Trends in mortality attributed to antimicrobial-resistant Acinetobacter baumannii in Pakistan from 1990 to 2021 based on the global burden of disease study 2021

Acinetobacter baumannii is classified as a critical-priority pathogen by the World Health Organization due to its high capacity for antimicrobial resistance (AMR). Despite being a leading cause of healthcare-associated infections globally, Pakistan-specific temporal trends in mortality attributable to drug-resistant A. baumannii across multiple antibiotic classes remain poorly characterised. This study quantifies trends in the age-standardised mortality rate attributable to AMR in A. baumannii for seven antibiotic classes in Pakistan from 1990 to 2021. Data were extracted from the Global Burden of Disease (GBD) 2021 study using the IHME Measuring Infectious Causes and Resistance Outcomes for Burden Estimation (MICROBE) tool. Age-standardised death rates per 100,000 population attributable to AMR in A. baumannii were obtained for Pakistan (both sexes combined) across seven antibiotic classes and a composite measure of resistance to one or more antibiotics, from 1990 to 2021. Point estimates with 95% uncertainty intervals are reported (UIs) derived from 100 posterior draws of the GBD estimation process. Absolute and relative changes between 1990 and 2021 were calculated for each drug class. The overall age-standardised death rate attributable to resistance to one or more antibiotics in A. baumannii decreased by 41·0% from 5·767 (95% UI 4·885–6·649) per 100,000 in 1990 to 3·403 (2·876–3·931) in 2021, after peaking at 6·544 in 1999. Carbapenems carried the highest individual-class burden throughout the study period, with a death rate of 2·277 in 1990, peaking at 2·980 in 2004, and declining to 1·581 (1·203–1·959) in 2021 (− 30·6%). The largest relative declines were observed for anti-pseudomonal penicillin/beta-lactamase inhibitor combinations (− 79·8%), fourth-generation cephalosporins (− 79·1%), and third-generation cephalosporins (− 73·1%). Beta-lactam/beta-lactamase inhibitor resistance was the only class showing a marginal increase (+ 5·9%). Fluoroquinolone resistance showed an inverted-U pattern, peaking at 1·599 in 2010 before declining to 0·938 (0·739–1·137) in 2021. Despite overall reductions, AMR-attributable mortality from A. baumannii in Pakistan remains substantial, with carbapenems accounting for the largest drug-class-specific burden. The persistent dominance of carbapenem resistance underscores the urgent need for strengthened antimicrobial stewardship, infection prevention in healthcare facilities, and investment in novel therapeutic agents. These findings provide a critical evidence base for national AMR action planning in Pakistan.