Pseudomonas guariconensis Necrotizing soft tissue infection, Denmark

UNLABELLED: We describe the first published case report of a successful treatment of Pseudomonas guariconensis-induced Necrotizing Soft Tissue Infection (NSTI). Since Pseudomonas guariconensis has been resistant to meropenem in all reported cases, clinicians and microbiologists should treat these patients with extreme care.

PATIENT AND METHODS: A 72-year-old man presented to the emergency department with a 3-day history of fever, pain in the right leg/foot and general malaise. He was diagnosed with NSTI, empirical meropenem and clindamycin was started, and surgery was quickly performed with removal of all dead skin and subcutaneous tissue. All fasciae were intact.

RESULTS: Blood cultures and tissue samples showed growth of Pseudomonas guariconensis, which a literature review revealed to be highly suspicious of meropenem resistance. This prompted quick change of antibiotics, first with ciprofloxacin and metronidazole added and then change of meropenem to cefiderocol. Susceptibility tests on both blood and tissue samples revealed resistance to meropenem (along with resistance to many other antibiotics). The patient improved, was changed to ceftazidim and ciprofloxacin and recovered fully from the infection.

CONCLUSIONS: Since clindamycin has no effect on any Pseudomonas species and since Pseudomonas guariconensis has been resistant to meropenem in all reported cases, clinicians and microbiologists should treat these patients with extreme care.