Section for Bacteriology, Norwegian Veterinary Institute, Ullevaalsveien 68, P.O. Box 750, Sentrum, 0106, Oslo, Norway.
Microb Ecol. 2012 Aug;64(2):370-7. doi: 10.1007/s00248-012-0023-0. Epub 2012 Feb 28.
We report the diversity and distribution of Francisella species in Norwegian coastal and fresh waters following a nationwide survey in which water and sediment samples were collected from locations spanning almost the entire Norwegian coastline. In total, samples were obtained from 149 and 64 seawater and freshwater sites, respectively. DNA extracts from these environmental samples were initially screened by polymerase chain reaction (PCR) using Francisella genus-specific 16S rDNA primers. Positive samples were then amplified with genus-specific primers targeting Francisella succinate dehydrogenase A gene and Francisella philomiragia group-specific sequences for the SAICAR synthetase/phosphoribosylamine-glycine ligase gene. Francisella-related bacteria were identified in approximately 30% of seawater sampled sites, mainly in southern Norway, although a single positive sample was identified in the far north of the country. No PCR positives were identified from the freshwater sources. Sequences related to recognised species, both pathogenic and environmental, were identified, with the majority closely associated with F. philomiragia. However, a number of identified sequences probably represent previously undescribed species. Our data provide evidence of a significant background of Francisella spp. in geographical areas associated with outbreaks of fish francisellosis in Norway.
我们报告了挪威沿海和淡水弗朗西斯菌属物种的多样性和分布情况，这是一项全国性调查的结果，调查中采集了来自几乎整个挪威海岸线的水样和沉积物样。总共从 149 个海水和 64 个淡水地点获得了样本。从这些环境样本中提取的 DNA 提取物最初通过聚合酶链反应（PCR）用弗朗西斯菌属特异性 16S rDNA 引物进行筛选。阳性样本随后用特异性针对琥珀酸脱氢酶 A 基因和 SAICAR 合成酶/磷酸核糖胺-甘氨酸连接酶基因的弗朗西斯菌属菲洛米利亚组特异性序列的引物进行扩增。在大约 30%的海水采样点中发现了与弗朗西斯菌相关的细菌，主要在挪威南部，但在该国最北部也发现了一个阳性样本。从淡水来源中未鉴定出 PCR 阳性样本。鉴定出与已识别的物种相关的序列，包括致病性和环境性物种，其中大多数与 F. philomiragia 密切相关。然而，一些鉴定出的序列可能代表以前未描述的物种。我们的数据提供了证据，表明在与挪威鱼类弗朗西斯菌病爆发相关的地理区域中，存在大量背景弗朗西斯菌属物种。
