Antimicrobial Susceptibility Pattern and Proportion of Multidrug-Resistant Organisms among Patients with Bloodstream Infections at Eastern Regional Referral Hospital, Bhutan: A Retrospective Descriptive Studyonal Referral Hospital, Bhutan: A Cross-Sectional Study

Abstract

Introduction: Growing antimicrobial resistance to commonly used antimicrobial exacerbates global burden of the bloodstream infection (BSIs). Understanding the local antimicrobial susceptibility pattern is crucial for effective antimicrobial stewardship. This study evaluated the antimicrobial susceptibility pattern and proportion of multidrug-resistant organisms (MDROs) among blood culture bacterial isolates at Eastern Regional Referral Hospital. Methods: The retrospective study reviewed blood culture records of 2025. A total of 79 positive blood cultures from 62 unique patients were included. Antimicrobial susceptibility testing was performed using standard microbiological methods and interpreted according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Data were collected in REDCap and analyzed using SPSS version 32 and R version 4.6.0. Results: Of 981 blood cultures performed in 2025, 8.1% showed positive culture. Most cases occurred in patients over 40 years (74.7%), with a female predominance (53.2%). Sepsis was the predominant clinical diagnosis (78.5%), and 70.9% had comorbidities. Gram-negative organisms accounted for 78.5% of isolates led by E. coli (45.2%), which exhibited high susceptibility to amikacin (86.7%). Staphylococcus aureus (82.4%) was the main Gram-positive isolate demonstrating complete susceptibility to cloxacillin (100%). Overall, 23.0% (17/74) of the isolates were MDROs. For carbapenem resistance, 35.7% (5/14) of tested isolates were identified as CRO, representing 6.3% (5/79) of the total cohort. Conclusion: Gram-negative organisms, particularly, E. coli was the main causative pathogen. The findings provide vital insights into the local susceptibility patterns to guide antimicrobial stewardship programs.