Michaud Sophie, Menard Suzanne, Gaudreau Christiane, Arbeit Robert D
*Centre Hospitalier Universitaire de Sherbrooke and †Direction de la Santé Publique de l'Estrie, Sherbrooke, ‡Centre Hospitalier de l'Université de Montreal, Hôpital St-Luc, Montréal, Québec, Canada; §Research Service, VA Medical Center, and Department of Medicine, Boston University School of Medicine, Boston, MA, USA.
J Med Microbiol. 2001 Dec;50(12):1075-1081. doi: 10.1099/0022-1317-50-12-1075.
Pulsed-field gel electrophoresis (PFGE) was used to analyse 147 isolates collected in two regions of Quebec province (Estrie and Montreal) between March 1998 and Feb. 1999, to determine the utility of molecular strain typing for a population-based collection of Campylobacter jejuni and to compare directly the discriminatory power of SmaI and KpnI restriction digests. With a combination of epidemiological criteria including space and time plus molecular strain typing, 49% of isolates from Estrie and 39% of isolates from Montreal were identified as belonging to a putative cluster. For 41% of the cases, sources were either missing or explicitly unknown; the remaining sources were subject to recall bias. Thus, the evaluation of sporadic cases of campylobacter enteritis by descriptive clinical investigation alone is neither sensitive nor reliable for identifying sources of infection. In the PFGE analysis, KpnI digests provided appreciably greater discriminatory power than SmaI digests. When combining the PFGE analyses with basic epidemiological criteria, 30% of the putative SmaI clusters were inconsistent with the epidemiological criteria compared with 17% of the KpnI clusters. Among the 98 isolates assigned to clusters by SmaI, only 65% gave concordant results with KpnI. In contrast, among the 81 isolates assigned to clusters by KpnI, 92% gave concordant results with SmaI. Finally, clusters that were epidemiologically related to ingestion of raw milk and specific water sources correlated better with the typing results based on KpnI than SmaI. Thus, KpnI is the enzyme of choice for molecular epidemiology studies of C. jejuni. The combination of continuous epidemiological surveillance and molecular strain typing may be useful for identifying new sources and mechanisms of transmission for community-acquired C. jejuni infection andultimately for developing new approaches to prevention.
脉冲场凝胶电泳（PFGE）用于分析1998年3月至1999年2月在魁北克省两个地区（埃斯特里和蒙特利尔）收集的147株分离株，以确定分子菌株分型在基于人群的空肠弯曲菌收集方面的效用，并直接比较SmaI和KpnI限制性酶切的鉴别力。结合包括空间和时间在内的流行病学标准以及分子菌株分型，埃斯特里49%的分离株和蒙特利尔39%的分离株被鉴定为属于一个假定的聚类。对于41%的病例，来源缺失或明确未知；其余来源存在回忆偏倚。因此，仅通过描述性临床调查评估空肠弯曲菌肠炎散发病例对于识别感染源既不敏感也不可靠。在PFGE分析中，KpnI酶切比SmaI酶切具有明显更高的鉴别力。当将PFGE分析与基本流行病学标准相结合时，30%的假定SmaI聚类与流行病学标准不一致，而KpnI聚类为17%。在通过SmaI分配到聚类的98株分离株中，只有65%与KpnI结果一致。相比之下，在通过KpnI分配到聚类的81株分离株中，92%与SmaI结果一致。最后，与饮用生牛奶和特定水源摄入在流行病学上相关的聚类与基于KpnI的分型结果比基于SmaI的分型结果相关性更好。因此，KpnI是用于空肠弯曲菌分子流行病学研究的首选酶。持续的流行病学监测和分子菌株分型相结合可能有助于识别社区获得性空肠弯曲菌感染的新来源和传播机制，并最终用于开发新的预防方法。
