Molecular epidemiology of methicillin-resistant Staphylococcus aureus isolated in serial cultures from the respiratory tract of children with cystic fibrosis.
Molecular epidemiology of methicillin-resistant Staphylococcus aureus isolated in serial cultures from the respiratory tract of children with cystic fibrosis.
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DOI：
10.1097/inf.0000000000000204
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发表时间：
2014-06
期刊：
影响因子：
--
通讯作者：
Fritz SA
中科院分区：
文献类型：
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作者：
Al-Zubeidi D;Hogan PG;Boyle M;Burnham CA;Fritz SA
背景：从囊性纤维化患者呼吸道分离的耐甲氧西林金黄色葡萄球菌(MRSA)的菌株相关性知之甚少。目的：了解儿童CF呼吸道连续培养中分离到的MRSA的遗传多样性，以及菌株相关性与临床特征的相关性。方法：对2005-2011年间从连续呼吸道培养中分离到MRSA的CF患儿进行回顾性分析。在个体患者中，用重复序列聚合酶链式反应确定分离株的亲缘关系，并对每个分离株的葡萄球菌盒染色体mec型进行鉴定。结果：我们确定了54例有连续MRSA培养的CF患者(145种不同的培养)。随着时间的推移，45名患者(83%)保持相同的菌株类型，9名(17%)患者至少拥有两种不同的菌株类型。总共对91对分离株进行了菌株相关性分析。在这些菌株中，81株(%)相同，10株(11%)为不同的菌株类型。约117株(83%)为葡萄球菌盒带染色体II型，24株(17%)为葡萄球菌盒带染色体IV型，4株为本方法不能分辨的其他类型。临床因素，包括时间间隔和在阳性培养之间有效对抗MRSA的抗生素处方，与个体患者获得不同的MRSA菌株无关。结论：我们的数据表明，CF患者持续存在MRSA最常见的原因是相同的菌株类型。在呼吸道中获得不同的MRSA菌株的情况很少见。
Background:Little is known about strain relatedness of methicillin-resistant Staphyloccocus aureus (MRSA) isolated at serial time points from the respiratory tract of patients with cystic fibrosis (CF). The objectives are to interrogate the genetic diversity of MRSA recovered in serial cultures from children with CF and to correlate strain relatedness with clinical characteristics.Methods:We performed a retrospective analysis of children with CF from whom MRSA was isolated from serial respiratory cultures from 2005 to 2011. Within individual patients, relatedness of isolated strains was determined by repetitive-sequence polymerase chain reaction, and the staphylococcal cassette chromosome mec type of each isolate was characterized. Medical records corresponding to the MRSA cultures were reviewed.Results:We identified 54 CF patients with serial MRSA cultures (145 distinct cultures). Over time, 45 (83%) patients maintained the same strain type and 9 (17%) possessed at least 2 distinct strain types. A total of 91 pairs of isolates were analyzed for strain relatedness. Of these, 81 (89%) were identical and 10 (11%) were distinct strain types. About 117 (83%) isolates were staphylococcal cassette chromosome mec type II, 24 (17%) were staphylococcal cassette chromosome mec type IV and 4 were other types not resolvable with our assay. Clinical factors, including time interval and prescription of antibiotics effective against MRSA between positive cultures, did not correlate with acquisition of a distinct MRSA strain by individual patients.Conclusions:Our data suggest that sustained presence of MRSA in CF patients is most commonly attributable to identical strain types. Acquisition of distinct MRSA strains in the airway is infrequent.