IMPROVING THE DIAGNOSIS OF BLOOD STREAM INFECTIONS WITH BECTON DICKINSON’S BACTEC™ AUTOMATED LIQUID CULTURE SYSTEM

Sepsis;diagnostics;bacteria;filtration;Chemical & Biomolecular Engineering

Martello, Shannon ElizabethSchulman, Rebecca ;

Johns Hopkins University

关键词: Sepsis;    diagnostics;    bacteria;    filtration;    Chemical & Biomolecular Engineering;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/60488/MARTELLO-THESIS-2018.pdf?sequence=1&isAllowed=n

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

Sepsis is a highly dynamic condition caused by a dysregulated host response to a pathogen in the bloodstream. Fast and accurate diagnosis of the causative pathogen is critical to provide effective treatment and minimize the risk of death. The current diagnostic workflow for a blood stream infection begins with a blood draw from the patient into a culture bottle, which is then incubated in an automated blood culture instrument to detect growth of the pathogen. Common automated blood culture systems, such as Becton Dickinson’s BACTEC franchise, utilize glass culture bottles containing a fluorescence-based sensor to aid detection of bacterial growth. After detection of growth by the instrument, the bacteria are isolated via an overnight subculture to provide a sample for downstream testing. Once isolated, bacteria can then be identified and tested for antimicrobial susceptibility. In this thesis, we characterize and optimize two aspects of the diagnostic workflow in order to improve sepsis diagnosis and patient management. The first chapter details characterization of and improvements to a filtration system designed to decrease the time to diagnosis by isolating bacteria from a positive blood culture in 15 minutes. To improve the quality of the isolated sample for accurate identification and antimicrobial susceptibility testing, we assessed the current performance of the system. We then improved recovery and downstream results by adjusting the filtration workflow and increasing the area through which the positive blood culture is filtered. The second chapter targets conversion of the current glass blood culture bottle to a safer, lighter polycarbonate bottle. We characterized formulations for the polycarbonate bottle’s fluorescence-based sensor in order to ensure proper adhesion to the bottle and define the signal ranges. With this, we selected a formulation for scale up to biological testing, which will assess the sensitivity of signal detection and allow the new polycarbonate bottle to be brought to market. Both conversion of the blood culture bottle to a safer material and reduction of bacterial isolation time will improve the diagnostic workflow for a bloodstream infection, ultimately allowing for easier diagnosis and treatment of sepsis.