Kanemitsu K, Endo S, Oda K, Saito K, Kunishima H, Hatta M, Inden K, Kaku M
Department of Infection Control and Laboratory Diagnostics, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aobaku, Sendai, Miyagi 980-8574, Japan.
J Hosp Infect. 2007 Jun;66(2):130-4. doi: 10.1016/j.jhin.2007.03.019. Epub 2007 May 18.
Routine surveillance in a cardiovascular ward showed that the incidence of Enterobacter cloacae isolated from sputum and oropharyngeal cultures in June 2004 increased to 27.6% (8/29) compared to 5.5% (12/219) from the rest of the hospital during the same period (OR=13.2; 95% CI 2.97-58.7; P<0.05). While an increase in E. cloacae pneumonia was not verified, an investigation was undertaken by the infection control team to prevent an outbreak. The estimate of relative risk for E. cloacae infection was based on a case-control study which measured exposure to intubation, history of a stay in the intensive care unit (ICU) and oral care between patients with E. cloacae and those negative for E. cloacae. An odds ratio of 13.2 suggested cross-contamination via the transoesophageal echocardiography (TOE) probe in the ICU prior to transfer to the cardiovascular ward. Pulsed-field gel electrophoresis and antibiogram patterns were also consistent with this hypothesis. Intervention was undertaken in the form of enforcing the disinfection of TOE probes using a 0.55% phtharal solution and the use of a single-use sheath to protect the probe from recontamination. Following intervention, the incidence rate returned to previous levels. This report illustrates the limitations in the effectiveness of current nosocomial surveillance strategies due to the retrospective nature of analysis. Improved surveillance methods such as data-mining tools specifically applicable to the institution, patient population, region and country are needed to increase the sensitivity of detecting unrecognized outbreaks, including cross-contamination.
心血管病房的常规监测显示，2004年6月从痰液和口咽培养物中分离出阴沟肠杆菌的发生率增至27.6%（8/29），而同期医院其他科室该发生率为5.5%（12/219）（比值比=13.2；95%可信区间2.97 - 58.7；P<0.05）。虽然未证实阴沟肠杆菌肺炎有所增加，但感染控制团队展开了调查以预防疫情爆发。阴沟肠杆菌感染的相对风险评估基于一项病例对照研究，该研究衡量了阴沟肠杆菌阳性患者与阴性患者之间的插管暴露情况、重症监护病房（ICU）住院史及口腔护理情况。13.2的比值比表明，在转至心血管病房之前，ICU内通过经食管超声心动图（TOE）探头发生了交叉污染。脉冲场凝胶电泳和抗菌谱模式也与这一假设相符。采取的干预措施包括使用0.55%邻苯二酚溶液对TOE探头进行强化消毒，以及使用一次性护套保护探头以免再次污染。干预措施实施后，发病率恢复到先前水平。本报告说明了由于分析具有回顾性，当前医院感染监测策略的有效性存在局限性。需要改进监测方法，如专门适用于该机构、患者群体、地区和国家的数据挖掘工具，以提高检测未识别疫情（包括交叉污染）的敏感性。
