University of Calgary, Calgary, Canada.
PLoS One. 2011;6(12):e28547. doi: 10.1371/journal.pone.0028547. Epub 2011 Dec 27.
Outbreaks of invasive pneumococcal disease (IPD) typically occur within institutions. Beginning in 2005, we detected an increase in serotype (ST) 5 and ST8 IPD cases, predominantly in homeless persons living in an open community.
METHODOLOGY/PRINCIPAL FINDINGS: CASPER (Calgary Area S. pneumoniae Epidemiology Research) surveillance study of all IPD (sterile site isolates) in our region (pop ~1,100,000). Interviews and chart reviews of all cases and all isolates phenotypically analyzed and selected isolated tested by multi-locus sequence typing (MLST).
CONCLUSIONS/SIGNIFICANCE: During 2005-2007, 162 cases of ST5 IPD and 45 cases of ST8 IPD were identified. The isolates demonstrated phenotypic and genotypic clonality. The ST5 isolates were sequence type (ST) 289 and demonstrated intermediate susceptibility to TMP-SMX. The ST8 isolates were predominantly ST1268, with a susceptible antimicrobial susceptibility profile. Individuals with ST5 IPD were more likely to be middle aged (OR 2.6), homeless (OR 4.4), using illicit drugs(OR 4.8), and asthmatic(OR 2.6). Those with ST8 were more likely to be male (OR 4.4), homeless (OR 2.6), aboriginal (OR7.3), and a current smoker (OR 2.5). Overlapping outbreaks of ST5 and ST8 IPD occurred in an open community in Calgary, Canada and homelessness was a predominant risk factor. Homelessness represents a unique community in which pneumococcal outbreaks can occur.
侵袭性肺炎球菌病 (IPD) 的爆发通常发生在医疗机构内。自 2005 年以来，我们发现血清型 (ST) 5 和 ST8 IPD 病例有所增加，主要发生在居住在开放社区的无家可归者中。
方法/主要发现：我们对本地区（人口约 110 万）所有侵袭性肺炎球菌病（无菌部位分离株）进行了 CASPER（卡尔加里地区肺炎球菌流行病学研究）监测研究。对所有病例进行访谈和图表审查，并对所有分离株进行表型分析和选择，通过多位点序列分型 (MLST) 进行测试。
结论/意义：在 2005 年至 2007 年期间，确定了 162 例 ST5 IPD 和 45 例 ST8 IPD。这些分离株表现出表型和基因型克隆性。ST5 分离株为序列型 (ST) 289，对 TMP-SMX 具有中度敏感性。ST8 分离株主要为 ST1268，具有敏感的抗菌药物敏感性谱。ST5 IPD 患者更有可能是中年人（OR 2.6）、无家可归者（OR 4.4）、使用非法药物（OR 4.8）和哮喘患者（OR 2.6）。ST8 患者更有可能是男性（OR 4.4）、无家可归者（OR 2.6）、原住民（OR7.3）和当前吸烟者（OR 2.5）。ST5 和 ST8 IPD 在加拿大卡尔加里的一个开放社区中发生了重叠爆发，无家可归是一个主要的危险因素。无家可归者代表了一个独特的社区，其中可能会发生肺炎球菌爆发。
