Necrotizing Cellulitis With Multiple Abscesses on the Leg Caused by Serratia marcescens
Serratia marcescens is an unusual cause of severe skin infection initially described in immunocompromised patients. We report a case of necrotizing cellulitis of the leg caused by S marcescens in a 68-year-old woman with diabetes mellitus and a history of chronic lymphoedema of the leg. We reviewed the literature and found 49 cases of severe skin infections from S marcescens that included 20 cases of necrotizing fasciitis (NF) as well as 29 cases of severe skin infections without NF (non-NF cases). Patients were immunocompromised in 59% to 70% of cases. The mortality rate was high in NF cases (60%) versus non-NF cases (3%). Surgery was required in 95% of NF cases and in 24% of non-NF cases. The other clinical manifestations of S marcescens skin infection reported in the literature included disseminated papular eruptions in patients infected with human immunodeficiency virus with folliculitis on the trunk. Serratia marcescens is naturally resistant to amoxicillin alone and amoxicillin associated with clavulanic acid. Broad-spectrum antibiotics are indicated to treat S marcescens skin infections, and surgery should be promptly considered in cases of severe skin infections if appropriate antibiotic therapy does not lead to rapid improvement.
Practice Points
- Serratia marcescens skin infection should be considered in cases of cellulitis in immunocompromised patients when conventional antibiotics are not effective.
 - Broad-spectrum antibiotics such as third-generation cephalosporins, fluoroquinolones, or imipenem-cilastatin are indicated in cases of S marcescens skin infections, and surgery should be promptly considered.
 
Conclusion
Although uncommon, an S marcescens skin infection may be suspected in cases of cellulitis in immunocompromised patients, especially when conventional antibiotics are not effective. Serratia marcescens naturally produces a cephalosporinase that confers resistance to amoxicillin and to amoxicillin associated with clavulanic acid. Broad-spectrum antibiotics such as third-generation cephalosporins, fluoroquinolones, or imipenem-cilastatin are indicated in cases of S marcescens skin infections, and surgery should be promptly considered if appropriate antibiotic therapy does not lead to rapid clinical improvement.