title: A Cell Phone-Based Microphotometric System for Rapid Antimicrobial Susceptibility Testing.
abstract: This study demonstrates a low-cost, portable diagnostic system for rapid antimicrobial susceptibility testing in resource-limited settings. To determine the antimicrobial resistance phenotypically, the growth of pathogens in microwell arrays is detected under different antibiotic conditions. The use of a colorimetric cell viability reagent is shown to significantly improve the sensitivity of the assay compared with standard absorbance spectroscopy. Gas-permeable microwell arrays are incorporated for facilitating rapid bacterial growth and eliminating the requirement of bulky supporting equipment. Antibiotics can also be precoated in the microwell array to simplify the assay protocol toward point-of-care applications. Furthermore, a low-cost cell phone-based microphotometric system is developed for detecting the bacterial growth in the microwell array. By optimizing the operating conditions, the system allows antimicrobial susceptibility testing for samples with initial concentrations from 10(1) to 10(6) cfu/mL. Using urinary tract infection as the model system, we demonstrate rapid antimicrobial resistance profiling for uropathogens in both culture media and urine. With its simplicity and cost-effectiveness, the cell phone-based microphotometric system is anticipated to have broad applicability in resource-limited settings toward the management of infectious diseases caused by multidrug-resistant pathogens.
authors.affiliation: Department of Agricultural and Biosystems Engineering, University of Arizona, Tucson, AZ, USA.
authors.forename: Meichei Wang
authors.initials: MW
authors.lastname: Kadlec
authors.affiliation: Department of Agricultural and Biosystems Engineering, University of Arizona, Tucson, AZ, USA.
authors.forename: David
authors.initials: D
authors.lastname: You
authors.affiliation: Department of Urology, Stanford University, Palo Alto, CA, USA.
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Liao
authors.affiliation: Department of Agricultural and Biosystems Engineering, University of Arizona, Tucson, AZ, USA Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, AZ, USA Biomedical Engineering and Bio5 Institute, University of Arizona, Tucson, AZ, USA pak@email.arizona.edu.
authors.forename: Pak Kin
authors.initials: PK
authors.lastname: Wong
mesh_terms: D000667:Ampicillin / Q000494:pharmacology / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D057205:Automation, Laboratory / Q000295:instrumentation; D040421:Cell Phone; D002863:Chromogenic Compounds / Q000378:metabolism; D002939:Ciprofloxacin / Q000494:pharmacology / Q000627:therapeutic use; D004338:Drug Combinations; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000382:microbiology* / Q000652:urine; D006801:Humans; D056656:Lab-On-A-Chip Devices; D046228:Microarray Analysis / Q000295:instrumentation; D008826:Microbial Sensitivity Tests / Q000295:instrumentation*; D050296:Microbial Viability; D015591:Microspectrophotometry / Q000295:instrumentation; D010084:Oxidation-Reduction; D019095:Point-of-Care Systems; D013419:Sulfamethizole / Q000494:pharmacology / Q000627:therapeutic use; D013778:Tetrazolium Salts / Q000378:metabolism; D014295:Trimethoprim / Q000494:pharmacology / Q000627:therapeutic use; D014552:Urinary Tract Infections / Q000188:drug therapy / Q000382:microbiology* / Q000652:urine; D000096926:Benzenesulfonamides
chemical_list: D000667:Ampicillin; D000900:Anti-Bacterial Agents; D002863:Chromogenic Compounds; D002939:Ciprofloxacin; D004338:Drug Combinations; D013419:Sulfamethizole; D013778:Tetrazolium Salts; D014295:Trimethoprim; C476329:2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H tetrazolium monosodium salt; C029078:trimethoprim sulfamethizole; D000096926:Benzenesulfonamides
keywords: clinical automation; lab-on-a-chip; microtechnology; point-of-care testing (POCT)