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Relationships in genotype, phenotype, T type and PFGE type among macrolide-resistant Streptococcus pyogenes strains isolated in the Czech Republic

Abstract number: p1812

Jakubù  V., Urbá[scaron]ková  P., Straková  L.

Objectives: 

To determine relationships between phenotypic and genotypic methods among erythromycin-resistant S. pyogenes strains.

Methods: 

A total of 1331 clinical isolates of S. pyogenes resistant to erythromycin were collected in 39 microbiology laboratories during 2001–2003. Erythromycin susceptibility was tested by the disk diffusion method. Strains with an inhibition zone <21 mm around the erythromycin disk (15 mg) were sent to the National Reference Laboratory for Antibiotics (NRL). Presences of MLSB resistance genes (ermTR, ermB and mefA) were tested by PCR. T serotypes were determined in randomly selected representatives of each phenotype (n = 370). PFGE type were determined in strains from year 2003 only (n = 68).

Results: 

The rate of the most prevalent phenotype (constitutive MLSB resistance) was 63%, 55% in the year 2001 and 2003, respectively. The major prevalent T types among the analysed strains were serotype T 28 (58%), T 12 (10%), T 4 (8%) and T B3264 (8%). Gene ermB was the most frequent (54%). The results of PCR method was highly congruent with observed phenotype of resistance. PFGE patterns of strains with constitutive MLSB resistance were highly identical.

Conclusion: 

M phenotypes, constitutive and inducible resistance to MLSB antibiotics were found and ermTR, ermB and mefA genes were detected among the analysed strains. The T serotype 28 was identified the mainly prevalent in our collection. The majority of strains harbouring T serotype 28 were constitutively resistant to macrolides. The study showed close relationships among genotypes, T types, specific resistotypes (phenotype) and PFGE types.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Subject:
Location: Oxford, UK
Presentation type:
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