# Cellulitis Caused by Pseudomonas putida: A Case Report and Review of the Literature

## TL;DR

A 78-year-old man with a weakened immune system developed cellulitis caused by Pseudomonas putida in his lower leg, which improved with treatment.

## Contribution

This case report highlights the rare occurrence of Pseudomonas putida causing cellulitis in immunocompromised elderly patients.

## Key findings

- Pseudomonas putida caused cellulitis in a 78-year-old man with nephrotic syndrome and immunosuppressive therapy.
- The patient's condition improved after intravenous meropenem and hemoperfusion for septic shock.
- Literature review suggests P. putida cellulitis occurs in immunocompromised elderly individuals and may lead to sepsis with poor outcomes.

## Abstract

Pseudomonas putida is a gram-negative bacterium often found in environments like water and soil. It is typically linked to hospital-acquired infections, particularly in people who have medical devices or catheters. The bacterium rarely causes skin and soft tissue infections (SSTIs). Herein, we present a case of cellulitis in the right lower extremity caused by P. putida. A 78-year-old Japanese man with a history of nephrotic syndrome due to membranous nephropathy, treated with oral prednisolone and cyclosporine, presented with painful swelling, warmth, and purpura in the right lower extremity. The exploratory incision findings excluded necrotizing soft tissue infections. Therefore, cellulitis was diagnosed, and intravenous meropenem hydrate was initiated. Because of persistent hypotension despite fluid therapy, the patient was transferred to the intensive care unit for vasopressor support. From day 2 to day 3, the patient underwent direct hemoperfusion with a polymyxin B immobilized fiber column to treat septic shock. On day 3, the patient’s vital signs and painful swelling had improved. Subsequently, two sets of blood cultures and a wound culture yielded P. putida alone. As the patient’s general condition and laboratory data had improved, meropenem hydrate was discontinued on day 11. In our literature review, we found that SSTIs, including cellulitis, caused by P. putida tend to occur in the lower extremities of older adults with multimorbidity or immunosuppression, and sepsis may be associated with poor prognosis.