Antibiotic resistance pattern of bacterial agents isolated from blood culture of patients with infective endocarditis

Background: Infective endocarditis occurs due to the presence of microorganisms in the endocardium or the heart valves. Nowadays, infective endocarditis is still a major cause of death with an incidence rate of 5 to 7.9 per 100,000 populations. The aim of the study was to determine antibiotic resistance pattern of bacterial agents isolated from blood culture of patients with infective endocarditis. Methods: In this retrospective study, infective endocarditis patients who were admitted to Sina and Ekbatan hospitals in Hamadan City, Iran, from March 2005 to February 2014, were enrolled. All demographic data, clinical manifestations, physical examinations and echocardiography reports of the patients were recorded in a check list. For all patients, blood cultures in Mueller Hinton agar and antimicrobial susceptibility testing for ceftriaxone, ceftazidime, oxacillin, cefazolin, vancomycin, imipenem, clindamycin, etc. were done by disk diffusion method. All data analyzed by SPSS statistical software, version 16 (IBM, Armonk, NY, USA). Results: A total of 61 patients with definitive infective endocarditis were included in the study, 50 of them (82%) were males and 11 patients (18%) were females. The mean age of the patients was 37.45±14.79 (range 17-74) years and 37 (60.7%) of the patients lived in urban areas. The mean duration of admission was 20±13.59 days. In addition, 38 patients (62.3%) were injection drug users (IDUs) and 23 (37.7%) non-IDU. Meanwhile, 54 (88.5%) of them had normal valve endocarditis and 7 cases (11.5%) had a prosthetic valve endocarditis. Moreover, the most common underlying disease in the natural valve endocarditis was rheumatoid fever (6.6%). Blood cultures were positive in 44.3% of the patients. The most common isolated organism was staphylococcus aureus in 15 cases (55.55%), which had the highest resistance to oxacillin. Most patients were managed by antibiotic therapy, but 15 cases (24.6%) underwent cardiac surgery. In follow up patients between 3 months to 9 years, 19.7% of the patients had complete recovery and 8.2% of them died. Conclusion: According to the findings, antibiotic resistance pattern of bacterial agents isolated from blood culture of patients with infective endocarditis was changed.