Harkness G A, Bentley D W, Mottley M, Lee J
University of Rochester School of Medicine, University of Rochester Medical Center, NY.
Am J Infect Control. 1992 Jun;20(3):142-8. doi: 10.1016/s0196-6553(05)80181-6.
Although outbreaks involving Streptococcus pyogenes have been uncommon among the elderly population, recent reports suggest that this organism is an important nosocomial pathogen among institutionalized older patients and carries significant morbidity and mortality. An outbreak of S. pyogenes, type M12, T12, occurred in a large long-term care institution serving the ill and chronically disabled. The outbreak involved 14 residents of the intermediate care facility and lasted for 4 months.
A prospective epidemiologic investigation was initiated at the onset of the outbreak. Pertinent clinical and demographic information regarding both residents and personnel was obtained by interview, review of medical and surveillance records, and examination of patients for lesions. Cultures were obtained within 24 hours of symptom onset from those with characteristic clinical symptoms. Unpaired convalescent sera were tested for group A streptococcal extracellular antigens by a rapid hemagglutination slide test. Control measures included active surveillance of residents and staff for suspicious clinical syndromes, transfer of high-risk patients, elimination of a common seating area, and improved handwashing and hygiene measures.
The attack rate was 7.5%, with 64.3% of these patients residing on one unit. S. pyogenes was isolated from eight residents, 5 residents had a characteristic syndrome and an elevated streptozyme hemagglutination titer of 400, and 1 resident died within hours of having cellulitis of the groin. Clinical syndromes included cellulitis, pharyngitis, bronchitis, pneumonia, and septicemia. Seven residents required acute care; two residents died within 3 weeks of the onset, yielding a case fatality rate of 14.3%.
The major means of transmission appeared to be direct contact between residents, although transmission from an infected staff member may have accounted for some cases. The hypothesis of long-term colonization was supported by the extended times between infections. The severity of illness and the apparent transmission through direct contact between residents warrants (1) early detection of infected lesions, (2) recognition of invasive illness, (3) prompt effective treatment, and (4) surveillance for S. pyogenes infections among residents and personnel.
虽然化脓性链球菌引起的疫情在老年人群中并不常见，但最近的报告表明，这种病原体是机构化老年患者中一种重要的医院病原体，会导致显著的发病率和死亡率。在一家为患病和慢性残疾者服务的大型长期护理机构中发生了一起M12、T12型化脓性链球菌疫情。此次疫情涉及中级护理机构的14名居民，持续了4个月。
疫情爆发时启动了一项前瞻性流行病学调查。通过访谈、查阅医疗和监测记录以及检查患者的病变情况，获取了有关居民和工作人员的相关临床和人口统计学信息。对出现特征性临床症状的患者在症状出现后24小时内采集培养样本。通过快速血凝玻片试验对配对的恢复期血清进行A组链球菌细胞外抗原检测。控制措施包括对居民和工作人员进行可疑临床综合征的主动监测、转移高危患者、消除一个公共座位区以及改进洗手和卫生措施。
发病率为7.5%，其中64.3%的患者居住在一个单元。从8名居民中分离出化脓性链球菌，5名居民有特征性综合征且链激酶血凝滴度升高至400，1名居民在腹股沟蜂窝织炎发作数小时内死亡。临床综合征包括蜂窝织炎、咽炎、支气管炎、肺炎和败血症。7名居民需要急性护理；2名居民在发病后3周内死亡，病死率为14.3%。
主要传播途径似乎是居民之间的直接接触，不过感染的工作人员传播可能也导致了部分病例。感染之间的时间延长支持了长期定植的假设。疾病的严重程度以及居民之间通过直接接触的明显传播表明有必要（1）早期发现感染性病变，（2）识别侵袭性疾病，（3）及时进行有效治疗，以及（4）对居民和工作人员中的化脓性链球菌感染进行监测。
