Introduction

Pseudomonas aeruginosa (PA) is a common gram-negative aerobic bacilli bacterial infection in chronic wounds.¹ PA is often present in soil, water, humans, and on the surface of medical devices, plants, and animals.^2,3 PA is an opportunistic infection that can cause serious disease. Patients with an immunocompromised state will often have PA infections. These conditions may include the following²:

• Cystic fibrosis
• Bronchiectasis
• Neutropenia
• Burns
• Cancer
• AIDS
• Organ transplant
• Uncontrolled diabetes mellitus
• ICU admissions

Treating PA with antimicrobial agents is often challenging due to the frequency of antibiotic resistance. To diagnose PA, clinicians should perform routine laboratory and imaging workups and, if necessary, obtain blood, urine, and tissue cultures. To confirm that soft tissue, bone, and joints are not involved, advanced imaging may be needed.⁴

Key Features

• It is common for patients with puncture wounds in the foot to become infected with PA species. Usually, a sweet, fruity-smelling discharge is present in these infections.⁴ Frequent complications are cellulitis and osteomyelitis.
• Neutropenic patients typically develop ecthyma gangrenosum in the form of erythematous, dark lesions. These skin lesions are ulcerated, purple, or black and usually found in the axillary, inguinal, or anogenital areas.⁵
• If PA infects patients who have burns with eschar, it may result in bacteremia or bacteria in the bloodstream. Bacteremia is a complication with a high mortality rate.⁶
• Chronic leg ulcers populated with PA, such as venous stasis ulcers, will often have a malodorous greenish superficial crust.⁷

Tips for Managing

As mentioned above, since PA is often antibiotic-resistant, areas of pseudomonas infection and severity often determine the treatment plan.² To guide therapy, clinicians should denote any sensitivity to different antimicrobials revealed on culture in pseudomonal infections.⁵The following is a list of considerations for such circumstances:

• Clinicians may use acetic acid, a topical antiseptic, to lower wound pH. A concentration of at least 0.5% is required for antimicrobial efficacy to make the environment unsuitable for PA growth.⁷
• As adjuvant treatment to antibiotic therapy, clinicians should debride necrotic tissue and/or drain abscesses.⁷
• If culture and sensitivity results are not yet available, select agents from multiple antibiotic groups may be of use. These agents include Carbapenems (eg, meropenem), cephalosporins (eg, ceftazidime, cefepime), aminoglycosides (eg, gentamicin, tobramycin, and amikacin), and fluoroquinolones (eg, ciprofloxacin and levofloxacin) ⁸
• Surgical debridement and removal of infected tissue may be necessary, which in rare cases, may result in amputation.

Conclusion

PA infections are opportunistic blue-green pus-producing bacteria that can infect wounds, especially in immune-compromised patients. Due to its rapidly emerging resistance to multiple classes of antibiotics, PA is often a concern due to the associated complexities of treatment.⁹ Early detection and appropriate treatment are essential for the management of PA infections.

References

1. Kerr KG, Snelling AM. Pseudomonas aeruginosa: a formidable and ever-present adversary. J Hosp Infect. 2009;73(4):338-44.
2. Mulcahy LR, Isabella VM, Lewis K. Pseudomonas aeruginosa biofilms in disease. Microb Ecol. 2014 ;68(1):1-12.
3. Tuon FF, Dantas LR, Suss PH, Tasca Ribeiro VS. Pathogenesis of the Pseudomonas aeruginosa Biofilm: A Review. Pathogens. 2022; 11(3):300. https://doi.org/10.3390/pathogens11030300
4. Niall DM, Murphy PG, Fogarty EE, Dowling FE, Moore DP. Puncture wound related pseudomonas infections of the foot in children. Ir J Med Sci. 1997;166(2):98-101.
5. Wilson MG, Pandey S. Pseudomonas Aeruginosa. StatPearls. Updated August 28, 2022. https://www.ncbi.nlm.nih.gov/books/NBK557831/?report=classic
6. Azzopardi EA, Azzopardi SM, Boyce DE, Dickson WA. Emerging gram-negative infections in burn wounds. J Burn Care Res. 2011;32(5):570-6.
7. Nagoba B, Wadher B, Kukarni P, Kolhe S. Acetic acid treatment of Pseudomonal wound infections. Eur J Gen Med. 2008;5(2):104-106.
8. Makhnevich A, Feldhamer KH, Kast CL, Sinvani L. Aspiration Pneumonia in Older Adults. J Hosp Med. 2019;14(7):429-435.
9. Zaman SB, Hussain MA, Nye R, Mehta V, Mamun KT, Hossain N. A Review on Antibiotic Resistance: Alarm Bells are Ringing. Cureus. 2017; 9(6): e1403.doi:10.7759/cureus.1403

About the Author

Emily Greenstein, APRN, CNP, CWON-AP, FACCWS is a Certified Nurse Practitioner at Sanford Health in Fargo, ND. She received her BSN from Jamestown College and her MSN from Maryville University. She is certified as an Adult-Gerontology Nurse Practitioner through the American Academy of Nurse Practitioners. She has been certified in wound and ostomy care through the WOCNCB for the past 12 years. At Sanford she oversees the outpatient wound care and is co-director for the limb preservation program. She currently serves as the President elect for the North Central Region Wound, Ostomy, and Continence Society. Emily has served as an expert reviewer for the WOCN Society and the Journal for WOCN. Her main career focus is on the advancement of wound care through evidence-based research.