Occurrence, Distribution, and Origins of Streptococcus pneumoniae Serotype 6C, a Recently Recognized Serotype
Occurrence, Distribution, and Origins of Streptococcus pneumoniae Serotype 6C, a Recently Recognized Serotype
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DOI：
10.1128/jcm.01524-08
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发表时间：
2009-01-01
影响因子：
9.4
通讯作者：
Sampath, Rangarajan
中科院分区：
文献类型：
--
作者：
Jacobs, Michael R.;Bajaksouzian, Saralee;Sampath, Rangarajan
肺炎链球菌血清型6C的流行率，最近认识到血清型6A交叉反应的血清型，进行了调查。回收不同收集物中的血清型6A的分离株，并通过使用适当的引物对DNA提取物进行多重PCR将血清型6C与6A区分开。抗菌药物的敏感性进行了临床和实验室标准化研究所微量肉汤稀释法，并选定的菌株进行了分型的脉冲场凝胶电泳，重复序列为基础的PCR分型，和快速多位点序列分型（MLST）的PCR产物的电喷雾电离质谱。共发现60个血清型6C分离株：1979年至2007年收集的122个克利夫兰分离株中的30个，2005年和2006年收集的39个儿科分离株中的19个，以及2006年和2007年收集的11个来自马萨诸塞州的儿科分离株。在2000年引入结合肺炎球菌疫苗之前，仅回收了4株分离株;最早的分离株于1989年回收。分离株的来源包括血液（n = 5）、下呼吸道（n = 27）、鼻窦（n = 5）、耳朵（n = 2）和鼻咽（n = 18）;分离株来自49名儿童和11名成人。在美国所有六个主要国家都发现了儿科分离株。S.地理区域。药敏结果显示，22株分离株对青霉素、大环内酯类和复方新诺明不敏感，8株具有其他耐药模式，30株完全敏感。所用的三种分型方法显示出相似的聚类，每个聚类最多8个分离株。MLST显示5个与血清型6A相关的簇，2个与血清型6 B相关的簇，1个与血清型3相关的簇，以及1个与血清型34相关的簇。本研究记录了这种最近被确认的血清型的发生、全国分布、多样性、可能的起源以及2001年后发病率的增加。血清型6C值得考虑添加到未来的结合肺炎球菌疫苗。
The prevalence of Streptococcus pneumoniae serotype 6C, a recently recognized serotype that cross-reacts serologically with serotype 6A, was investigated. Isolates of serotype 6A in various collections were recovered, and serotype 6C was differentiated from 6A by multiplex PCR of DNA extracts by using appropriate primers. Antimicrobial susceptibility was performed by Clinical and Laboratory Standards Institute broth microdilution, and selected isolates were typed by pulsed-field gel electrophoresis, repetitive sequence-based PCR typing, and rapid multilocus sequence typing (MLST) by electrospray ionization mass spectrometry of PCR products. A total of 60 serotype 6C isolates were found: 30 of 122 Cleveland isolates collected from 1979 to 2007, 19 of 39 pediatric isolates collected nationwide in 2005 and 2006, and 11 pediatric isolates from Massachusetts collected in 2006 and 2007. Only four isolates were recovered prior to introduction of the conjugate pneumococcal vaccine in 2000; the earliest isolate was recovered in 1989. The sources of the isolates included blood (n = 5), the lower respiratory tract (n = 27), the sinus (n = 5), the ear (n = 2), and the nasopharynx (n = 18); isolates were recovered from 49 children and 11 adults. Pediatric isolates were found in all six major U. S. geographic regions. Antimicrobial susceptibility showed that 22 isolates were nonsusceptible to penicillin, macrolides, and trimethoprim-sulfamethoxazole, 8 had other resistance patterns, and 30 were fully susceptible. The three typing methods used showed similar clusters of up to eight isolates per cluster. MLST showed five clusters related to serotype 6A, two clusters related to serotype 6B, one cluster related to serotype 3, and one cluster related to serotype 34. This study documents the occurrence, nationwide distribution, diversity, likely origins, and increasing incidence after 2001 of this recently recognized serotype. Serotype 6C warrants consideration for addition to future conjugate pneumococcal vaccines.