A Cell Phone-Based Microphotometric System for Rapid Antimicrobial Susceptibility Testing

J Lab Autom. 2014 Jun;19(3):258-66. doi: 10.1177/2211068213491095. Epub 2013 May 22.


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.

Keywords: clinical automation; lab-on-a-chip; microtechnology; point-of-care testing (POCT).

Publication types

  • Validation Study

MeSH terms

  • Ampicillin / pharmacology
  • Ampicillin / therapeutic use
  • Anti-Bacterial Agents / pharmacology*
  • Anti-Bacterial Agents / therapeutic use
  • Automation, Laboratory / instrumentation
  • Cell Phone
  • Chromogenic Compounds / metabolism
  • Ciprofloxacin / pharmacology
  • Ciprofloxacin / therapeutic use
  • Drug Combinations
  • Drug Resistance, Multiple, Bacterial*
  • Escherichia coli / drug effects*
  • Escherichia coli / growth & development
  • Escherichia coli / metabolism
  • Escherichia coli Infections / drug therapy
  • Escherichia coli Infections / microbiology*
  • Escherichia coli Infections / urine
  • Humans
  • Lab-On-A-Chip Devices
  • Microarray Analysis / instrumentation
  • Microbial Sensitivity Tests / instrumentation*
  • Microbial Viability
  • Microspectrophotometry / instrumentation
  • Oxidation-Reduction
  • Point-of-Care Systems*
  • Sulfamethizole / pharmacology
  • Sulfamethizole / therapeutic use
  • Tetrazolium Salts / metabolism
  • Trimethoprim / pharmacology
  • Trimethoprim / therapeutic use
  • Urinary Tract Infections / drug therapy
  • Urinary Tract Infections / microbiology*
  • Urinary Tract Infections / urine


  • 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H tetrazolium monosodium salt
  • Anti-Bacterial Agents
  • Chromogenic Compounds
  • Drug Combinations
  • Tetrazolium Salts
  • Sulfamethizole
  • Ciprofloxacin
  • trimethoprim sulfamethizole
  • Ampicillin
  • Trimethoprim