PREVALENCE OF MULTIDRUG-RESISTANT (MDR) ORGANISMS IN ICU VS. NON-ICU SETTINGS.

Abstract

Background: Antimicrobial resistance (AMR) is a major global public health threat, with multidrug-resistant (MDR) organisms posing a disproportionate burden in hospital settings, particularly in Intensive Care Units (ICUs). Critically ill ICU patients are uniquely susceptible to MDR infections due to compromised immunity, invasive procedures, and prolonged antibiotic exposure. Despite growing evidence at the global level, comparative data from tertiary care private medical college settings in eastern India remain limited, necessitating institution-specific microbiological and clinical analyses.

Materials and Methods: A retrospective observational study was conducted over six months (Jan 2018 – June 2018) at a tertiary care center in West Bengal, India. A total of 100 adult patients (≥18 years) with culture-confirmed bacterial infections were enrolled: 45 from the ICU and 55 from non-ICU general wards. Bacterial identification was performed using standard microbiological methods, and Antimicrobial Susceptibility Testing (AST) was carried out by the Kirby-Bauer disk diffusion method as per CLSI guidelines. MDR was defined as acquired non-susceptibility to at least one agent in three or more antimicrobial categories. Clinical outcomes including hospital length of stay, mechanical ventilation requirement, and progression to sepsis were recorded. Statistical analysis used Chi-square, Fisher's exact test, Student's t-test, and Odds Ratio (OR) with 95% CI; p < 0.05 was considered significant.

Results: Gram-negative bacteria accounted for 74.0% of all isolates, with Klebsiella pneumoniae (26.0%) and Escherichia coli (22.0%) being the most prevalent pathogens. The overall MDR prevalence was 54.0%, with a significantly higher burden in the ICU compared to non-ICU wards (71.1% vs. 40.0%; OR 3.69, 95% CI: 1.58–8.61; p = 0.002). Acinetobacter baumannii demonstrated alarming carbapenem resistance (75.0% to meropenem), while K. pneumoniae showed high-level cephalosporin resistance (73.1% to ceftriaxone). MDR-infected patients had a significantly prolonged mean hospital stay (16.4 ± 6.2 vs. 9.8 ± 4.1 days; p < 0.001), greater requirement for mechanical ventilation (44.4% vs. 23.9%; p = 0.033), and higher rates of progression to sepsis (35.2% vs. 17.4%; p = 0.046).

Conclusion:The present study demonstrates a significantly higher burden of MDR organisms in the ICU compared to non-ICU wards, with Klebsiella pneumoniae and Acinetobacter baumannii showing alarming resistance to cephalosporins and carbapenems. MDR infections were associated with prolonged hospital stays, increased mechanical ventilation requirements, and higher rates of sepsis, imposing a substantial burden on tertiary care resources. These findings highlight the urgent need for institution-specific antibiograms, robust Antimicrobial Stewardship Programs (AMSP), and stringent Infection Prevention and Control (IPC) protocols in critical care settings.