THE ROLE OF ANTIBIOTIC RESISTANCE OF STAPHYLOCOCCUS AUREUS AND STREPTOCOCCUS PYOGENES IN THE DEVELOPMENT OF CHRONIC PYODERMA

Abstract

Relevance. Chronic pyodermas remain one of the most widespread and clinically significant infectious pathologies of the skin, accompanied by a high frequency of relapses and a reduced effectiveness of standard therapy. The most serious problem is the growth of antibiotic resistance in the leading pathogens — Staphylococcus aureus and Streptococcus pyogenes — including the spread of MRSA and MLSB phenotypes. These strains possess increased virulence, the ability to form biofilms and a pronounced inflammatory potential, which leads to a protracted and torpid course of the disease. Under conditions of growing resistance, the need to study its role in the chronification of pyoderma acquires particular importance for the choice of effective and personalised antibacterial therapy. Aim of the study. To assess the role of the antibiotic resistance of Staphylococcus aureus and Streptococcus pyogenes in the development of chronic pyoderma in adults and children. Materials and methods. The study included 168 patients with chronic recurrent pyoderma observed in 2023–2025. Bacteriological examination, identification of the pathogens by MALDI-TOF MS, determination of antibiotic susceptibility (EUCAST 2023), detection of methicillin resistance genes (mecA, mecC) and of MLSB resistance phenotypes (ermA, ermB, ermC) were carried out. Statistical processing was performed using SPSS 26.0 (χ², p<0.05). Results. It was established that the leading pathogens of chronic pyoderma are S. aureus (62.5 %) and S. pyogenes (27.4 %), while mixed infections form the most severe course of the disease (10.1 %). The frequency of MRSA was 38.9 %, resistance to macrolides 41.3 % and to tetracyclines 27.5 %. Biofilm formation was detected in 52.4 % of S. aureus strains, which was associated with an increase in the duration of treatment and in the frequency of relapses (6–7 per year). In S. pyogenes the cMLSB (29.6 %) and iMLSB (14.8 %) phenotypes were registered, significantly affecting the effectiveness of macrolides and lincosamides. Patients with MRSA and mixed infections had the highest levels of inflammatory markers (CRP 25.6–27.3 mg/l; IL-6 21.8–23.1 pg/ml) and a low response to standard therapy. The average duration of treatment varied from 9–11 days (susceptible strains) to 19–23 days (mixed infections). Conclusion. The antibiotic resistance of S. aureus and S. pyogenes is a leading factor in the chronification of pyoderma; it increases the frequency of relapses, intensifies the inflammatory response and reduces the effectiveness of standard therapy. The data obtained emphasise the importance of mandatory microbiological examination, of the determination of resistance mechanisms and of the personalised selection of antibacterial treatment.