CASP3 and infection: During the early and intermediate stages of the infection (2 and 4 h p.i.), we found that STM-D23580-infected cells displayed increased expression of the apoptosis-related cysteine peptidase Caspase 3 (CASP3), the vacuolar protein sorting 25 (VPS25) required for multivesicular body (MVB) formation, and a group of genes involved in the metabolism of fatty acids (MUT, CHST13, APOBEC3A).