Multilocus sequence typing of Campylobacter jejuni isolates from humans, chickens, raw milk, and environmental water in Quebec, Canada
Multilocus sequence typing of Campylobacter jejuni isolates from humans, chickens, raw milk, and environmental water in Quebec, Canada
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DOI：
10.1128/jcm.00042-08
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发表时间：
2008-10-01
影响因子：
9.4
通讯作者：
Michaud, Sophie
中科院分区：
文献类型：
--
作者：
Levesque, Simon;Frost, Eric;Michaud, Sophie
分子菌株分型对于解释空肠弯曲菌感染的流行病学是必不可少的。我们应用两种不同的方法，多位点序列分型（MLST）和flaA短可变重复序列（SVR）分析，289株（163人，56只鸡，34人乳和36环境水分离株），收集自加拿大魁北克省，3年以上;此外，该分析还包括先前研究的131个分离株的脉冲场凝胶电泳（PFGE）分型结果。MLST定义了96个序列类型（ST）和20个克隆复合体（CC），包括49个ST（73个分离株，25%）和39个以前未在国际数据库中记录的等位基因。新ST在水分离株中的频率显著高于来自其他来源的分离株（分别为18/36 [50%]和55/253 [22%]; P < 0.001）。10种最流行的CC中有9种包括来自人类和至少一种其他来源的分离株; 5种CC完全或主要由人类和鸡分离株组成。然而，水和牛奶是其余CC的主要非人类来源，这表明散发性C。人类的空肠感染可能经常由鸡以外的来源引起。所有三种分型系统都具有歧视性（歧视指数> 0.9）。在131个分离株的PFGE分析，每20个类型的代表两个或两个以上的菌株对应于一个单一的CC。相比之下，在通过分析flaA SVR检测到的14种最流行的类型（各5 - 27株分离株）中，8株（57%）包含代表多种不同CC的分离株。这些不一致结果的依据尚不确定。抗菌药物耐药性是随机分布的CC之间，似乎更密切相关的分离株的来源比其基因型。虽然MLST是劳动密集型和昂贵的，它仍然是单一的最佳方法的基因分型的C。空肠分离株和破译分离株之间的流行病学关系。
Molecular strain typing is essential for deciphering the epidemiology of Campylobacter jejuni infections. We applied two different methods, multilocus sequence typing (MLST) and analysis of the flaA short variable repeat (SVR), to 289 isolates (163 human, 56 chicken, 34 raw milk, and 36 environmental water isolates) collected in the province of Quebec, Canada, over 3 years; in addition, the analysis included the pulsed-field gel electrophoresis (PFGE) typing results for a subset of 131 isolates studied previously. MLST defined 96 sequence types (STs) and 20 clonal complexes (CCs), including 49 STs (73 isolates, 25%) and 39 alleles not previously documented in an international database. The frequency of new STs was significantly higher among water isolates than among isolates from other sources (18/36 [50%] and 55/253 [22%], respectively; P < 0.001). Nine of the 10 most prevalent CCs included isolates from humans and at least one other source; five CCs comprised exclusively or mostly human and chicken isolates. However, water and milk were the predominant nonhuman sources among the remaining CCs, suggesting that sporadic C. jejuni infections in humans may frequently arise from sources other than chickens. All three typing systems were discriminatory ( discriminatory index > 0.9). Among 131 isolates analyzed by PFGE, each of the 20 types represented by two or more isolates corresponded to a single CC. In contrast, among the 14 most prevalent types detected by analysis of the flaA SVR (5 to 27 isolates each), 8 (57%) included isolates that represented multiple different CCs. The basis for these discordant results was uncertain. Antimicrobial resistance was randomly distributed among the CCs and appeared to be more closely related to the source of an isolate than its genotype. Although MLST is labor-intensive and expensive, it remains the single best method for the genotyping of C. jejuni isolates and deciphering the epidemiologic relationships among isolates.