Isolation of Kingella kingae from synovial fluids using four commercial blood culture bottles

According to the literature, Kingella kingae may be an underdiagnosed cause of joint and bone infections in children. The use of the Bactec blood cult ure system for culture of joint fluids has dramatically improved the isolat ion of this fastidious bacterium. The aim of this study was to test the rec overy rate and detection time of four commercial blood culture systems: thr ee different BacT/Alert (Organon Teknika, USA) bottles and one Bactec (Bect on Dickinson Microbiology Systems, USA) bottle, all inoculated with Kingell a kingae strains mixed with pooled synovial fluids. For each strain the sam e inoculum and volume of synovial fluid was distributed into each of the fo ur bottles. All 24 strains tested grew in the BacT/Alert Aerobic (100%) and the BacT/Alert Pedi-BacT (100%) bottles. Twenty-one strains grew in the Ba cT/Alert FAN aerobic (88%) bottle, and 15 strains grew in the Bactec Plus A erobic F (63%) bottle, in both systems within 12 days (P < 0.01). The Kinge lla kingae strains were first detected in the BacT/Alert Pedi-BacT bottles (P<0.001). The results were reproducible. The BacT/Alert blood culture bott les were superior to previously described blood culture systems in isolatin g Kingella kingae from synovial fluid, even with small inoculums and small volumes of synovial fluid.