Sanchez Inma, Garcia-Nuñez Marian, Ragull Sonia, Sopena Nieves, Pedro-Botet Maria Luisa, Rey-Joly Celestino, Sabria Miquel, Esteve Maria
Infectious Diseases Unit, Hospital Universitari Germans Trias i Pujol, Autonomous University of Barcelona, Badalona, Spain.
Environ Microbiol. 2008 Feb;10(2):395-9. doi: 10.1111/j.1462-2920.2007.01460.x.
Genotypic variability and clonal persistence are important concepts in molecular epidemiology as they facilitate the search for the source of sporadic cases or outbreaks of legionellosis. We studied the genotypic variability and persistence of Legionella pulsed-field gel electrophoresis (PFGE) patterns over time (period > 6 months) in 34 positive cooling towers from two different areas. In area A, radius of 70 km, 52 indistinguishable PFGE patterns were differentiated among the 27 cooling towers. In 13 cooling towers we observed >or= 2 PFGE patterns. Each cooling tower had its own indistinguishable Legionella PFGE pattern which was not shared with any other cooling tower. In area B, radius of 1 km, 10 indistinguishable PFGE patterns were obtained from the seven cooling towers. In four, we observed >or= 2 PFGE patterns. Three of these 10 indistinguishable PFGE patterns were shared by more than one cooling tower. In 27 of 34 cooling towers the same PFGE pattern was recovered after 6 months to up to 5 years of follow-up. The large genotypic diversity of Legionella observed in the cooling towers aids in the investigation of community outbreaks of Legionnaires' disease. However, shared patterns in small areas may confound the epidemiological investigation. The persistence of some PFGE patterns in cooling towers makes the recovery of the Legionella isolate causing the outbreak possible over time.
基因型变异性和克隆持续性是分子流行病学中的重要概念，因为它们有助于寻找散发病例或军团病暴发的源头。我们研究了来自两个不同区域的34个阳性冷却塔中军团菌脉冲场凝胶电泳（PFGE）图谱随时间（超过6个月）的基因型变异性和持续性。在A区域，半径70公里，27个冷却塔中区分出52种无法区分的PFGE图谱。在13个冷却塔中，我们观察到≥2种PFGE图谱。每个冷却塔都有其自身无法区分的军团菌PFGE图谱，且不与任何其他冷却塔共享。在B区域，半径1公里，从7个冷却塔中获得了10种无法区分的PFGE图谱。在4个冷却塔中，我们观察到≥2种PFGE图谱。这10种无法区分的PFGE图谱中有3种被不止一个冷却塔共享。在34个冷却塔中的27个中，经过6个月至长达5年的随访后，回收了相同的PFGE图谱。在冷却塔中观察到的军团菌的大量基因型多样性有助于调查军团病的社区暴发。然而，小区域内共享的图谱可能会混淆流行病学调查。冷却塔中某些PFGE图谱的持续性使得随着时间的推移有可能回收导致暴发的军团菌分离株。
