Bacteremia Due to Mycolicibacterium Mucogenicum

Male patient, 43 years old, with hypertensive nephrosclerosis, on hemodialysis since October 2021, via a central venous catheter (CVC). Five months before the current episode, the patient was hospitalized for candidemia, and the tunneled catheter was replaced with a temporary Quinton-type catheter. Fifteen days before the current hospitalization, he presented fever during a hemodialysis session, receiving antimicrobials for five days during sessions. On the day of hospital admission, he had a new febrile episode, malaise, and hypotension during hemodialysis. Given the suspicion of catheter-related infection, the CVC was removed and meropenem and daptomycin were started, with partial clinical improvement, but with persistently elevated laboratory parameters. After identification of Mycolicibacterium mucogenicum (formerly Mycobacterium mucogenicum) in blood cultures, the antimicrobial regimen was adjusted to clarithromycin 500 mg/day and moxifloxacin 400 mg/day, planned for four weeks, with progressive clinical improvement and no recurrences. Bacteremia due to M. mucogenicum is a rare but emerging infection in immunocompromised patients or those with intravascular devices, especially in hemodialysis. This environmental pathogen, ubiquitous in water systems, has the ability to form biofilm on catheters, which explains outbreaks in dialysis units. Its typical presentation – febrile bacteremia without evident local signs – combined with slow growth in cultures (3-15 days) and initial confusion with contaminants, delays diagnosis by up to 15 days. In dialysis patients, factors such as immunosuppression, chronic exposure to catheters, and frequent manipulation of devices amplify risk. Management requires immediate catheter removal (recurrence rates reach 60% if maintained) and combined antibiotic therapy for 4-6 weeks. The susceptibility profile includes macrolides (clarithromycin), fluoroquinolones (moxifloxacin), and aminoglycosides, but resistance to ceftriaxone and antituberculosis drugs is common. Prognosis is favorable with early intervention (>80% success), highlighting collaboration between clinical teams and microbiology for molecular identification (16S rRNA gene or MALDI-TOF). Preventive strategies include strict control of water quality, specific filters, and education in catheter hygiene.