Outcome for invasive Staphylococcus aureus infections

We report a survey of invasive Staphylococcus aureus (ISA) infections concerning outcome variables such as mortality, recurrence and residual symptoms. A prospective, population-based study of all cases of ISA was conducted in the catchment area of Skaraborg Hospital (population 255,109) in western Sweden during the period from 1st March 2003 to 28th February 2005. One hundred and fifty-seven patients were included. Recurrences were seen in 13 cases (9.3%). Thirty patients (19.1%) died during the first 28 days. Mortality rates for complicated bacteraemia and severe sepsis were 32% and 54%, respectively. Older patients (>65 years of age), patients with concomitant heart disease and patients with endovascular infections all suffered higher mortality. Line-associated infections had a higher recurrence rate. Residual symptoms were common, with 34% of the living patients reporting incomplete recovery. Accessory gene regulator (agr) type within the bacteria did not affect disease presentation. We conclude that ISA infections are of major medical importance, with high rates of mortality (19.1%), recurrence (9.3%) and residual functional impairment (34%).