Trends in prevalence and antibiotic non-susceptibility of Acinetobacter baumannii–calcoaceticus complex in Thailand (2000–2022): A secondary data analysis

Abstract

Objectives: Antimicrobial resistance (AMR) is a significant global health concern. Due to its high prevalence in nosocomial infections and its increasing resistance to multiple antibiotics, Acinetobacter baumannii–calcoaceticus complex (ABC) is listed as a critical pathogen. This study aimed to determine the prevalence and antibiotic non-susceptibility trends of ABC in Thailand over two decades using national surveillance data. Methods: We analysed secondary data from the National Antimicrobial Resistance Surveillance Thailand (NARST) from 2000 to 2022, covering 529 538 ABC isolates. Linear regression was used to evaluate trends in overall ABC prevalence and antibiotic non-susceptibility rates across ward types (ICU, inpatient, outpatient) and specimen types (sputum, blood, urine). Results: The prevalence of ABC increased from 8% in 2000 to 14% in 2022, with inpatient wards and sputum specimens showing the highest occurrence. By 2022, the majority of tested antibiotics showed antibiotic non-susceptibility rates exceeding 70%, with increasing trends. ICU isolates had the highest non-susceptibility, followed by inpatient and outpatient settings. Although non-susceptibility rates were lower in the outpatient setting, it exhibited the steepest increasing trends. Among specimen types, urine isolates had the highest non-susceptibility, followed by sputum and blood. Carbapenem non-susceptibility increased significantly across all ward types. Conclusions: The increasing prevalence and high non-susceptibility of ABC in Thailand highlight a growing threat to public health. These findings underscore the urgent need for enhanced infection control, robust antibiotic stewardship, and further research into molecular epidemiology and alternative therapies.