The Legionella pneumophila Collagen-Like Protein Mediates Sedimentation, Autoaggregation, and Pathogen-Phagocyte Interactions

Abstract

iAlthough only partially understood, multicellular behavior is relatively common in bacterial pathogens. Bacterial aggregates can resist various host defenses and colonize their environment more efficiently than planktonic cells. For the waterborne pathogen Legionella pneumophila, little is known about the roles of autoaggregation or the parameters which allow cell-cell interactions to occur. Here, we determined the endogenous and exogenous factors sufficient to allow autoaggregation to take place in L. pneumophila. We show that isolates from Legionella species which do not produce the Legionella collagen-like protein (Lcl) are deficient in autoaggregation. Targeted deletion of the Lcl-encoding gene (lpg2644) and the addition of Lcl ligands impair the autoaggregation of L. pneumophila. In addition, Lcl-induced autoaggregation requires divalent cations. Escherichia coli producing surface-exposed Lcl is able to autoaggregate and shows increased biofilm production. We also demonstrate that L. pneumophila infection of Acanthamoeba castellanii and Hartmanella vermiformis is potentiated under conditions which promote Lcl dependent autoaggregation. Overall, this study shows that L. pneumophila is capable of autoaggregating in a process that is mediated by Lcl in a divalent-cation-dependent manner. It also reveals that Lcl potentiates the ability of L. pneumophila to come in contact, attach, and infect amoebae.

Anti-biofilm Activities from Resveratrol against Fusobacterium nucleatum

“…The ability of bacterial cells to come into contact and form aggregates, or autoaggregation is considered important for colonization of host cells in pathogenic bacteria ( Lee et al, 2010 ; Abdel-Nour et al, 2014 ). During biofilm development, autoaggregation is a process through which a strain within the biofilm produces polymers to boost the integration of genetically identical strains, and is also a prerequisite of biofilm formation ( Zhang et al, 2004 ; Das et al, 2010 ; Nyenje et al, 2012 ).…”

Collagen-Like Proteins (ClpA, ClpB, ClpC, and ClpD) Are Required for Biofilm Formation and Adhesion to Plant Roots by Bacillus amyloliquefaciens FZB42

“…We found that the roles of CLPs in biofilm formation are consistent with previous studies of CLPs in Streptococcus pyogenes , B . anthracis , and Legionella pneumophila [ 8 , 10 , 13 , 16 ].…”

“…Most proteins that contain collagen-related structural motif (CSM) patterns are distributed in the Firmicutes group (including mycobacteria and Gram-positive bacteria) and in some cases a single genome encodes more than one CSM-containing protein [ 7 ]. Interestingly, some recent reports suggest that collagen-like proteins (CLPs) may play important roles in the infectious processes of some Gram-positive human pathogens, such as Bacillus anthracis , [ 8 – 10 ], Streptococcus [ 11 , 12 ], and Legionella pneumophila [ 13 ]. Some studies have shown that CLPs are always involved in the colonization, motility, and location processes when bacteria interact with their hosts [ 14 ].…”

Environmental (Saprozoic) Pathogens of Engineered Water Systems: Understanding Their Ecology for Risk Assessment and Management

“…Also, upstream biofilm members appear to influence the composition of downstream biofilms [ 36 ], and certain phenotypic features of bacteria, such as the presence of fimbriae and autoaggregation influence biofilm formation by individual members [ 37 , 38 , 39 ]. Autoaggregation by intracellular pathogens like L. pneumophila may also increase their uptake by biofilm amoebae [ 40 ], leading to a higher likelihood of selecting for virulent biofilm community members [ 41 ].…”