Rushana Hussain, Clinical Scientist, Royal Bolton Hospital discusses improved clinical outcomes of sepsis thanks to Bruker’s Sepsityper diagnostic kit.
Hospitals worldwide are overwhelmed with the prevalence of sepsis and are facing pressure to tackle the morbidity and mortality rates associated with the infection. Sepsis is the result of the body’s immune system generating a larger than necessary response to infection, which, if not detected and treated promptly, can lead to septic shock, multiple organ failure and death. However, sepsis is one of the most preventable causes of death and disability, and therefore prompt diagnosis and efficient treatment is vital to desired clinical outcomes.
There is an ongoing need for rapid detection and identification methods for the infectious organism. This would enable clinicians to narrow down treatment from broad spectrum antibiotics to specific targeted treatment for that organism. A timely change in therapy lowers mortality rates in many cases, decreases treatment costs and improves overall patient outcomes [1].
Technological developments
Biochemical methods are widely used in clinical laboratories for identifying infecting organisms from patient samples, however these tests are unable to provide more detailed information beyond differentiating between Gram positive and Gram negative species, from the point of detection in the sample. Only once the sample has been cultured can clinical scientists gain more specific information about the infecting organism. This lag means that specific antibiotics cannot be administered before this time period, usually approximately 24 hours, during which sepsis can rapidly spread and lead to organ failure and, in many cases, death.
Emerging technologies in the clinical diagnostics field, such as mass spectrometry (MS), offer powerful advantages over traditional biomedical techniques. Specifically, matrix-assisted laser desorption/ionisation (MALDI) time-of-flight (TOF) MS and the specific processing procedures provide highly accurate microbial identification directly from a positive blood culture. This method eliminates the time consuming step of culturing the microorganisms, making identification possible directly from the primary sample within 30 minutes.
Benefits of rapid detection
At the Microbiology Laboratory at the Royal Bolton Hospital (RBH), UK, we have integrated MALDI-TOF MS into the identification workflow for sepsis patients. In the laboratory, we use this technology to process positively flagged blood culture specimens with the Sepsityper kit (Bruker Daltonics, Bremen), which is performed in conjunction with MALDI-TOF MS analysis. We carried out a retrospective analysis of this protocol, in comparison to the previous standard laboratory protocol (SLP), to find out whether faster and more accurate microbial identification could be achieved, and how this impacts patients and the hospital.
The Bruker MALDI Biotyper (MBT) + Sepsityper protocol was audited between April and May 2015 for the processing of positive blood culture broths, and compared to the SLP results during the same period (April – May) in 2014, to determine if the new protocol was more efficient. Positive blood culture broths were collected from patients admitted to the A&E department with suspected sepsis. All samples with growth were flagged and processed for Gram staining, to classify the infecting organism as Gram positive cocci (GPC), Gram positive bacilli (GPB), Gram negative cocci (GNC) or Gram negative bacilli (GNB), and subjected to further testing to complete the identification.
We found that, although the MBT + Sepsityper protocol requires additional steps, such as blood centrifugation before MBT analysis, there was a significant improvement in turnaround time (TAT) to presumptive identification compared to the SLP, of 18-23 hours depending on the Gram stain result. There was also a statistically significant reduction in length of hospital stay for patients with bacteraemia during the MBT + Sepsityper protocol.
Patient outcomes and cost savings
The benefits of the reduction in length of bed stay for sepsis patients is twofold: the patient is able to leave hospital sooner, which is the most desirable outcome, but the cost savings for the hospital associated with this are substantial. Based on an estimated cost per bed day of £500 in the UK, the hospitalization cost savings alone are £22,600 for the RBH study cohort of 27 patients admitted from the A&E department (or £837 per patient).
The study results also showed a reduction in the use of intravenous (IV) and oral antibiotics, by 33% and 35% respectively, using the MBT + Sepsityper protocol compared to the SLP. This reflects the ability of clinicians to make informed decisions and alter antibiotic regimes sooner, based on more accurate and rapid identification of the infecting organism. This reduction frees up more nurse time, and also enables the hospital to adhere to NICE Guidelines on Antimicrobial Stewardship [2], by minimizing use of broad-spectrum antibiotics to help combat the growing threat of antimicrobial resistance.
Tackling sepsis into the future
It is estimated that for every hour that appropriate antibiotics are delayed, sepsis survival decreases by 7.6% [3]. The reasons for inappropriate course of treatment could be due to the initial broad-spectrum antibiotics not covering the infecting organism, an incorrect assessment of the source of infection, or antibiotic resistance. The fast identification of organisms after positive blood culture with MALDI-TOF MS enables the accurate, specific and efficient clinical decision making required to improve survival rates from sepsis.
The cost savings associated with a rapid progression from empirical antibiotic treatment to narrow-spectrum therapy, as well as reduced overall IV and oral administration and reduced length of hospital stay, make new technologies such as MALDI-TOF MS a viable option for hospital trusts worldwide.
For more information on Bruker’s Sepsityper diagnostic kit, please click here
About the author
Rushana Hussain is a Clinical Scientist in the Microbiology Department at the Royal Bolton Hospital. She focuses on the hospital’s service development and innovation, which involves being aware of upcoming scientific and management innovations that will develop the service. She is also responsible for the evaluation of clinical impact or outcomes for patients and cost effectiveness for the Trust.
About Royal Bolton Hospital
Bolton NHS Foundation Trust provides patient care at the Royal Bolton Hospital. Laboratory Medicine underpins the diagnosis, monitoring and management of disease and within this department, Microbiology specializes in diagnosing infectious diseases caused by microorganisms and assisting clinicians reach the most appropriate treatment decision.
About Bruker Corporation (NASDAQ: BRKR)
Bruker is enabling scientists to make breakthrough discoveries and develop new applications that improve the quality of human life. Bruker’s high-performance scientific instruments and high-value analytical and diagnostic solutions enable scientists to explore life and materials at molecular, cellular and microscopic levels. In close cooperation with our customers, Bruker is enabling innovation, improved productivity and customer success in life science molecular research, in applied and pharma applications, in microscopy and nanoanalysis, and in industrial applications, as well as in cell biology, preclinical imaging, clinical phenomics and proteomics research and clinical microbiology. For more information, please visit: www.bruker.com.
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