Secondary atypical mycobacterial infection after peritoneal catheter removal.

Dear Editors, Atypical mycobacterial infection of peritoneal catheter (PC) exit site is occasionally seen, especially in warm and humid localities. Secondary atypical mycobacterial infection may also arise after removal of PC and should be suspected in cases of non-healing wound infection despite appropriate treatment of primary bacterial exit site infection (ESI) and after prolonged antibiotics use. We present here two cases of atypical mycobacterial wound infection after removal of PC. Our first case was a 34-year-old lady, who had a history of end-stage renal failure due to immunoglobulin A (IgA) nephropathy. She was started on peritoneal dialysis (PD) in 2001. She suffered from recurrent episodes of Pseudomonas ESI and PC was revised in October 2003. She suffered from tunnel tract infection again 2months later. Exit site culture was negative. PC was removed and she was put empirically on intravenous ceftriazone 1 gm daily for 1week followed by oral cefuroxime 500mg twice daily for 6weeks. Her wound had persistent purulent discharge. A repeated culture 3weeks later revealed growth ofMycobacterium fortuitum. Shewas switched to intravenous amikacin 375mg twice weekly for 3weeks and oral clarithromycin 250mg twice daily for 8weeks. PC was reinserted 10weeks later and she resumed successfully on PD. Our second case was a 50-year-old man with a history of end-stage renal failure due to reflux nephropathy from neurogenic bladder. PDwas commenced in 2003. As he had recurrent episodes of Pseudomonas aeruginosa ESI, gentamycin ointment was applied daily. In March 2011, he had ESI again with a small abscess just adjacent to the exit site. Although he was empirically treated with a course of oral amoxicillin and clavulanate for 2weeks together with incision and drainage of the abscess, PC was removed due to persistent infection. Abscess culture grew Pseudomonas aeruginosa. Intravenous ceftaxidime was given for 2weeks. However, his surgical wound appeared persistently infected, despite appropriate therapy. A repeated culture grew Mycobacterium chelonae. He was given oral clarithromycin 250mg twice daily for 4weeks. His wound healed completely. PC was reinserted and he was successfully resumed on PD with no recurrence of atypical mycobacterial infection. Mycobacterium chelonae, Mycobacterium fortuitum and Mycobacterium abscessus are the most commonly seen atypical mycobacteria to cause infections in PD patients. Similar to other atypical mycobacteria, they are ubiquitous, mostly present in the soil, dust and water. They usually cause skin and soft tissue infections after trauma or surgical procedures in opportunistic hosts (1). They produce tuberculoid, poorly formed granulomas, non-specific chronic inflammation involving the dermis and hypodermis and suppuration. Table 1 Clinical features and laboratory findings of two patients with secondary atypical mycobacterial infection after removal of PC