Significant increase in the prevalence of S. pyogenes strains resistant to erythromycin but susceptible to clindamycin and myocamycin in Spain

In 1998, a multicenter study was carried out in Spain, the aim of which was to determine the sensitivity of Streptococcus pyogenes to macrolides with 14, 15, 16 limbs and clindamycin. The number of strains studied was proportional to the number of inhabitants in each of the regions examined. The objective of this work, carried out in 2001, was to study the sensitivity of S. pyogenes with the participation of the same centers according to the same methodology as in 1998, to determine the phenotypes of sensitivity to macrolides and lincosamides and compare the results with 1998 data

The study included 529 S. pyogenes strains from 21 laboratories, of which 417 were obtained by examining throat samples. 435 (82.2%) S. pyogenes were isolated from children and 94 (17.8%) from adults. 157 strains (29.7%) were resistant to erythromycin and azithromycin with resistance to 16-member myocamycin macrolide and clindamycin 1.5% and 1.3%, respectively. Most (98.7%) of the 157 S. pyogenes resistant to erythromycin had an M phenotype, which determines resistance to 14-15 member macrolides while maintaining sensitivity to macrolides and lincosamides with 16 members.

By comparing the results obtained in 1998 and 2001, a statistically significant increase in the growth of resistance to erythromycin and azithromycin (p = 0.02; test X 2) and a lack clindamycin and myocamycin growth p (0.47; X 2 test). A significant increase in the spread of resistance of S. pyogenes to certain macrolides in Spain requires continuous monitoring of the antimicrobial resistance of this microorganism.