Identification of Francisella tularensis by both culture and real-time TaqMan PCR methods from environmental water specimens in outbreak areas where tularemia cases were not previously reported

Tularemia is an endemic disease in Turkey. In this study, we aimed to detect Francisella tularensis by two methods from natural water supplies thought to cause tularemia epidemiologically. A total of 154 water specimens from three different outbreaks caused by drinking water were collected. Water specimens were cultured on antibiotic-added cysteine heart agar base with blood and incubated at 37°C in a humidified atmosphere containing 5% CO₂ for 4–10 days. The suspected colonies were confirmed by F. tularensis antiserum (BD) and the real-time TaqMan polymerase chain reaction (PCR) method. DNA was isolated from samples obtained from filters. The primer and probe sets targeting the ISFtu2 genome were used. A total of four F. tularensis isolates were obtained from 154 water samples. At the same time, the presence of F. tularensis DNA from 17 water specimens was shown by the real-time TaqMan PCR method. Although the DNA presence of F. tularensis has been detected from water sources by the PCR method in Turkey up to now, there has been no isolation directly from water specimens by culture. In this study, the determination of F. tularensis from water sources has been exhibited as the first data by both culture and real-time TaqMan PCR methods.