Please have a look at these links.

http://link.springer.com/chapter/10.1007%2F3-540-28185-1_3#page-1

https://www.researchgate.net/post/Gut_microflora_of_earthworm_species

http://www.jove.com/visualize/abstract/23847816/isolation-characterization-aerobic-microorganisms-with-cellulolytic

http://www.sciencedirect.com/science/article/pii/S0944501315000373

Please check these PDF attachments also.

 Thank you very much Dr Arvind for sending me the papers on gut microbes of earthworms. 

Regards