Mqtt publish and subscribe using python

How to publish from one system and subscribe from another system in Matt using python programming

Harish,
I havent worked on Python but there must be lot of libraries available.
The Dreamfactory IOT platfor has an example of MQTT using Python, Try going through it, might be helpful.

Publishing and subscribing using Mosquitto doesnt make any difference when running on different systems.
Once you get the Python libraries, you can make use of public brokers like test.mosquitto.org or cloudmqtt.com and run your publisher and subscriber code on separate machines with the brokers being the intermediaries.