Implications for Diagnosis and Treatment of Infective Endocarditis: Eight year Experience of an Infectious Disease Team in a Private Tertiary Care Centre

Abstract

Background: The profile of Infective endocarditis (IE) has been evolving continuously. Like other infectious Diseases (ID) syndromes, IE has not escaped from antibiotic resistance issues. The aim of this study was to determine the implications for diagnosis and treatment by studying the clinical profile and outcome of patients admitted with IE in a tertiary care centre in Mumbai during the period from 2007-2015.

Methods: 53 patients having definite or possible IE as per Modified Duke's Criteria (MDC), that were referred to the ID division, were included in this study.

Results: 44 (83%) patients had definite IE and 9 (17%) patients had possible IE. 77.4% of the patients were above 40 years of age. 3 patients presented as euthermic IE. Vegetations were not seen on transthoracic echocardiography (TTE) in 3 patients and were seen only on transesophageal echocardiography (TEE). 15 patients had prosthetic valve IE. 7 patients had rheumatic heart disease. 3 patients had bicuspid aortic valve and 4 had ventricular septal defect (VSD). The rest had no apparent underlying heart disease (45.3%). 41 patients (77.3%) had culture-positive IE and 12 patients (22.6%) had culture-negative IE. Streptococcus spp. was found in 14 (26.4%) patients, Enterococcus spp. in 9 patients (17%). Other organisms isolated were methicillin-sensitive S. aureus (3), Methicillin Resistant S. aureus (1), Eikenella corrodens (1), B. cepacia (2), Salmonella Typhi (1), P. aeruginosa (1), M. abscessus (2) and other rapidly growing mycobacteria (RGM) (5), Candida parapsilosis (1), Candida pelliculosa (1) and Aspergillus fumigatus (1). Notably there was only one case of MRSA. Among the Streptococcus spp., Penicillin MIC testing was done in 11 cases of the 14 cases of Strep spp. 3 of them showed intermediate resistance and 2 were resistant. Among enterococcal IE, 3 had high level aminoglycoside resistance (HLAR) and 2 had β-lactamase producing enterococci with HLAR and 1 had Vancomycin resistance. These were successfully treated with combinations of Ampicillin with Ceftriaxone, Ampicillin-Sulbactam with Imipenem and Daptomycin respectively. The only case of MRSA prosthetic valve endocarditis was successfully treated with Vancomycin and Rifampicin in addition to surgery. Surgery for IE was performed in 26 out of 53 (49%) patients. Early valve surgery (within 15 days of hospital admission) was performed in 6 of these 26 patients. .

Conclusion: There is a change in the spectrum and antimicrobial susceptibility of organisms causing IE. We encountered several difficulties with the use of the MDC as 43.5% patients had no predisposing factors for IE and blood cultures were negative in 22.6% cases. In our study, PVE was the most common predisposing condition for IE. VGS followed by enterococci were found to be the commonest cause for IE in our setting. Both organisms show variable drug resist patterns. MRSA was isolated in 1 patient only. Thus vancomycin may not be required as empiric treatment in our setting. This is important from the perspective of antimicrobial stewardship Good infection control practices are essential to prevent nosocomial IE due to pathogens such as non-tuberculous mycobacteria (NTM). Important changes in the disease characteristic, treatment, and outcome are noted. Surgery, whenever indicated, helps in improving outcome in these patients thus reiterating the need for a team approach for optimal management of this complex, challenging condition..