Development of Loop-Mediated Isothermal Amplification with a Lateral Flow Dipstick for Detection of the...

Carbapenem-resistant Acinetobacter baumannii (CRAB) is a major cause of hospital-acquired infections. Conventional phenotyping for carbapenem resistance requires more than 24 h, which delays clinical decisions and increases the risk of outbreaks. This study aims to develop a lateral flow dipstick (LFD) assay that detects loop-mediated isothermal amplification (LAMP) products targeting the bla_OXA-23-like gene, providing results within 1-1.5 h. Primer specificity was evaluated using seven Gram-positive and nine Gram-negative species commonly present in clinical samples, as well as carbapenem-susceptible A. baumannii and CRAB isolates harboring other resistance genes. The assay detected the bla_OXA-23-like gene at concentrations as low as 1.57 pg/µL, demonstrating ~10-fold greater sensitivity than conventional PCR. The gene was present in 224/268 CRAB samples (83.6%) and absent in 100 carbapenem-susceptible A. baumannii samples. Results were fully concordant with PCR, yielding 100% sensitivity and specificity. The method requires no expensive or complex instrumentation. Future studies should validate the assay across multiple hospitals and clinical specimens to confirm its generalizability and clinical utility. Multiplex LAMP with dual LFD readouts could also enable simultaneous detection of additional carbapenem resistance genes, supporting rapid CRAB surveillance and outbreak control.