“Rapid Identification and Antimicrobial Susceptibility Testing of Bacteria”

Brandon McNaughton, PhD and Duane Newton, PhD
- Third year of funding – 2010 funding: $150,649; funding to date $350,649

Emergent antimicrobial resistance in bacteria is one of the world’s most pressing health problems, and a major contributor to patient morbidity and mortality. Both the generation of new resistant strains and adverse effects of existing strains are effectively combated through accurate diagnosis and susceptibility testing of the specific pathogen responsible for an infection. But this is impeded by the slow turnaround of existing tests, two-four days.

The development of new antibiotics provides one avenue to address resistance, but alone this has proven to be a partial and temporary remedy in the ongoing battle against increased antimicrobial resistance. Instead, both new antimicrobials and technologies that will allow physicians to quickly determine appropriate antimicrobial therapy need to be developed. With current clinical instruments requiring several days to obtain results, there is a clear need to develop rapid means of identifying bacteria and determining their respective susceptibility to antibiotics, on the time-scale of hours rather than days. Fast methods for identifying antibiotic susceptibility are thus needed both to improve the efficacy of therapy, and to impede the severe health problems caused by rising bacterial resistance.

In a well-cited clinical study (Barenfanger 1999), a microbiology lab studied the effect of reducing AST time from 44.4 hours to 39.2 hours. With this five-hour reduction the hospital involved in the study saved a total of $4.2 million ($2,395/patient). In addition to these cost savings there were also measurable changes in patient outcomes, where the mortality rate of patients who had culture tests ordered dropped to 7.9% from 9.6%. The final major effect from reducing the AST time was a shorter hospital stay, where bed time was reduced by two days. We anticipate that the clinical impact of reducing AST time from 44.4 hours to within 8 hours, with our technology, will be even more dramatic.

The project team has fine-tuned an instrument that can perform identification and rapid antimicrobial resistance measurements on the time-scale of hours, substantially outperforming existing diagnostics. Building on the work completed in the Coulter Translational Research Partnership award they received last year, their current objective is to validate the technology for pathogen detection and susceptibility testing with urine samples in a clinical setting.

A list of all the U-M Coulter funded projects is found on the UM BME Coulter Site.

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This entry was posted by Brandon Baier on Monday, September 20th, 2010 at 11:28 am and is filed under All News, Faculty News, Spotlight.