A quick genetic test might one day help doctors determine within hours whether a baby’s fever is from a virus or a serious bacterial infection.
“Doctors have great difficulty in distinguishing whether a child with a high fever has a bacterial or viral infection on clinical features alone,” said Dr. Michael Levin. He is a professor of pediatrics and international child health at Imperial College London in England.
“As a result, thousands of children each day worldwide undergo investigations to rule out bacterial infection and are generally treated with antibiotics while the results are awaited,” said Levin.
While viral infections generally resolve without treatment, bacterial infections can be life-threatening, so it’s important to identify and treat them. But antibiotic overuse has led to a problem called antibiotic resistance — bacteria that don’t respond to commonly used antibiotics — and experts say children shouldn’t take antibiotics unless they’re needed.
Levin was lead researcher of one of two new studies that explored the use of genetic tests as diagnostic tools in children with fever. Both studies looked at viral and bacterial infections to identify genes linked to one or the other.
The findings might eventually lead to a simple test that would spare children unnecessary medications and painful testing, the researchers said.
One expert said an accurate test would be a major breakthrough.
“If a pediatrician can confidently say to a mother with a child with a 104-degree fever, ‘Don’t worry, don’t go to the emergency room, it’s not a serious bacterial infection,’ that would be unbelievable. I think it’s a brilliant technique,” said Dr. Marcelo Laufer. He is a pediatric infectious disease specialist at Nicklaus Children’s Hospital in Miami.
It’s still early days in the development of such a test, and much more research is needed. Still, Levin said, “our study is a proof of principle that bacterial and viral infection can be distinguished by differences in the genes that are activated in the patient’s blood.”
Currently, doctors rule out bacterial infection by attempting to grow the bacteria from the patient’s blood, spinal fluid or urine samples. But that may take 48 hours, and many patients receive antibiotics or are hospitalized while awaiting the results, Levin explained.
For the study, Levin’s team studied 240 children, half of them 19 months old or younger. Fifty-two had an obvious bacterial infection, 92 had a definite viral infection, and 96 had an indeterminate infection.
Levin’s team identified genes in the blood that distinguished bacterial from viral infection. The gene “signature” also distinguished bacterial infection from childhood inflammatory diseases such as lupus erythematosus and juvenile idiopathic arthritis, the researchers said.
Of those 96 undetermined infections, less than half were classified as having bacterial infection, but nearly all received antibiotic treatment, according to the study.
“Our results open the way to developing a test based on our two-gene signature, which could transform the diagnosis and treatment of [patients with fever],” Levin said.
In the other study, Dr. Octavio Ramilo, an infectious disease specialist at Nationwide Children’s Hospital in Columbus, Ohio, also studied gene “biosignatures” in infants with fevers at age 2 months or younger.
His team examined genes in nearly 300 infants — 89 with bacterial infections, 190 without bacterial infections, and 19 healthy infants without fever.
The researchers said they identified 66 genes that distinguished infants with and without bacterial infections.
Ramilo said their goal is to narrow the number of genes needed to identify bacterial versus viral infections and then develop a quick, inexpensive test.
How quick? Maybe just two to four hours in the hospital, he said.
“This is the first step, but the first step is very positive,” Ramilo said.
Both studies were published in the Aug. 23/30 issue of the Journal of the American Medical Association.
For more on fever in children, visit the American Academy of Family Physicians.