Wednesday, October 17, 2007

Oooh...another resistant organism!

Ear Bacteria Resist Treatment

October 17, 2007; Page D8

WASHINGTON -- Researchers have found a strain of bacteria that can cause ear infections that is resistant to all antibiotics approved for use in children.

Doctors at the University of Rochester have found the resistant bacteria in at least nine children diagnosed with ear infections during a three-year period.

Specifically, they found a type strain of Streptococcus pneumoniae bacteria known as serotype 19A in the children's ear fluid. The type of bacteria isn't included in a pneumococcal vaccine, Wyeth's Prevnar, commonly given to children to protect against seven strains of bacteria that can cause ear infections, pneumonia and meningitis.

Michael Pichichero, a pediatric infectious diseases researcher at the University of Rochester and a pediatrician in private practice in Rochester, N.Y., said he and a colleague, Janet Casey, started tracking whether bacteria that commonly cause infections in children would start to shift following the introduction of Prevnar in 2000. Dr. Pichichero's study appears in this week's Journal of the American Medical Association.

In an interview, Dr. Pichichero noted that the incidence of pneumococcal disease, along with the number of ear and other infections, has dropped significantly in children and adults in the years following Prevnar's introduction. However, in 2003 researchers started documenting the emergence of bacteria not covered by Prevnar.

What's alarming, Dr. Pichichero said, is that the 19A strain of bacteria he's seen in his patients is resistant to all antibiotics approved for use in children.

From 2003 to 2006, Dr. Pichichero and Dr. Casey looked at 1,816 of their patients in which an ear infection was diagnosed. In 212 patients, they performed a procedure known as tympanocentesis, which uses a needle to remove fluid from the middle ear, in order to test the fluid for the type of bacteria causing the infection.

They found 59 cases of S pneumoniae infection, and of those, found nine cases of the 19A bacteria. Dr. Pichichero said in two cases it was the child's first ear infection. Two cases each were documented in the 2003-2004 and the 2004-2005 cold seasons, with the other five resistant cases documented in 2005-2006.

"If it's [the bacteria] in Rochester, it's probably in New York City or Baltimore this season," Dr. Pichichero said of the resistant strain of bacteria.

Dr. Pichichero said the first four patients had ear tubes inserted to treat the infection and the other five were successfully treated with levofloxacin, a powerful antibiotic only approved for use in adults. Levofloxacin is sold under the brand name Levaquin by a unit of Johnson & Johnson. Dr. Pichichero urged doctors treating patients who aren't responding to antibiotics to test the ear fluid for antibiotics resistance before using Levaquin in children, otherwise it will likely generate new bacteria that's resistant to Levaquin.

Dr. Pichichero said Levaquin isn't approved for children, so it's not clear what the drug's side effects might be in people age 18 and younger.

Wyeth is currently developing a new version of Prevnar that would help protect against 13 strains of bacteria, including serotype 19A. Lili Gordon, a Wyeth spokeswoman, said the company is planning to file for regulatory approval of the vaccine in 2009.

(What this means is: don't overuse antibiotics for ear infections or any other infection - if you don't take the whole course, or sometimes even if you do, the chance increases that resistant bacteria will survive. Side note - don't ask the doctor for antibiotics if s/he says you have a VIRAL infection; they won't do any good.)

(Just to warn y'all, I may use this article or another one as a launching pad for a story starring microbes. Each story will be one post, but I will write in installments - so check the post you're following frequently! I was inspired by my introductory microbiology teacher a few summers ago, and it just went from there...)

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