PP 2 - Epidemiology and clinical outcomes of Carbapenem-Resistant Gram- Negative Bacteremia: A retrospective study at Army Hospital Colombo A retrospective study at Army Hospital Colombo

Liyanage SPM, Palliyaguruge PDGI, Udugama SGArmy Hospital, Colombo

Abstract

Background

Antimicrobial resistance (AMR), particularly among carbapenem-resistant Gram-negative bacilli (CR-GNB), represents a critical global health threat with South Asian mortality rates often exceeding 35%.

Objectives

This study quantifies the microbiological spectrum and mortality burden associated with carbapenem-resistant Gram-negative bacteraemia (CR-GN Bacteraemia) at Army Hospital Colombo.

Design, setting and methods

A retrospective observational study was conducted from 01 January 2025 to 31 December 2025 at Army Hospital Colombo. Clinical and microbiological data were obtained by tracing laboratory records and bed head tickets of 90 non-duplicate cases of adult GN bacteraemia. The BD Phoenix™ automated identification and antibiotic susceptibility testing system was utilized. Patients were stratified into carbapenem-resistant (CR) and carbapenem-sensitive (CS) cohorts. Statistical analysis including Chi-square, Odds Ratio (OR), and independent t-tests, was performed.

Results

The total microbiological spectrum (N=90) comprised Enterobacteriaceae (n=58, 64.4%), Pseudomonas spp. (n=22, 24.4%), Acinetobacter spp. (n=10,11.1%).  Carbapenem resistance was present in 35.5% (n=32) of isolates. Urosepsis was the most frequent clinical presentation (n=42, 46.7%) followed by hospital-acquired pneumonia (n=19, 21.1%), skin and soft tissue infections (n=10, 11.1%), abdominal sepsis (n=8, 8.8%) and others (n=11,12.2%). Direct cohort stratification was done into CR (n=32) versus CS (n=58) groups. Analysis demonstrated that urosepsis contributed the largest proportion of CR-GN bacteraemia (13/42, 40.6%), whereas abdominal sepsis had the highest proportion of carbapenem-resistant isolates (4/8, 50.0%). The all-cause mortality rate for the CR group was significantly higher than the CS group (41.4% vs. 18.0%; p=0.014). Patients with CR-GN bacteraemia faced a 3.21-fold increase in the odds of death (OR 3.21; p=0.014). Furthermore, the mean ward stay for the CR cohort was significantly longer (43.9 vs.16.7 days; p=0.003), representing an additional 27.2 days of acute care per resistant case.

Conclusions

CR-GN bacteraemia at Army Hospital Colombo was significantly associated with increased mortality and hospital stay. Urosepsis was the most frequent overall clinical presentation whereas abdominal sepsis carried the highest rate of carbapenem resistance. Therefore, the study findings highlight the need to strengthen the existing antimicrobial stewardship programme, to mitigate the localized burden of resistant infections and preventable deaths.