Comparison of DOT-ELISA and Standard-ELISA for Detection of the Vibrio cholerae Toxin in Culture Supernatants of Bacteria Isolated from Human and Environmental Samples

Abstract

A comparison of DOT-ELISA and Standard-ELISA was made for detection of Vibrio cholerae toxin in culture supernatants of bacteria isolated from human and environmental samples. A total of 293 supernatants were tested in a double blind assay. A correlation of 100 % was obtained between both techniques. The cholera toxin was found in 20 Inaba and 3 Ogawa strains. Positive samples were from seafood (17 samples), potable water (1 sample) and sewage (5 samples). The DOT-ELISA was useful as the standard-ELISA to confirm the presence of cholera toxin in the environmental samples.

Label-free, real-time monitoring of membrane binding events at zeptomolar concentrations using frequency-locked optical microresonators

“…S3c). After lipid functionalization, microtoroids still maintained a high Q-factor in the range of ~10 6 which is suitable for high-sensitivity biosensing (Fig. S3d).…”

“…For bare microtoroids, we generally obtained Q-factors in the range of 10 6 -10 7 in aqueous buffer solution. The Q-factors of optical microresonator cavities in aqueous solutions are typically lower than in air due to the smaller difference in refractive index between the resonator material and surrounding environment (Fig.…”

“…Conventional methods for studying membrane-protein binding events include the use of in vivo animal models 4 (typically functional readouts with implied affinities) or selected cells in vitro 5 . Enzyme linked-immunosorbent assays (ELISA), 6 liposome microarrays, 7,8 radioisotope labeling assays, 9 and fluorescent imaging 10 are also methods used with cells or tissue homogenates to ascertain these interactions, each having limitations such as those described above. Of particular interest are label-free sensing schemes, which can directly and rapidly detect the binding of molecular ligands to receptors targets.…”

Solid-phase enzyme-linked immunosorbent assay (direct option) for detecting toxigenic vibrio cholerae serogroups О1 and О139

“…Кроме того, в ряде ситуаций прямое выявление токсина остаётся предпочтительным, поскольку отмечен высокий уровень мутаций в локусе ctx, которые могут приводить к ложноотрицательным результатам [Ahn-Yoon et al, 2003;Tuteja et al, 2007; Петрова и др., 2009; Алексеева и др., 2019; Bayat et al, 2019]. В связи с этим одновременно используются и иммунологические методы с высокой чувствительностью и специфичностью, так как штаммы холерных вибрионов Эль Тор и серогруппы О139 отличаются низким уровнем продукции токсина in vitro [Shlyapnikov et al, 2012;Meza-Lucas et al, 2016]. В последние годы отечественными специалистами зарегистрированы две тестсистемы: иммунохроматографическая «Тест-полоска Vibrio cholerae tox + » [Баранова и др., 2020] и сэндвич-вариант «Тест-система ИФА для определения продукции ХТ штаммами V. cholerae» [Михеева и др., 2014.].…”