. Results have also shown that not all the spp. are able to invade intestinal epithelial cells