Child at Sick Kids' Hospital has new superbug
CTV.ca News Staff
Published Thursday, November 8, 2007 12:17PM EST
Doctors in Ontario have identified a new antibiotic-resistant strain of bacteria that's led to a case of meningitis in a child.
The "superbug," a new substrain of Streptococcus pneumoniae 19A, has caused dozens of ear infections in Massachusetts and New York State.
Now, CTV News has learned that this new substrain of 19A has caused a serious infection in a child at the Hospital for Sick Children in Toronto.
The child's illness developed into bacterial meningitis, a potentially fatal infection of the fluid around the spinal cord and brain.
After trying numerous antibiotics designed for children, doctors eventually turned to levofloxicin, a powerful antibiotic not typically used in children. That drug was effective against the bacteria. The child is still quite ill, says hospital official Dr. Upton Allen, and treatment is continuing.
The child had been otherwise healthy and had received all the vaccinations recommended for children. Experts believe the child caught the infection in the community -- not in hospital.
Doctors may soon be asked by the Ministry of Health to watch for recurrent ear infections that don't respond to treatment with antibiotics, because they could be the result of this new strain.
S. pneumonia is not new in Canada. It causes hundreds of chest and throat infections, ear infections. In rare cases, it triggers pneumonia and meningitis, the illnesses that are usually easily treated with antibiotics.
The 19A strain is not new either. But doctors have identified the growth of a subtype of 19A that can't be killed off with any of the antibiotics approved for use in children.
The patient at SickKids Hospital was treated with one antibiotic after another without success. The infection only responded to a powerful antibiotic usually reserved for adults called levofloxacin.
Dr. Michael Pichichero, a professor of microbiology, immunology and pediatrics at the University of Rochester Medical Center was the first to identify the new 19A super-strain while he was treating children whose ear infections wouldn't clear up.
In October, he published a report in the Journal of the American Medical Association, describing his experience with the 19A superbug. He tried 18 antibiotics approved in the U.S. for children. The only drug that worked was levofloxacin, (also called Levaquin), which is approved for adults and is not recommended for children.
For one child, the cure came too late; the infection led to permanent hearing loss.
Pichichero's team believes the new substrain was most likely created by a combination of the superbug's ability to evolve quickly and the over-prescribing of antibiotics, which has led to antibiotic resistance.
Pichichero told CTV News that he's worried that this multi-drug-resistant superbug could cause infections that invade the lungs and bloodstream, where it could cause pneumonia or blood infections.
"If this germ starts to cause infections in the brain or in the lungs it could have devastating consequences," he says. "And if doctors aren't aware that it could be the 19A superbug, they would not normally use the one antibiotic that might work because that one antibiotic is not actually approved for use in children."
What's more, the strain could also cause illnesses in adults, he says.
"We've learned over the years that young children spread their germs, not only to each other in daycares and in schools, but also to their parents and to their grandparents. So that the fact that we found this superbug in children also has significant implications for the possibility that it would also occur in adults," he says.
There is a childhood vaccine currently in wide use for S. pneumoniae, a vaccine called Prevnar. Since its introduction in 2000, the incidence of pneumonia and meningitis caused by pneumococcus has fallen by at least 69 per cent. As well, difficult-to-treat ear infections were reduced by 24 per cent.
But Prevnar does not include this new 19A strain and so that vaccine offers no protection against it.
The makers of Prevnar are reportedly aware that the vaccine needs to include the new strain and are reformulating their vaccine. Other vaccine makers are working on other formulations that are still being tested. But it will take two years for a new vaccine to be approved and placed on the market.
In the meantime, doctors need to know that this strain is circulating, and that if a patient has a pneumococcal infection that isn't resolving -- such as an ear infection that defies treatment -- it may need more aggressive treatment.
With a report by CTV medical specialist Avis Favaro and Elizabeth St. Philip