Arcanobacterium pyogenes spondylodiscitis in a veterinary surgeon: A plea for cooperation between medical and veterinary microbiologists in identification of causal agents of zoonotic infections

Abstract

cholesterolemia. His medications were160 mg of acetylsalicylic acid per day,75 mg of clodipogrel per day, and 40 mgof pravastatin per day. The patient hadextensive contact with cattle and swineand did not wear gloves. He regularlysuffered from excoriations on bothhands. Since treatment with oral sodiumdiclofenac did not relieve his back pain,he consulted an orthopedic surgeon andwas treated with a series of 10 epiduralinfiltrations of methylprednisone, aswell as oral sodium diclofenac. Bloodanalysis ordered by his general practi-tioner revealed anemia with a hemo-globin level of 10.5 g/dl (normal range; 14 to18 g/dl), a white blood cell countof 8,000/µl (normal range; 4,000 to9,000/µl) with 78.4% polymorphonu-clear cells, an elevated erythrocyte sedi-mentation rate (ESR), and an increasedC-reactive protein (CRP) level of 145mg/l (normal range; 0.02 to 7 mg/l).Screening for autoimmune antibodieswas negative. The patient was HLAB27 negative. Conventional X raysshowed spondylodiscitis of the L3-L4interspace. Nuclear magnetic resonanceimaging showed significant destructionof lumbar vertebrae L3 and L4 withsome minor abscess formation in theintervertebral disk, in addition to lim-ited epidural invasion. Transthoracicechocardiography excluded endocardi-tis. Transcutaneous puncture of the lum-bar joint L3-L4 yielded a bloody fluidwith streptococcus-like gram-positivebacteria seen on Gram-stained smear.Culture on horse blood agar grew beta-hemolytic colonies reacting with aLancefield group G antigen reagent(Pro-Lab Diagnostics, Neston, Wirral,United Kingdom), which erroneouslyled to further processing of the isolateas a streptococcus. Molecular identifi-cation at the Laboratory of VeterinaryBacteriology and Mycology (Faculty ofVeterinary Medicine, Ghent University),by using tRNA intergenic length poly-morphism analysis (tDNA-PCR) com-bined with capillary electrophoresis (1)characterized the organism as