Do Wolbachia confer their hosts with resistance to pathogenic bacteria?

From today, I am going to read (relatively) recent papers about Wolbachia, intracellular symbionts of arthropods and nematodes.

Rotschaefer SM & Lazzaro BP (2012) No effect of Wolbachia on resistance to intracellular infection by pathogenic bacteria in Drosophila melanogaster. PLoS ONE 7: e40500

For the last several years, many papers have been published that shows Wolbachia confer insects with resistance to infection by various viruses and Plasmodium (malaria parasites). 

So I expected that Wolbachia may also confers their hosts with resistance to infection by other bacteria, and I was thinking about verifying this possibility. However, this paper clearly shows that Wolbachia has no effect on resistance to pathogenic bacteria such as Listeria, Salmonella and Providencia. I must not be the only person who was disappointed by reading this paper.