Soft tissue infections occur in over 30% of patients with chemotherapy-induced
neutropenia. Gram-positive bacterial infections predominate early in
neutropenia, and likelihood of infection by resistant bacteria and fungi
increases with prolonged neutropenia. Prior infections and exposures influence
the risk of rare pathogens. A 55-year-old woman with chemotherapy-induced
neutropenia was scratched on her forearm by a dog. She cleaned the wound with
isopropanol and was treated empirically with amoxicillin-clavulanate. Over the
next 4 days, she developed fever along with erythema, edema, and mild tenderness
of the forearm without purulence or crepitus. She was hospitalized and received
empiric treatment with intravenous vancomycin, piperacillin-tazobactam,
tobramycin, and voriconazole. Despite therapy, her fevers persisted and the
cellulitis progressed for over a week. After 10 days of hospitalization, her
neutrophil count began to recover and a bulla developed at the wound site.
Culture of the bullous fluid grew
Serratia marcescens
, and
antibiotics were switched to cefepime based on susceptibility. She defervesced
and showed substantial improvement of cellulitis within 48 hours and was
discharged on oral ciprofloxacin.
Serratia marcescens
skin
infections are rare, and this may be the first report of
Serratia
cellulitis associated with trauma from dog
contact. This case highlights the need to consider unusual pathogens based on
exposure history and immune status and to obtain cultures from fluid collections
or tissue in cases of treatment-resistant soft tissue infections.