Ahn Gyun Yeol, Yu Feng Nan, Jang Sook Jin, Kim Dong-Min, Park Geon, Moon Dae Soo, Park Young Jin
Department of Laboratory Medicine, Chosun University Medical School, Gwangju, Korea.
Korean J Lab Med. 2007 Jun;27(3):205-9. doi: 10.3343/kjlm.2007.27.3.205.
We noticed an abrupt increase in the isolation of Stenotrophomonas maltophilia from bronchoalveolar lavage (BAL) specimens collected at Chosun University Hospital. We performed surveillance cultures in order to identify the source of what appeared to be a pseudo-outbreak.
To investigate a possible nosocomial outbreak of S. maltophilia, we performed culture of 11 environmental specimens obtained from a bronchoscopy room and two bronchoscopes. Pulsed-field gel electrophoresis (PFGE) was used to examine the genetic relatedness among the strains of S. maltophilia recovered from BAL specimens of 3 patients and 1 environmental sample, as well as 9 unrelated strains of S. maltophilia as a control.
During a 7 day-period in March 2006, S. maltophilia was isolated from the BAL specimens of 7 of 13 (54%) patients, compared to only 5 of 188 (2.6%) patients during the 6-month period prior to that period. S. maltophilia was isolated from 1 of the 11 environmental samples, which was obtained from a fiberoptic bronchoscope suction channel. All 7 patient isolates and one environmental isolate exhibited similar antibiotic susceptibility patterns. PFGE analysis of the genomic DNA from epidemic strains demonstrated an identical banding pattern, whereas each of epidemiologically unrelated strains showed a unique electrophoretic pattern.
Apparently one of the hospital bronchoscopes became contaminated with S. maltophilia during a bronchoscopic procedure. It is likely that subsequent specimen contamination occurred because the bronchoscope had been inadequately cleaned and disinfected. The pseudo-outbreak was controlled successfully by removing the source of infection.
我们注意到，在朝鲜大学医院采集的支气管肺泡灌洗（BAL）标本中，嗜麦芽窄食单胞菌的分离率突然增加。我们进行了监测培养，以确定这一看似假暴发的源头。
为调查嗜麦芽窄食单胞菌可能的医院内暴发情况，我们对从支气管镜检查室获取的11份环境标本和两台支气管镜进行了培养。脉冲场凝胶电泳（PFGE）用于检测从3例患者的BAL标本及1份环境样本中分离出的嗜麦芽窄食单胞菌菌株，以及9株不相关的嗜麦芽窄食单胞菌菌株（作为对照）之间的遗传相关性。
在2006年3月的7天时间里，13例患者中有7例（54%）的BAL标本分离出嗜麦芽窄食单胞菌，而在此之前的6个月期间，188例患者中只有5例（2.6%）分离出该菌。从11份环境样本中的1份（取自纤维支气管镜吸引通道）分离出嗜麦芽窄食单胞菌。所有7株患者分离株和1株环境分离株表现出相似的抗生素敏感性模式。对流行菌株的基因组DNA进行PFGE分析显示出相同的条带模式，而每株流行病学不相关的菌株都显示出独特的电泳模式。
显然，医院的一台支气管镜在一次支气管镜检查过程中被嗜麦芽窄食单胞菌污染。由于支气管镜未得到充分清洁和消毒，随后很可能发生了标本污染。通过消除感染源，成功控制了这次假暴发。
