Bacterial agents as etiological factors of infective endocarditis

Objective. To analyse bacterial agents as etiological factors of infective endocarditis in patients with mitral valve disease. Materials and methods. The study included 287 patients who underwent mitral valve surgery, 205 men and 82 women. The mean age of the patients in this sample was (50.1 ± 2.9) years, and they had a history of informative endocarditis with mitral valve involvement. All patients underwent surgical treatment – mitral valve repair (experimental group)/prosthetics (control group). The data of primary medical records (medical histories, primary medical records), results of histological and bacteriological studies and instrumental examination were analysed. Results. In 49.1% of patients, the etiological factors of infective endocarditis were bronchopulmonary (16.4%), urological (12.2%), general surgical (6.6%) diseases, and in 20.6% – hospital–acquired infection. In 30.3% of patients, the cause of infective endocarditis was not identified. The most common microflora was identified: Staphylococcus spp. (19.2%); Enterococcus spp. (15.0%); Streptococcus spp. (3.5%). In detailing the identification of the pathogen during the histological examination of intraoperative material, the most common bacterial agents were found to be etiological factors of infective endocarditis. Enterococcus, Staphylococcus and Staphylococcus epidermidis. The most common microflora in the study group: Enterococcus – 15.4%, Staphylococcus – 9.5%, Staphylococcus epidermidis – 9.5% and Staphylococcus aureus – 7.4% in the control group: Enterococcus – 23.2%, Staphylococcus – 10.6%, Staphylococcus epidermidis – 6.7% and Streptococcus – 4.7% (p ≥ 0.05). Histological examination of mitral valve vegetations revealed the most common bacterial agents: Staphylococcus aureus (3.6%), Staphylococcus epidermidis (5.1%) and Enterococcus faecalis (10.7%). Histological examination of the mitral valve revealed differences in predisposition factors for the development of infective endocarditis. Conclusions. It was determined that patients who underwent mitral valve repair were free of fungal microflora and mixed forms of microorganisms, and in patients who underwent MV prosthetics, they were found only rarely. It was found that the bacterial microflora in the experimental and control groups had differences. It was found that primary infective endocarditis of the mitral valve was statistically significantly more common in the study group (56.2%) than in the control group (38.7%) (p = 0.004, χ2  = 8.15).