Salmonella Abscess of the Anterior Chest Wall in a Patient With Type 2 Diabetes and Poor Glycemic Control: A Case Report

Skin and soft tissue infections within the dermis and deeper skin tissues can be due to 1 or more pathogens and may include skin flora as well as organisms from adjacent mucous membranes. A retrospective study¹ that analyzed the specimens of cutaneous or subcutaneous abscesses (N = 86) revealed Staphylococcus aureus monoinfection (either methicillin-susceptible or methicillin-resistant) occurred in up to 50% of cases; more than 96% of the pathogens were Staphylococcus and Streptococcus species. However, a comprehensive review² of Salmonella infection found nontyphoid Salmonella (NTS) can cause not only self-limited acute gastrointestinal infections, but also bacteremia with or without extra-intestinal focal infections. These hardy bacteria are especially problematic in a wide variety of immunocompromised individuals, including patients with malignancy, human immunodeficiency virus, or diabetes and those receiving immunotherapy agents. A retrospective study³ found that among 129 NTS patients, 39.5% had extra-intestinal focal infections, including endovascular infection (14.7%), pneumonia (10.1%), osteomyelitis (5.4%), intra-abdominal abscess (5.5%), and soft tissue infection (0.8%). Extra-intestinal focal infections often require prolonged antimicrobial therapy and hospital stays. A review of in vitro and in vivo research⁴ analyzed impaired immune responses and increased susceptibility in patients with diabetes to specific infections. A case report of a Salmonella abscess in the anterior chest wall of a patient with type 2 diabetes and poor glycemic control is herein presented.

Mr. D, a 30-year-old with a 10-year history of diabetes treated with 500 mg metformin twice a day, presented to the plastic and reconstructive surgery department of Tri-Service General Hospital (Taipei, Taiwan) with a painful nodule of 1 month’s duration over his anterior chest region. Two (2) weeks before his hospital admission, the nodule ruptured and the surrounding tissue revealed erythema and warmth. He received sharp debridement and bacterial culture for pathogen identification by a physician in the outpatient department. Oral antibiotics (amoxycillin/clavulanate) were prescribed for high suspicion of multispecies skin and soft tissue infections. One week later, culture of wound discharge revealed Salmonella group D resistant to ampicillin and susceptible to ceftriaxone and ciprofloxacin. The ulcerative wound continued to exhibit purulent discharge and tenderness. 

Mr. D was admitted to the authors’ plastic surgery department on December 31, 2013. He denied any recent diarrhea, vomiting, abdominal pain, or fever. His physical examination was unremarkable except for a 2-cm, ulcerative chest wound above the sternum about the fifth intercostal space that exhibited purulent discharge (see Figure 1a). Blood tests revealed elevated C-reactive protein (112 mg/L) and hyperglycemia (318 mg/dL). His glycosylated hemoglobin A1c (HbA1c) — a serologic marker for average glucose over a 2- to 3-month period — was 11.7% (16.0 mmoL/moL). Blood and stool cultures were negative for Salmonella. His chest x-ray revealed normal distribution without local infiltration. Ceftriaxone 2.0 g was administered intravenously daily for 10 days; the oral antidiabetic agent was discontinued and he was started on insulin therapy. The insulin dose was adjusted based on blood sugar pattern to reach optimal blood glucose control (premeal target of <140 mg/dL with all random glucoses <180 mg/dL). On hospital day 2, he underwent surgical debridement, which revealed abscess formation in the subcutaneous layer of approximately 7 cm x 4 cm below the ulcerative wound (see Figure 1b). After radical debridement, a wet dressing (wet aqueous betadine gauze without topical antibiotic ointment) was provided to keep the wound clean; it was changed twice a day. No pus was noted in the open wound.

Owing to the large and deep open wound defect over the anterior chest wall, negative pressure wound therapy for secondary intention healing was not indicated — Mr. D’s physician believed in the presence of a deep and wide wound, secondary intention requires a great deal of time for healing and a skin graft will cause scar contracture and limited mobility and not fulfill functional and cosmetic goals. A local flap for anterior chest wall wound reconstruction is known to be an accepted option. Therefore, 2 days post radical debridement, the authors performed rotational fasciocutaneous flap surgery for wound reconstruction (see Figure 2a). This type of rotation flap starts with an incision at the top of the circular defect. The length of the circular cut to create the flap depends on the degree of wound edge firmness (ie, laxity) of the donor site as determined subjectively by the surgeon. In this case, the flap was 3 times the area of the defect. The wound edge was undermined deep to the fascia layer to decrease tension for wound closure. After the rotation flap was applied, a Jackson-Pratt drain was placed until drainage was <10 mL/day; in Mr. D’s case, this occurred 1 week after surgery. 

