Image: The SNDA-AST quickly analyzes bacteria isolated from patients with infections (Photo courtesy of Technion).
Nanotechnology, image processing tools, and statistical analysis can enable faster diagnostics and earlier and more effective treatment of infectious bacteria, according to a new study.
The SNDA-AST technique, developed at the Israel Institute of Technology (Technion; Haifa, Israel) and Rambam Health Care Campus (Haifa, Israel), is based on hundreds of stationary nanoliter droplet arrays that allow rapid and scalable antimicrobial susceptibility testing in about half the time of conventional methods. Detection of bacterial response is via fluorescent markers, image processing tools, and automated statistical analysis of the colors obtained from bacteria in all of the nanoliter wells, using a data analysis algorithm and multiplexing.
The researchers tested the efficacy of the approach on numerous clinical isolates retrieved directly from urine samples of hospital patients with urinary tract infections, successfully demonstrating the likelihood of a two-day reduction in overall diagnostic time by skipping the isolation step. Subsequent testing of 12 bacteria-antibiotic combinations also proved accurate, allowing for early and effective treatment of the infectious bacteria. The findings were published on June 29, 2017, in Proceedings of the National Academy of Sciences (PNAS).
“Every day, tens to hundreds of tests are carried out at every hospital in Israel to map the resistance levels of infectious bacteria from samples taken from patients. The problem is that this is a very long test, since it is based on sending the sample to the lab, growing a bacterial culture in a petri dish and analyzing the culture,” said lead author Jonathan Avesar, PhD, of the faculty of biomedical engineering. “The use of the technology that we developed reduces the size of the required sample by several orders of magnitude, reduces the scanning time by around 50%; significantly reduces the lab space required for testing; and reduces the cost per test.”
According to established estimates, for every hour that effective antibiotic treatment is delayed for patients with septic shock, survival rates drop by about 7.6%. As a result, and to provide the patient without adequate protection while awaiting lab results, many doctors will prescribe large doses of antibiotic with a broad spectrum of activity. This phenomenon facilitates the emergence of antimicrobial resistance (AMR) and also affects the microbiota.
Israel Institute of Technology
Rambam Health Care Campus