Pseudoglutamicibacter cumminsii in Polymicrobial Osteomyelitis of the Tibia in a Female Patient—A Case Report

Introduction: Pseudoglutamicibacter cumminsii (formerly Arthrobacter cumminsii) is a microorganism rarely reported as a cause of infection. It is a Gram-positive, non-motile, and non-spore-forming bacterium belonging to the Micrococcaceae family. It is known for its environmental ubiquity, being frequently found in soil, water, and other ecological niches. Case report: A 39-year-old woman with a history of glucose-6-phosphate dehydrogenase deficiency and multiple surgeries at the left lower extremity for osteomyelitis at the left tibia presented with a relapse of chronic osteomyelitis of the left tibia. She underwent surgical debridement, and cultures grew Enterococcus faecalis, Pseudomonas aeruginosa, Klebsiella oxytoca, Proteus mirabilis, and Pseudoglutamicibacter cumminsii, according to identification with matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Targeted antimicrobial treatment with ciprofloxacin and amoxicillin-clavulanate for six weeks led to patient recovery. Conclusions: Accurate identification by advanced diagnostic techniques is essential for effectively managing rare pathogens. Further research and reporting of cases are needed to understand better the epidemiology, pathogenesis, optimal treatment, and improved clinical outcomes associated with P. cumminsii infections.