Abstract
To the Editor:
Eikenella corrodens is a slow-growing, gram-negative facultative anaerobic bacillus that colonizes the flora of the oral cavity, upper respiratory tract, and mucosal surfaces of the digestive tract [1]. The head and neck are the most common sites involved, whereas other sites such as intra-abdominal, skin, and joint are rare [2]. Here, we report a rare case of abdominal subcutaneous abscess caused by Eikenella corrodens.
A 60-year-old man presented with a 50-day history of localized erythema and sclerosis on his left abdomen, accompanied with sharp pain and irregular fever. Fifty days prior, a sharp pain developed on his left abdomen accompanied with localized erythema and sclerosis. He was diagnosed with herpes zoster in the society clinic and given ceftriaxon and ribavirin orally for 10 days without any relief. Twenty days prior to his presenting at our hospital, the patient started having irregular fever, with Tmax at 38.6°C. Previously, he had been diagnosed with alcoholism for 15 years.
Physical examination revealed an irregular erythema on his left abdominal (Fig. 1A). Laboratory examination found increased leukocyte (14.54 × 109/L) with elevated neutrophil making up 73.7%. The patient's erythrocyte sedimentation rate was 51 mm/h (normal, 0–20) and high-sensitivity C-reactive protein was 68.4 mg/L (normal, <5). Ultrasound showed two subcutaneous cysts with low echo intensity beneath the left abdominal wall with a tunnel in between (diameter, 0.9 cm). On the cross-sectional view, the upper cyst was found to be 6.7 × 1.8 cm and the deeper cyst found to be 11.3 × 2.9 cm. An abdominal computer tomography presented normal except the subcutaneous low intensity area in line with the ultrasound findings (Fig. 1B).
We subsequently performed transcutaneous paracentesis under sonographic guidance and obtained approximately 80 mL pus that was blood tinged and foul smelling, from which Eikenella corrodens was isolated after five-day culture. According to the drug sensitivity test, sodium cefoperazone sulbactam was used (2 g/d) for 20 days along with drainage, followed by a resection surgery. After the treatment, the patient's symptoms including the erythema, pain, and fever resolved.
Eikenella corrodens rarely causes infection beyond the colonized sites and usually because of periodontal disease or bite wounds. Nevertheless, in our case, the lesion presented in suddenly and without either periodontal disease or trauma history. Based on the disease history and examinations, we detected no clue of the path via which the pathogen formed the subcutaneous abscess in this case. According to the clinical features reported by Sheng et al. [2], the 15-year history of alcoholism was probably a potential risk factor for the patient to develop Eikenella corrodens infection but still could not fully explain how the bacteria invaded the abdomen wall. Eikenella corrodens infection is usually accompanied by other bacterial infections, such as streptococci, prevotellaoralis, and actinomyces [3,4], however, in our case, it was the only strain isolated from the pus in the cultures.
To the best of our knowledge, this patient is the first case of abdominal subcutaneous abscess caused by Eikenella corrodens alone without wound. Treatment of this type of abdominal subcutaneous abscess infection depends on antibiotic agents and sometimes needs a surgical approach.