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Macrolide-resistant Streptococcus pyogenes in Norway: population structure and resistance determinants
P Littauer1, D A Caugant, M Sangvik
1Department of Microbiology and Infection Control, University Hospital of North Norway and Department of Microbiology and Virology, Faculty of Medicine, Institute for Medical Biology, University of Tromsø, N-9037 Tromsø, Norway. Pia.Littauer@unn.no
Antimicrobial Agents and Chemotherapy
|April 28, 2006
Summary
Macrolide resistance in Streptococcus pyogenes is 2.7% in Norway, mainly from erm(TR) and mef(A) genes. Resistant strains are often imported or emerge from susceptible clones.
Area of Science:
- Microbiology
- Molecular Biology
- Epidemiology
Background:
- Streptococcus pyogenes (group A Streptococcus) is a significant human pathogen.
- Macrolide antibiotics are crucial for treating S. pyogenes infections.
- Monitoring antimicrobial resistance is essential for effective public health strategies.
Purpose of the Study:
- To determine the prevalence and genetic basis of macrolide resistance in clinical isolates of Streptococcus pyogenes in Norway.
- To investigate the clonal structure of resistant and susceptible S. pyogenes strains.
Main Methods:
- Analysis of 1,657 clinical isolates of Streptococcus pyogenes from Norway.
- Detection and characterization of macrolide resistance genes (erm(TR) and mef(A)).
- Molecular typing to identify clonal complexes.
Main Results:
- A macrolide resistance prevalence of 2.7% was observed.
- The erm(TR) gene accounted for 59% and mef(A) for 20% of resistance.
- Four major clonal complexes represented 75% of all isolates.
Conclusions:
- Macrolide resistance in Norwegian S. pyogenes is driven by specific resistance genes, primarily erm(TR).
- Resistance appears to be introduced via imported strains or selected locally within globally disseminated susceptible clones.
- Continued surveillance of macrolide resistance in S. pyogenes is warranted.
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