An unusual case of E. coli cellulitis in an immunocompetent patient

Cellulitis due to Escherichia coli is uncommon and thought to be limited to immunodeficient patients. An unusual case of serious E. coli cellulitis was reported in an immunocompetent 84-year-old woman. 

Cellulitis is an infection of the dermis and subcutaneous tissue. While the causative organism is not always identified, cellulitis caused by E. coli is rare and has exclusively been reported in immunodeficient patients. However, Ms Jacqueline Nguyen (St Vincent’s Hospital Melbourne Docklands, Australia) shared an unusual case of E. coli cellulitis with associated bacteraemia in an immunocompetent patient [1].

An 84-year-old woman presented with a 10-day history of a painful, progressive rash on the right lower limb. It was tender with no blistering, necrosis, or crepitus. Her past medical history included atrial flutter, hypertension, hypercholesterolaemia, and breast cancer. She presented septic, hypotensive, tachycardic, and afebrile. On investigation, CRP was elevated and blood culture was positive for E. coli. Skin biopsies demonstrated patchy perivascular and focally interstitial inflammatory infiltrates in the dermis consistent with cellulitis. Cultures of skin and fascia both yielded light growth of sensitive E. coli. She received ongoing intravenous antibiotics and vasopressor support during her prolonged 32-day admission, which was further complicated by poor wound healing of the cellulitis. She was discharged with a 6-week course of amoxicillin-clavulanate. At 1 month follow-up, the cellulitis was resolved and the wound was healed.

A review of existing literature showed 11 reported cases of E. coli cellulitis, of which all have occurred in patients with underlying disease. The presented case is the first to be reported in an immunocompetent patient. One of the proposed mechanisms of infection is that congestive heart failure can increase intestinal permeability or promote bacterial overgrowth allowing translocation of gastrointestinal enteric flora such as E. coli to cause sepsis and cellulitis.

While uncommon, it is important to consider E. coli as a potential causative agent in both immunocompromised and immunocompetent patients. Early investigation with blood cultures, CT imaging, and skin biopsy may guide diagnosis.

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   1. Nguyen N, et al. A Rare Case Of Escherichia Coli (E.coli) Cellulitis With Associated Bacteraemia In An Immunocompetent Patient. Abstract 88, ICD 2021, 10–13 November 2021.

 

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Posted on 2 December, 20212 December, 2021