Identification and Antimicrobial Susceptibility Testing of Campylobacter Using a Microfluidic Lab-on-a-Chip Device.

Abstract

Campylobacter spp. have been recognized as major foodborne pathogens worldwide. An increasing frequency of antibiotic-resistant pathogens, including Campylobacter spp., have been identified to transmit from food products to humans and cause severe threats to public health. To better mitigate the antibiotic resistance crisis, rapid detection methods are required to provide timely antimicrobial resistance surveillance data for agri-food systems. Herein, we developed a polymer-based microfluidic device for the identification and antimicrobial susceptibility testing (AST) of Campylobacter spp. An array of bacterial incubation chambers were created in the microfluidic device, where chromogenic medium and antibiotics were loaded. The growth of Campylobacter spp. was visualized by color change due to chromogenic reactions. This platform achieved 100% specificity for Campylobacter identification. Sensitive detection of multiple Campylobacter species (C. jejuni, C. coli, and C. lari) was obtained in artificially contaminated milk and poultry meat, with detection limits down to 1 × 102 CFU/ml and 1 × 104 CFU/25 g, respectively. On-chip AST determined Campylobacter antibiotic susceptibilities by the lowest concentration of antibiotics that can inhibit bacterial growth (i.e., no color change observed). High coincidences (91% to 100%) of on-chip AST and the conventional agar dilution method were achieved against several clinically important antibiotics. For a presumptive colony, on-chip identification and AST were completed in parallel within 24 h, whereas standard methods, including biochemical assays and traditional culture-based AST, take several days for multiple sequential steps. In conclusion, this lab-on-a-chip device can achieve rapid and reliable detection of antibiotic-resistant Campylobacter spp.IMPORTANCE Increasing concerns of antibiotic-resistant Campylobacter spp. with regard to public health emphasize the importance of efficient and fast detection. This study described the timely identification and antimicrobial susceptibility testing of Campylobacter spp. by using a microfluidic device. Our developed method not only reduced the total analysis time, but it also simplified food sample preparation and chip operation for end users. Due to the miniaturized size of the lab-on-a-chip platform, the detection was achieved by using up to 1,000 times less of the reagents than with standard reference methods, making it a competitive approach for rapid screening and surveillance study in food industries. In addition, multiple clinically important Campylobacter species (C. jejuni, C. coli, and C. lari) could be tested by our device. This device has potential for wide application in food safety management and clinical diagnostics, especially in resource-limited regions.