Monash Infectious Diseases, Southern Health, Melbourne, VIC, Australia.
Med J Aust. 2013 Mar 18;198(5):267-9. doi: 10.5694/mja12.11757.
Clinical utility of carbapenem antibiotics is under threat because of the emergence of acquired metallo-β-lactamase (MBL) genes. We describe an outbreak in an intensive care unit (ICU) possibly associated with contaminated sinks.
DESIGN, SETTING AND PARTICIPANTS: Four clusters of gram-negative bacteria harbouring the MBL gene blaIMP-4 were detected in the ICU at Dandenong Hospital between November 2009 and July 2012. Epidemiological investigations were undertaken in order to identify a common point source. During September 2012, screening using rectal swabs for all ICU patients, and environmental swabs targeting all ICU handwashing sinks and taps were collected. Samples were cultured onto selective carbapenem-resistant Enterobacteriaceae (CRE) agar. Suspected CRE isolates were further characterised using the modified Hodge test and VITEK 2 and confirmed by polymerase chain reaction and sequencing of MBL genes. Clinical and environmental CRE isolates were typed by pulsed-field gel electrophoresis.
Ten clinical isolates and one screening isolate of CRE (consisting of Klebsiella pneumoniae [5], Serratia marcescens [4], Enterobacter cloacae [1] and Escherichia coli [1]) were detected with the blaIMP-4 gene over the 30-03 period. S. marcescens was isolated persistently from the grating and drain of eight central sinks. Molecular typing confirmed that clinical and environmental isolates were related. Tap water cultures were negative. Several attempts to clean and decontaminate the sinks using detergents and steam cleaning proved unsuccessful.
This report highlights the importance of identification of potential environmental reservoirs, such as sinks, for control of outbreaks of environmentally hardy multiresistant organisms.
由于获得性金属β-内酰胺酶（MBL）基因的出现，碳青霉烯类抗生素的临床实用性受到威胁。我们描述了一起可能与污染水槽有关的重症监护病房（ICU）爆发事件。
设计、地点和参与者：2009 年 11 月至 2012 年 7 月，在丹德农医院的 ICU 中检测到 4 株携带 MBL 基因 blaIMP-4 的革兰氏阴性菌簇。进行了流行病学调查，以确定一个共同的源头。2012 年 9 月，对所有 ICU 患者进行直肠拭子筛查，并对所有 ICU 洗手水槽和龙头进行环境拭子采集。将样本接种到选择性碳青霉烯类耐药肠杆菌科（CRE）琼脂上。对疑似 CRE 分离株进行改良 Hodge 试验和 VITEK 2 进一步鉴定，并通过聚合酶链反应和 MBL 基因测序进行确认。对临床和环境 CRE 分离株进行脉冲场凝胶电泳分型。
在 30-03 期间，共检测到 10 株临床 CRE 分离株和 1 株筛查分离株（包括肺炎克雷伯菌[5]、粘质沙雷菌[4]、阴沟肠杆菌[1]和大肠埃希菌[1]），均带有 blaIMP-4 基因。8 个中央水槽的格栅和排水口持续分离出粘质沙雷菌。分子分型证实临床和环境分离株相关。自来水培养物呈阴性。使用清洁剂和蒸汽清洁多次尝试清洁和消毒水槽均不成功。
本报告强调了识别潜在环境储库（如水槽）对于控制环境适应性强的多耐药生物体爆发的重要性。
