Evaluation of epidemiological, clinical, and microbiological features of definite infective endocarditis

Microbiological and Clinicoepidemiological Profile of a Series of Patients with Infective Endocarditis at a Center in Eastern Nepal

Background

The microbiological and clinicoepidemiological profile of infective endocarditis (IE) has undergone significant change over time. The pattern of IE studied at local level provides broader vision in understanding the current scenario of this disease. This study aimed to depict the overall picture of IE and its changing profile by evaluating the microbiological and clinicoepidemiological features in the context of a tertiary care center of eastern Nepal.

Methods

The descriptive study was conducted from September 2017 to August 2018 among IE patients presenting to B. P. Koirala Institute of Health Sciences, Nepal. Detailed history and clinical manifestations of patients were noted. Microorganisms isolated from the blood culture were processed for identification by standard microbiological methods, and susceptibility testings were done. Each patient was assessed daily during hospital stay.

Results

Ten definite and 7 possible endocarditis cases were studied. The mean age was 41.4 ± 15.85 (17–70) years with predominance of male (4.7 : 1). Rheumatic heart disease (41.1%) was the most common underlying heart disease observed followed by injection drug user endocarditis (23.5%). All the cases had native valve endocarditis. Aortic valve was the most common valve involved (35.3%) followed by mitral, tricuspid, and pulmonary valves. Blood culture positivity was 53%. Staphylococcus aureus was the major causative agent responsible for 23.5% of the cases followed by Enterococcus faecium, Enterococcus faecalis, and Pseudomonas aeruginosa. Mortality of 2 cases (11.8%) was associated with S. aureus and P. aeruginosa. Majority of patients developed acute kidney injury (35.3%) and congestive cardiac failure (23.5%).

Conclusion

IE patients in our center exhibited differences from the west in terms of age at presentation and predisposing factors but held similarity in terms of commonly isolated microorganisms. The changing patterns of IE, etiological agents, and their antimicrobial susceptibility observed in this study may be helpful for clinicians in formulating a new empirical antibiotic treatment protocol.

Staphylococcal Enterotoxins and Toxic Shock Syndrome Toxin-1 and Their Association among Bacteremic and Infective Endocarditis Patients in Egypt

Purpose

Infective endocarditis (IE) is a major complication in patients with bacteremia of Staphylococcus (S.) aureus infection. Our aim was to determine the association of the major Staphylococcal superantigens (SAgs), including Staphylococcal enterotoxins (SEs) and toxic shock syndrome toxin-1 (TSST-1), among hospitalized patients diagnosed with bacteremia and those with IE.

Methods

This study was conducted on 88 patients; of these, 84 (95.5%) had two positive blood cultures. Eighteen out of the 84 patients (21.4%) were diagnosed based on the modified Duke criteria by a cardiologist to have IE. The recovered isolates were screened phenotypically using ELISA followed by molecular analysis of sea, seb, sec, sed, see, and tsst-1, the major SAg coding genes, and the obtained findings were statistically analyzed.

Results

Phenotypic screening for SE production of 26 selected Staphylococci (15 isolated from the IE patients (10 S. aureus and 5 coagulase negative staphylococci (CoNS)) and 11 from bacteremic patients (10 S. aureus and 1 CoNS)) using ELISA revealed that 12/26 (46%) isolates were SE producers. PCR analysis showed that 19 (73%) isolates were PCR positive for SAg genes with the highest prevalence of the sea gene (79%), followed by seb (63%) and tsst-1 (21%). The least frequent gene was sed (5.3%). Statistical correlations between bacteremic and IE isolates with respect to prevalence of SAgs showed no significant difference (P value = 0.139, effect size = 0.572) indicating no specific association between any of the detected SAgs and IE.

Conclusion

There is high prevalence of SEs among clinical isolates of Staphylococci recovered from patients suffering bacteremia and those with IE. No significant difference was found among Staphylococcal isolates recovered from patients with bacteremia or IE regarding both phenotypic and genotypic detection of the tested SAgs.