Comparison of the VersaTREK blood culture system against the Bactec9240 system in patients with suspected bloodstream infections

Venous blood from patients with suspected bacterial sepsis was evenly distributed into bottles of each system. Positive signals were recorded and bottles processed onto standard media for organism recovery. False positive signals were regarded if no organisms were seen on Gram stain and no growth was observed.177 bottles were available for analysis; the Bactec9240 system yielded 43 positive, 134 negative results and no false positive signals. The VersaTREK system had 58 positive signals with 14 being false positives.In our setting with high background burden of immuno-compromised patients, the VersaTREK system compared favourably with the Bactec9240 in recovering blood stream aerobic and facultative anaerobic pathogens from patients with suspected bacterial sepsis. A concern is the high false positivity rate. Due to its versatility to accommodate small and large workloads as well as using smaller volumes of blood, this system may establish itself as a useful alternative for the recovery of bloodstream pathogens.The detection of bacteraemia is crucial for early and appropriate antimicrobial therapy. Blood cultures are considered as one of the most important specimen types and diagnostic laboratories process these as rapidly as possible. Despite newer molecular techniques being applied in diagnostic microbiology, recent analyses confirm the use of automated blood culture systems as the primary choice for detection of pathogens from blood specimens [1,2]. This is because results are generated rapidly compared to manual blood culture systems and antimicrobial susceptibility testing can also be performed which is a limitation of molecular techniques.In South Africa, with its human immune-deficiency virus (HIV) burden, patients are at an increased risk of developing sepsis due to bacterial, fungal and mycobacterial infections [3]. Most established referral diagnostic laboratories in South Africa use large automated blood culture systems. However, there is a need for small