Development of a LAMP method for detection of carbapenem-resistant Acinetobacter baumannii during a hospital outbreak

Introduction: Carbapenem-resistant A. baumannii (CRAB) represents a public health threat increasing worldwide. We assess the suitability of a loop-mediated isothermal amplification (LAMP) method for on-site screening of CRAB in a hospital facility. Methodology: A set of six primers were designed for recognizing eight distinct sequences on six targets: bla(OXA-23-like), bla(OXA)-(24-like), bla(OXA-51-like), bla(OXA-58-like), bla(IMp), and bla(VIM). A LAMP method was developed, optimized and evaluated for the identification of CRAB in thirty-three environmental samples from an outbreak in an Intensive Care Unit (ICU) facility. Results: The sensitivity of the LAMP assay for the detection of A. baumannii was ten-fold higher than the PCR assay (1.0 ng.mu L-1). The LAMP assays showed a higher detection rate for CRAB samples and robust diagnosis performance in comparison to a conventional PCR, with clinical sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 100% for bla(OXA-23-like), bla-(OXA-51-like) and bla(VIM). Conclusions: The developed LAMP assays are powerful tools that can be useful in on-site screening of CRAB causing local outbreaks in clinics and hospitals facilities where costs and equipment restraints are imperative.