Superbug causing acute otitis media is identified

An article in the October 17 issue of the Journal of the American Medical Association (JAMA 2007:298;1772), reports on a small study done by clinicians who found the emergence of a strain of S pneumoniae (serotype 19A) that is resistant to all of the antibiotics approved for children, due to extensive use of the pneumococcal 7-valent conjugate vaccine (PCV7). This bacterial strain causes acute otitis media (AOM) in the pediatric population.

Two physicians (one a practicing pediatrician) from Rochester, N.Y., studied 1,816 children diagnosed with AOM. Tympanocentesis was performed in 212 of the patients—59 cases of S pneumoniae infection were found. Nine of these cases were found to be infected with the serotype 19A bacterial strain (two in 2003 to 2004, two in 2004 to 2005, and five in 2005 to 2006). Four of the children were unsuccessfully treated with two or more antibiotics, including high-dose amoxicillin or amoxicillin-clavulanate and three injections ceftriaxone. Three had recurrent AOM and two had a first infection. Tymponostomy tube insertion was required in the first four cases and levofloxacin (an oral fluoroquinolone not approved for pediatric use) had to be administered in the remaining five cases.

In the US, the pneumococcal 7-valent conjugate vaccine was introduced in 2000—by 2003 reports of an increase of non-PCV7 strains of pneumococci began to appear in children with AOM. In 2004 to 2006, the emergence of the serotype 19A strain was found among native Alaskan children, however these strains were not multidrug resistant.

“Clinicians need to be aware that an S pneumoniae strain has emerged in the United States that is multidrug resistant but susceptible to levofloxacin,” said the doctors. They recommend the use of levofloxacin to treat children only after a tympanocentesis has been performed and the 19A serotype identified.