Molecular characterization of macrolide resistance mechanisms among Streptococcus pneumoniae and Streptococcus pyogenes isolated from the PROTEKT 1999-2000 study

Abstract

In this study, the distribution of macrolide resistance mechanisms was determined for isolates of Streptococcus pneumoniae and Streptococcus pyogenes obtained from the PROTEKT 1999-2000 study (a global, longitudinal study of the antibacterial susceptibility of bacterial pathogens associated with community-acquired lower respiratory tract infections). The global macrolide resistance mechanism distribution results for 1043 macrolide-resistant S. pneumoniae isolates collected from 25 countries were as follows: 35.3% mef(A), 56.2% erm(B), 6.8% both mef(A) and erm(B), 0.2% erm(A) subclass erm(TR) and 1.5% negative for mechanisms tested. Mechanisms of macrolide resistance were found to vary widely between countries and different geographical regions with mef(A) predominating in North America and erm(B) in Europe. Approximation of genotype from macrolide MIC without molecular determination of the mechanism of resistance resulted in an error of 10.2% (106 isolates). Overall, for 143 macrolide-resistant S. pyogenes isolates, 46.1% of the isolates tested were mef(A), 30.8% were erm(B), 23.1% were erm(A) subclass erm(TR) and no isolates were negative for all the genetic markers tested. Again, the distribution varied widely between countries and geographical regions. This study provides valuable baseline data for the continued monitoring of the evolution of macrolide resistance development in these important respiratory tract pathogens. The ketolide telithromycin retained excellent anti-pneumococcal activity irrespective of macrolide resistance mechanism, having a MIC(90) of 0.25, 0.5 and 0.5 mg/L against mef(A), erm(B) and mef(A)+erm(B) macrolide-resistant S. pneumoniae, respectively. It also exhibited potent activity against S. pyogenes that had become resistant to macrolides via either mef(A), (MIC(90 )0.5 mg/L) or erm(TR), (MIC(90) 0.03 mg/L).

Prevalence and Molecular Analysis of Macrolide and Fluoroquinolone Resistance among Isolates of Streptococcus pneumoniae Collected during the 2000-2001 PROTEKT US Study

“…As this report shows, the mef(A) gene clearly predominates in the United States; other research has suggested that the same is true in Canada (20). In contrast, for Europe overall, erm(B) prevails among macrolide-resistant S. pneumoniae isolates (although this varies widely from country to country) (13). In the Far East, the prevalence of macrolide resistance mechanisms among isolates of S. pneumoniae is more diverse.…”

Prevalence and Mechanisms of Erythromycin Resistance in Group A and Group B Streptococcus : Implications for Reporting Susceptibility Results

“…Regional differences in mechanisms of resistance need to be taken into consideration when deciding whether to report clindamycin susceptibility results on the basis of in vitro test results. Testing by the double-disk diffusion method would be an approach that could be used to address this issue, especially for GAS.In Canada, as in other regions of North America and Europe, the rates of erythromycin resistance among isolates of the group A Streptococcus (GAS; Streptococcus pyogenes) and the group B Streptococcus (GBS; Streptococcus agalactiae) have been increasing (1,8,16). In Ontario, Canada, the rate of erythromycin resistance among GBS isolates has increased from 5 to 13% over a period of 3 years (4).…”

Characterization of ermB Gene Transposition by Tn 1545 and Tn 917 in Macrolide-Resistant Streptococcus pneumoniae Isolates

“…On the other hand, target modification due to methylase, encoded by ermB, confers macrolide-lincosamide-streptogramin B (MLS B ) resistance (10). Among Japanese clinical isolates of S. pneumoniae, 42.7, 52.7, and 3.3% of strains have mefA, ermB, or both genes, respectively (6).…”