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P. aeruginosa

Emery Haley, PhD, Scientific Writing Specialist

Pseudomonas aeruginosa

Clinical Summary

  • P. aeruginosa is recognized as a classical, urease-variable, gram-negative, biofilm-forming, motile uropathogen.
  • P. aeruginosa is associated with complicated, persistent, and recurrent UTI (the same population for which the Guidance UTI assay is indicated).
  • In symptomatic UTI patients, P. aeruginosa:
    • Is not a contaminant (is found in catheter-collected urine specimens).
    • Is viable (can grow out on culture).
    • Is pathogenic (associated with elevated urine biomarkers of infection).
  • Reported severe complications of P. aeruginosa UTI include pyelonephritis, bacteremia, infective endocarditis, urosepsis, and death.
  • Multidrug-resistant P. aeruginosa is an “ESKAPE” pathogen and a well-studied significant global health threat.

Bacterial Characteristics

Gram-stain

Gram-negative

Morphology

Bacillus

Growth Requirements

Non-fastidious (grows well in standard urine culture conditions)
Obligate anaerobe 

Nitrate Reduction

Yes

Urease

Variable

Biofilm Formation

Yes

Pathogenicity

Pathobiont or Pathogen

Clinical Relevance in UTI

P. aeruginosa is a gram-negative, urease-variable,[1] motile bacillus with potent biofilm-forming capabilities. It is a classically recognized as a common uropathogen, particularly well-known for its association with catheter-associated UTIs (CAUTIs) and hospital-acquired UTIs (HAUTIs). This organism’s tendency to form biofilms on urinary catheters and to travel up the urinary tract toward the kidney, as well as its intrinsic and acquired resistance to several classes of antibiotics makes this uropathogen particularly challenging to treat.[2] Indeed, P. aeruginosa is one of the six so-called “ESKAPE pathogens” identified as critical multidrug-resistant bacteria requiring urgent development of effective therapeutics.[3]

P. aeruginosa and Enterococcus species have been found to act synergistically in polymicrobial infections, increasing the formation of biofilms, causing increased kidney histopathology, and resulting in higher antibiotic resistance.[4] In contrast, P. aeruginosa exhibits antagonism with other gram-negative uropathogens, including P. mirabilis and E. coli.[4]

Thanks to its ability to form both biofilms and intracellular reservoirs in epithelial cells of the urinary tract, P. aeruginosa is associated with persistent and recurrent UTIs.[5,6]  P. aeruginosa is also commonly associated with complicated UTIs in older adults, immunocompromised individuals, and individuals with urinary tract abnormalities. For example, P. aeruginosa is reported to be the most frequent cause of pyelonephritis in children with vesicoureteral reflux (VUR).[7] In a study of older adult males and females with clinically suspected complicated UTI, P. aeruginosa was detected in both midstream voided and in-and-out-catheter collected specimens indicating that it was truly present in the bladder, not simply a contaminant picked up during voiding.[8]  Furthermore, elevated markers of immune system activation in the urinary tract have been measured from the same clinical urine specimens in which P. aeruginosa was detected, indicating that the presence of P. aeruginosa was associated with an immune response to urinary tract infection.[9–11]  ​

Reported severe complications of P. aeruginosa UTI include pyelonephritis, bacteremia, infective endocarditis, urosepsis, and death.[12–14]

Together, these findings indicate that P. aeruginosa should be seriously considered as a uropathogen and demonstrate the value of detecting this organism, particularly in individuals with indwelling catheters or other risk factors for complicated UTI.

Treatment

Evidence of Efficacy (Checkmarks): Cefepime, Ceftazidime, Ciprofloxacin, Levofloxacin, Meropenem, and Piperacillin/Tazobactam.

