Dynamics of resistance of Streptococcus pneumoniae strains to antibacterial drugs for the period 2015–2019 in Samara: opportunities for overcoming

Abstract

According to the World Health Organization (WHO), diseases caused by Streptococcus pneumoniae are one of the most dangerous diseases, that can be completely prevented by vaccination. Studies conducted in various regions of the Russian Federation and other countries have revealed certain features in the prevalence of pneumococcus strains, resistant to different antibacterial drugs, which requires local studies among patients of different age groups.The aim of the study was to determine the level of sensitivity of S. pneumoniae, isolated from adult patients, to antibacterial drugs (ABD) and the dynamics of resistance to ABD in Samara for the period of 2015–2019.Methods. A retrospective analysis of data from the microbiological department of clinical diagnostic laboratories of the Clinics of Samara State Medical University, Healthcare Ministry of Russia for 2015–2019 was carried out. The microorganism resistance to several groups of ABD was studied – macrolides (erythromycin, azithromycin, clarithro mycin), cephalosporins (ceftriaxone, cefotaxime), fluoroquinolones (levofloxacin) and penicillin. The sensitivity was determined by the disk diffusion method. Statistical processing was performed using the SPSS Statistic 22.0 program. When comparing groups, the χ2 criterion was used; to compare small groups (n < 5), the exact Fisher test was used.Results. Since 2017, there has been a tendency to increase the frequency of pneumococcus isolation in the carrier group. At the same time, a 3-fold decrease in S. pneumoniae excretion from patients with ENT pathology occurred. The highest sensitivity was detected for cephalosporins – 100% sensitivity of all S. pneumoniae strains, detected from ENT organs and during carriage. There is a low level of pneumococcus resistance to levofloxacin. The general sensitivity to ABD from penicillin group is 96.4–98.8%, while the most common resistant strains were found in patients with respiratory tract damage. The highest resistance of S. pneumoniae was revealed to ABD from the macrolide group with a tendency to increase from 4.6% in 2016 to 14.0% in 2019.Conclusion. According to the study results, a rather low level of resistance of S. pneumoniae to most ABD groups, with the exception of macrolides, was demonstrated in Samara. The greatest number of ABD-insensitive pathogens was isolated in patients with pathology of the bronchopulmonary system. A mandatory microbiological examination of the sputum of such patients is necessary with a determination of the sensitivity of the isolated microorganisms to ABD and subsequent correction of therapy upon the identification of resistant strains. Given the increasing resistance of S. pneumoniae in carriers, it is necessary to vaccinate patients in this group.