Why do we need an effective antimicrobial program?
In 1929 Alexander Fleming accidentally discovered the first antibiotic, penicillin and since then antibiotics have been used to save uncountable lives. It has been found that usage of antibiotics has not only saved more than 2,00000 lives per year in the USA alone, but also it has increased the life expectancy of Americans by 5- 10 years[1]. But just like us bacteria and pathogens are always evolving to survive. Unsupervised use of antibiotics has led to the development of a broad range of resistant bacteria which are very difficult to manage by currently available antibiotics. And discovering new antibiotics is a very long process. According to the AMR review [2] it has been estimated that by 2050 if the resistance keeps increasing and is not controlled the rising AMR can claim one person’s life in every 3 sec.
Apart from early diagnostics, surveillance and awareness about AMR, an administered and evidence based antibiotic therapy can help in saving antibiotics for future generations. In the present scenario antibiotics are mostly prescribed based on symptoms and advised to continue the treatment even when the symptoms subsides to avoid resistance development. To avoid the unnecessary use of extended antibiotics doses we need a mechanism to identify the load of bacteria present without culturing it. And the level of Procalcitonin is one of the most promising markers.
How can Procalcitonin be used to achieve this goal?
In healthy individuals, circulatory PCT levels are extremely low. During a bacterial infection, the inflammatory release of PCT produces a significant increase in blood levels. It has been well established that the Level of Procalcitonin (PCT) is an indicator of bacterial infection and it is proportional to the load of bacteria too. Hence, the PCT level can not only tell us about the infection severity but also helps us in distinguishing whether to prescribe antibiotics or not. Traditional inflammatory markers like, CRP (C-Reactive Protein), IL-6 (Interleukin 6) and lactate levels don't tell anything about the cause of inflammation whereas high PCT level indicates bacterial infectiona and the level remains low in viral infection [3].
Based on several published findings Philipp Schuetz et. al.has come up with a PCT based algorithm for when to stop antibiotics therapy in different medical conditions. One of these proposed methods is for sepsis, if PCTlevel is more than 1 ug/l the chances of ongoing infection is high and antibiotic therapy should be continued till the PCT level decreases to 80% of its maximum level. The figure below explains it in more detail [4].
Planning antibiotics therapy in patients with sepsis with the help of PCT level [4].
PCT can be an efficient method for reducing antibiotic usage. And it can only be possible by awareness and an accessible test kit for measuring PCTlevel regularly for the patients. Point-of-care or bedside based PCT tests can play a crucial role in it.
What are some of the other biomarkers which are being utilized for this?
How does PCT compare with other common clinical biomarkers?
Indian studies where PCT was utilised to inform clinical algorithms
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