# Evaluation of risk factors and outcome of patients with polymyxin-resistant critical pathogens gram-negative bacilli in Hospital Kuala Lumpur

## TL;DR

This study examines risk factors and outcomes of patients infected with polymyxin-resistant gram-negative bacteria in a Malaysian hospital.

## Contribution

Identifies prior ICU admission as a significant risk factor for polymyxin-resistant gram-negative bacilli infections.

## Key findings

- Prior ICU admission within 90 days increased odds of PR-CP-GNB isolation by six times.
- No significant difference in mortality or hospital stay duration between PR-CP-GNB and PS-CP-GNB patients.
- 71.4% of patients had polymyxin-resistant isolates.

## Abstract

Polymyxin-resistant gram-negative bacilli pose a formidable challenge in clinical settings globally and the increasing prevalence of resistance has raised concerns regarding treatment options and patient outcomes. This study aimed to evaluate the risk factors, length of hospital stay and mortality among patients with polymyxin-resistant critical pathogens gram-negative bacilli (PR-CP-GNB) and polymyxin-susceptible (PS-CP-GNB) isolates.

A one-year case–control study was conducted using retrospective data from patients admitted to Kuala Lumpur Hospital with a positive culture of CP-GNB. CP referred to Carbapenem-Resistant Acinetobacter baumannii and Carbapenem-Resistant Enterobacterales. Patients with PR-CP-GNB isolates were classified as cases, while those with PS-CP-GNB isolates served as controls. Mortality outcomes were assessed using Chi-Square and Fisher’s exact tests, while the length of hospital stay was evaluated using the Mann–Whitney U test. Simple and multiple logistic regression analyses were performed to identify risk factors for PR-CP-GNB.

The median age of the 70 patients was 55.5 (IQR 42.6-64.9), with an equal distribution between males and females. Of 70 patients, 50 (71.4%) were identified as PR-CP-GNB and the remaining were PS-CP-GNB. Additionally, 15 isolates were identified as colonisers (12 PR-CP-GNB and 3 PS-CP-GNB). Among the 55 non-coloniser, 38 (69%) were identified as PR-CP-GNB while 17 (31%) had PS-CP-GNB. No significant difference in all-cause mortality (PR-CP-GNB: 60.5%; PS-CP-GNB: 64.7%, p = 0.768) or infection-related mortality (PR-CP-GNB: 65.2%, PS-CP-GNB: 45.5%, p = 0.458) among non-coloniser patients. The median length of hospital stay post-infection was also comparable (PR-CP-GNB: 24 days vs PS-CP-GNB: 25 days, p = 0.791). A previous ICU admission within the last 90 days was associated with approximately six times higher odds of isolating PR-CP-GNB (AOR = 5.90, 95% CI 1.17-29.77, p = 0.032).

Prior ICU admission significantly increased the risk of PR-CP-GNB isolation. Clinicians should consider a history of ICU admission as a major risk factor when evaluating patients for potential polymyxin-resistant infections.