Faecal carriage of optrA-positive enterococci in asymptomatic healthy humans in Hangzhou, China
Faecal carriage of optrA-positive enterococci in asymptomatic healthy humans in Hangzhou, China
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中国杭州无症状健康人粪便中携带 optrA 阳性肠球菌
DOI：
10.1016/j.cmi.2018.07.025
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发表时间：
2019-05-01
影响因子：
14.2
通讯作者：
Wang, Y.
中科院分区：
文献类型：
--
作者：
Cai, J.;Schwarz, S.;Wang, Y.
目的：了解杭州地区健康人群粪便中OptrA阳性肠球菌的携带情况，探讨OptrA基因的遗传背景。方法：收集杭州地区健康人群粪便标本3458份，在含10 mg/L氟苯尼考的选择性培养基上进行培养，用聚合酶链式反应(PCR法)对检出的肠球菌进行检测。通过与粪肠球菌E349的原始OptrA的氨基酸序列比较，确定了OptrA变异体。结果：成人(55/1558)和儿童(66/1900)的Optra携带率相近(3.5%)。对粪肠球菌、粪肠球菌和其他肠球菌的耐药率分别为58.5%(38/65)、42.3%(11/26)和0%(0/31)。鉴定了19种表现不同利奈唑胺MIC的Optra变异体。携带野生型OptrA及其变异体RDK、KLDP、KD、D、RDKP和EDP的分离物的最低抑菌浓度一般为8 mg/L。OptrA变异体的上游为fexA，下游为erm(A)，其一侧或两端带有IS1216E。FexA-OptrA(野生型)位于Tn554转座子下游，并插入到radC基因中。在利奈唑胺耐药的肠球菌中检出31/73株EDM变异
Objectives: To investigate the faecal carriage of optrA-positive enterococci among asymptomatic healthy humans in Hangzhou, China, and to characterize the genetic context of optrA.Methods: A total of 3458 stool samples from healthy individuals were collected and cultured on a selective medium containing 10 mg/L florfenicol and resulting enterococci were screened for the presence of optrA by PCR. OptrA variants were determined by amino acid sequence comparison with the original OptrA from Enterococcus faecalis E349. Whole genome sequencing and PCR mapping were performed to obtain and analyse the genetic environment of optrA.Results: Similar optrA carriage rates (similar to 3.5%) were detected in samples from adults (55/1558) and children (66/1900). Linezolid resistance rates for E. faecalis, Enterococcus faecium and other Enterococcus species were 58.5% (38/65), 42.3% (11/26) and 0% (0/31), respectively. Nineteen OptrA variants exhibiting different linezolid MICs were identified. Isolates carrying wild-type OptrA and variants RDK, KLDP, KD, D, RDKP, and EDP generally demonstrated linezolid MICs >= 8 mg/L. The OptrA variants, with fexA upstream and erm(A) downstream, were flanked by IS1216E at one or both ends. The fexA-optrA(wild-type) was located downstream of a Tn554 transposon, and was inserted into the radC gene. The EDM variant was detected in 31/73 enterococci with linezolid MICs