Human rotavirus infection enhances invasiveness of enterobacteria in MA-104 cells.

To study the interaction between common pathogens causing infectious diarrhea in humans, MA 104 cell cultures were infected with human rotavirus and Salmonella typhimurium or Shigella flexneri or enteroinvasive Escherichia coli (EIEC) concomitantly. When MA-104 cells were preinfected with human rotavirus, invasiveness of S. typhimurium was significantly enhanced. The enhancement was evident after 48 h of virus preincubation. At this time virus specific antigens were demonstrated in the cell cultures. Also, the invasiveness of S. flexneri and EIEC was enhanced after virus preincubation, though not significantly before 72 h. When the virus preincubation time was prolonged to 96 h a further increase in invasive ability was observed. No cytopathogenic effect of the virus on the cells was demonstrated. Two control strains of non-enteropathogenic E. coli did not show any invasiveness in MA-104 cells pretreated with virus. The results indicate a specific interaction between rotavirus infected cells and facultatively intracellular enteropathogenic bacteria.