Survival of Shigella dysenteriae type 1 on fomites.

Studies have shown that various objects, such as utensils, toys, and clothes, can serve as vehicles for transmission of Shigella spp. Shigellae can become viable but non-culturable (VBNC) when exposed to various environmental conditions as shown in earlier studies. The present study was carried out to detect VBNC Shigella dysenteriae type 1 on various fomites by direct viable counting, polymerase chain reaction (PCR), and fluorescent antibody methods. S. dysenteriae type 1 was inoculated onto cloth, wood, plastic, aluminum, and glass objects. Results showed that 1.5-4.0 hours after inoculation, S. dysenteriae type 1 became non-culturable, and after five days, non-culturable but viable S. dysenteriae type 1 could be detected by both PCR and fluorescent antibody techniques. Fomites can be considered an important potential route of transmission of VBNC S. dysenteriae type 1 and a significant factor in the epidemiology of shigellosis.