Microbacterium paraoxydans Bloodstream Infection in a Patient with Long-Term Indwelling Central Venous Catheter: A Case Report and Literature Review.

Microbacterium species, a genus of aerobic Gram-positive coryneform rods, are rare causes of human infection with only a few sporadic cases reported worldwide. MALDI-TOF MS, 16S rRNA gene sequencing, and even whole-genome sequencing are used to identify the species in a clinical laboratory setting. The study reports a case of Microbacterium paraoxydans bloodstream infection and reviews the literature, including eight additional reported cases of M. paraoxydans infection. We summarize the characteristics of each case, highlight the identification methods, and identify recurrent characteristics for M. paraoxydans infection. A 65-year-old man presented with stable condition of esophageal cancer and long-term prednisolone therapy for psoriasis. A central venous catheter (CVC) was placed for years for treatment of esophageal cancer. The patient presented with fever and chills, and Microbacterium paraoxydans was identified by MALDI-TOF MS from blood culture samples via chemo port. After the chemo port was removed, vancomycin followed by levofloxacin was administered for the entire 14-day treatment course according to susceptibility tests. This study highlights that a long-term central venous catheter and immunocompromised status were common characteristics among the reported cases of Microbacterium spp. infection. The susceptibility of Microbacterium spp. is not fully characterized and varies across reports; gentamicin and trimethoprim/sulfamethoxazole appeared more consistently active, whereas susceptibility to vancomycin was variable. We report this case to highlight the increasing number of infections caused by Microbacterium spp. in the current era and to provide information on the treatment of M. paraoxydans.