Emergence ofStreptococcus pyogenes strains resistant to erythromycin in Gipuzkoa, Spain

Abstract

The aim of this study was to determine the evolution of resistance to macrolides and other antibiotics in strains of Streptococcus pyogenes isolated in the province of Gipuzkoa, Spain. During the period 1984-1996, all 2561 strains of Streptococcus pyogenes studied showed full susceptibility to penicillin. Until 1990, only 1.2% of Streptococcus pyogenes isolates were resistant to erythromycin. Since then, resistance to erythromycin increased every year until 1995, when 34.8% (87/250) of Streptococcus pyogenes strains were found to be resistant. In 1996 the rate of resistance to erythromycin was 17.8% (75/422). During the study period, 96.1% (246/256) of the Streptococcus pyogenes isolates resistant to erythromycin were susceptible to clindamycin. Of the remaining erythromycin-resistant Streptococcus pyogenes strains, resistance to clindamycin was constitutive in seven strains and inducible in three. When investigated by the polymerase chain reaction (PCR), all Streptococcus pyogenes strains resistant to erythromycin and susceptible to clindamycin showed the 1.4 kb fragment of the mefA gene, recently described as the novel macrolide-efflux-resistance determinant. The most frequent T-agglutination patterns among Streptococcus pyogenes resistant to erythromycin were T4 and T8,25. The emergence and rapid spread of erythromycin-resistant Streptococcus pyogenes in Gipuzkoa and its relationship to the presence of the mefA gene are described.

Molecular Detection of Antimicrobial Resistance

“…Nineteen of these strains were shown by PCR to possess the ermTR gene, and a single constitutively resistant strain harbored an ermB gene. Similar investigations were performed with strains from Spain by PerezTrallero et al (244) and Portillo et al (252). These authors have analyzed 256 and 40 erythromycin-resistant S. pyogenes isolates, respectively; they found that 96.1 and 90% of the isolates, respectively, possessed the mefA gene.…”

“…In addition, macrolide efflux encoded by the mefA gene has been described (53). Several authors have screened group A, C, and G streptococci by PCR for the presence of these genes (62,142,143,244,252).…”

Survey of emm Gene Sequences from Pharyngeal Streptococcus pyogenes Isolates Collected in Spain and Their Relationship with Erythromycin Susceptibility

“…After overnight incubation at 35°C, the presence of blunting in the zone of inhibition of the clindamycin disk was recorded (21). If the clindamycin inhibition zone was blunted toward the erythromycin disk, the strain was interpreted as clindamycin inducible.…”

Resistance to Macrolides in Streptococcus pyogenes in France in Pediatric Patients

“…However, for patients sensitive to ␤-lactam antibiotics, and when these drugs fail, macrolides are often the recommended substitute. Penicillin resistance has not yet been described in S. pyogenes, but resistance to erythromycin and related antibiotics has been widely reported (2,3,5,8,10,11,17,20,29,33,43,46). The mechanism of acquired resistance to erythromycin involves a target site modification mediated by a methylase which modifies the 50S ribosomal subunit, leading to the MLS B resistance phenotype encoded by erm genes (25,36,47).…”