Low-cost in-house re-formulated brain heart infusion medium for effective planktonic growth and early detection of bloodstream bacterial pathogens

Sepsis, a clinically defined life-threatening condition, is a global contributor to high morbidity and mortality rates in humans. It is caused by systemic bloodstream bacterial infections, primarily involving aerobic pathogens such as <i>Escherichia coli</i>, <i>Staphylococcus aureus</i>, and <i>Klebsiella pneumoniae</i>. Rapid and accurate identification of these pathogens is a high-demand task, as prolonged diagnosis may increase the mortality rate among sepsis patients. Globally, commercial blood culture systems like the BD BACTEC™ FX blood culture system, which utilizes BD BACTEC™ PLUS Aerobic/F culture bottles (used in this study), are commonly used to detect aerobic bloodstream infections. However, due to high costs (∼$10.00-$15.00/bottle), limited availability of culture media (especially in low- and middle-income countries, and war zones), and a lack of customization for antibiotic susceptibility assay and epidemiology research, there is a need for secondary alternatives to facilitate the growth and identification of bloodborne pathogens. Therefore, we developed a low-cost (∼$4-$5/bottle) in-house culture medium with a newly improved formulation of Brain Heart Infusion media that enhances bacterial growth from spiked human blood tested on a panel of bacteria (<i>Escherichia coli</i>, <i>Staphylococcus aureus</i>, <i>Klebsiella pneumoniae</i>, <i>Acinetobacter baumannii</i>, <i>Pseudomonas aeruginosa</i>, and <i>Enterococcus faecalis</i>). The growth dynamics of these microbes in in-house formulated BHI-Blood+ culture media coincide with those in BACTEC™ Plus Aerobic/F culture vials, which primarily suggests the compatibility of bloodborne pathogens with this media and can be flagged positive <8 h based on cellular growth rate. Additionally, conventional qPCR-based early detection (<24 h) and validation with the Oxford Nanopore MinION NGS platform highlight the value of this in-house culture media as an alternative to commercial culture media in terms of low-cost availability.