Frankly, I am usually amused at how absolutely awful science reporting is.
As has been already pointed out, many mammalian species produce these molecules, including H. sapiens. Discovering them in pandas is not surprising. Second, when posting science reporting, please link to the journal article [http://www.sciencedirect.com/science/article/pii/S0378111911006652]. I think it took me thirty seconds to find it. And while you're at it, at least dig as far as the abstract. And if reporting for a major publication, maybe have them pay for the full scientific article past the pay wall.
The actual article only states that the protein has anti-microbial properties where it interferes with cell walls (incidentally the mechanism of action of many classes of antibiotics as well as quite a few of our innate defenses). That's it. That's what this class of molecule is for. If the reporters had dug as far as the end of the first paragraph of the abstract, they would have found out that this class of molecule is already known and sequenced across many species. It's so well known that the researchers were able to find out which species the panda's version most resembled - namely, dog. So nothing really special about the panda. Maybe there will be a slight advantage because the variations between species. Bacteria which infect humans already resist the human version of the protein, so a novel version of it might provide a challenge the bacteria haven't seen before. However, these kinds of carefully speculative statements are a far cry from the way reporters report findings.