Influenza and Antibiotics

From the archives comes this post about the effect antibiotic resistance could have during an influenza outbreak.

I recently corresponded with someone in a position to make public health policy who wanted to know what effect antibiotic resistance would have on avian influenza (this makes me think of Kristof's recent column). Since I regularly encounter similar questions, I thought it worthwhile to share this (I've removed other parts that aren't relevant to the matter).

Also, on occasion, I like to demonstrate that the Mad Biologist isn't always Mad...:

1. Anti-viral resistance. While antibiotic resistance will not be a direct concern (antibiotics are effective against bacteria, not viruses such as influenza), antiviral resistance will be. In other words, Tamiflu and other antiviral drugs could become ineffective if not administered correctly. There has been one reported case of this in Vietnam, which resulted from doctors administering an insufficient dose of Tamiflu. This resulted in the evolution of Tamiflu-resistant influenza. We need to inform health care providers and patients that they need to take the full course of treatment (a similar problem currently exists with TB; preventing it from arising in influenza would be desirable), and we need to tell health care providers what those guidelines are.
2. Secondary bacterial infections. About half of the deaths from influenza are not caused by the influenza virus directly, but from secondary bacteria pneumonial infections (note: 50% is a rough estimate; obviously, there are many things that could increase or decrease this number). Some have called for vaccination against some of the most common bacteria that cause pneumonia, but in the absence of such a program, these secondary bacterial infections will have to be treated with antibiotics. Given the critical state of the patient, the newest antibiotics which have the highest probability of successand which also are the 'antibiotics of last resort'-will be used disproportionately. It is not unrealistic to think that during an avian influenza outbreak that anywhere from 250,000 to 1,000,000 patients during a six-month period (or however long the outbreak might last) could need antibiotic therapy. While we can not definitively predict what might happen, having to treat so many patients with a very small subset of important antibiotics in such a concentrated time frame would most likely increase antibiotic resistance in these organisms-and these organisms also cause pneumonia in non-influenza settings and others can cause other diseases unrelated to pneumonia (e.g., K. pneumoniae, Acinetobacter).