Case ReportMisidentification of Brucella suis as Ochrobactrum anthropi in a Patient with Septic Arthritis
Introduction
We report a case of a 24-year-old resident of North Queensland who presented to our facility with a native joint septic arthritis. A bacterial isolate recovered from an initial joint aspirate culture was misidentified as Ochrobactrum anthropi using an automated identification system. A subsequent specimen grew an isolate that was identified as Brucella sp. by the same automated system, with a single biochemical reaction (adonitol) differentiating the identities of the two organisms. Subsequent real-time PCR testing of the IS711 element of the Brucella genome confirmed both isolates as Brucella suis. The initial bacterial misidentification resulted in inappropriate antibiotic therapy for the patient and a significant risk of infectious exposure for laboratory workers. A subsequent detailed clinical history revealed a significant risk factor for exposure to B. suis, given the patient's recent history of feral pig hunting and evisceration of a killed pig.
Section snippets
Case Report
A 24-year-old man from North Queensland, Australia, was admitted to our hospital with a clinical history and physical examination findings suggestive of chronic septic arthritis of 3-months duration, affecting the right knee. There was no history of trauma to the knee. The patient had presented 2 years previously with similar symptoms, which resolved with a single intra-articular steroid injection.
Prior to admission, the patient was treated empirically with oral cephalexin. Once admitted, a
Discussion
Brucella spp. are small, intracellular, Gram-negative coccobacilli that are nonmotile and non-spore forming and grow aerobically. There are 9 recognized species within the genus, 3 of which are further subdivided into biovars on the basis of biologic and serologic criteria. Four species are human pathogens: B. abortus (seven biovars), B. melitensis (three biovars), B. suis (five biovars), and Brucella canis. Only B. suis and Brucella ovis are found in Australia. B. suis is endemic in the feral
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Cited by (1)
Isolation of two Ochrobactrum sp. strains capable of degrading the nootropic drug—Piracetam
2018, New BiotechnologyCitation Excerpt :Both species O. anthropi and O. intermedium are classified as biosafety level 2 in Switzerland; some strains have been recently associated with human infections [23]. Ochrobactrum and Brucella species are difficult to distinguish by analysis of 16S rRNA genes, cultivation or biochemical assays using commercially available test systems [24–26]. To overcome this problem Scholz et al. [20] developed multi-primer single-target PCR (MP-ST-PCR) based on sequence variations in the recA gene that allows accurate differentiation of O. anthropi, O. intermedium and Brucella spp.