BMC Pediatrics 2010, 10:89
|Published:||8 December 2010|
Early diagnosis and treatment of the newborn infant with suspected sepsis are essential to prevent severe and life threatening complications. Diagnosis of neonatal sepsis is difficult because of the variable and nonspecific clinical presentation. Therefore, many newborns with nonspecific symptoms are started on antibiotic treatment before the presence of sepsis has been proven. With our recently published single-centre intervention study we were able to show that Procalcitonin determinations allowed to shorten the duration of antibiotic therapy in newborns with suspected early-onset sepsis.
The study is designed as randomized controlled international multicenter intervention trial on the efficacy and safety of Procalcitonin guided treatment. Term and near-term infants (gestational age greater than or equal to 34 0/7 weeks) with suspected sepsis in the first 3 days of life requiring empiric antibiotic therapy will be included. The duration of antibiotic therapy in the standard group is based on the attending physician's assessment of the likelihood of infection (infection unlikely, possible, probable or proven). In the Procalcitonin group, if infection is considered to be unlikely or possible, antibiotic therapy is discontinued when two consecutive Procalcitonin values are within the normal range. Co-primary outcome measures are the duration of antibiotic therapy (superiority aspect of the trial) and the proportion of infants with a recurrence of infection requiring additional courses of antibiotic therapy and/or death in the first month of life (safety of study intervention, non-inferiority aspect of the trial). The number of infants to be included equals 800 per arm. With these numbers the power of the study to demonstrate superiority for duration of antibiotic therapy as well as non-inferiority regarding safety, i.e. excluding a disadvantage difference larger than 2% for the experimental arm, will both be greater than 80%.
Benefit of the study is a possible limitation of unnecessary use of antibiotics. The results of our first study suggest that there is a low risk on discontinuing antibiotic treatment too early, resulting in the development of a neonatal infection with its morbidity and mortality. Trial registration: This trial is registered in the U.S. National Institutes of Health's register, located at http://www.clinicaltrials.gov. (NCT00854932).
Another biomarker that has been discovered more recently, PCT, is proven to be a good marker of severe, invasive bacterial infections in children. All studies on severe, invasive bacterial infections in children report higher sensitivities and specificities of PCT than for CRP [12-16]. PCT is a 116–aminoacid peptide and one of the precursors of calcitonin. The physiological function of calcitonin remains unknown. No disorders attributable to either an excess or a deficiency of calcitonin have been identified. Most microbial infections induce a ubiquitous increase in CALC1 gene expression and a subsequent release of calcitonin precursors from all tissues and cell types throughout the body . In bacterial infections, PCT increases from concentrations in the picogram range (below the detection level of current PCT assays) to plasma concentrations ranging from 1 to 1000 ng/ml. This increase often correlates with the severity of the disease and with mortality [18-21]. Increases in PCT occur more rapidly than increases in CRP. PCT can be detected in the plasma 2 hours after the injection of endotoxins. Within 6–8 hours, PCT concentrations rise and a plateau is reached after approximately 12 hours . CRP can be detected in the plasma after 12 h and reaches a plateau after 20–72 hours. PCT and CRP decrease to their normal values after 2–3 days and 3–7 days, respectively [23-25].
The use of PCT as a marker of neonatal bacterial infection is complicated by several factors. First, infants with respiratory distress syndrome, hemodynamic failure, perinatal asphyxia, intracranial hemorrhage, pneumothorax, or after resuscitation have raised serum PCT concentrations that do not differ from those of septic neonates up to 48 h after onset of clinical signs of distress or infection [26-28]. Second, a physiological increase of PCT has been reported up to 48 h post partum . Third, prepartum and intrapartum administration of antibiotics may affect PCT concentrations in the umbilical cord , and postnatal administration of antibiotics will decrease PCT concentrations more rapidly than CRP concentrations [31,32]. When these pitfalls are taken into account, PCT performs better than CRP in diagnosing neonatal bacterial infection.
Chiesa et al developed a nomogram for PCT  and Assumma and colleagues performed a longitudinal study on PCT values in healthy neonates . In his findings Chiesa was able to report two major differences in between healthy and septic neonates which formed the basis of his nomogram. Firstly, the level of elevation in PCT was much higher in septic neonates versus healthy newborns and secondly, the absence of a decrease of PCT values after the initial cytokine release post-partum is indicative of a bacterial infection. With all PCT values being increased during the first two days of life, a reference range covering this time period with intervals of several hours is a tool to identify septic neonates. The adult reference ranges apply from three days after birth. Using PCT in this manner has been proven extensively to be a very reliable marker for the diagnosis of neonatal sepsis [35-39].
In recent years a novel indication for the use of PCT has been discovered, related to its described high negative value. It has been reported in many interventional trials [40-44] that a low PCT indicates the absence of a need for antimicrobial therapy. In several countries the recent adult intensive care guidelines have been altered to the extent that PCT has displaced CRP in the recommendations [45,46]. Applying this principle to neonatology, we performed a single-centre intervention trial in Lucerne, Switzerland that showed that serial PCT determinations allowed to shorten the duration of antibiotic therapy in term and near-term infants with suspected early-onset sepsis . This study is designed to test the reliability of a PCT-based strategy in a larger cohort of neonates.
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