multidrug resistance patterns among clinical isolates of acinetobacter baumannii

Background and aim: acinetobacter baumannii is a major cause of hospital‑acquired infections and exhibits increasing multidrug resistance (mdr). this study aimed to determine antibiotic resistance patterns and the prevalence of mdr and xdr phenotypes among clinical isolates from a tertiary‑care hospital in tehran.methods: clinical isolates were collected over 12 months. identification was performed using standard biochemical tests and pcr (blaoxa‑51). antimicrobial susceptibility testing was conducted using the clsi‑standardized kirby–bauer disk diffusion method. mdr and xdr were defined according to international criteria.results: high resistance was observed to carbapenems and cephalosporins. colistin remained the most effectivee agent. overall, 92% of isolates were mdr and 47% were xdr.conclusion: mdr and xdr a. baumannii strains were widely prevalent, indicating an urgent need for antibiotic stewardship and routine surveillance.