Graman P S, Quinlan G A, Rank J A
Department of Medicine, Strong Memorial Hospital, Rochester, NY, USA.
Infect Control Hosp Epidemiol. 1997 Sep;18(9):637-40. doi: 10.1086/647689.
To investigate a case of nosocomial legionellosis, identify pathways of transmission, and effect control of the environmental source.
Case investigation and environmental culture surveillance.
A 720-bed university teaching hospital. CASE PATIENT: A ventilator-dependent 66-year-old male developed nosocomial pneumonia due to Legionella pneumophila serogroup 6 after 3 months in an intensive-care unit (ICU). The patient had no intake of potable water except for ice chips from an ice machine in the ICU.
Cultures revealed L pneumophila serogroup 6 in the ice (4.3 colony-forming units/mL) and ice machine cold water (too numerous to count). Cultures from adjacent hot and cold taps, plus taps located near the patient, all were negative; ice machines and cold water on seven other patient units also were negative. Only sterile water had been used for tube feedings, mouth care, suctioning, and ventilator humidification. Hospital hot water previously had been colonized with L pneumophila serogroup 6, but all surveillance water cultures had been negative since chlorination of the hot-water system began the previous year; cold-water cultures had never before grown Legionella. The ice machine was disinfected with a 2-hour flush of 2.625% sodium hypochlorite. The supply line to the ice machine was replaced, and the cold-water pipe from the floor below was treated with 83 ppm sodium hypochlorite for 48 hours. All follow-up surveillance cultures of the ice machine remained negative through mid-1996. No additional cases of nosocomial legionellosis occurred.
Ice machines may be reservoirs of L pneumophila in hospitals. Both ice and water dispensed from these machines may be contaminated, and nosocomial transmission may occur. Successful long-term decontamination and control can be accomplished with shock chlorination.
调查一例医院内军团菌病病例，确定传播途径，并对环境源进行控制。
病例调查和环境培养监测。
一家拥有720张床位的大学教学医院。
一名66岁的男性，依赖呼吸机，在重症监护病房（ICU）住了3个月后，因嗜肺军团菌血清型6感染而患上医院内肺炎。该患者除了饮用ICU制冰机提供的冰块外，未摄入其他饮用水。
培养结果显示，冰块中（4.3个菌落形成单位/毫升）和制冰机冷水（菌数太多无法计数）存在嗜肺军团菌血清型6。相邻的冷热自来水龙头以及患者附近的水龙头培养结果均为阴性；其他七个患者单元的制冰机和冷水培养结果也为阴性。仅使用无菌水进行管饲、口腔护理、吸痰和呼吸机加湿。医院的热水此前曾被嗜肺军团菌血清型6定植，但自前一年对热水系统进行氯化处理以来，所有监测水样培养结果均为阴性；冷水培养此前从未培养出军团菌。制冰机用2.625%的次氯酸钠冲洗2小时进行消毒。更换了制冰机的供应管线，对来自楼下的冷水管用83 ppm的次氯酸钠处理48小时。到1996年年中，制冰机的所有后续监测培养结果均为阴性。未再发生医院内军团菌病病例。
制冰机可能是医院中嗜肺军团菌的储存源。从这些机器中取出的冰和水都可能被污染，从而可能发生医院内传播。通过冲击氯化可成功实现长期去污和控制。
