Profile of Infective Endocarditis: At a Tertiary Care Referral Centre

Infective endocarditis (IE) remains a serious challenge with a persistently high morbidity and mortality despite the availability of improved diagnostic and treatment amenities in the developing world. Data on the clinical and microbiological profile of IE in India is still limited. The emergence of modern risk factors such as hospitalization and device insertion has changed the epidemiology of the disease in the western world, whereas in India and other parts of the developing world the situation is more complex because of the concomitant burden of rheumatic heart disease and congenital heart defects. We therefore attempted to describe the changing epidemiology of the disease in a cohort of patients with definite IE admitted to a tertiary care centre.

145 cases were identified as IE during the period January 2010-December 2015 (6 years) of which 120 'definite' cases of IE according to the modifies Dukes' criteria were analysed.

The mean age of patients was 53 years ± 15 years (age range 18 to 79 years) with a male preponderance of 72%. Native valve disease was seen in 103 cases and 17 cases had prosthetic valve infections. IE was classified as community acquired in 87 (72.5%) cases and healthcare associated in 33(27.5%) events. Predisposing factors contributing to healthcare associated events included hemodialysis in 8.3%, recent surgical intervention which included urological instrumentation with urosepsis and gastrointestinal procedures in 5.8% events. Postpartum IE was seen in 1.7% cases. There was evidence of remote abscess, prior bacteraemia or septic foci in the preceding 3 months of presentation with IE in 8.3% of patients and 3.3% patients underwent prior dental procedure. Prior structural heart disease was present in 47.5% of cases of which Rheumatic heart disease (RHD) was seen in 15%. A previous episode of infective endocarditis was observed in significantly more patients with PVE (29.4%) than with NVE (1.9%). Blood cultures were negative in 50 (41.7%) of cases of whom 60% had received antibiotics prior to admission. Nine of 17 patients with PVE (52.9%) were culture negative. In the 70(58.3% of all patients) patients with positive blood cultures, Streptococcus sp were the commonest bacteria isolated in 15.8%, of which Viridans group Streptococci (VGS) was seen in majority of the cases (13.3%) followed by Staphylococcus sp (14.2%) with methicillin resistant staphylococcus was seen in 3.3% and Enterococcus sp in 13.3%. Gram negative bacteraemia were seen in 8.3%. In addition, ESBL E coli constituted 4% of our culture positive cases, perhaps representing a complication of this common community acquired bacteraemia and increasing resistance in E coli. Tissue / valve cultures in patients who underwent surgery was positive in four cases, 3 of whom where blood culture negative The mortality rate was higher among PVE (33%) compared to 10% in NVE. The most common cause of death in IE was usually congestive cardiac failure.

Thought Rheumatic heart disease continues to be the most common predisposing factor, degenerative heart diseases and healthcare associated IE are also gradually increasing. Use of antibiotics prior to sending blood cultures remains a significant cause of culture negativity. Viridans streptococci continue to be the commonest pathogen and though ESBL E coli constituted a significant minority it could expound the changing epidemiology and risk factors for Gramnegative endocarditis especially non-HACEK group necessitating an updated review of this subject.