RETRACTED: Evaluation of colorimetric loop-mediated isothermal amplification assay for visual detection of Streptococcus agalactiae and Streptococcus iniae in tilapia

Abstract

Significance and Impact of Study: The application of colorimetric LAMP with pre-addition of calcein offers simple, rapid and sensitive technique with applicability for small field laboratories. This technique explored the possible vertical transmission mode of Strep. agalactiae and Strep. iniae under natural aquatic environment. It could be such preliminary data provided for the screening broodstock before breeding and/or the specific-pathogen-free production. AbstractStreptococcus agalactiae and Strep. iniae are bacterial pathogens that cause streptococcosis in many fish species. An accelerated colorimetric loop-mediated isothermal amplification (LAMP) assay with pre-addition of calcein was established, and the transmission and detection of Strep. agalactiae and Strep. iniae in tilapia under natural aquatic environment were investigated. A positive reaction was observed by a colour change from orange to green through the naked eyes after completion at 63°C for 30 min with 10 times higher sensitivity than that of nested PCR assays and without cross-amplification with other fish bacterial pathogens. All sample types of Nile and red tilapia (broodstock, fertilized egg, fry) were Strep. agalactiae-and Strep. iniae positive by this new method, implying that they could be vertically transmitted. With its application for screening broodstock and fry before stocking and for monitoring fish health in grow-out ponds, the method would become very useful in fish farming industry.

Rapid detection of Streptococcus uberis in raw milk by loop-mediated isothermal amplification

“…Applications of LAMP for the detection of mastitiscausing pathogens (Tie et al, 2012;Suebsing et al, 2013) and relevant resistance genes (i.e., for methicillinresistant Staph. aureus and extended-spectrum betalactamase; Anjum et al, 2013;Su et al, 2014) have been reported.…”

Vertical transmission and concurrent infection of multiple bacterial pathogens in naturally infected red tilapia (Oreochromisspp.)

“…Previous studies have confirmed that LAMP assay can be more specific and sensitive than other conventional molecular tools for identifying virulent pathogens from tilapia (Suebsing et al . ; Suebsing, Kampeera, Sirithammajak, Withyachumnarnkul et al . ; Suebsing, Kampeera, Sirithammajak, Pradeep et al .…”

“…So far, disease studies on tilapia have overlooked the synergistic effect of mixed pathogens and the risk of vertical transmission of these pathogens. Recent studies have provided some evidence that vertical transmission could be a route for transmission of some diseases between generations of tilapia (Suebsing, Kampeera, Tookdee, Withyachumnarnkul, Turner & Kiatpathomchai ; Suebsing, Kampeera, Sirithammajak, Pradeep, Jitrakorn, Arunrut, Sangsuriya, Saksmerprome, Senapin, Withyachumnarnkul & Kiatpathomchai ; Suebsing, Kampeera, Sirithammajak, Withyachumnarnkul, Turner & Kiatpathomchai ; Pradeep, Suebsing, Sirthammajak, Kampeera, Jitrakorn, Saksmerprome, Turner, Palang, Vanichviriyakit, Senapin, Kiatpathomchai & Withyachumanarnkul ). However, confirmation of vertical transmission for other commonly reported pathogens in tilapia farming is still lacking.…”

Development of a loop-mediated isothermal amplification assay for the detection and quantification of epizootic epitheliotropic disease virus (salmonid herpesvirus-3)

“…In total, these quantification results lend further support to that this qLAMP assay can serve as an early valuable detection tool both in the laboratory and under field conditions. In addition, calcein is a complexmetric indicator meaning that positive reactions can be visualized by the naked eye, a matter that allows the LAMP reaction to be performed in fish hatcheries under field conditions (Suebsing et al, 2013(Suebsing et al, , 2015. Q.…”