Results from an evaluation of the BacT/Alert® Virtuo blood culture bottle system for culturing periprosthetic tissue specimens published in BMC Infectious Diseases led investigators to recommend this system because of its ability to detect a wider range of bacteria efficiently and rapidly compared with conventional microbiology methods.

The assessment was performed by analyzing 36 spiked and 158 periprosthetic tissue samples using the blood culture bottle method. Clinical samples analyzed by blood culture bottle were then compared with those analyzed by the conventional microbiologic culture-based method for time to detection and microorganisms identified.

In both the spiked and clinical samples, the BacT/Alert® Virtuo system detected relevant bacteria related to prosthetic joint infection. The analyses of clinical samples demonstrated that blood culture bottle was as sensitive as the conventional method, 79% vs 76% (P =.844), respectively. The positive results were also obtained faster using blood culture bottle than with the conventional method, 89% compared with 27% detection within 24 hours, respectively. Median detection time was 11.1 hours using blood culture bottle and 12 hours and 11 hours for the aerobic and anaerobic blood culture bottles, respectively.

The study had some technical limitations, such as low total numbers of clinical samples and limited number of samples per patient. There was also limited clinical data about the patients available, making it difficult to define a sample selection criterion to distinguish true prosthetic joint infection or contamination. Investigators also acknowledged that the faster detection rate observed may be a result of larger inoculum volumes used in blood culture bottle vs conventional methods, 1 mL and 0.1 mL, respectively. In addition, comparative studies looking at time to detection also contained a bias related to the different reading frequency between the 2 methods.

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According to investigators, these results demonstrated a laboratory procedure that could be an important tool for diagnosis of prosthetic joint infections. They also recommended the use of the BacT/ALERT® BCB system for culturing periprosthetic tissue as it can reliably and rapidly detect commonly found bacteria associated with these infections and therefore facilitate early clinical decision making.

Reference

Sanabria A, Røkeberg MEO, Johannessen M, Sollid JE, Simonsen GS, Hanssen AM. Culturing periprosthetic tissue in BacT/Alert® Virtuo blood culture system leads to improved and faster detection of prosthetic joint infections. BMC Infect Dis. 2019;19:607.