Research Projects

Multidrug resistance in hospital settings is caused mostly by a clique of gram-negative and gram-positive pathogens comprising Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp (ESKAPE). As per World Health Organisation (WHO) estimates, 1.27 million deaths were caused due to antibiotic resistant bacteria in 2019. Intercellular communication among the pathogens involve use of certain chemical molecules as signals or auto inducers. Such a phenomenon is termed as quorum sensing (QS), wherein the density of pathogens pertaining to an environment holds a direct correlation with the concentration of QS molecules. QS molecules for gram-negative and gram-positive bacteria include primarily acylated homoserine lactones (AHLs) and autoinducing peptides (AIPs) respectively. AHLs and AIPs facilitate nosocomial infections by controlling the bacterial virulence genes and reducing the immune response in the host body. Detection of QS molecules is therefore of utmost importance to combat antimicrobial resistance and bacterial virulence. Traditional techniques including High-Performance Liquid Chromatography-tandem Mass Spectrometry (HPLC-MS), Mass Spectrometry (MS) and Enzyme Linked Immunosorbent Assay (ELISA) have been utilised for detection of QS molecules. However, such techniques are time prohibitive and labour intensive in nature. Hence, there is a need for a simpler technique that enables real time monitoring of QS molecules in clinical samples including blood, urine and sputum of patients subjected to different nosocomial infections. In the last few decades, quartz crystal resonator (QCR) has been widely used for detection of various biomolecules. A QCR in conjunction with an appropriate biorecognition element including molecular imprinted polymer, recombinant protein and peptides, to name but a few will be explored for the first time for QS molecule detection. A QCR will be actuated and analysed using a novel fixed frequency drive (FFD) technique. A binding event resulting from an interaction between a QS molecule specific receptor immobilised QCR and a QS molecule is measured in terms of changes in resonance frequency and dissipation of a QCR. Resonance frequency and dissipation will be estimated from each impedance data point in FFD technique by utilising analytically derived expressions, which enables real time monitoring of QS molecules. The unique attributes of FFD method involving simplicity, high data acquisition capability and probable implementation on a microfluidic chip will lead to indirect and real time diagnosis of infections caused due to ESKAPE pathogens via monitoring of QS molecule concentrations specific to ESKAPE pathogens in clinical samples.