S. amnii was cytotoxic and adhered to Me180 cells. To assess cytotoxicity, bacteria were added to Me180 monolayers and monitored by light microscopy during the incubation for phenotypic alterations. In stark contrast to monolayers treated with PBS alone as a control (a), monolayers exposed to S. amnii rapidly induced cell rounding and loss of adherence (b). To determine whether or not S. amnii adhered, bacteria were added to Me180 monolayers grown on glass coverslips. Following incubation, the glass coverslips were washed extensively in PBS, stained, and analyzed by SEM (c).