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

Legionella spp. is a causative agent of Legionnaires' disease that creates public health problems. 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 designed and characterized to detect Legionella pneumophila in water samples rapidly.

Thiolated probes designed for the mip gene were attached to gold nanoparticles and then water samples containing Legionella pneumophila were examined.

The limit of detection for PCR and biosensor was 10⁴ and 10³ 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.

According to the obtained results, this method has the potential to diagnose L. pneumophila with high sensitivity 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.