The Health Protection Agency assists infection control and the control of antimicrobial resistance in the healthcare setting by monitoring these infections with mandatory and voluntary surveillance schemes covering bacteraemia (blood stream infections) caused by Staphylococcus aureus - both meticillin-resistant Staphylococcus aureus (MRSA) and meticillin-sensitive Staphylococcus aureus (MSSA), E.coli and glycopeptide-resistant enterococcus(GRE) as well as Clostridium difficile infection (C. diff/CDI), surgical site infections (of which some orthopaedic categories are mandatory) via the surgical site infection surveillance scheme (SSISS). Other healthcare associated infections, including antimicrobial (antibiotic) resistant micro-organisms are also monitored via a voluntary microbiology laboratory reporting system.