Molecular characterization of erythromycin-resistant Streptococcus agalactiae strains
Molecular characterization of erythromycin-resistant Streptococcus agalactiae strains
复制标题
DOI：
10.1093/jac/dkn388
复制
发表时间：
2008-12-01
影响因子：
5.2
通讯作者：
Quentin, Roland
中科院分区：
文献类型：
--
作者：
Domelier, Anne-Sophie;van der Mee-Marquet, Nathalie;Quentin, Roland
目的：本研究的目的是鉴定耐红霉素（Erm(r)）无乳链球菌菌株的分子特征，并与菌株的临床来源相关联。方法：从711株无乳链球菌中采集119株Erm(r)(17%)，进行血清分型和大环内酯类耐药基因筛选。通过PFGE分析，确定了菌株间的亲缘关系。对菌株进行scpB基因下游的II组内含子GBSi1、hyIB基因中的IS1548、4个噬菌体DNA片段和一个多位点序列分型定义为ST-17的谱系的检测。结果:血清Ia型为8%，血清Ib型为15%，血清II型为9%，血清III型为16%，血清IV型为31%，血清v型为35%。从新生儿胃液中分离出的Erm(r)菌株的流行率（33%）高于早发性疾病（EOD）或晚发性疾病期间从菌血症和脑膜炎中分离出的菌株（7%和11%）（P = 0.001）（-）Erm(r)菌株在阴道（22%）和新生儿（18%）中比在EOD（0%）中更常见（P = 0.03）。mef(A)基因在Ia血清型中最常见（55%），erm(A)基因在Ib血清型中最常见（75%），erm(B)基因在其他血清型中最常见（56% ~ 75%）。所有具有IS1548的耐药菌株都含有erm(B)基因。Erm(r)菌株在不同PFGE基因组中没有随机分布，11%的菌株含有GBSi1内含子，37%的菌株含有至少一个前噬菌体DNA片段，7%的菌株属于ST-17。结论：无乳链球菌对红霉素的耐药性因其临床来源、血清型和分子特征而异。
Objectives: The aim of this study is to identify the molecular characteristics of erythromycin-resistant (Erm(r)) Streptococcus agalactiae strains and to correlate with the clinical origin of strains.Methods: From 711 S. agalactiae strains, 119 Erm(r) strains (17%) were collected, serotyped and screened for macrolide resistance genes. The genetic relationship between strains was established by the PFGE analysis. Strains were tested for the group II intron GBSi1 downstream of the scpB gene, IS1548 in the hyIB gene, four prophage DNA fragments and a lineage defined by multilocus sequence typing as ST-17.Results: Erythromycin resistance involved 8% of serotype Ia, 15% of serotype Ib, 9% of serotype II, 16% of serotype III, 31% of serotype IV and 35% of serotype V. The prevalence of Erm(r) strains was higher among strains isolated from the gastric fluid of neonates (33%) than in those isolated from bacteraemia and meningitis during early-onset disease (EOD) or late-onset disease (7% and 11%) (P = 0.001)(-) In serotype III, Erm(r) strains were more frequent in vaginal carriage (22%) and colonized neonates (18%) than in EOD (0%) (P = 0.03). The mef(A) gene was the most common in serotype Ia (55%), the erm(A) gene in serotype Ib (75%) and the erm(B) gene in the other serotypes (56% to 75%). All resistant strains with IS1548 also had the erm( B) gene. Erm(r) strains were not randomly distributed in the different PFGE genogroups, and 11% had the GBSi1 intron, 37% had at least one prophage DNA fragment and 7% belonged to ST-17.Conclusions: Erythromycin resistance varied according to the clinical origin, serotype and molecular characteristics of S. agalactiae strains.