Successful Treatment of Peritoneal Dialysis-related Peritonitis due to <i>Mycobacterium iranicum</i>

Abstract

A 68-year-old man on peritoneal dialysis (PD) was hospitalized with the clinical picture of peritonitis. The patient was diagnosed with peritonitis caused by nontuberculous mycobacteria (NTM) according to positive Ziehl-Neelsen staining and negative Mycobacterium tuberculosis polymerase chain reaction results. Oral levofloxacin and clarithromycin, and later intraperitoneal imipenem were started. According to the anti-NTM susceptibility test results, oral minocycline was administered. The patient was treated for 6 months. He recovered without PD catheter removal; thus, PD was successfully continued. A genetic analysis identified the isolate as Mycobacterium iranicum. This is the first report of PD-related peritonitis caused by M. iranicum.

Mycobacterium iranicum septic arthritis and tenosynovitis

“…M. iranicum has been isolated in various regions including Iran; the Mediterranean (Italy, Greece); Northern Europe (the Netherlands, Sweden); the United States; and Asia (Malaysia, Japan). [7], [8], [9] It is a newly discovered species, with the first documented case reports dating back to 2005[3]. Prior to the publication of this current report, M. iranicum was isolated in both immunocompetent patients and those with immunocompromising conditions, including renal transplantation, cancer, diabetes mellitus, Crohn's disease, and human immunodeficiency virus (HIV) infection (Table 1).…”

“…[8] Based on phylogenetic analysis, M. iranicum may be closely related to another rapid grower M. gilvum . [9] It may have acquired virulence genes via horizontal transfer with other mycobacteria, Gram-positive bacteria ( Rhodococcus, Corynebacterium, Nocardia ), and Gram-negative bacteria ( Achromobacter ). [8]…”

“…[5] M. iranicum , however, was implicated as a true pathogen in a Japanese patient who developed peritonitis after washing his peritoneal dialysis catheter exit site with tap water, which may have been contaminated with soil after he had finished cultivating flowers. [9] M. iranicum was also isolated three times from a hand wound of a renal transplant recipient, who was subsequently treated with amikacin. [3]…”

“…Extra-pulmonary NTM disease is typically treated with at least two antibiotics to which the organism is susceptible. [1], [9], [10] Based on minimum inhibitory concentrations of five clinical strains, M. iranicum is usually susceptible to amikacin, cefoxitin, clarithromycin, ethambutol, imipenem, minocycline, sulfamethoxazole, and linezolid. However, it may be intermediately susceptible to ciprofloxacin, rifampicin, and streptomycin.…”

“…[3] Given the relative paucity of clinical data to base treatment recommendations for M. iranicum infections, one must clinically interpret drug susceptibility testing results with caution. In past case reports, combinations containing amikacin, ciprofloxacin, levofloxacin, minocycline, or clarithromycin have been used successfully [3], [5], [7], [9]. Treatment duration was three months in patients with other sites of infection, but must be based on the syndrome being treated.…”