1663 - The Significance of Acid Fast Cultures in Peritoneal Dialysis-associated Infections: A Non-tuberculous Mycobacteria Case Series

Background: Non-tuberculosis mycobacteria (NTM) are a group of Mycobacterium that are defined as species other than Mycobacterium tuberculosis complex and Mycobacterium leprae. Rapid growing NTM’s grow on culture media as early as 5-7 days. NTM's are considered a rare cause of peritoneal dialysis (PD) associated infections.

Methods: We highlight four cases of PD catheter associated infections due to rapid growing NTMs to covey the importance of these bacteria in the setting of PD associated infections.

Results: All of our cases all were on PD due to their end stage renal disease (ESRD). Case 1 is a 55-year-old man who was on PD due to IgA nephropathy. He had ulceration around catheter site and abdominal pain for 3 months prior to presentation. Catheter site and peritoneal fluid were both positive for Mycobacterium abscessus. Case 2 is a 59-year-old woman with who was on PD due to Alport syndrome. She presented with fever and pain around PD catheter site. Cultures were positive for Mycobacterium fortuitum. Case 3 is a 68-year-old woman who was on PD due to diabetic nephropathy. She presented after increased drainage around PD-catheter site after 2 months duration. Cultures from catheter site grew Mycobacterium porcinum. Case 4 is a 73-year-old male with who was on PD due to diabetic nephropathy. He presented due to erythema around his PD catheter site. Catheter site cultures were positive for M. abscessus.  Each case was treated based upon culture data and for varied length of time, which can be further seen in Table 1.
 Table 1


Conclusion: Typical organisms that cause peritonitis and PD exit site infections are from skin flora contamination. The International Society of Peritoneal Dialysis recommends anaerobic and aerobic cultures to be obtained in suspected peritonitis. Expected culture negative rate are typically about 10-20%. NTM's can be often missed and diagnosed as a culture negative infection if routine acid-fast bacilli (AFB) cultures are not obtained. Also, NTMs are likely to be under represented since these are not considered reportable. A high index of suspicion would mandate culturing for NTMs as a potential cause of PD catheter associated infection. With having 4 cases all in Florida, we would like to stress the importance of ordering AFB cultures in PD catheter associated infections.