LeVoScan; a pre-enrichment PCR method for rapid detection of culturable Legionella pneumophila in water.

L. pneumophila is responsible for >90% of the legionellosis cases and is a public health concern. In the Netherlands, specific regulations have therefore been established to prevent Legionella contamination in public (drinking) water installations. These regulations include, among other measures, the periodic monitoring of the installations for the presence of Legionella. The Dutch government is currently revising the Legionella regulations which will include a more effective approach to public health risk management by focusing on L. pneumophila in most buildings. Therefore, a specific method for detection of culturable L. pneumophila is desirable. We, therefore, developed LeVoScan, a rapid pre-enrichment PCR method designed to specifically detect culturable L. pneumophila within 50 h. The method employs liquid pre-enrichment in a selective broth medium for 48 h at 37 °C followed by PCR confirmation to determine the presence or absence of L. pneumophila. LeVoScan was extensively validated and evaluated using real-world drinking water samples. Validation followed ISO16140-4 with ISO11731 as a reference method using naturally and artificially contaminated and uncontaminated drinking water samples. The results demonstrated that LeVoScan performs at least equivalent to the current standardized culture-based ISO 11731 reference method when applied to samples with low background flora. LeVoScan substantially reduced turnaround time, providing results five days faster than the reference method. This aspect, combined with operational simplicity and reduced material and waste requirements, makes LeVoScan a reliable, faster and more sustainable alternative for detection of culturable L. pneumophila in drinking water samples.