Here are the reasons to be skeptical that I picked up from that blog post:

• The website of the Journal of Cosmology is ugly
• The figures in the paper are "annoying"
• Perhaps the claimed bacteria aren't bacteria at all, but just squiggles.
• The photos of the found bacteria aren't at the same magnification as photos of real bacteria
• It seems like the bacteria are too well-preserved for having traveled the solar system for such a long time.
• Haha, maybe next they'll find bigfoot footprints on a meteor.