 The "S. aureus" clonal complex CC121 is known to exhibit multi-host tropism for both humans and rabbits.This is thought to be due to a single nucleotide mutation that evolved the CC121 complex into ST121 clonal complex, the clone capable of infecting rabbits.Enteropathogenic and enterohaemorrhagic "Escherichia coli" (EPEC and EHEC respectively) exhibit tropism for human gut epithelial cells, leading to food poisoning and digestive problems.