Discovertebral infection (DVI) is the most common hematogenous osteomyelitis in persons >50 years of age and typically involves intervertebral disks and adjacent vertebral bodies. Diagnosis relies on clinical, radiologic, microbiological, and histopathological findings (1). Primary manifestations are neurologic compression and residual posttreatment pain. Gram-positive cocci, primarily Staphylococcus aureus bacteria, coagulase-negative staphylococci, and streptococci, are the most common pathogens (2). We describe DVI caused by Camelimonas species bacterium in France.

In May 2025, a man in his forties was referred to Bordeaux University Hospital with gait impairment and 4 months of low back pain that had worsened progressively over the preceding 2 months. His history included Child-Pugh C alcoholic cirrhosis (MELD 23), for which he was awaiting liver transplantation. A transjugular intrahepatic portosystemic shunt had been placed 2 years earlier. He had controlled diabetes mellitus and took only analgesics and rifaximin for hepatic encephalopathy prevention. He lived in the countryside, occasionally helped on his father’s cattle farm, and had not traveled abroad recently.

Figure 1

Figure 1. Imaging from study of human discovertebral infection caused by Camelimonasspecies bacteria, France, 2025. T1-weighted axial magnetic resonance imaging after gadolinium injection shows discovertebral infection associated with secondary abscess...

Previous computed tomography showed multilevel disc degeneration; L4–L5 discopathy was suggestive of DVI, characterized by erosion of the superior L5 vertebral end-plate and right perivertebral tissue infiltration. Diagnosis was confirmed by magnetic resonance imaging (MRI), revealing anterior epidural inflammatory infiltration, canal narrowing, right neural foramen extension, and psoas muscle abscess (Figure 1).

Results of multiple blood cultures were negative, but tests for panfungal blood markers were repeatedly positive (β-D-glucan >10 pg/mL, galactomannan antigen >1.2). A computed tomography–guided vertebral biopsy performed 10 days after MRI yielded negative bacteriology, mycology, and histology. Thus, another biopsy was performed 1 month later. Mycological cultures and targeted PCRs for Aspergillus species, A. fumigatus, and Mucorales fungi were performed, all with negative results. However, aerobic culture of biopsy (37°C, 5% carbon dioxide) grew a small gram-negative bacillus after 62 hours (Appendix Figure, panel A). Colonies were gray, translucent, smooth, 0.2–0.5 mm in diameter, nonhemolytic (Appendix Figure, panel B), oxidase- and catalase-positive, and strictly aerobic, demonstrating fastidious growth on Drigalski and bromocresol purple agar media. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identification failed (Appendix Figure, panel C).

Figure 2

Figure 2. Phylogenetic and genomic relatedness of Camelimonas isolate FR25DVI from study of human discovertebral infection caused by Camelimonas species bacteria, France, 2025. A) Evolutionary relationships of ...

Phylogenetic analysis based on the 16S ribosomal RNA gene of strain FR25DVI (Figure 2, panel A) suggests a novel Camelimonas species near human Camelimonas strain ID_303_24 and more distant from C. lactis M2040^T and C. fluminis XZ2^T. The genome size was 4,292,006 bp (63% guanine-cytosine content). Comparisons with available Camelimonas genomes showed average nucleotide identity and digital DNA–DNA hybridization values below species thresholds. The highest similarity was with human Camelimonas ID_303_24 (82.3% identity) and C. abortus UK34/07-5T (23.3% hybridization) sequences (Figure 2, panels B and C).

Given the scarcity of human Camelimonas cases, the absence of sepsis or neurologic compression, and the positive biopsy, another vertebral biopsy was performed 3 weeks later. Culture and sequencing confirmed the growth of Camelimonas species bacteria.

Antibiotic susceptibility testing showed low MICs: 0.016 mg/L for trimethoprim/sulfamethoxazole (TMP/SMX), 0.25 mg/L for doxycycline, and 2 mg/L for amoxicillin. Therapy with TMP/SMX (800/160 mg 3×/day) and doxycycline (100 mg 2×/day) was started; TMP/SMX was stopped after 8 days because of renal deterioration and replaced by amoxicillin (2 g 4×/day) for 6 weeks (3). The patient also wore a rigid brace.

The 6-week amoxicillin/doxycycline course was well tolerated, resulting in reduced pain and stabilized MRI lesions. Clinical evaluation confirmed symptomatic improvement, and antibiotics were discontinued. Six months after treatment, the patient showed progress and had no evidence of disease progression, although residual lumbar pain persisted.

Camelimonas is a gram-negative, aerobic, non–spore-forming, short rod-shaped bacterium of the Beijerinckiaceae family (Gammaproteobacteria). Isolated from camel milk in the United Arab Emirates in 2010 (4), it was later identified in the environment (5), bovine placenta (6), and human blood (7). We describe a human Camelimonas discovertebral bacterial infection in a young man with advanced liver disease. Sequencing identified Camelimonas species bacteria in 2 biopsies. Culture-guided dual antibiotic therapy resolved the infection after 6 weeks.

Repeated microbiological isolation, combined with the patient’s cattle farm exposure, strongly support its clinical significance. Cattle are a recognized reservoir for the bacterium (4,6), but the patient reported no illness in the herd. Plausible transmission routes include direct zoonotic contact with infected animals or consumption of contaminated raw milk. Furthermore, the patient’s underlying liver disease likely caused relative immunosuppression, enabling the infection.

Camelimonas sp. bacterium has been associated with abortions in cattle (6) and has been isolated from blood in an immunocompromised human (7), indicating its ability to cross mucosal barriers and disseminate systemically. Its tropism for collagen-rich tissues, such as vertebrae and intervertebral disks, likely provides a suitable substrate for bacterial adhesion and colonization.

Because no standardized antibiotic guidelines exist for Camelimonas infections, treatment relied on oral bioavailability and bone-penetrating agents. However, renal impairment necessitated a change from TMP/SMX to amoxicillin, resulting in a prolonged course of amoxicillin and doxycycline.

This case demonstrates a pathogenic role for Camelimonas species bacteria in humans. The pathogen appears to have a bone tropism, warranting consideration in the differential diagnosis of subacute discovertebral infection, particularly in patients who have dairy farm exposure.

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Suggested citation for this article: Chombart L, Blosse A, Desclaux A, Jehanne Q, Dauchy FA, Neau D, et al. Human discovertebral infection caused by Camelimonas species bacteria, France, 2025. Emerg Infect Dis. 2026 Dec [date cited]. https://doi.org/10.3201/eid3212.260924