Volume 193, no. 7, p.1515–1526, 2011. Problems related to images published in this paper have been brought to our attention. Figure 8 contains duplicated images as well as images previously published in articles in Microbiology and Microbial Pathogenesis, i.e., the following: S. A. Sousa, C. G. Ramos, L. M. Moreira, and J. H. Leitão, Microbiology 156:896–908, 2010. http://dx.doi.org/10.1099/mic.0.035139-0. C. G. Ramos, S. A. Sousa, A. M. Grilo, L. Eberl, and J. H. Leitão, Microb. Pathog. 48:168–177, 2010. http://dx.doi.org/10.1016 /j.micpath.2010.02.006. Therefore, we retract the paper.Wedeeply regret this situation and apologize for any inconvenience to the editors and readers of Journal of Bacteriology, Microbial Pathogenesis, and Microbiology.