A 64 year old Caucasian male with recent history of constrictive pericarditis and 4.7 cm ascending aortic aneurysm was admitted to the hospital for an elective surgery. He underwent repair of his ascending aortic aneurysm and pericardiectomy on day 1 of admission. During his hospital stay, he had a cardiac arrest with ventricular fibrillation and underwent pacemaker placement (day 7). He also developed acute kidney injury and underwent tunneled central venous catheter (CVC) placement for hemodialysis (day 10).
He was transferred to the intensive care unit (ICU) with hypotension and fever, and blood cultures were drawn (day 20). Microbiology laboratory reported blood cultures positive for RGM, possibly mycobacterium smegmatis based on in-house MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight mass spectrometry) (day 24). Mycobacterium tuberculosis PCR was negative. Infectious diseases team was consulted and CVC was removed per their advice (day 26). Repeat blood cultures drawn on day 24 and day 26 were reported positive for RGM. The patient was started on empiric intravenous (IV) amikacin 15 mg/kg every 24 h, IV meropenem 1 g every 8 h, oral (PO) ethambutol 1200 mg daily and PO doxycycline 100 mg daily (day 26). The CVC tip was positive for Mycobacterium smegmatis (day 28). Post catheter removal, he improved clinically and his repeat blood cultures obtained on day 28 were negative. Mycobacterium smegmatis isolate was send to National Jewish Medical Center for susceptibility testing (day 35). The isolate was resistant to ceftriaxone, cefotaxime and cefepime; intermediate to clarithromycin, cefoxitin and amoxicillin/clavulanate; and susceptible to aminoglycosides, trimethroprim/sulfamethaxole, tetracyclines, imipenem, fluoroquinolones, linezolid, and clofazamine based on RPOB (beta subunit of bacterial RNA polymerase) gene sequencing (day 48). The patient received 28 days of empiric IV amikacin 15 mg/kg every 24 h, IV meropenem 1 g every 8 h, PO ethambutol 1200 mg daily and PO doxycycline 100 mg daily and once susceptibilities were available, he was deescalated to PO doxycycline 100 mg daily and PO ciprofloxacin 500 mg twice a day for 8 weeks. Patient was followed at the infectious diseases outpatient clinic at the end of treatment and was still clinically stable by week 12.