Some newborns, after birth, can develop life-threatening infections such as sepsis due to their underdeveloped immune systems. But pioneering research published Thursday in Nature Communications can enable doctors to identify the presence of infection-causing bacteria in the bloodstream of newborns, and target them. And how can they identify the pathogens? By decoding a signal generated from the baby’s DNA.

The signal is like an SOS, sent by the messenger RNA of the baby’s genome. By analyzing this code, the doctors can understand if there is a sepsis present in the blood. The signal can be deciphered using just a single drop of blood. Scientists are now trying to develop tests based on this signal detection, so that fatality due to bacterial infections can be significantly reduced.

Bacterial infections in newborns are difficult to diagnose unless blood tests are performed, and this generally requires testing large amounts of blood. Babies can develop infections either during childbirth or a few days after being born. If the mother is suffering from an active infection, then pathogens can be inhaled by the newborn when passing through the birth canal. After birth, the child may catch contagious bugs on contact with someone who has cold or flu. Pathogens that cause sepsis include Group B Streptococci, E. coli, Listeria, and viruses.

Since the baby’s body cannot put up much of a fight, pathogens multiply fast and the newborn can get very sick very quickly. So it is prudent that the infection is discovered and treated soon. Also, typical symptoms like high fever may not occur, and even if they do, they are not indicative of an infection. If a blood culture is performed to identify the pathogens, it takes two to three days for the results to come. Since the infant is put on antibiotics before the results are in, even children without sepsis may end up getting antibiotics or they may be given antibiotics not suited for that particular infection. Unnecessary use of meds also increases the risk of antibiotic resistance. 

Scientists from the University of Edinburgh spent years trying to find causes and methods of identification of blood infections in preterm and full-term babies. Using blood samples from newborn babies in Edinburgh, they investigated thousands of signals written in mRNAs. With meticulous code breaking, the scientists identified a signal consisting of 52 molecular characters specific to bacterial infection. This signal, with complete accuracy, can tell if the baby is suffering from sepsis.

"Just as a Twitter user can send a 140 character message so a baby's genome produces short messages or signals that produce code information to communicate with the infant's immune and metabolic systems so that it can fight the infection," said Dr. Peter Ghazal, professor of molecular genetics and biomedicine at the University of Edinburgh's Division of Pathway Medicine, in a statement. "The 52-character 'tweet' or message that we have identified appears to be specific for bacterial but not viral infection." Ghazal said researchers believe the detection method could also be used in children and adults. Essentially, researchers would use a single drop of blood to detect the vital distress signal in DNA. The findings create hope for also "tackling antibiotics resistance," he added.

Stressing that infections lead to a number of deaths or disabilities in infants worldwide, Dr. Claire Smith states that there is a need to develop tests for quick and accurate identification of sepsis.

“This work is enabling us to move towards being able to distinguish between babies with true infection who need urgent treatment, and those who are not infected and therefore don't require antibiotics. The potential benefits to babies and their families are important. We are grateful to the families who consented to take part in the study," she said.

Source: Ghazal P, Smith CL, Dickinson P, et al. Identification of a human neonatal immune-metabolic network associated with bacterial infection. Nature Communications. 2014.