References

  1. BacDive | The Bacterial Diversity Metadatabase Available online: https://bacdive.dsmz.de/ (accessed on 11 February 2025).
  2. AL-Khikani, F.H.; Ayit, A.S. Pseudomonas Aeruginosa a Tenacious Uropathogen: Increasing Challenges and Few Solutions. Biomed. Biotechnol. Res. J. (BBRJ) 2022, 6, 311–318, doi:10.4103/bbrj.bbrj_256_21.
  3. Miller, W.R.; Arias, C.A. ESKAPE Pathogens: Antimicrobial Resistance, Epidemiology, Clinical Impact and Therapeutics. Nat. Rev. Microbiol. 2024, 22, 598–616, doi:10.1038/s41579-024-01054-w.
  4. Gaston, J.R.; Johnson, A.O.; Bair, K.L.; White, A.N.; Armbruster, C.E. Polymicrobial Interactions in the Urinary Tract: Is the Enemy of My Enemy My Friend? Infect Immun 2021, 89, doi:10.1128/iai.00652-20.
  5. Mekonnen, S.A.; Husseini, N.E.; Turdiev, A.; Carter, J.A.; Belew, A.T.; El-Sayed, N.M.; Lee, V.T. Catheter-Associated Urinary Tract Infection by Pseudomonas Aeruginosa Progresses through Acute and Chronic Phases of Infection. Proc. Natl. Acad. Sci. 2022, 119, e2209383119, doi:10.1073/pnas.2209383119.
  6. Penaranda, C.; Chumbler, N.M.; Hung, D.T. Dual Transcriptional Analysis Reveals Adaptation of Host and Pathogen to Intracellular Survival of Pseudomonas Aeruginosa Associated with Urinary Tract Infection. Plos Pathog 2021, 17, e1009534, doi:10.1371/journal.ppat.1009534.
  7. Parente, G.; Gargano, T.; Pavia, S.; Cordola, C.; Vastano, M.; Baccelli, F.; Gallotta, G.; Bruni, L.; Corvaglia, A.; Lima, M. Pyelonephritis in Pediatric Uropathic Patients: Differences from Community-Acquired Ones and Therapeutic Protocol Considerations. A 10-Year Single-Center Retrospective Study. Children 2021, 8, 436, doi:10.3390/children8060436.
  8. Wang, D.; Haley, E.; Luke, N.; Mathur, M.; Festa, R.; Zhao, X.; Anderson, L.A.; Allison, J.L.; Stebbins, K.L.; Diaz, M.J.; et al. Emerging and Fastidious Uropathogens Were Detected by M-PCR with Similar Prevalence and Cell Density in Catheter and Midstream Voided Urine Indicating the Importance of These Microbes in Causing UTIs. Infect. Drug Resist. 2023, Volume 16, 7775–7795, doi:10.2147/idr.s429990.
  9. Haley, E.; Luke, N.; Mathur, M.; Festa, R.A.; Wang, J.; Jiang, Y.; Anderson, L.A.; Baunoch, D. The Prevalence and Association of Different Uropathogens Detected by M-PCR with Infection-Associated Urine Biomarkers in Urinary Tract Infections. Res. Rep. Urol. 2024, 16, 19–29, doi:10.2147/rru.s443361.
  10. Akhlaghpour, M.; Haley, E.; Parnell, L.; Luke, N.; Mathur, M.; Festa, R.A.; Percaccio, M.; Magallon, J.; Remedios-Chan, M.; Rosas, A.; et al. Urine Biomarkers Individually and as a Consensus Model Show High Sensitivity and      Specificity for Detecting UTIs. BMC Infect Dis 2024, 24, 153, doi:10.1186/s12879-024-09044-2.
  11. Parnell, L.K.D.; Luke, N.; Mathur, M.; Festa, R.A.; Haley, E.; Wang, J.; Jiang, Y.; Anderson, L.; Baunoch, D. Elevated UTI Biomarkers in Symptomatic Patients with Urine Microbial Densities of 10,000 CFU/ML Indicate a Lower Threshold for Diagnosing UTIs. MDPI 2023, 13, 1–15, doi:10.3390/diagnostics13162688.
  12. Wu, Y.; Li, P.; Huang, Z.; Liu, J.; Yang, B.; Zhou, W.; Duan, F.; Wang, G.; Li, J. Four-Year Variation in Pathogen Distribution and Antimicrobial Susceptibility of Urosepsis: A Single-Center Retrospective Analysis. Ther. Adv. Infect. Dis. 2024, 11, 20499361241248056, doi:10.1177/20499361241248058.
  13. Babich, T.; Naucler, P.; Valik, J.K.; Giske, C.G.; Benito, N.; Cardona, R.; Rivera, A.; Pulcini, C.; Fattah, M.A.; Haquin, J.; et al. Risk Factors for Mortality among Patients with Pseudomonas Aeruginosa Bacteraemia: A Retrospective Multicentre Study. Int. J. Antimicrob. Agents 2020, 55, 105847, doi:10.1016/j.ijantimicag.2019.11.004.
  14. Dimadi, I.I.Y.; Murillo, M.R.; Zúñiga, M.A.V. Infectious Endocarditis by Pseudomonas Aeruginosa in an Immunocompetent Adult. Cureus 2023, 15, e35072, doi:10.7759/cureus.35072.

About the Author

Dr. Emery Haley is a scientific writing specialist with over ten years of experience in translational cell and molecular biology. As both a former laboratory scientist and an experienced science communicator, Dr. Haley is passionate about making complex research clear, approachable, and relevant. Their work has been published in over 10 papers and focuses on bridging the gap between the lab and real-world patient care to help drive better health outcomes.

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