There are several libraries to track RSS feeds: https://wiki.python.org/moin/RssLibraries
But the key issue here is how you implement the model in a trading strategy:
Using some other trigger event (like a 1-minute data feed) you pull to see if a new event is available and act accordingly. This doesn't preclude background processing, in which case the pulled info will not be directly the feed but whatever you want to make out of it
Whenever your listening thread and processing engine detect something, you do immediately act. In this case and within the context of backtrader and using the 1-minute data feed from above, it could mean that when you act with the RSS event, your price information is, for example, 45 seconds too old. Where you are the one defining too old. It might be that you need to react with the latest info and latest price quotes to make your strategy work or that 45 seconds is an acceptable delay.
You can of course reduce the timeframe resolution and work with 10-seconds bars to reduce the lag.