Sensitivity to Antibiotics of Staphylococcus Aureus Strains, Able to Biofilm Formation

Abstract

The problem of respiratory diseases associated with staphylococcal carriers is considered to be one of the most acute in modern society due to its high prevalence and problems with treatment due to the high resistance of these bacteria to antibiotics. The purpose of the study was to determine the sensitivity of Staphylococcus aureus strains, able to form biofilm, isolated from the upper respiratory tract of human. Materials and methods. Bacteriological methods of isolation and identification of staphylococci, the method of rapid determination of the ability to form biofilm on a tablet and the disk-diffusion method of determining the susceptibility to antibiotics were used to perform the research. As a result of the conducted researches it was established that in the structure of pathogens of exacerbations of seasonal rhinitis S. aureus prevailed. It was isolated from 34 samples of biological material from the nose, which accounted for 69.4% of all examined cases of rhinitis. Staphylococcus spp. (6.1%) and Streptococcus spp. (24.5%) among the isolated strains of S. aureus, 27 (79.4%) had the ability to form a biofilm. A feature associated with antibiotic resistance is the ability of strains of microorganisms to form a biofilm, in which they acquire enhanced ability to survive under adverse environmental factors, including the use of drugs. Results and discussion. In our research we showed that more than 80% of film-forming strains were found to be susceptible to ciprofloxacin, amoxicillin / clavulanic acid and azithromycin. 4 (14.8%) are methicillin-resistant. Resistance to methicillin was detected simultaneously with resistance to ciprofloxacin (3 cases) and to azithromycin (2 cases), 1 strain was resistant to gentamicin and 2 – to tetracycline. 1 of the methicillin-resistant strains of S. aureus was multidrug-resistant (showed resistance to all studied antibiotics). Among non-biofilm strains, more than 80% of the strains were also sensitive to ciprofloxacin, amoxicillin / clavulanic acid and azithromycin. Sensitivity to tetracycline was low in both groups (42-63% sensitive). Conclusion. The prevalence of antibiotic resistance among clinical strains of opportunistic bacteria, unfortunately, shows an increasing trend. This requires constant monitoring of susceptibility to antimicrobial drugs in order to develop schemes of rational antibiotic therapy, taking into account the individualized approach to patients. In this sense, it is promising when studying the biological properties of clinical isolates to determine not only the resistance to antibiotics, but also their ability to form a biofilm