Pseudomonas aeruginosa in hospitalized patients – A Saudi Arabian study on resistance patterns and virulence factors

Pseudomonas aeruginosa is categorized by global health authorities as a “critical” pathogen due to its increasing propensity for antibiotic resistance. It is a significant cause of severe healthcare-associated infections, including ventilator-associated pneumonia and bloodstream infections, especially in critically ill patients.

A recent retrospective observational study conducted at King Khalid Hospital in Saudi Arabia and published in Nature Scientific Reports analyzed data from 817 hospitalized patients with P. aeruginosa infections.

The patient cohort carried a high burden of co-morbidities, with cardiovascular disease (53.7%), diabetes mellitus (36.3%), and cancer (14.8%) being the most common.

The majority of patients frequently utilized invasive medical devices, including central lines (44.8%), Foley catheters (41.1%), and prolonged tracheal intubation (22.9%), factors known to increase susceptibility to this opportunistic pathogen.

The majority of isolates (70.8%) were considered community-acquired or present on admission, identified within the first three days

Multi-Drug Resistance (MDR) was observed in 73% of the P. aeruginosa isolates. This high prevalence of MDR was strongly and significantly linked to hospital-onset infections and the use of invasive medical devices, specifically central lines and tracheal intubation. Conversely, diabetes mellitus was significantly associated with community-onset cases.

Colistin (84.5%), Amikacin (83.0%), and the fourth-generation cephalosporin Cefepime (73.2%) demonstrated the highest rates of susceptibility followed by Piperacillin/Tazobactam (70.4%), Meropenem (65.4%), Ciprofloxacin (63.5%), Levofloxacin (61.2%), and Imipenem (60.8%). In contrast, Ceftazidime proved least effective, with a susceptibility rate of only 34.6%.

Analysis of virulence factors indicated a clear difference between resistant and non-resistant strains. Phenotypically, phospholipase C was associated with non MDR isolates, while biofilm formation correlated with MDR strains. Genotypically, toxA and plcH were more prevalent in non-MDR isolates, while biofilm production was significantly associated with the plcN gene.

The study’s findings emphasize the urgent public health challenge posed by MDR P. aeruginosa in hospital settings. The authors stress the critical need for enhanced infection control measures, robust antimicrobial stewardship programs, and targeted treatment strategies to mitigate nosocomial spread and improve patient outcomes.

Reference Source:
Moursi, S. A., et al. Resistance patterns and virulence factors of Pseudomonas aeruginosa in hospitalized patients: A Saudi Arabian study. Scientific Reports 15, 38118 (2025). https://doi.org/10.1038/s41598-025-18388-x