Researchers have tested propolis against several dangerous microbes, and the results suggest that propolis is powerful against aggressive bacteria.  Although the strength of propolis can vary based on geography, its protective benefits remain constantly present. Part of the reason for the action may be due to it containing a wide spectrum of flavonoids.
Antibiotic resistance is a growing problem in medicine, often due to the overuse of antibiotic medication. People who are taking antibiotics are often advised to take probiotics to aid in the preservation of good bacteria in the intestines. Researchers have determined that propolis offers powerful antibiotic properties. The isolated acids from propolis have been shown to be an effective agent against many bacteria, including staph.
In one study, Brazilian propolis was tested against a common prescription cream used to help burns. The results? The propolis was just as effective. Propolis was even more soothing for minor burns than the conventional medication.  
Middle-ear infections affect millions of children each year, and even adults. Sometimes it can lead to temporary hearing loss, a terrifying prospect for most people. A compound in propolis, caffeic acid phenethyl ester, has shown effectiveness at easing inner ear inflammation. Although preliminary, this new research is causing a buzz (pun intended) of hopeful outlook for the use of propolis.