Colonization of eight animals with S. gordonii LTH 5597. Faecal samples were plated on both BHI (◆) and BHI including erythromycin (■). From day eight, all rats were dosed with 100 μg erythromycin each day to restore the population of pMK110 containing cells. The detection limit for detection of transformants was 10 cfu/g faeces. Vertical bars represent SEM.