Dynamics of methicillin-resistant staphylococcus aureus prevalence among patients of the Chernivtsi region

Abstract

The aim of this study was to analyze the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) during 2018–2020 among patients with purulent-inflammatory diseases of different localization in the Chernivtsi region. Materials and methods. A total of 804 strains of S. aureus were studied. Isolates were identified by morphological, tinctorial, physiological and biochemical characteristics, and their sensitivity to antibiotics was tested. Preparation and the susceptibility testing were performed in accordance with the recommendations of the Clinical & Laboratory Standards Institute (2017), as well as quality control of each batch of antibiotic discs (Oxoid, UK). Determination of methicillin resistance was performed by a surrogate test using a disk of 30 μg cefoxitin. Results. The significant increasing in the frequency of MRSA were found in 2020 as compared to previous years – a total of 1.6–2.0 times compared to 2018 and 2019. The difference between 2019 and 2020 was statistically significant: tφ = 2.49 (P ˂ 0.05). There was also a clear upward tendency in the isolation frequency of poly-resistant strains during the observation period. Conclusions. Significant changes in the frequency of isolation of Staphylococcus aureus strains from foci of purulent-inflammatory processes of different localization were not detected over the years of observations. There was an increase in the isolation frequency of the MRSA strains from patients with purulent-inflammatory diseases in the Chernivtsi region in 2020 mainly due to isolation of such strains from the mucous membranes of the oral cavity and tonsils. The proportion of MRSA poly-resistant strains increased significantly (almost twice) during the observation period suggesting that their spread should be monitored.