Pneumococcus Strain Resistant To All Kids' Antibiotics

ROCHESTER, N.Y., Oct. 16 -- A strain of pneumococcus resistant to all of the antibiotics approved for use in children has emerged in the wake of the widespread use of the heptavalent pneumococcal vaccine, researchers here said.

The pathogen -- serotype 19A of Streptococcus pneumoniae -- was isolated from nine children in a single pediatric practice here over a three-year period, according to Michael Pichichero, M.D., and Janet Casey, M.D., of the University of Rochester.

The 19A serotype is not included in the current pneumococcal vaccine, and has previously been reported to have caused disease among Native Alaskan children, they noted in the Oct. 17 issue of the Journal of the American Medical Association.

But the pathogens seen in Alaska were not multi-drug resistant, Drs. Pichichero and Casey said. (See: Pneumococcal Disease Rebounding in Alaskan Native Children)

In the nine cases they found -- two in the respiratory season from September 2003 through June 2004, two in 2004-2005 season, and five in 2005-2006 season -- the first four required a tympanostomy tube insertion after a series of unsuccessful antibiotic therapies, including high-dose amoxicillin (Amoxil), amoxicillin-clavulanate (Augmentin), and ceftriaxone (Rocephin).

The last five were successfully treated with levofloxacin (Levaquin), an oral fluoroquinolone that is not approved for use in children, the researchers said.

While the numbers are small, the researchers said, the "observations are clearly worrisome" -- especially since no new antibiotics for children are in the late stages of testing.

The finding means that "old diseases have learned new tricks" and clinicians and public health authorities will need to work closely together in order to curb them, said Elizabeth Bancroft, M.D., of the Los Angeles County Department of Public Health in an accompanying editorial.

The study "highlights the importance of surveillance for antibiotic resistance and strain detection in a community setting," Dr. Bancroft said.

The emergence of the resistant serotype "clearly bears watching," Blaise Congeni, M.D., of Akron Children's Hospital in Akron, Ohio, told MedPage Today, because treatment options are limited and the number of cases -- while small -- appears to be rising over time.

But, he added, "I'm not overly alarmed by this (because) we still have options" including drugs such as levofloxacin or tympanocentesis, aspirating infectious material from the ear.

Drs. Pichichero and Casey uncovered the nine cases from a prospective longitudinal investigation aimed at characterizing S. pneumoniae that caused acute otitis media in children.

All told, 1,816 children were seen for acute otitis media over the three-year study; all of them had been given the pneumococcal vaccine. The researchers focused on 375 who had a first or second episode of acute otitis media, recurrent disease, or acute otitis media with treatment failure.

For the 375 children, Drs. Pichichero and Casey performed tympanocentesis 212 times, and were successful in culturing a pathogen in 162 cases, of which 59 were S. pneumoniae.

Over the study period, the prevalence of vaccine serotypes fell significantly -- from 16 of 28 (or 57%) in the 2003-2004 season to five of 19 (or 26%) in the 2005-2006 season.

At the same time, the proportion of non-vaccine serotypes rose significantly from 12 of 28 (or 43%) at the start of the study to 14 of 19 (or 74%) at the end.

Both comparisons were significant at P