Accelr8 Technology Corporation announced study results today that were presented at the joint sessions of the 48 th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC, www.icaac.org) and the Infectious Diseases Society of America (IDSA, www.idsociety.org), October 25-29 in Washington, DC.
The purpose of the study was to characterize a rapid test run on Accelr8 ' s BACcel diagnostic system to detect a broad multiple antibiotic resistance mechanism known as " ESBL, " which stands for " extended spectrum beta-lactamase. " This type of resistance includes hundreds of variant enzymes produced by pathogenic bacteria. The enzymes destroy almost all drugs in the beta-lactam antibiotic class, which is the largest single family of antibiotics and contains more than 50 different types. Beta-lactams include penicillins and cephalosporins. They are the most widely prescribed antibiotics and most favored because of their speed, potency, and safety. ESBLs represent one of the most threatening, rapidly spreading, complex forms of drug resistance according to IDSA and the CDC (US Centers for Disease Control and Prevention). Organisms that express ESBLs also tend to carry additional resistance mechanisms against other antibiotic families. Therefore ESBLs also serve as markers of multiple drug resistance (MDR) or " superbugs. "
Standard culture-based confirmation tests for ESBLs typically require 2-3 days to perform. Using pure clinical strains, the new study demonstrated reportable test results in 90 to 180 minutes. The test achieved sensitivity of 96% and specificity of 96%, on 53 positive and 73 negative (control) strains. The test used the same agents as standard tests, but performed with high speed and accuracy through the use of automated microscopy and image analysis of small numbers of immobilized individual bacteria.
The research investigators included scientists from the Barnes-Jewish Hospital and the Washington University in St. Louis School of Medicine (St. Louis, MO), and from Accelr8. The study analyzed bacterial strains previously characterized for ESBL expression, and control strains that lacked the resistance enzymes. Species included Klebsiella pneumoniae and E. coli , which commonly infect ICU patients. These species are leading members of a large family of bacteria that account for approximately 25% to 35% of serious hospital infections.