Comparative analysis of Streptococcus pyogenes sensitivity and effectiveness of antibacterial therapy in chronic tonsillitis

Background. The rise in antibiotic resistance of Streptococcus pyogenes in chronic tonsillitis remains a global issue, exacerbated by irrational use of antibacterial drugs, low patient adherence to therapy, and the spread of resistant strains. The discrepancy between the relatively high in vitro sensitivity of microorganisms and the reduced clinical efficacy of drugs in vivo is of particular concern and requires an in-depth analysis of the causes of such disparities.

Aim. The study aims to evaluate the efficacy of various groups of antibacterial drugs in vitro and in vivo used to treat chronic tonsillitis during exacerbations.

Material and methods. Based on outpatient records and microbiological studies, a group of patients was identified in whom S. pyogenes was the primary significant factor in the development of chronic tonsillitis. The sensitivity of the pathogen to commonly used antibacterial drugs was assessed using the disk-diffusion method. Clinical efficacy of antibiotic therapy was evaluated based on objective criteria. Additionally, isolates of S. pyogenes co-incubated with antibacterial agents were analyzed using Raman spectroscopy.

Results. The analysis revealed discrepancies between in vitro disk-diffusion data and clinical outcomes. According to the disk-diffusion test, 87.6% of patients showed sensitivity to semi-synthetic penicillins, yet incomplete or absent clinical efficacy was observed in 28.2% of cases. Slightly better results were obtained with inhibitor-protected penicillins. Macrolides, demonstrating 88.5% efficacy in vitro, failed to achieve full therapeutic effects in 26.6% of patients. Comparable results were observed with cephalosporins. The lowest in vitro sensitivity of S. pyogenes was noted for fluoroquinolones, leading to inadequate clinical efficacy in 28.0% of patients. Raman spectroscopy enabled the assessment of sensitivity to one of the most frequently used antibacterial agents.

Conclusions. The significant gap between laboratory and clinical data is attributed not only to potential antibiotic resistance mechanisms (which are also discussed) but also to the influence of internal factors that must be considered when selecting etiotropic therapy for chronic tonsillitis during exacerbations.