The health of the sinuses, like the health of the intestinal tract and other tissues is based on the microbial diversity of that tissue. That means, the more bacteria, the better. Anything which destroys this diversity, destroys health, as is the case with antibiotics. Other research shows that antibiotics are worthless when it comes to treating sinus conditions, yet most MDs prescribe antibiotics for this.
http://www.sciencedaily.com/releases/2012/09/120912161932.htm

“The team reports this week in the journal Science Translational Medicine that sinusitis may be linked to the loss of normal microbial diversity within the sinuses following an infection and the subsequent colonization of the sinuses by the culprit bacterium, which is called Corynebacterium tuberculostearicum.

In their study, the researchers compared the microbial communities in samples from the sinuses of 10 patients with sinusitis and from 10 healthy people, and showed that the sinusitis patients lacked a slew of bacteria that were present in the healthy individuals. The patients also had large increases in the amount of Corynebacterium tuberculostearicum in their sinuses, which are located in the forehead, cheeks and eyes.

The team also identified a common bacterium found within the sinuses of healthy people called Lactobacillus sakei that seems to help the body naturally ward off sinusitis. In laboratory experiments, inoculating mice with this one bacterium defended them against the condition.

“Presumably these are sinus-protective species,” said Susan Lynch, PhD, an associate professor of medicine and director of the Colitis and Crohn’s Disease Microbiome Research Core at UCSF.

What it all suggests, she added, is that the sinuses are home to a diverse “microbiome” that includes protective bacteria. These “microbial shields” are lost during chronic sinusitis, she said, and restoring the natural microbial ecology may be a way of mitigating this common condition.”

What the authors omit is the detrimental and common effect of antibiotics on this diversity.