Molecular epidemiology of macrolide resistance in beta-haemolytic streptococci of Lancefield groups A, B, C and G and evidence for a new mef element in group G streptococci that carries allelic variants of mef and msr(D).

Maria Rosario Amezaga, Hamish McKenzie

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Objectives: To study the molecular mechanisms of erythromycin resistance in beta-haemolytic streptococci of Lancefield groups A, B, C and G.

Methods: Erythromycin-resistant clinical isolates from North East Scotland were collected over 2 years. Resistance phenotypes were determined by disc diffusion and MICs by Etest. Resistance genes mef, msr(D), erm(B) and erm(TR) were identified by PCR and mef and msr(D) were sequenced.

Results: Erythromycin resistance prevalence was 1.9% in group A streptococci (31 of 1625), 4.3% in group B (53 of 1233), 3.8% in group C (18 of 479) and 6.2% in group G (64 of 1034). The numbers of resistant isolates available were 26, 42, 9 and 52 in each group respectively. The majority of resistant isolates in groups A (57.7%, 15 of 26), B (88.1%, 37 of 42) and G (90.4%, 47 of 52) were MLSB. The contribution of M phenotype was significant in groups C (77.8%, 7 of 9) and A (42.3%, 11 of 26). Group A isolates carried mef(A) and group B carried mef(E) exclusively. A mef sequence distinct from mef(A) and mef(E) was identified in group G and was associated with a new msr(D) sequence. These sequence variants appear to be part of a new genetic element that is inserted in the comEC gene. A bimodal distribution of erythromycin MICs was noted in erm(TR) isolates.

Conclusions: The results demonstrate significant differences in the mechanisms of macrolide resistance amongst different Lancefield groups in the same geographical area. New sequences show that resistance mechanisms are still evolving.

Original languageEnglish
Pages (from-to)443-449
Number of pages6
JournalJournal of Antimicrobial Chemotherapy
Volume57
DOIs
Publication statusPublished - Mar 2006

Keywords

  • M phenotype
  • MLSB phenotype
  • erm(B)
  • erm(TR)
  • MEDIATED ERYTHROMYCIN RESISTANCE
  • EFFLUX GENE MEF(A)
  • PYOGENES STRAINS
  • NORTH-AMERICA
  • PNEUMONIAE
  • MECHANISMS
  • SUSCEPTIBILITY
  • DETERMINANTS
  • LINCOSAMIDE
  • AGALACTIAE

Cite this

@article{35e423bd736c4096ad554918389a9ab6,
title = "Molecular epidemiology of macrolide resistance in beta-haemolytic streptococci of Lancefield groups A, B, C and G and evidence for a new mef element in group G streptococci that carries allelic variants of mef and msr(D).",
abstract = "Objectives: To study the molecular mechanisms of erythromycin resistance in beta-haemolytic streptococci of Lancefield groups A, B, C and G.Methods: Erythromycin-resistant clinical isolates from North East Scotland were collected over 2 years. Resistance phenotypes were determined by disc diffusion and MICs by Etest. Resistance genes mef, msr(D), erm(B) and erm(TR) were identified by PCR and mef and msr(D) were sequenced.Results: Erythromycin resistance prevalence was 1.9{\%} in group A streptococci (31 of 1625), 4.3{\%} in group B (53 of 1233), 3.8{\%} in group C (18 of 479) and 6.2{\%} in group G (64 of 1034). The numbers of resistant isolates available were 26, 42, 9 and 52 in each group respectively. The majority of resistant isolates in groups A (57.7{\%}, 15 of 26), B (88.1{\%}, 37 of 42) and G (90.4{\%}, 47 of 52) were MLSB. The contribution of M phenotype was significant in groups C (77.8{\%}, 7 of 9) and A (42.3{\%}, 11 of 26). Group A isolates carried mef(A) and group B carried mef(E) exclusively. A mef sequence distinct from mef(A) and mef(E) was identified in group G and was associated with a new msr(D) sequence. These sequence variants appear to be part of a new genetic element that is inserted in the comEC gene. A bimodal distribution of erythromycin MICs was noted in erm(TR) isolates.Conclusions: The results demonstrate significant differences in the mechanisms of macrolide resistance amongst different Lancefield groups in the same geographical area. New sequences show that resistance mechanisms are still evolving.",
keywords = "M phenotype, MLSB phenotype, erm(B), erm(TR), MEDIATED ERYTHROMYCIN RESISTANCE, EFFLUX GENE MEF(A), PYOGENES STRAINS, NORTH-AMERICA, PNEUMONIAE, MECHANISMS, SUSCEPTIBILITY, DETERMINANTS, LINCOSAMIDE, AGALACTIAE",
author = "Amezaga, {Maria Rosario} and Hamish McKenzie",
year = "2006",
month = "3",
doi = "10.1093/jac/dki490",
language = "English",
volume = "57",
pages = "443--449",
journal = "Journal of Antimicrobial Chemotherapy",
issn = "0305-7453",
publisher = "Oxford University Press",

}

TY - JOUR

T1 - Molecular epidemiology of macrolide resistance in beta-haemolytic streptococci of Lancefield groups A, B, C and G and evidence for a new mef element in group G streptococci that carries allelic variants of mef and msr(D).

