A fast impedance-based antimicrobial susceptibility test

Abstract

There is an urgent need to develop simple and fast antimicrobial susceptibility tests (ASTs) that allow informed prescribing of antibiotics. Here, we describe a label-free AST that can deliver results within an hour, using an actively dividing culture as starting material. The bacteria are incubated in the presence of an antibiotic for 30 min, and then approximately 105 cells are analysed one-by-one with microfluidic impedance cytometry for 2–3 min. The measured electrical characteristics reflect the phenotypic response of the bacteria to the mode of action of a particular antibiotic, in a 30-minute incubation window. The results are consistent with those obtained by classical broth microdilution assays for a range of antibiotics and bacterial species.

A Novel Bioimpedance-Based Detection of Miltefosine Susceptibility Among Clinical Leishmania donovani Isolates of the Indian Subcontinent Exhibiting Resistance to Multiple Drugs

“…Hence, we further tried to focus on membrane fluidity which has also been previously reported to be higher in SSG-R isolates ( Mukhopadhyay et al., 2011 ). Recently, impedance-based spectral analysis has been shown to correctly determine anti-microbial susceptibility in drug-resistant bacterial pathogens ( Spencer et al., 2020 ). Our impedimetric analysis could only detect the degree of Mil susceptibility among different LD isolates showing differential susceptibility towards different anti-leishmanial drugs, probably owing to the significantly higher membrane fluidity of Mil-R isolates.…”

Nanomotion Detection-Based Rapid Antibiotic Susceptibility Testing

“…Changes in biophysical properties of bacteria measured by impedance cytometry. [42] Electrochemical Measurement of the change in current due to electrochemical reactions. [43][44][45] Electrical AST (e-AST)…”

Recent Advances in Electrical Impedance Sensing Technology for Single-Cell Analysis

“…Recent IFC devices applied in single-cell analysis are summarized in Table 1 . These applications, discussed in this subsection, are simply classified according to cell species, including blood cells [ 110 , 111 , 112 , 113 , 114 ], tumor cells [ 43 , 52 , 115 , 116 , 117 , 118 , 119 , 120 , 121 , 122 ], stem cells [ 123 , 124 , 125 , 126 , 127 ], plant cells [ 60 , 128 , 129 , 130 , 131 , 132 ] and microbes [ 53 , 62 , 133 , 134 , 135 , 136 , 137 , 138 , 139 , 140 , 141 ]. In terms of blood cells, researchers focused on the identification and counting of normal or diseased blood cells.…”

“…IFC devices have been utilized extensively in detection, separation and viability analysis of unicellular microbes, including bacteria [ 53 , 62 , 133 , 134 , 135 , 140 , 141 ], protozoa [ 136 , 149 ] and fungi [ 137 , 138 , 139 ].…”

“…In detail, the loss of membrane integrity corresponded to changes in impedance signal amplitude and phase ( Figure 7 D). Notably, Spencer et al developed a method to optimize the prescription of antibiotic by an impedance-based fast antimicrobial susceptibility test (iFAST) [ 141 ]. By applying microfluidic impedance cytometry with differential electrode configuration, the phenotype response (electrical opacity and electrical diameter) of Klebsiella pneumoniae ( K. pneumoniae ) to specific antibiotic was accurately analyzed.…”