Retrospective cohort study links prior antibiotic exposure and Gram-negative infections to high MDR rates in adult patients with chronic liver disease.

Chronic liver disease (CLD) predisposes patients to bacterial infections, with multidrug-resistant (MDR) pathogens posing significant challenges to clinical management and outcomes. Understanding the prevalence, resistance patterns, and predictors of MDR is essential for optimizing antimicrobial therapy. This study aimed to generate real-world evidence on the clinical, demographic, and healthcare-related predictors of antimicrobial resistance and to characterize local pathogen distribution and resistance patterns among patients with CLD in a tertiary care setting. This retrospective observational cohort study (February–August 2024) included adult patients with CLD and culture-positive bacterial infections from tertiary care hospitals in Coimbatore, India. Antimicrobial susceptibility patterns, including MIC50, MIC90, and trends, were analyzed using WHONET v5.6. Categorical and continuous variables were compared using Chi-square and Mann–Whitney U-tests, respectively. Predictors of MDR infection were identified using logistic regression analysis. Among 317 patients with CLD, the mean age was 50.9 ± 10.4 years (median 50, IQR 44-59), and 83.9% were male. Single-organism infections accounted for 76.0%, and 56.5% were community-acquired. Escherichia coli (37.5%) and Klebsiella pneumoniae (14.5%) were the most frequently isolated pathogens, with high MDR rates (78.2% and 82.6%, respectively). Both organisms were significantly associated with increased odds of MDR (E. coli: OR 2.41, 95% CI 1.45-4.01; K. pneumoniae: OR 3.12, 95% CI 1.58–6.15; p < 0.001). MDR prevalence was higher among Gram-negative isolates compared with Gram-positive isolates (70.2 vs. 51.9%; RR 1.35, 95% CI 1.07–1.70; p = 0.003). Gram-positive isolates remained largely susceptible to glycopeptides, oxazolidinones, and tetracyclines, while tigecycline (79.1%; p-trend = 0.041) and aminoglycosides (60.3%; p-trend = 0.019) retained activity against Gram-negative isolates. Independent predictors of MDR infection included age >60 years (adjusted OR 1.89), male gender (adjusted OR 1.67), healthcare-associated infection (adjusted OR 3.14), Gram-negative etiology (adjusted OR 2.73), and prior antibiotic exposure (adjusted OR 2.98; all p < 0.05). MDR infections are highly prevalent among patients with CLD, predominantly driven by Gram-negative pathogens such as Escherichia coli and Klebsiella pneumoniae. Resistance was more common in healthcare-associated infections and was characterized by reduced susceptibility to carbapenems, cephalosporins, and fluoroquinolones. Tigecycline and aminoglycosides retained relatively preserved activity. Key predictors of MDR included older age, male gender, Gram-negative etiology, healthcare exposure, and prior antibiotic use, underscoring the need for targeted antimicrobial stewardship strategies.