Rapid Detection and Monitoring of Flavobacterium psychrophilum in Water by Using a Handheld, Field‐Portable Quantitative PCR System

Abstract

Advances in technology are making it easier for rapid, field detection of microbes in aquaculture. Specifically, real‐time polymerase chain reaction (qPCR) analysis, which has traditionally been confined to laboratory‐based protocols, is now available in a handheld field‐portable system. The feasibility of using the Biomeme handheld qPCR system for rapid (Flavobacterium psychrophilum from filtered water samples was evaluated. Paired water samples were collected over a 23‐d period from microcosm tanks that housed fish injected with known F. psychrophilum levels. Water samples were filtered through 0.45 μm nitrocellulose filters and analyzed with both the Biomeme qPCR platform and a traditional bench qPCR protocol. Both methods identified similar fluctuations in F. pychrophilum DNA throughout the study. Standard curves relating quantification cycles to the number of F. pychrophilum colony forming units (CFU) were constructed and analyzed, and results indicate that CFU increased rapidly between days 6 and 8 of the trial, then progressively decreased during the remaining 15 days. Average calculated log(CFU/mL) values were significantly correlated between the two platforms (r = 0.79, p = 0.006). Rapid, field‐based qPCR can be incorporated into daily water quality monitoring protocols to help detect and monitor microbes in aquaculture systems.