Recent Advances and Future Perspectives in the Detection of Carbapenem-Resistant Acinetobacter Baumannii

Carbapenem-resistant Acinetobacter baumannii (CRAB) is a major global public health threat. The World Health Organization (WHO) has classified CRAB as a critical priority pathogen. This threat is mainly attributed to its multidrug resistance, efficient nosocomial transmission, and limited therapeutic options. Timely and accurate detection is essential for early diagnosis, targeted antimicrobial therapy, and effective infection control. This review summarizes recent advances in CRAB detection technologies, including conventional phenotypic methods, nucleic acid amplification-based assays, genomic and AI-assisted diagnostics, mass spectrometry-based methods, and biosensor platforms. Conventional antimicrobial susceptibility testing (AST) remains the reference standard. However, it requires bacterial culture and isolation before testing, and the process usually takes 18-24 h after bacterial colony growth. This delay may limit its value for early therapeutic decision-making. Phenotypic carbapenemase assays provide complementary information on carbapenemase activity and resistance mechanisms, but their sensitivity, specificity, and clinical applicability vary across methods. Molecular methods substantially shorten turnaround times, with PCR and qPCR generally producing results within approximately 2-3 h. Isothermal amplification platforms further accelerate detection. LAMP-based assays report turnaround times of approximately 21-60 min, whereas RPA-based assays complete detection within approximately 40-90 min, supporting their potential application in point-of-care testing (POCT). Emerging genomic approaches, including whole-genome sequencing, nanopore sequencing, and metagenomic sequencing, enable comprehensive resistance profiling, outbreak investigation, and surveillance, while AI-assisted diagnostics may enhance resistance prediction and clinical interpretation. Mass spectrometry-based methods enable high-throughput species identification and can support resistance profiling in selected assay formats, with some assays detecting resistance-associated features within 15-90 min. Biosensor-based and CRISPR-integrated platforms offer highly sensitive, rapid, and portable detection, although challenges remain in multiplexing, standardization, cost, and clinical validation. Overall, this review highlights the transition of CRAB diagnostics from culture-based susceptibility testing toward integrated, automated, and clinically adaptable platforms, emphasizing the need to balance analytical performance, turnaround time, cost, and suitability for POCT.