Understanding of colistin usage in food animals and available detection techniques: a review

Progress in the medical profession is determined by the achievements and effectiveness of new antibiotics in the treatment of microbial infections. However, the development of multiple-drug resistance in numerous bacteria, especially Gram-negative bacteria, has limited the treatment options. Due to this resistance, the resurgence of cyclic polypeptide drugs like colistin remains the only option. The drug, colistin, is a well-known growth inhibitor of Gram-negative bacteria like Acinetobacter baumanni, Enterobacter cloacae, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Technological advancements have uncovered the role of the mcr-1(mobilized colistin resistance) gene, which is responsible for the development of resistance in Gram-negative bacteria, which make them distinct from other bacteria without this gene. Additionally, food animals have been determined to be the reservoir for colistin resistance microbes, from which they spread to other hosts. Due to the adverse effects of colistin, many developed countries have prohibited its usage in animal foods, but developing countries are still using colistin in animal food production, thereby imposing a major risk to the public health. Therefore, there is a need for implementation of sustainable measures in livestock farms to prevent microbial infection. This review highlights the negative effects (increased resistance) of colistin consumption and emphasizes the different approaches used for detecting colistin in animal-based foods as well as the challenges associated with its detectio

Milk adulterant detection: Conventional and biosensor based approaches: A review

Milk adulteration is one of the major global concerns as milk is being consumed as a wholesome dairy product in every part of the world. The fraudulent practice of milk adulteration is on the rise, which is making people apprehensive about the purity and quality of milk. The adulterants such as water, vegetable and animal fat, extraneous proteins and chemical components viz. melamine, urea, formalin, detergents, ammonium sulphate, boric acid, caustic soda, benzoic acid, salicylic acid, hydrogen peroxide and sugars deliberately mixed in milk can be an be harmful to the health of consumers. This necessitates the availability of procedures and technologies that could curb this ill practice of milk adulteration. Over the years, various methods have been developed for the detection of milk adulterants. The chromatographic methods such as HPLC and GC, coupled with mass spectrometry have been used for selective identification as well as detection of different milk adulterants. Immunological techniques such as ELISA and various DNA based procedures like PCR have also been used for the specific detection of some common milk adulterants. Spectroscopic methods, namely FTIR and NIR in association with chemometrics have raised the bar of adulterant detection systems. The equipments such as electronic nose and electronic tongue are some of the fancy procedures used in milk and other food adulterants detection. The biosensors are the detection systems that can be used for rapid and real time detection of milk adulterants. This review brings insight into the biosensor application in milk adulterant detection and also tries to explore the potential of biosensors in identifying some common milk adulterants

Advancements in CRISPR-Based Biosensing for Next-Gen Point of Care Diagnostic Application

With the move of molecular tests from diagnostic labs to on-site testing becoming more common, there is a sudden rise in demand for nucleic acid-based diagnostic tools that are selective, sensitive, flexible to terrain changes, and cost-effective to assist in point-of-care systems for large-scale screening and to be used in remote locations in cases of outbreaks and pandemics. CRISPR-based biosensors comprise a promising new approach to nucleic acid detection, which uses Cas effector proteins (Cas9, Cas12, and Cas13) as extremely specialized identification components that may be used in conjunction with a variety of readout approaches (such as fluorescence, colorimetry, potentiometry, lateral flow assay, etc.) for onsite analysis. In this review, we cover some technical aspects of integrating the CRISPR Cas system with traditional biosensing readout methods and amplification technologies such as polymerase chain reaction (PCR), loop-mediated isothermal amplification (LAMP), and recombinase polymerase amplification (RPA) and continue to elaborate on the prospects of the developed biosensor in the detection of some major viral and bacterial diseases. Within the scope of this article, we also discuss the recent COVID pandemic and the numerous CRISPR biosensors that have undergone development since its advent. Finally, we discuss some challenges and future prospects of CRISPR Cas systems in point-of-care testing

Optical Density Optimization of Malaria Pan Rapid Diagnostic Test Strips for Improved Test Zone Band Intensity

For the last few decades, the immunochromatographic assay has been used for the rapid detection of biological markers in infectious diseases in humans and animals The assay, also known as lateral flow assay, is utilized for the detection of antigen or antibody in human infectious diseases. There are a series of steps involved in the development of these immuno-chromatographic test kits, from gold nano colloids preparation to nitrocellulose membrane coating (NCM). These tests are mostly used for qualitative assays by a visual interpretation of results. For the interpretation of the results, the color intensity of the test zone is therefore very significant. Herein, the study was performed on a malaria antigen test kit. Several studies have reported the use of gold nanoparticles (AuNPs) with varying diameters and its binding with various concentrations of protein in order to optimize tests. However, none of these studies have reported how to fix (improve) test zone band intensity (color), if different sized AuNPs were synthesized during a reaction and when conjugated equally with same amount of protein. Herein, different AuNPs with average diameter ranging from 10 nm to 50 nm were prepared and conjugated equally with protein concentration of 150 µg/mL with KD = 1.0 × 10−3. Afterwards, the developed kits’ test zone band intensity for all different sizes AuNPs was fixed to the same band level (high) by utilization of an ultraviolet-visible spectrophotometer. The study found that the same optical density (OD) has the same test zone band intensity irrespective of AuNP size. This study also illustrates the use of absorption maxima (λ max) techniques to characterize AuNPs and to prevent wastage of protein while developing immunochromatographic test kits