We must fix broken blood culture practice
Dr Mike Weinbren, Microbiology Consultant at King’s Mill Hospital in Mansfield, a part of Sherwood Forest Hospitals NHS Foundation Trust, has answered Dame Sally Davies’ call to become an Antimicrobial Resistance Fighter. Here Dr Weinbren discusses how improving blood culture practice can help in the fight against antimicrobial resistance (AMR).
In 30 years, we do not want to be looking back wishing we had listened to Dame Sally Davies. As Dame Sally noted in the last edition of Hospital Times, the crisis of antimicrobial resistance continues to develop, at alarming pace. But when talking about this issue one can often overlook simple steps that produce tangible results.
The potential for blood culture tests to preserve the current crop of antimicrobials is massive. “If you can streamline the blood culture process you won’t be saving hours, you will be saving days in antibiotic treatment,” says Dr Weinbren.
Blood cultures tests detect the presence of bacteria in blood. In identifying the specific nature of an infection, blood cultures are essential in guiding a clinician to remove deficiencies in a patient’s treatment plans, thereby reducing reliance on broad-spectrum antibiotics used in early phases of treatment.
According to Dr Weinbren, “there is a large number of people each year who are suspected as having sepsis, and it’s a major driver of broad-spectrum antibiotics.”
Precious time wasted
Indeed, it can be argued that the effective use of blood cultures is essential to comprehensive adherence to antimicrobial stewardship guidance but, “whilst our blood culture analyser machines are now extremely powerful, we have not changed the ways in which our labs work accordingly,” says Dr Weinbren.
The Sepsis Alliance currently states on its website that it takes “several days” to obtain the results of a blood culture. “This is an example of disinformation on blood cultures that needs to be corrected,” says Dr Weinbren, who says that, “50 per cent of bottles will be positive just 12 hours after collection.” He insists that if blood culture results are taking several days to obtain, it is down to bad practice.
As Dr Weinbren puts it, “you could strap a blood culture specimen to a snail, and it would probably work its way through a laboratory faster than we are seeing now.” Indeed, some hospitals have allowed 24 hours to pass before a specimen is even placed in an analyser, ultimately results in patients not receiving the specialised treatment they need and increases the chance of unnecessary antibiotic usage.
“Taking blood specimens quickly is one thing,” says Dr Weinbren, “but doctors need rapid identification of bloodstream pathogens in order to administer effective treatment.”
Ground-breaking measures are not required to create tangible improvements to blood culture practice. Dr Weinbren, who previously worked in Chesterfield NHS Trust, says there are very simple steps that clinical leadership can take, “When I was at Chesterfield, we had to educate our staff to treat blood cultures as urgent specimens,” he says, “as a result, we were able to ensure the loading of 96 per cent of our blood culture specimens 90 minutes after collection.”
Microbiology labs do not operate around the clock, as such Dr Weinbren and his team took the decision to move their blood analyser machines to the central reception of the blood labs, which operate 24 hours a day. This ensures that there are staff on hand to ensure that blood cultures are loaded promptly without the need for additional resource or financial cost. Dr Weinbren does not see why this should not be standard practice in microbiology labs, he says, “loading a specimen takes minutes and doing it promptly makes huge differences to patient care.”
Auditing the pathway
That blood cultures are not always considered as urgent specimens is largely down to the fact that a blood culture is not guaranteed to be positive, and the time taken to reach a conclusion can vary. However, as Dr Weinbren astutely notes, “we cannot allow biological variability to provide a shroud for poor practice to hide behind.” Therefore, extensive auditing and monitoring of blood culture pathways is essential to root out poor practice.
“I very much hope that more comprehensive guidelines are established – and I think that this will in part be driven by the Diagnostic Stewardship Programme,” says Dr Weinbren. To illustrate the need for effective guidelines, Dr Weinbren points to the quantities used in current culture testing, in which you realistically need 16-20 ml of blood, “we ran an audit on our own practice recently, and found that 10 per cent of our bottles only had two ml of blood,” with this type of quantity there is little to no chance of ever producing a positive result.
The key to connecting infection pathways
“There is a frustrating disconnect right now,” says Dr Weinbren, “on the one hand we have a drive to use broad spectrum antibiotics to fight sepsis, and then on the other is a drive to preserve the antibiotic in accordance with AMR stewardship guidelines.” Dr Weinbren argues that improving blood culture practice could be used as a potential means to connect sepsis and AMR into one pathway.
“Each NHS Trust will have an AMR stewardship committee and a sepsis committee,” he says, “and they must work together to understand whether their labs are providing the right level of service.”
The recommendations outlined here do not require significant financial investment or additional resource across trusts, and yet the benefits to patient care are huge. What is required is a far greater sense of diligence towards blood culture practice; this should be encouraged through willing clinical leadership. Rapid identification of blood pathogens will result in lower mortality rates for sepsis patients, lower treatment costs and a vital reduction in unnecessary antibiotic usage.
Indeed, as Dr Weinbren notes, “if we can fully optimise our blood culture practice, then it will be a win-win situation for everyone involved.”