Staphylococcus aureus bacteraemia with known sources.

Meticillin-resistant Staphylococcus aureus (MRSA), both hospital-acquired and community-acquired MRSA (CA-MRSA) strains, have increased in frequency in the last few years, reaching epidemic dimensions. This review discusses several clinical forms of staphylococcal infection leading to bacteraemia in a high proportion of cases. Staphylococcal (MRSA) bacteraemic pneumonia is predominantly seen in hospital-acquired pneumonia and ventilator-associated pneumonia, reaching a frequency of 8.4% of all bacteraemias, 30% of all nosocomial bacteraemias and 68% of all bacteraemias of patients hospitalised in Intensive Care Units. In patients with CA-MRSA pneumonia, the rate of bacteraemia is as high as 62%. Whereas in nosocomial bacteraemic pneumonia blood cultures become positive on the ninth day of pneumonia, in CA-MRSA bacteraemic pneumonia positive blood cultures appear early in the course of the infection. The pneumonia has a stormy course with the development of abscesses, empyema and extensive pulmonary damage. Vertebral osteomyelitis commonly occurs during intravenous catheter use, causing local thrombophlebitis that will seed to vertebral bodies and disks and may cause secondary sustained bacteraemia. Non-vertebral osteomyelitis is also on the increase, with a frequency that has doubled in recent years, mainly due to MRSA. Patients with haematological malignancies are particularly prone to this complication, usually following line infections. Epidural abscess is the most serious consequence of staphylococcal bacteraemia, leading to permanent neurological damage if not diagnosed early enough.