ABSTRACT
Carbapenemase-producing Gram-negative bacilli (CPGNB) is a type of antibiotic-resistant pathogens that often lead to severe clinical consequences. Phenotypic tests, such as Carba NP and blue Carba, are able to detect the resistant mechanism and provide rapid detection of carbapenemase producers to potentially guide personalized therapy. However, these tests require relatively tedious hands-on fluidic operations, and the assay format is ill-suited for automation and parallelization for improved throughput. In this study, we report an automated magnetic digital microfluidics-based platform, known as DropCarba, for parallel CPGNB detection in droplets. It automates the entire carbapenemase testing process and eliminates the need for almost all hands-on fluidic operations, which ensures high consistency and minimizes human errors with a simple "press-and-go" operation. DropCarba was validated with a large number of bacterial isolates of various Enterobacterales species (200 strains in total with 100 CPGNB and 100 non-resistant strains) in a blinded manner, and the results agree well with the benchmark Carba NP. DropCarba, with its full automation, simple operation, reduced reagent consumption, parallelization processing, and scalable manufacturing, will greatly improve CPGNB screening and make a valuable contribution to our fight against antibiotic resistance.
Subject(s)
Biosensing Techniques , Microfluidics , Humans , Bacteriological Techniques/methods , beta-Lactamases , Bacterial Proteins , Gram-Negative Bacteria , Magnetic Phenomena , Sensitivity and SpecificityABSTRACT
Carbapenemase-producing Enterobacteriaceae (CPE) are a group of drug-resistant Gram-negative pathogens that are classified as a critical threat by the World Health Organization (WHO). Conventional methods of detecting antibiotic-resistant pathogens do not assess the resistance mechanism and are often time-consuming and laborious. We have developed a magnetic digital microfluidic (MDM) platform, known as MDM Carba, for the identification of CPE by measuring their ability to hydrolyze carbapenem antibiotics. MDM Carba offers the ability to rapidly test CPE and reduce the amount of reagents used compared with conventional phenotypic testing. On the MDM Carba platform, tests are performed in droplets that function as reaction chambers, and fluidic operations are accomplished by manipulating these droplets with magnetic force. The simple droplet-based magnetic fluidic operation allows easy system automation and simplified hands-on operation. Because of the unique "power-free" operation of MDM technology, the MDM Carba platform can also be operated manually, showing great potential for point-of-care testing in resource-limited settings. We tested 27 bacterial isolates on the MDM Carba platform, and the results showed sensitivity and specificity that were comparable to those of the widely used Carba NP test. MDM Carba may shorten the overall turnaround time for CPE identification, thereby enabling more timely clinical decisions for better clinical outcomes. MDM Carba is a technological platform that can be further developed to improve diagnostics for other types of antibiotic resistance with minor modifications.
