Molecular Detection of PersistentFrancisella tularensisSubspeciesholarcticain Natural Waters

[摘要] Tularemia, caused by the bacteriumFrancisella tularensis, whereF. tularensissubspeciesholarcticahas long been the cause of endemic disease in parts of northern Sweden. Despite this, our understanding of the natural life-cycle of the organism is still limited. During three years, we collected surface water samples (n=341) and sediment samples (n=245) in two areas in Sweden with endemic tularemia. Real-time PCR screening demonstrated the presence ofF. tularenis lpnAsequences in 108 (32%) and 48 (20%) of the samples, respectively. The 16S rRNA sequences from those samples all grouped to the speciesF. tularensis. Analysis of the FtM19InDel region oflpnA-positive samples from selected sampling points confirmed the presence ofF. tularensissubspeciesholarctica-specific sequences. These sequences were detected in water sampled during both outbreak and nonoutbreak years. Our results indicate that diverseF. tularensis-like organisms, includingF. tularensissubsp.holarctica, persist in natural waters and sediments in the investigated areas with endemic tularemia.

[学科分类] 微生物学和免疫学