Design of an optical nanobiosensor for detection of Legionella pneumophila in water samples

Background and Objectives: Legionella spp. is a causative agent of Legionnaires disease that creates public health prob- lems. Isolation of these bacteria from water sources is essential to identify outbreak origins and prevent disease. Diagnostic biosensors for water quality control to protect consumers from water-borne infections can predict many outbreaks. Gold nanoparticles conjugated probes are a new generation of diagnostic tools. In this study, an optical nano biosensor was de- signed and characterized to detect Legionella pneumophila in water samples rapidly. Materials and Methods: Thiolated probes designed for the mip gene were attached to gold nanoparticles and then water samples containing Legionella pneumophila were examined. Results: The limit of detection for PCR and biosensor was 10^4 and 10^3 copy numbers/μl, respectively. Biosensor sensitivity and PCR were reported to be 90% (18 out of 20) and 85% (17 out of 20), respectively. Specificity 100% has been reported for both methods. Conclusion: According to the obtained results, this method has the potential to diagnose L. pneumophila with high sensi- tivity and specificity. This system can be employed as a practical tool for rapid, accurate, high-sensitivity, and acceptable detection of Legionella pneumophila in contaminated water, which is cost- effective in terms of cost and time.