Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Goldenfelsstrasse 19-21, 50935, Cologne, Germany.
German Centre for Infection Research (DZIF), Partner site Bonn-Cologne, Germany.
Eur J Clin Microbiol Infect Dis. 2017 Oct;36(10):1847-1851. doi: 10.1007/s10096-017-3000-1. Epub 2017 May 5.
Screening for multidrug-resistant Enterobacteriaceae is performed in many institutions as part of infection control measures. However, the sensitivity of current standard diagnostics is modest. Furthermore, patients are usually screened by rectal swabs (mostly rayon based), which have been shown to be sub-optimal for the recovery of Enterobacteriaceae. Therefore, it is likely that many patients colonised with multidrug-resistant Enterobacteriaceae remain undetected. The present study aimed to analyse if the detection of multidrug-resistant Enterobacteriaceae can be improved when screening with rayon swabs is done in combination with an additional pre-enrichment step. The detection of third-generation cephalosporin-resistant Enterobacteriaceae (3GCREB) was assessed in 514 rectal samples by the standard diagnostic approach (direct plating of swabs on selective ESBL agar) and after pre-enrichment in 5 mL of a semi-selective MacConkey broth. The recovery rate of 3GCREB and extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E), patient characteristics and isolate characteristics were evaluated for both diagnostic approaches. Overall, by pre-enrichment, the detection of 3GCREB carriers increased by 22.8% (13/57, p = 0.004) and the detection of ESBL-E carriers by 21.4% (9/42, p = 0.01). This study demonstrates the low sensitivity of rectal screening by direct plating and the improvement by pre-enrichment. We believe that it is no longer acceptable to refrain from pre-enrichment as, with the standard approach, more than 20% of 3GCREB and ESBL-E carriers remain undetected.
许多机构将对多药耐药肠杆菌科的筛查作为感染控制措施的一部分。然而，目前标准诊断方法的灵敏度并不高。此外，患者通常通过直肠拭子进行筛查（主要基于人造纤维），而这种方法对于肠杆菌科的恢复效果并不理想。因此，许多定植有多药耐药肠杆菌科的患者可能未被检测到。本研究旨在分析在使用人造纤维拭子时，结合额外的预富集步骤，是否可以提高多药耐药肠杆菌科的检测率。通过标准诊断方法（直接在选择性 ESBL 琼脂上接种拭子）和预富集在 5ml 半选择性 MacConkey 肉汤中，对 514 份直肠样本进行了第三代头孢菌素耐药肠杆菌科（3GCREB）的检测。评估了两种诊断方法的 3GCREB 检出率、广谱β-内酰胺酶产生肠杆菌科（ESBL-E）检出率、患者特征和分离株特征。总的来说，通过预富集，3GCREB 携带者的检出率提高了 22.8%（13/57，p=0.004），ESBL-E 携带者的检出率提高了 21.4%（9/42，p=0.01）。本研究表明，直接接种平板进行直肠筛查的灵敏度较低，而预富集可以提高其灵敏度。我们认为，不进行预富集已经不能接受，因为按照标准方法，超过 20%的 3GCREB 和 ESBL-E 携带者未被检测到。
