A 23-year-old man presented with one year history of recurrent pyorrhoea from the umbilical area. Specifically, the patient had 5 episodes of omphalitis during the last year prior to his admission to the hospital. All episodes were successfully treated with courses of antimicrobial agents (second generation cephalosporins or amoxicillin/clavulanic acid) by mouth. No fever, abdominal pain or other complaints were reported. His past medical history was significant for dysfunction of the left kidney (79% loss of function in a recent nuclear medicine renal scan), which was attributed to recurrent urinary tract infections during his childhood.
Physical examination on admission showed temperature of 37,4 degrees C, signs of inflammation (redness, tenderness, swelling, and increased temperature) in the umbilical area (Figure 1) as well as purulent umbilical discharge (Figure 2).
Routine laboratory tests including a complete blood count, blood urea, serum creatinine, blood glucose, liver function tests, C-reactive protein, erythrocyte sedimentation rate, and a urinalysis were normal. No growth of microorganisms was found from the culture of the umbilical discharge.
What are the likely underlying causes for the recurrent omphalitis of this young adult?