Editor's Note: In the global health arena, especially in low- and middle-income countries (LMICs), access to diagnostic resources is often limited by infrastructure and economic constraints. A recent letter to the editor published in Clinical Microbiology and Infection brings hope to diagnostic practices in these countries. The study suggests that even after expiration, blood culture bottles (BCBs) can remain effective for months when stored under simulated tropical conditions.In resource-limited settings, the use of medical equipment is often restricted by expiration dates and storage conditions. However, new research conducted by the Institute of Tropical Medicine (ITM) in Antwerp, Belgium, and the FIND organization in Geneva, Switzerland, shows that some blood culture bottles can still effectively culture blood samples even after exceeding their manufacturer’s stated expiration dates when stored under controlled room temperature and extreme “tropical” conditions.
Blood culture bottles are critical tools for diagnosing sepsis, but their storage stability in high-temperature, high-humidity LMICs poses a challenge. Currently, most manufacturers recommend storing BCBs at temperatures between 20-25°C, a range often exceeded in LMIC climates. Additionally, Target Product Profiles (TPPs) suggest a 12-month shelf life for BCBs used in LMICs, but this does not account for the lengthy processes of international shipping, customs clearance, and domestic distribution. To verify the stability of BCBs, the research team selected five brands of aerobic pediatric BCBs, including Autobio, DL-Biotech, Schenker, Mindray, and bioMérieux. Some BCBs were stored at controlled room temperature, while others were stored in a climate chamber simulating tropical conditions (45°C, 90% humidity) for 4-7 months past their expiration date. Each month, the researchers inoculated the BCBs with defibrinated horse blood containing various concentrations of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pneumoniae, and Candida albicans, and incubated them in blood culture machines from the respective manufacturers.
The study’s results showed that all tested BCBs exceeded their labeled shelf life when stored at controlled room temperature. Moreover, some brands maintained performance even under extreme “tropical” conditions, while others were significantly affected. For example, bioMérieux’s BCBs could no longer support the growth of C. albicans and P. aeruginosa after short-term storage under 45°C high-temperature, high-humidity conditions. Meanwhile, DL-Biotech’s BCBs started to show reduced yields for all tested species and increased time to positivity (TTP) from the 12th month onwards.
The significance of this study lies in its valuable insights for clinical bacteriology services in LMICs. Currently, only 1.3% of biological laboratories in Africa offer bacteriology testing, and the continent is suffering from the highest antibiotic resistance mortality rates worldwide. The study’s lead author, Liselotte Hardy, emphasizes the need to reconsider the shelf life of diagnostic products to improve access to diagnostics. The research team urges manufacturers to reevaluate their storage temperature guidelines and report longer-term stability testing results. This would not only help reduce costs and waste but also promote greater access to diagnostic services in remote areas and LMICs. Moreover, policymakers should encourage manufacturers to report stability testing under prolonged and higher-temperature conditions. This study provides a new perspective on medical practice in LMICs, indicating that even after traditional expiration dates, medical supplies may still retain their effectiveness. This is a positive signal for resource-limited regions and offers valuable insights into more effective utilization and distribution of medical resources globally.
