Ear superbug resistant to all paediatric antibiotics

Researchers at the University of Rochester Medical Centre in New York say they have discovered a strain of bacteria resistant to all approved drugs used to fight ear infections in children.

The article, which was published on 18 October 2007 in the Journal of the American Medical Association (JAMA), revealed that paediatricians discovered the strain because it was standard practice to drain the inner ears of children when several antibiotics failed to clear up their ear infections.

The procedure involves puncturing the child's eardrum and draining fluid to relieve pressure and pain. Analysing the drained fluid is the only way to describe the bacterial strain causing the infection.

Even after the ear tap and extra antibiotics, infections persisted in a small group of children in their paediatric practice, leading to ear tube surgery and, in one case, to permanent hearing loss.

The doctors realised they might be dealing with a 'superbug' and tested the children's ear tap fluid at the University of Rochester Medical Center. The tests showed that the 19A strain of bacteria could be killed only by an antibiotic Levaquin (levofloxacin), which is approved for adults but contains a warning in its label against use in children. Despite the warning, the doctors successfully treated the children off-label by crushing the pills.

Off-label use of drugs, such as fluoroquinolones, has been heavily debated because of potential safety issues. More importantly, if the drug were to be prescribed 'excessively' in children, the new super strain could become resistant.

The study authors say that the 19A strain was probably created by a combination of the speed of bacterial evolution and over-prescribing of antibiotics. They went on to warn that the medical profession must now consider the possibility that this multi-drug-resistant bacterial ear infection will spread to other communities, or even invade the lungs and bloodstream.

Dr Michael Pichichero, author of the JAMA study and professor of microbiology, immunology and paediatrics at the University of Rochester Medical Centre, said: "Children with the new strain of superbug represented a small subset of those in our practice, but the results are worrisome, especially since there are no new antibiotics in the pipeline for ear infections in children. While we must be careful not to create undue alarm, the potential exists for newly evolved strains to spread to the ears of more children."

Prevnar vaccine holds promise
US-based pharmaceutical company Wyeth is working on its Prevnar vaccine which would also protect against the next six commonest strains of S. pnemoniae, including 19A. The 13-strain vaccine is not expected on the US market before 2010, however.