AU - Amezaga, Maria Rosario

AU - McKenzie, Hamish

PY - 2006/3

Y1 - 2006/3

N2 - Objectives: To study the molecular mechanisms of erythromycin resistance in beta-haemolytic streptococci of Lancefield groups A, B, C and G.Methods: Erythromycin-resistant clinical isolates from North East Scotland were collected over 2 years. Resistance phenotypes were determined by disc diffusion and MICs by Etest. Resistance genes mef, msr(D), erm(B) and erm(TR) were identified by PCR and mef and msr(D) were sequenced.Results: Erythromycin resistance prevalence was 1.9% in group A streptococci (31 of 1625), 4.3% in group B (53 of 1233), 3.8% in group C (18 of 479) and 6.2% in group G (64 of 1034). The numbers of resistant isolates available were 26, 42, 9 and 52 in each group respectively. The majority of resistant isolates in groups A (57.7%, 15 of 26), B (88.1%, 37 of 42) and G (90.4%, 47 of 52) were MLSB. The contribution of M phenotype was significant in groups C (77.8%, 7 of 9) and A (42.3%, 11 of 26). Group A isolates carried mef(A) and group B carried mef(E) exclusively. A mef sequence distinct from mef(A) and mef(E) was identified in group G and was associated with a new msr(D) sequence. These sequence variants appear to be part of a new genetic element that is inserted in the comEC gene. A bimodal distribution of erythromycin MICs was noted in erm(TR) isolates.Conclusions: The results demonstrate significant differences in the mechanisms of macrolide resistance amongst different Lancefield groups in the same geographical area. New sequences show that resistance mechanisms are still evolving.

AB - Objectives: To study the molecular mechanisms of erythromycin resistance in beta-haemolytic streptococci of Lancefield groups A, B, C and G.Methods: Erythromycin-resistant clinical isolates from North East Scotland were collected over 2 years. Resistance phenotypes were determined by disc diffusion and MICs by Etest. Resistance genes mef, msr(D), erm(B) and erm(TR) were identified by PCR and mef and msr(D) were sequenced.Results: Erythromycin resistance prevalence was 1.9% in group A streptococci (31 of 1625), 4.3% in group B (53 of 1233), 3.8% in group C (18 of 479) and 6.2% in group G (64 of 1034). The numbers of resistant isolates available were 26, 42, 9 and 52 in each group respectively. The majority of resistant isolates in groups A (57.7%, 15 of 26), B (88.1%, 37 of 42) and G (90.4%, 47 of 52) were MLSB. The contribution of M phenotype was significant in groups C (77.8%, 7 of 9) and A (42.3%, 11 of 26). Group A isolates carried mef(A) and group B carried mef(E) exclusively. A mef sequence distinct from mef(A) and mef(E) was identified in group G and was associated with a new msr(D) sequence. These sequence variants appear to be part of a new genetic element that is inserted in the comEC gene. A bimodal distribution of erythromycin MICs was noted in erm(TR) isolates.Conclusions: The results demonstrate significant differences in the mechanisms of macrolide resistance amongst different Lancefield groups in the same geographical area. New sequences show that resistance mechanisms are still evolving.

KW - M phenotype

KW - MLSB phenotype

KW - erm(B)

KW - erm(TR)

KW - MEDIATED ERYTHROMYCIN RESISTANCE

KW - EFFLUX GENE MEF(A)

KW - PYOGENES STRAINS

KW - NORTH-AMERICA

KW - PNEUMONIAE

KW - MECHANISMS

KW - SUSCEPTIBILITY

KW - DETERMINANTS

KW - LINCOSAMIDE

KW - AGALACTIAE

U2 - 10.1093/jac/dki490

DO - 10.1093/jac/dki490

M3 - Article

VL - 57

SP - 443

EP - 449

JO - Journal of Antimicrobial Chemotherapy

JF - Journal of Antimicrobial Chemotherapy

SN - 0305-7453

ER -