Mr. D was discharged 1 week after his surgery and antibiotic therapy was changed to oral ciprofloxacin for 1 week. His wound remained completely healed without local recurrence at his 4-month follow-up (see Figure 2b).

Salmonellosis may present in different clinical forms, ranging from asymptomatic chronic carrier to gastroenteritis, bacteriemia, and extra-intestinal focal infections. In recent years, several retrospective studies^3,5 reported NTS infection with extra-intestinal focal infections, such as urinary tract infection, endovascular infection, meningitis, osteomyelitis, pneumonia, and soft tissue infection. To the best of the authors’ knowledge, chest wall abscesses caused by NTS have been reported in the literature in only 7 patients between 1990 and 2014: 4 had no underlying disease, 2 had autoimmune deficiency syndrome (AIDS), and 1 had diabetes.⁶ A recent review of the clinical literature⁷ reported most extra-intestinal focal infections of NTS develop in patients with underlying diseases or predisposing conditions, such as malignancies, diabetes mellitus, immunosuppressive therapies, liver cirrhosis, renal insufficiency, or AIDS.

Poorly controlled type 2 diabetes mellitus is associated with major complications, such as cardiovascular disease, atherosclerosis, retinopathy, nephropathy, and neuropathy. Infections are also much more prevalent in individuals with diabetes; this increased susceptibility to infection has been attributed to neutrophil dysfunction, dehydration, malnutrition, vascular insufficiency, and neuropathy.⁴ A prospective, randomized study⁸ involving 245 patients has shown hyperglycemia interferes with wound healing in patients with ulcers and contributes to increased rates of infection. A retrospective study⁹ reported poor glycemic control also has been associated with increased rates of wound infection and other complications in patients after colectomy. The role of HbA1c has expanded in the diagnosis and treatment of diabetes. A retrospective study¹⁰ that analyzed a prospectively collected database of 79 patients reported postoperative blood glucose and preoperative HbA1c levels are associated with wound infection, wound dehiscence, and wound reoperation.

According to the practice guidelines for the diagnosis and management of skin and soft tissue infection from the Infectious Diseases Society of America,¹¹ the first step in treating purulent skin and soft tissue infections is incision and drainage with wound culture, followed by empiric antibiotic therapy. For skin and soft tissue infections due to NTS, ciprofloxacin or ceftriaxone are reasonable options.³ The current case study suggested NTS should be considered as a possible cause of chest wall abscess in individuals with a history of diabetes under poor glycemic control. A high level of HbA1c indicated poor glycemic control before the acute wound developed. During hospitalization, the oral antidiabetic agent was discontinued in favor of insulin therapy. According to the consensus statement by the American Diabetes Association and the American Association of Clinical Endocrinologists¹⁰ and the clinical practice guideline of the Endocrine Society,¹² the insulin dose should be adjusted based on blood sugar pattern to reach optimal blood glucose control (premeal target of <140 mg/dL with all random glucoses <180 mg/dL) and to reduce postoperative wound complications. The surgical options include incision and drainage, curettage, and debridement. The type of surgical procedure depends on the radiological findings, clinical presentation, severity of the infection, and intraoperative findings. In this case, early incision and drainage (ie, immediately upon noting redness and tenderness surrounding the wound and poor response to oral antibiotics; for Mr. D, this occurred 1 week after presentation), culturing the wound, and providing appropriate antibiotic therapy, wound care, and radical debridement proved to be an effective treatment option for a patient with an advanced soft tissue infection, type 2 diabetes mellitus, and poor glycemic control.

Successful wound reconstruction was achieved after surgical debridement, appropriate antibiotic therapy, and good glycemic control in a patient with an infected anterior chest wound. In immunocompromised patients such as persons with type 2 diabetes with poor glycemic control, clinicians should remain vigilant for the presence of Salmonella species as a cause of skin and soft tissue infections. Screening for HbA1c levels will elucidate the effectiveness of recent glycemic control. Oral antihyperglycemic drugs or insulin can be administered to obtain optimal blood glucose control. n