Melioidotic septic arthritis and its risk factors.

BACKGROUND: Melioidotic septic arthritis is an infection caused by the gram-negative bacillus Burkholderia pseudomallei. It is commonly found in Northeast Thailand. The goal of our study was to identify specific characteristics of patients with melioidotic septic arthritis by comparing them with patients with non-melioidotic septic arthritis and to describe the results of treatment of melioidotic septic arthritis.

METHODS: We conducted a retrospective study of seventy-seven patients with septic arthritis who were treated in our hospital over a period of four years. Twenty-five of the patients had melioidotic septic arthritis, and fifty-two had non-melioidotic septic arthritis. Univariate and multivariate analyses were conducted to identify the risk factors for melioidotic septic arthritis, and the clinical course of the twenty-five patients with melioidotic septic arthritis was followed until the infection resolved.

RESULTS: Patients with melioidotic septic arthritis differed significantly (p = 0.002 ) from those with non-melioidotic septic arthritis with regard to the frequency of diabetes mellitus and of involvement of an upper-extremity joint. The odds ratio that melioidosis was the cause of the infection was 15.7 (95% confidence interval, 4.5 to 55.6) in a patient with diabetes mellitus and 4.51 (95% confidence interval, 1.04 to 19.65) in a patient with involvement of an upper-extremity joint. Twenty-two of the twenty-five patients with melioidotic septic arthritis responded to treatment, which consisted of six months of antibiotic therapy combined with needle aspiration, as well as surgical drainage of the affected joint when necessary (sixteen patients).

CONCLUSIONS: A diagnosis of melioidotic septic arthritis should be considered when septic arthritis is seen in an individual who is indigenous to or has recently visited Southeast Asia. The infection is more likely to be melioidotic septic arthritis if it involves an upper-extremity joint and if the patient has diabetes mellitus.