Antimicrobial Susceptibility Trends of WHO Critical Gram-negative Pathogens in Fijian Hospitals, 2016-2021

Introduction:Understanding antimicrobial susceptibility patterns is essential for guiding clinical management and informing surveillance strategies. This study aimed to analyse antimicrobial susceptibility trends of WHO-designated critical Gram-negative pathogens in Fijian hospitals. Methods:We conducted a retrospective study of antimicrobial susceptibility among Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae isolated from three hospitals in Fiji from 1 January 2016 to 31 December 2021. Data were stratified by hospital, hospital setting, and specimen type. Only the first isolate per patient was included. Chi-square tests and linear regression were used to assess group differences and temporal trends. Results:A total of 44 524 isolates were analysed: K. pneumoniae 17 016 (38.2%), E. coli 14 935 (33.5%), P. aeruginosa 6632 (14.9%), and A. baumannii 5941 (13.3%). Specimens included blood 4612 (10.4%), urine 13 369 (30.0%), and other types 26 543 (59.6%). Meropenem susceptibility declined significantly in A. baumannii (60.4% to 40.8%, P = 0.0004) and P. aeruginosa (100% to 40.8%, P = 0.005). Ceftriaxone susceptibility was low in E. coli (49.8%) and K. pneumoniae (32.7%). Meropenem susceptibility remained high in K. pneumoniae (96.6% in 2021) and E. coli (>80%). ESBL production was identified in 18.2% of E. coli and 37.6% of K. pneumoniae. Conclusions:These findings highlight substantial AMR challenges in Fijian hospitals, including declining carbapenem susceptibility and high ceftriaxone resistance, underscoring the need for strengthened antimicrobial stewardship, infection control, and surveillance systems.