The epidemiology of glycopeptide-resistant enterococci on a haematology unit - analysis by pulsed-field gel electrophoresis
The epidemiology of glycopeptide-resistant enterococci on a haematology unit - analysis by pulsed-field gel electrophoresis
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DOI：
10.1017/s0950268802007033
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发表时间：
2002-08-01
影响因子：
4.2
通讯作者：
Scott, GM
中科院分区：
文献类型：
--
作者：
Bradley, SJ;Kaufmann, ME;Scott, GM
1995年6月至1996年12月期间，作为一项确定三病房血液科中糖肽耐药肠球菌（GRE）获得性的介入性研究的一部分，研究人员每周对293名患者进行直肠拭子取样。采用脉冲场凝胶电泳（PFGE）对120例定植患者首次直肠拭子阳性分离株、7例临床感染患者分离株和43例病房环境分离株进行比较。120例患者中有63例被A-H菌株定殖，49例被独特菌株定殖。前18周与直肠拭子感染GRE的最高流行率相关，单个菌株a在2号病区占52%，在3号病区占22%，在4号病区占36%。其他较小的病区相关的星团也很明显。在此期间，2病区的环境采样显示，30株分离株中除2株外，其余均与A株难以区分。随着GRE患病率的下降，直肠拭子和环境分离株变得更加异质，菌株A在第55周后消失。在研究的最后15周，GRE患病率再次上升，在2病房出现了新的优势菌株B，占新感染病例的50%。在7例临床感染GRE的患者中，将临床分离株与同期直肠拭子分离株进行比较，发现只有2例相同。对5名长期携带者定殖的分析显示，定殖时间中位数为19周（范围11-34周），至少有两种不同的菌株，在一个病例中有6种不同的菌株，这提出了一个问题，即在任何时候，有多少菌株可能定殖在一个病人身上，并建议应该分析多个菌落。这些数据表明，当定植率高时，交叉感染是GRE传播的重要因素。
As part of an interventional study to determine glycopeptide-resistant enterococci (GRE) acquisition on a three-ward haematology unit, rectal swabs were taken weekly from 293 patients recruited to the study between June 1995 and December 1996. The GRE isolates obtained from the first positive rectal swab from 120 colonized patients, the isolates from 7 patients with clinical infection and 43 isolates obtained from the ward environment were compared by pulsed-field gel electrophoresis (PFGE). Sixty-three of 120 patients were colonized by one of strains A-H, while 49 were colonized by unique strains. The first 18 weeks were associated with the highest prevalence of GRE by rectal swab, with a single strain A responsible for 52% of acquisitions on ward 2, 22% on ward 3 and 36% on ward 4. Other smaller ward associated clusters were evident. Environmental sampling of ward 2 during this time showed that all but 2 of 30 isolates were indistinguishable from strain A. As the GRE prevalence fell, rectal swab and environmental isolates became more heterogeneous, and strain A disappeared after week 55. GRE prevalence rose again in the final 15 weeks of the study, and a new predominant strain B emerged on ward 2 responsible for 50% of new acquisitions. In the seven patients with clinical infection with GRE, the clinical isolates were compared with the contemporaneous rectal swab isolate, and were found to be the same in only two cases. An analysis of five long-term carriers colonized for a median of 19 weeks (range 11-34) showed colonization with at least two and in one case six distinct strains, raising the question of how many strains may be colonizing a patient at any one time, and suggesting that multiple colonies should be analysed. These data suggest that cross-infection was an important factor in the spread of GRE when the colonization rate was high.