This technology could provide medical labs a quick, cost-effective way to diagnose methicillin-resistant Staphylococcus aureus
Even as in vitro diagnostics manufacturers are bringing rapid molecular tests to market that can identify infectious diseases within hours, a research collaboration involving a major university and a medical laboratory at an air force base has demonstrated the ability to identify antibiotic-resistant strains of Staphylococcus in just minutes.
This innovative research is being done by Auburn University’s College of Veterinary Medicine and clinical laboratory professionals at Keesler Air Force Base. Funding is by the U.S. Air Force. This research was of particular interest to the military because the risk for Staph infection increases when individuals are subjected to unhygienic conditions in close quarters.
Rapid Detection of Antibiotic-resistant Bacteria
The project is using microfluidic biosensor technology developed by Vitaly Vodyanoy, Ph.D., Professor of Physiology and Director of the Biosensor Laboratory at Auburn University. His technology can detect antibiotic resistant bacteria within minutes.
The technique specifically targets Staphylococcus (Staph), which was one of the first pathogens to be classified as a “Super Bug”. It becomes deadly in immune-compromised patients or in internal organs, such as lungs or the respiratory tract, noted a report published by Science Daily.
Biosensor Technology Cuts Time to Diagnose ‘Super Bugs’ to Minutes
“In our method, we can determine bacterial antibiotic resistance in 10-12 minutes, while other methods take hours,” explained Vodyanoy, noting that methods traditionally used to detect antibiotic resistance require time-intensive purification steps before multi-hour sequencing protocols.
The hypothesis behind this method is new: it uses stress activation of biochemical pathways—that are targets of antibiotics—to accelerate antibiotic susceptibility testing.
“Our technique is complex and involves many steps and disciplines,” stated Vodyanoy in a press release issued by Journal of Visualized Experiments. This journal published the study about this biosensor technology.
Technology Takes Advantage of Harmless Virus That Kills Bacteria
As explained by Vodyanoy, the technology involves a rapid microfluidic method for antibiotic susceptibility testing in a stress-based environment. Fluid containing bioteriophages, or phages, and antibody beads is passed at high speeds over bacteria immobilized on the bottom of a microfluidic channel. Phages, and antibody beads can discriminate between methicillin resistant (MRSA) and sensitive Staph bacteria because phages are immobilized by a Langmuir-Blodgett method onto the surface of a quartz crystal microbalance sensor and work as broad range Staph probes. In the presence of stress and an antibiotic, susceptible strains of bacteria die rapidly. Resistant bacteria, however, survive these stressful conditions. The antibody beads recognize MRSA.
This JoVEJournalVideo shows how lytic phage biosensors and antibody beads are able to discriminate between methicillin resistant (MRSA) and sensitive staphylococcus bacteria. The phages were immobilized by a Langmuir-Blodgett method onto the surface of a quartz crystal microbalance sensor and worked as broad range staphylococcus probes. Antibody beads recognize MRSA. (Video copyright by JoVEJournalVideo.)
The new biosensor technology takes advantage of bacteriophages. These are simple viruses that can target and kill bacteria, but are benign in humans. A bacteriophage, when combined with specific antibodies, produces a color change in a sample that indicates antibiotic resistance.
The standard parts of Vodyanoy’s method include bacterial culture protocols, defining microfluidic channels in polydimethylsiloxane (PDMS), cell viability monitoring with fluorescence, and batch image processing for bacteria counting. Innovative parts of the method are used in culture media flow for mechanical stress application, enzymes to damage but not kill the bacteria, and microarray substrates for bacterial attachment.
Technology Offers Labs Quick, Cost-Effective Method to Diagnose MRSA
This technology, with its promise of a very fast time-to-answer, could provide medical laboratories with a quick and cost-effective way to diagnose Super Bugs in patients. It would be particularly useful in hospital, prison, and military settings.
“We envision a future where clinicians do tests with real blood or saliva samples,” predicted Vodyanoy. “We are interested in someone else reproducing our results [of our research study]. This technology can be used on a larger scale and for antibiotic resistance other than Staphylococcus.”
Vodyanoy also hopes to apply the technology to making antimicrobial surfaces and glassware that kill the bacteria. Of course, this technology is years away from gaining FDA clearance for clinical use. What should interest pathologists, microbiologists, and clinical laboratory managers is how Vodyanov and his collaborators are using multiple technologies in new ways to deliver a lab test result in a short amount of time with acceptable sensitivity and specificity.
—by Patricia Kirk