Lactobacillus Discitis/Osteomyelitis in an Intravenous Drug Abuser

Vertebral osteomyelitis is usually secondary to hematogenous seeding from direct inoculation during spinal surgery or from adjacent soft tissue infection; the most common organism being Staphylococcus aureus. We present a case of a 31-year-old male who was found to have vertebral osteomyelitis secondary to Lactobacillus species. The patient with a past medical history significant for hepatitis C, intravenous (IV) drug use, and nicotine dependence presented with severe back pain that started one month ago. His pain was located in the middle and lower back, radiating to his abdomen, and both lower extremities. The patient admitted to abusing IV heroin daily and sharing needles with his fiancée. CT of the abdomen and pelvis with contrast revealed marked irregularity of the endplates at the L3-L4 level and mild irregularity of the endplates at the L4-L5 level suggestive of osteomyelitis/discitis with no evidence of a paraspinal fluid collection. Core biopsy of the superior endplate of L4 and adjacent disc material was done and sent for microbiology and pathology review. His bone culture came back positive for Lactobacillus species; however, blood cultures remained negative. Clinical improvement was noted after starting antibiotics, and the patient was discharged on six weeks of oral clindamycin. When thinking of Lactobacillus, a simple probiotic comes to mind, clinicians need to be more vigilant in recognizing its different strains as possible infectious microorganisms. As described in our case, and other cases of bacteremia secondary to Lactobacillus, Lactobacillus should no longer be regarded as merely a contaminant.

Keywords: clindamycin; disciitis; intravenous drug user; lactobacillus; osteomyelitis.