Centro de Recursos Microbiológicos, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516, Caparica, Portugal.
Eur J Clin Microbiol Infect Dis. 2012 May;31(5):849-57. doi: 10.1007/s10096-011-1384-x. Epub 2011 Oct 21.
The asymptomatic oropharyngeal colonization rate by Streptococcus pyogenes was 10.7% in children (901 among 8,405 children 0-16 years old) and 3.3% in adults (37 among 1,126 households of children) in the Lisbon area during 2000-2006. Macrolide-resistant S. pyogenes from children (n = 149) was variable with time: 9.8-10.7% in 2000-2002, 28.1% in 2003, 19.6-2.7% in 2004-2005 and 14.6% in 2006. Eight lineages (97.3% of isolates) were identified based on at least 80% similarity of PFGE patterns, T types, emm types and multilocus sequence types (ST). The elevated frequency of macrolide resistance was associated with M phenotype lineages I (emm12/ST36) and V (emm4, emm75/ST39 and a novel emmstMrp6 type) and with one cMLS(B) lineage IV (emm28/ST52) known to be associated with upper respiratory tract and invasive infections. Significant associations (p < 0.05) between emm type/virulence genotype were found, such as emm1/speA (+) ssa (-), emm4/ssa (+) prtF1 (+), emm12/speA (-) ssa (-). The high prevalence (>20%) of speC, prtF1 or ssa was probably caused either by clonal dissemination (speC), or to horizontal gene transfer events (prtF1 and ssa). This report contributes to a better understanding of the molecular epidemiology and evolution of macrolide-resistant S. pyogenes causing symptom-free oropharyngeal colonization. These colonizing strains carry macrolide resistance and virulence genes capable of being transferred to other bacterial species sharing the same niche.
2000-2006 年期间，在里斯本地区，0-16 岁儿童（8405 名儿童中有 901 名）无症状咽峡部链球菌带菌率为 10.7%，儿童家庭成人（1126 户中有 37 名）为 3.3%。2000-2002 年期间，儿童分离的大环内酯类耐药性链球菌（n = 149）呈时间变化：9.8-10.7%，2003 年为 28.1%，2004-2005 年为 19.6-2.7%，2006 年为 14.6%。基于 PFGE 模式、T 型、emm 型和多位点序列型（ST）至少 80%的相似性，鉴定了 8 个谱系（分离株的 97.3%）。大环内酯类耐药性的高发频率与 M 表型谱系 I（emm12/ST36）和 V（emm4、emm75/ST39 和一种新型 emmstMrp6 型）以及一个已知与上呼吸道和侵袭性感染相关的 cMLS(B)谱系 IV（emm28/ST52）有关。发现了 emm 型/毒力基因型之间的显著关联（p < 0.05），例如 emm1/speA(+)ssa(-)、emm4/ssa(+)prtF1(+)、emm12/speA(-)ssa(-)。speC、prtF1 或 ssa 的高流行率（>20%）可能是由于克隆传播（speC）或水平基因转移事件（prtF1 和 ssa）引起的。本报告有助于更好地了解引起无症状咽峡部定植的大环内酯类耐药性链球菌的分子流行病学和进化。这些定植菌株携带能够转移到具有相同生态位的其他细菌物种的大环内酯类耐药性和毒力基因。
