A New Rapid Test for Detecting Multi-Drug Resistance

One of the major complications of treating bacterial infections is the potential for multi-drug resistant (MDR), extensively drug-resistant (XDR), or pan-drug-resistant (PDR) organisms. Multi-drug resistance is defined as "non-susceptibility to at least one agent in three or more antimicrobial categories", XDR is defined as "non-susceptibility to at least one agent in two or fewer categories", and PDR is defined as non-susceptibility to all agents in all antimicrobial categories" (1). Fortunately, XDR and PDR organisms are much fewer in number than MDR organisms. However, antimicrobial resistance has increased dramatically over the past 20 years, particularly in regards to gram-negative rods, and broad-spectrum antibiotics such as cephalosporins and carbapenems (which used to be last-resort options) are now losing their efficacy.

A new rapid test, CarbAcineto NP, has been developed by Patrice Nordmann and Laurent Poirel which detects the presence of carbapenemase in Acinetobacter baumanii. This test detects "the acidification properties generated by the enzymatic hydrolysis of a carbapenem, imipenem, when it is cleaved by a carbapenemase". The acid produced by the breakdown of imipenem causes a pH indicator to turn from red to yellow. Either isolated bacteria or swabs of a site infection can be used in the test, which produces results in less than 2 hours, much faster than the 24-72 hours required for current methods. This new rapid test allows treatment decisions to be made much more quickly and effectively, as well as allowing for the identification of potential MDR organisms as a screening tool.

Article Sources
(1): http://www.ncbi.nlm.nih.gov/pubmed/21793988
Article: http://www.sciencedaily.com/releases/2014/06/140626095705.htm
Image: http://bacteriasactuaciencia.blogspot.com/2013/10/esperanza-en-la-lucha-contra.html