# P-1070. Antimicrobial Susceptibility Trends and Mortality of Pseudomonas aeruginosa Hospital-acquired Pneumonia and Ventilator-associated Pneumonia among Adult Patients: A Retrospective Single-center Study

## TL;DR

This study analyzed antimicrobial resistance trends and mortality in Pseudomonas aeruginosa hospital-acquired pneumonia patients over five years, finding a decreasing mortality trend despite resistance patterns.

## Contribution

The study provides updated insights into antimicrobial susceptibility trends and mortality factors for Pseudomonas aeruginosa HAP/VAP in a single hospital over five years.

## Key findings

- High attributable mortality (46%) was observed in Pseudomonas aeruginosa HAP/VAP patients.
- Mortality rates decreased over time for patients with MDR-PA and XDR-PA HAP/VAP.
- Prolonged antibiotic therapy (≥14 days) was associated with better survival outcomes.

## Abstract

Pseudomonas aeruginosa is a leading cause of nosocomial infections. This study examined the antimicrobial susceptibility trends (AST), clinical profile and outcomes of P. aeruginosa hospital-acquired and ventilator-associated pneumonia (HAP/VAP).Figure 1Flow diagram of study inclusionTable 1Demographic and clinical characteristics of adult patients with Pseudomonas aeruginosa HAP/VAP admitted to the Philippine General Hospital (2020-2024)

Flow diagram of study inclusion

Demographic and clinical characteristics of adult patients with Pseudomonas aeruginosa HAP/VAP admitted to the Philippine General Hospital (2020-2024)

A retrospective observational study of adults with P. aeruginosa HAP/VAP from 1/1/2020 to 8/31/2024 was undertaken. Relevant data were extracted from electronic records, and P. aeruginosa identified using VITEK 2 and MALDI-TOF technology. Continuous variables were expressed in median and range, and categorical variables as frequencies and percentages. The Mann–Whitney U test was used for non-parametric comparison of continuous variables, and the Chi-square test for univariate analysis of categorical variables. A binary logistic regression model identified factors associated with mortality in patients with P. aeruginosa HAP/VAP.Figure 2Proportion of susceptible and resistant Pseudomonas aeruginosa HAP/VAP isolates among adult patients admitted to the Philippine General Hospital over 5 years (2020-2024)Table 2Univariate and Multivariate regression analysis on the factors associated with all-cause mortality among patients with Pseudomonas aeruginosa HAP/VAP

Proportion of susceptible and resistant Pseudomonas aeruginosa HAP/VAP isolates among adult patients admitted to the Philippine General Hospital over 5 years (2020-2024)

Univariate and Multivariate regression analysis on the factors associated with all-cause mortality among patients with Pseudomonas aeruginosa HAP/VAP

Of 687 patients, 413 were included in the final analysis (Fig. 1). The median age was 54 (range 19-90) years. The most common comorbidities were hypertension (185/413, 44.8%), solid organ malignancy (127/413, 30.8%), and type 2 diabetes mellitus (89/413, 21.5%) (Table 1). The proportion of patients with multi-drug resistant-PA (MDR-PA) increased, carbapenem-resistant (CRPA) decreased, and extremely drug-resistant (XDR-PA) fluctuated over time (Fig. 2). Although there was no significant change in AST, increasing susceptibility to carbapenems and decreasing susceptibility to piperacillin-tazobactam were observed. All-cause mortality rate was 46% (190/413), with 80% (152/190) attributed to P. aeruginosa HAP/VAP. A decreasing mortality trend was observed in patients with MDR-PA and XDR-PA HAP/VAP. Prolonged antibiotic therapy (≥14 days) was associated with better survival outcomes compared to short-course therapy (≤7 days) (p 0.000).

In our study, P. aeruginosa HAP/VAP had high attributable mortality. However, a decreasing mortality trend was observed among patients with MDR-PA and XDR-PA HAP/VAP over the 5-year period, suggesting that factors other than antimicrobial resistance may influence mortality outcomes. Patients with P. aeruginosa HAP/VAP may benefit from prolonged antibiotic therapy.

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