Monday, March 30, 2009

Novel Type of Streptococcus pneumoniae Causing Multidrug-Resistant Acute Otitis Media in Children

Here's another interesting article from this month's Emerging Infectious Disease, published by the CDC. Streptococcus pneumoniae is a bacteria that causes a lot of different illnesses, including pneumonia, otitis media (ear infections), meningitis, and others. S. pneumoniae strain A19 is one of the most common strains found in children, and the same group of researchers writing this article had previously reported a "superbug" version of A19 that is resistant to all FDA-approved drugs for treating ear infections and an additional 8 drugs that are not FDA-approved for the purpose but commonly prescribed. To make matters worse, this superbug is not covered by the childhood vaccine PCV7.

In this article, the researchers wanted to determine how the superbug was spreading and evolving in children. They used a genetics technique called "multilocus typing." Samples were collected from children 6-36 months old with infections, and then the bacteria were cultured to obtain pure S. pneumoniae isolates (40 different isolates total). Next, they picked 7 different sections of the bacteria's DNA to compare between the different isolates they'd gotten from the children. The amount of difference between the sections (called loci) tells the scientists how the bacteria strain is evolving.

Of the 40 isolates of S. pneumoniae, 16 were strain A19. Half of the A19 isolates were resistant to multiple anitibiotics. Most of the resistant strains were very closely related to the original "superbug" strain identified by the authors earlier, and the origin of all of these strains was traced to an isolate identified in 1988 in Spain. In the last 20 years the descendants of that Spanish strain have spread to 18 different countries!

The spread of multidrug resistant bacteria highlights the need to be responsible in our use of antibiotics. Don't take antibiotics if you have a viral infection "just in case" you might get a bacterial infection later. If you need antibiotics, make sure you take the entire prescription even if you feel better. Only taking part of a prescription will only kill off the bacteria that are very susceptible to the antibiotic and leave the ones that are slightly resistant to grow.

No comments:

Post a Comment