Purpose: The discovery of the plasmid-mediated colistin resistance genes, mcr, revealed a mechanism of transmission of colistin resistance, which is a major, global public health concern especially among individuals infected with carbapenem-resistant Gram-negative bacteria. To monitor the spread and epidemiology of mcr genes, a convenient and reliable method to detect mcr genes in clinical isolates is needed, especially in the primary care institutions. This study aimed to establish a restriction endonuclease-based multiplex loop-mediated isothermal amplification (multi-LAMP) assay to detect mcr genes (mcr-1 to mcr-5) harbored by colistin-resistant bacteria. Methods: A triple-LAMP assay for mcr-1, mcr-3, and mcr-4 and a double-LAMP assay for mcr-2 and mcr-5 were established. The sensitivity and specificity of the LAMP reactions were determined via electrophoresis and visual detection. Results: The sensitivity of the LAMP assay was 10-fold greater than that of PCR, with high specificity among the screened primers. Specific mcr genes were distinguished in accordance with band numbers and the fragment length of the digested LAMP amplification products. Furthermore, the LAMP assay was confirmed as a rapid and reliable diagnostic technique upon application for clinical samples, and the results were consistent with those of conventional PCR assay. Conclusion: The multi-LAMP assay is a potentially promising method to detect mcr genes and will, if implemented, help prevent infections by drug-resistant bacteria in primary-care hospitals due to rapid and reliable surveillance. To our knowledge, this is the first study to report the application of LAMP to detect mcr-2 to mcr-5 genes and the first time that multi-LAMP has been applied to detect mcr genes.

Wang W, et al. Nutr Res Pract. 2023 Dec;17(6):1070-1083. https://doi.org/10.4162/nrp.2023.17.6.1070

Background: The objective of the present study is to examine the total phenolic and flavonoid content of an ethanol extract of Sanghuangporus sanghuang and to evaluate its phytochemical properties, antioxidant activity, and capacity to protect DNA from damage. This pharmaceutical/food resource mushroom may serve as a novel substitute functional food for health-conscious consumers, given its promising source of phenolics and flavonoids. Methods: S. sanghuang ethanol extract (SEE) was evaluated for total phenolic and flavonoid contents, while UPLC-MS analysis was used for terpenoids, phenylpropanoid, flavonoids, steroidal, phenols identification, and function prediction. Antioxidant and anti-DNA damage activities were tested in vitro using ferric reducing antioxidant power (FRAP), 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis-3-ethylbenzotiazolin-6-sulfonic acid (ABTS), and DNA damage protection assay. Results and Conclusion: Total phenolic content (TPC) in SEE was 385.38 ± 1.36 mg GA/g extract, while total flavonoid content (TFC) was 298.22 ± 2.38 mg QE/g extract. The extracts exhibited high antioxidant and free radical scavenging activities with relatively stronger free radical scavenging activity. A total of 491 metabolites were investigated by Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Most of the top 20 compounds were predicted to have various functions like antioxidant, anti-cancer and anti-inflammatory. This study highlighted S. sanghuang was a beneficial source of phenolics and flavonoids. It contains potential natural antioxidant that could be used as a lead contender in the development of antioxidant medicines for the treatment of a wide range of oxidative stress-related illnesses.