Clinical and pathogenic aspects of the ineffectiveness of the eradication of penicillin S. pyogenes localized intracellularly
In recent years, the frequency of reports of ineffectiveness of penicillin in eradicating group A beta-hemolytic streptococcus (Streptococcus pyogenes, GABA) from the tonsils and posterior pharyngeal wall. At the same time, despite confirmation of the ability of this microorganism to penetrate the epithelial cells of the mucous membranes, the effectiveness of antibacterial drugs widely used in the treatment of infections caused by it on localized intracellular streptococci remains not studied.
In a study by E.L. Kaplan et al. (Germany), a study was carried out on the viability of intracellularly located BHSA after exposure to epithelial cells of the pharyngeal mucosa (HEp-2) of antibiotics recommended for the treatment of infections caused by this microorganism. The results of exposure to the drugs (penicillin, erythromycin, azithromycin, cephalotin and clindamycin) were evaluated using three methods: electron microscopy of ultrathin sections of BHCA located intracellularly, qualitative confirmation of the presence of antibiotic in epithelial cells and a special assessment of the viability of localized intracellular BHCA.
According to the results obtained, the GABA located intracellularly remained viable despite the exposure to penicillin on the epithelial cells. At the same time, macrolide group antibiotics (erythromycin and azithromycin) had a bactericidal effect on these microorganisms. The results of electron microscopy confirmed the absence of intracellular fragmentation of BHSA, which indicates their death after exposure to penicillin epithelial cells, in contrast to the obvious fragmentation of microorganisms after exposure to antibiotics of the macrolide group. Cephalotin and clindamycin were superior to penicillin, but inferior to erythromycin and azithromycin in the efficacy of destroying localized intracellular BHSA.
The data obtained during the study allow us to conclude that the ineffectiveness of eradicating BSA in a certain number of patients is their intracellular localization and the weak capacity of penicillin to penetrate into epithelial cells.