We investigated the genotypes of Francisella tularensis (F. tularensis) strains isolated in Poland during the period 1953–2013 and studied their genetic relationship to F. tularensis strains isolated in other countries using MLVA. We examined the mosquito and tick samples collected in Poland for the presence of F. tularensis DNA using PCR. Our results revealed a high genetic diversity among the strains of F. tularensis collected from Poland, suggesting that the bacterium is commonly found in the environment. However, we did not detect F. tularensis DNA in ticks and mosquitoes, showing that the arthropod bites might not be the main source of infection.

We also propose the application of a practical assay called v4-genotyping that can be directly performed on the clinical and environmental samples.

In addition, we discovered genetic variations among Schu S4 reference strains used in various laboratories and showed that MLVA analysis should not be based on amplicon sizes only because point mutations occurring within the MLVA loci might not always be manifested by a change in the amplicon size.

我们调查了1953–2013年期间在波兰分离的弗朗西斯菌（T. tularensis）菌株的基因型，并使用MLVA研究了它们与在其他国家分离的T. tularensis菌株的遗传关系。我们使用PCR检查了在波兰收集的蚊子和壁虱样本中是否存在图拉菌F. tularensis DNA。我们的研究结果表明，从波兰收集的F. tularensis菌株之间具有很高的遗传多样性，这表明该细菌通常在环境中发现。但是，我们没有在虱子和蚊子中检测到土拉弗朗西斯菌DNA，这表明节肢动物叮咬可能不是主要的感染源。

我们还提出了可直接在临床和环境样本上进行的称为v4-基因分型的实用检测方法的应用。

此外，我们发现了在各个实验室使用的Schu S4参考菌株之间的遗传变异，并表明MLVA分析不应仅基于扩增子大小，因为MLVA基因座中发生的点突变可能并不总是通过扩增子大小的变化来体现。