Bacterial Information	Value
Taxonomy level	Species
NCBI Taxonomy ID	2035
Phylum	Actinobacteria
Family	Microbacteriaceae
Genus	Curtobacterium
Gram stain	Gram-positive
Oxygen requirements	Obligate aerobic
Spore-forming	No
Motile	Yes
Image

• Overview
• Biological information
  • Detection
  • Septic arthritis
  • Bacterial keratitis

Curtobacterium flaccumfaciens are short, yellow- or orange-pigmented, Gram-positive, rod-shaped bacteria. It is a well-established plant pathogen (Collins 1983), although it has been isolated from humans in clinically-relevant settings, such as septic arthritis in a child following skin puncture with a Coxspur Hawthorn thorn (Francis 2011)(Funke 2005).

Because of its relevance in plant pathology, it has a number of pathovars for practical, quarantine purposes (Collins 1983):

• C. flaccumfaciens pv. flaccumfaciens: causes a vascular wilt in beans.
• C. flaccumfaciens pv. betae: causes a vascular wilt and leaf spot in red beets.
• C. flaccumfaciens pv. oortii: causes a vascular disease, and leaf and bulb spots in tulips.
• C. flaccumfaciens pv. poinsettiae: causes a stem canker and leaf spot in the poinsettia.

Colonies are non-haemolytic, smooth, entire, low convex, with yellow pigment, and 1 – 1.5 mm in diameter after 48 hours aerobic culture (either at 30°C or 37°C).

C. flaccumfaciens is rarely detected in clinical samples, and its pathogenicity is believed to be typically be low given humans likely come into contact with curtobacteria every day (Funke 2005).

C. flaccumfaciens has been identified in:

• Synovial fluid: following skin puncture by a plant thorn.
• Cornea: after ocular exposure to banana bell sap.

After skin puncture of the knee with a Coxspur Hawthorn thorn, a 7-year old boy developed swelling and redness at the site, followed by progressive and ongoing fever up to 39°C, accompained with reduced knee flexion and a joint effusion. Peripheral blood leukocyte count was 13.1 x 10⁹ cells/litre (77% neutrophils). Arthroscopic washout and synovial biopsy revealed a 1 cm-long piece of thorn, and histology revealed acute synovitis and septic arthritis (Francis 2011).

Following ocular exposure to white sap from a banana bell (in the Atherton Tablelands, Queensland, Australia), a man presented with irritation and photophobia in one eye, associated with excessive lacrimation, but was otherwise systemically healthy. Corneal scrapings were taken, and C. flaccumfaciens growth on chocolate agar was observed at 48 hours. The infection responded to ciprofloxacin treatment, and microbiology tests also revealed sensitivity to vancomycin, tetracycline, daptomycin, and gentamicin (Mallick 2022).