Necrotizing fasciitis caused by Aeromonas caviae
A 71-year-old male patient presented with a wound over the right foot discharging pus, along with fever and subcutaneous swelling of the lower right extremity extending up to the knee joint. The patient gave a history of trauma due to foreign body to the foot 10 days back, following which bullous lesions developed over the lower leg, associated with insidious swelling of the lower leg. The patient also gave a history of self manipulation of the bulla, in order to drain the pus, which led to active pus discharge from the wound, fever and rapid extension of the soft-tissue swelling. The patient was seen by a general practitioner, who prescribed the patient oral amoxicillin + clavulanic acid, but despite the therapy the patient's condition deteriorated and the patient then presented to our hospital. The patient's past medical history revealed that he was on medications for hypertension and had undergone a coronary artery bypass graft (CABG) four years back.\nThe On general examination of the patient was conscious, alert and cooperative, with a heart rate of 80/min, blood pressure 130/70 mm Hg, and all his peripheral pulses were palpable. Extensive necrosis of the underlying skin and muscle of the right lower extremity was noted. His laboratory investigations were: urea 37 mg/dl; creatinine 0.9 mg/dl; total protein 5.2 mg/dl; bilirubin 1.5 mg/dl, fasting blood sugar 93 mg/dl; post-prandial blood sugar 136 mg/dl. The leukocyte count was 3800 cells/mm3 with 41% segmented neutrophils, 33% metamyelocytes, 1% myelocytes, 4% monocytes, 4% lymphocytes, and 17% band neutrophils. HIV test was negative.\nA diagnosis of necrotizing fasciitis was made and the patient underwent extensive fasciotomy and debridement along with removal of the necrotic skin. Extensive necrosis of the underlying skin and muscle also was noted. The drained pus was sent for culture and the patient was started on intravenous ceftriaxone and amikacin. The Gram stain of the pus showed pus cells with plenty of Gram-negative bacilli. The culture on MacConkey's agar showed non-lactose fermenting colonies, which were oxidase-positive. The organism exhibited the “suicidal phenomenon”, was anaerogenic and esculin-positive and was identified to be Aeromonas caviae by standard laboratory techniques.[] The isolate was sensitive to amoxycillin-clavuanic acid, cefazolin, cefotaxime, gentamicin, tetracycline, ciprofloxacin and cotrimoxazole and was resistant to ampicillin and piperacillin. The isolate was tested for production of extended-spectrum β lactamase (ESBL) and carbapenemase as per the Clinical Laboratory Standards Institute (CLSI) guidelines, but the tests were negative.[]\nMeanwhile the patient responded well, with subsidence of the fever and his blood counts returning to normal levels. Daily dressing of the wound was applied. The subsequent wound swab cultures taken after seven days were negative. The patient was taken up for split-skin grafting of the bare area of the right leg after 10 days. He was discharged with satisfactory graft uptake after one week without any further antibiotics advice.