Rapid and sensitive detection of Pseudomonas aeruginosa in bottled water by loop-mediated isothermal amplification

A loop-mediated isothermal amplification (LAMP) assay for the rapid detection of Pseudomonas aeruginosa in bottled water was developed and evaluated. Four primers, including two outer primers and two inner primers, were specially designed by targeting the ecfX gene. The LAMP assay showed high specificity, with no false-positive or false-negative results among the 108 bacterial strains tested, including 81 strains of P. aeruginosa. The detection limit in pure culture was 15.7 CFU/mL, which is approximately 100-fold more sensitive than that of ecfX-PCR. In artificially contaminated water samples spiked with low level (3.1 CFU/250 mL) of P. aeruginosa, the LAMP assay could detect the target organisms accurately after 10 h of enrichment, in contrast to 12 h of enrichment for ecfX-PCR. In the case of bottled water samples, 9.17 % (10/109) of the samples were found to be positive by LAMP, which was in accordance with the results from GB 8538-2008 method. The LAMP assay established in this study is a simple, sensitive, and rapid protocol for the detection of P. aeruginosa. It provides an important diagnostic tool for the drinking water produce industry and regulatory agencies to better control potential risks associated with consumption of bottled water.