Resolution of Non-tuberculous Mycobacterial Peritonitis Following Antibiotic Selection Based on Clarithromycin Resistance

The occurrence of peritoneal dialysis-related peritonitis (PD-related peritonitis) caused by non-tuberculous mycobacteria (NTM) is rare； therefore, case reports of rapidly growing mycobacteria (RGM) are limited. Here, we present a case of PD-related peritonitis caused by Mycobacterium abscessus (M. abscessus) for which treatment was successful after considering clarithromycin (CAM) resistance on selecting antimicrobial agents. A 50-year-old male presented with fever and abdominal pain, leading to a diagnosis of PD-related peritonitis based on clinical and laboratory findings. Initial antibiotic therapy led to limited improvement, and on the 3rd day, growth of NTM colonies was observed, prompting a diagnosis of peritonitis caused by RGM. After considering CAM resistance, combination therapy with imipenem (IPM), amikacin (AMK), and ciprofloxacin (CPFX) was initiated, resulting in an improved inflammatory response. It is noteworthy that CAM resistance is frequently reported in RGM, with M. abscessus acquiring resistance at a frequency of 79.3 to 93.8％. The mechanisms of resistance are known to involve the erm and rrl genes, and there are differences in the rate of resistance acquisition among subspecies of M. abscessus. Due to the high frequency of RGM among NTM, it is advisable to consider RGM on selecting antimicrobial agents when NTM infection is suspected.