Study shows most ear infections host both bacteria and viruses

They have generally been considered bacterial diseases and are therefore usually treated with antibiotics. New research, published in the December 15 issue of Clinical Infectious Diseases and currently available online, provides evidence that viruses are found in a great many ear infection cases and may complicate treatment.

The researchers used a variety of laboratory techniques to identify the pathogen that caused ear infections, known clinically as acute otitis media (AOM), in 79 young children. They found bacteria in 92 percent of the cases, viruses in 70 percent, and both bacteria and viruses in 66 percent.

According to Aino Ruohola, MD, PhD, from the Turku University Hospital in Finland and lead author of the study, “the major finding of the study is that acute otitis media is a coinfection of bacteria and viruses in the great majority of children. This is actually logical since acute otitis media is virtually always connected to viral respiratory infection.”

Antibiotics, which are effective against the bacteria that cause AOM, have no effect on the viruses found in AOM infections. Therefore, the standard treatment for AOM–antibiotics–can be, at best, partially effective in the majority of cases. “Based on this and previous research,” said Dr. Ruohola, “it is possible that viruses cause a considerable proportion of clinical treatment failures. Thus, in these cases a new antibiotic is not necessarily the best choice although bacteria resistant to common antibiotics are wide-spread.”

The good news is that many cases of AOM recover spontaneously without antibiotic treatment, a fact that has led the American Academy of Pediatrics and the American Academy of Family Physicians to recommend withholding antibiotic treatment in mild AOM cases.