Investigation of the Presence of Francisella tularensis and Acanthamoeba spp. in the Drinking Water of Sivas Province, Turkey

Introduction: Tularaemia is a zoonotic disease caused by Francisella tularensis. F. tularensis subsp. holarctica is primarily isolated in Northern Europe, the Balkans, Turkey, Siberia, and the Far East, and it is mostly responsible for waterborne outbreaks. F. tularensis, which is a facultative intracellular bacterium, may survive inside Acanthamoeba castellani, which is a free-living amoeba in water resources; this symbiotic life allows the bacteria to survive in water and mud for months. In this study, drinking water samples taken during the tularaemia outbreak and non-outbreak regions were compared in terms of the presence of Francisella tularensis and Acanthamoeba spp., and the role of Acanthamoeba was investigated in tularemia outbreaks observed in Turkey. Materials and Methods: This study was conducted in the province of Sivas located in the central Anatolia region in Turkey, and a total of 300 water samples were used. Glucose-cysteine-blood agar (GCBA) and non-nutrient agar (NNA) were used for the isolation of F. tularensis and Acanthamoeba, respectively. Each isolate was identified by PCR technique. Results: A total of 30 (10%) F. tularensis and 28 (9.33%) Acanthamoeba spp. isolates were produced by culture method. All bacterial strains were confirmed with PCR as to be F. tularensis subsp. holarctica. In our study, concurrent presence of F. tularensis and Acanthamoeba were detected in two water samples. There were no statistically significant differences between the water samples taken from outbreak and non-outbreak regions in terms of the presence of Acanthamoeba (p> 0.05). Conclusion: Even though experimental studies have shown that F. tularensis may survive inside Acanthamoeba spp. and its viability continues, our study could not identify a relationship between tularemia outbreak and Acanthamoeba spp. New research on this issue may have a contribution on tularemia epidemiology.