Chronic wound infections: the role of Pseudomonas aeruginosa and Staphylococcus aureus

Abstract

Chronic leg ulcers affect 1–2% of the general population and are related to increased morbidity and health costs. Staphylococcus aureus and Pseudomonas aeruginosa are the most common bacteria isolated from chronic wounds. They can express virulence factors and surface proteins affecting wound healing. The co-infection of S. aureus and P. aeruginosa is more virulent than single infection. In particular, S. aureus and P. aeruginosa have both intrinsic and acquired antibiotic resistance, making clinical management of infection a real challenge, particularly in patients with comorbidity. Therefore, a correct and prompt diagnosis of chronic wound infection requires a detailed knowledge of skin bacterial flora. This is a necessary prerequisite for tailored pharmacological treatment, improving symptoms, and reducing side effects and antibiotic resistance.

Keywords:

• antibiotics
• chronic leg ulcers
• chronic wounds
• Pseudomonas aeruginosa
• Staphylococcus aureus

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Key issues

• Chronic leg ulcers, such as venous, diabetic and pressure ulcers, affect 1–2% of the general population.

• Infection is a frequent event that often complicates chronic wound, affecting its healing course.

• With regard to chronic wounds and their infection, Staphylococcus aureus and Pseudomonas aeruginosa play a central role certainly.

• Evidence suggests that P. aeruginosa–S. aureus co-infections are more virulent than monoculture infection with either species.

• Although they are the most commonly associated microbial species in chronic wound infections, very little is known about their relationship.

• P. aeruginosa and S. aureus form a pathogenic group capable of making a strong biofilm that maintains the chronic infection impairing the healing of the wound and increasing the development of antibiotic resistance.

• Pharmacological treatment of P. aeruginosa and S. aureus involves very low systemic antibiotics recommended by the European guidelines, while to date, no topical antibiotics are indicated for this co-infection related to the management of chronic leg ulcers.