The changing profile of bacterial endocarditis as seen at an Australian provincial centre

Background: The clinical profile of endocarditis has changed over the past four decades with studies showing trends towards increasing age, more nosocomial and prosthetic valve infection and increasing rates of Staphylococcus aureus infection. However, these studies have been biased by referral patterns. Methods: We reviewed data collected at three hospitals in the Barwon-South-West region in Victoria, Australia. All cases identified between 1994 and 1999 were reviewed according to the Duke criteria. Results: During this period, 58 patients were diagnosed as having endocarditis. The incidence rate during this time was 3.0 per 100 000 with a rise in the rate of admissions from 0.15 to 0.26 per 1000 from 1995 to 1999. Sixteen (28%) were nosocomial with the majority from line-related sepsis. No intravenous drug users were identified. Eighteen (31%) involved endovascular prosthetic material. S. aureus was the causative pathogen in 23 (40%), with 'viridans' streptococci contributing 12 (21%) and other organisms accounting for 12 (21%). Attributable mortality in this series was 17%. Conclusions: We have seen a rise in the rate of endocarditis during this time. The proportions of endocarditis due to S. aureus and 'viridans' streptococci, as well as rates of nosocomial and prosthetic valve infection, are consistent with more recent series at referral hospitals and district hospitals, representing a change since studies performed in the 1960s and 1970s. Our findings confirm a trend towards a clinical profile seen at referral centres and reinforce the emerging importance of S. aureus, nosocomial bacteraemia and prosthetic valve endocarditis.