Determination of the bacterial pathogen Edwardsiella tarda in fish species by capillary electrophoresis with blue light‐emitting diode‐induced fluorescence

Abstract

High-performance capillary electrophoresis (HPCE) has been applied to the identification, separation, and quantitation of intact bacteria. We demonstrate that a pathogen (Edwardsiella tarda) which causes systemic infection in commercially important fish species can be rapidly identified and determined (< 10 min) after direct injection into fish fluid by CE blue light-emitting diode (LED)-induced fluorescence. SYTO 13 (488 nm/509 nm), a cell-permeable green nucleic acid stain, was used to stain the cells. Remarkably high efficiency (> 1,200,000 theoretical plates/m) was achieved with this rapid and efficient CE method. It was found that proper sample vortexing (90 s) would be beneficial to disperse aggregated cells and facilitate the focusing of intact cells during electrophoresis. Ionization of the surface constituents of Edwardsiella tarda cells provided efficient surface charges for the intact cells to be separated from the EOF and damaged or lysed cells when the separation was performed in running buffer (3.94 mM Tris, 0.56 mM borate, 0.013 mM EDTA) at pH 10.5. The limit of detection (LOD) and recovery were found to be 4.2 x 10(4) cells/mL and 70.0%, respectively. This proposed CE method could become an effective tool for diagnosis and tracking of certain diseases caused by bacteria in fish species as well as in human beings.

Isolation and identification of Escherichia coli and Edwardsiella tarda from fish harvested for human consumption from Zeway Lake, Ethiopia

“…The absence of significant difference in the occurrence of E.coli and E.tarda between male and female indicate that both sex are equally susceptible to the bacterium ,this is an agreement with several work were both sex are equal chance of being infected E.tarda (Savan et al, 2005;Yu et al, 2004). The isolation of E. coli and E. tarda, important zoonotic bacteria, from apparently healthy fish harvested for human consumption may indicate that the fish product presents potential risk to public health if consumed raw or improperly cooked.…”

CE detector based on light‐emitting diodes

“…Yu et al [40] demonstrated that a pathogen could be rapidly identified and determined after direct injection into fish fluid by CE-LED-induced fluorescence. SYTO 13 (488 nm/509 nm), a cell-permeable green nucleic acid stain, was used to stain the cells.…”

Optical fiber light‐emitting diode‐induced fluorescence detection for capillary electrophoresis

“…Due to their reduced size, low costs, and ease of operation, the possibility of using LEDs as excitation sources in CEinduced fluorescence detection has become very attractive. In the past decade, many efforts have been focused on the application of LED as light source in CE [16][17][18][19][20][21][22][23][24][25]. In these reports, a traditional mode of light excitation is still used.…”