Effect of Bacterial Interference on Biofilm Development by Legionella pneumophila

Abstract

In the ecology of Legionella pneumophila a crucial role may be played by its relationship with the natural flora; thus we investigated the interactions between Legionella and other aquatic bacteria, particularly within biofilms. Among 80 aquatic bacteria screened for the production of bacteriocin-like substances (BLSs), 66.2% of them were active against L. pneumophila. The possible effect of some of these aquatic bacteria on the development and stability of L. pneumophila biofilms was studied. Pseudomonas fluorescens, the best BLS producer, showed the greatest negative effect on biofilm formation and strongly enhanced the detachment of Legionella. Pseudomonas aeruginosa, Burkholderia cepacia, Pseudomonas putida, Aeromonas hydrophila, and Stenotrophomonas maltophilia, although producing BLSs at different levels, were less active in the biofilm experiments. Acinetobacter lwoffii did not produce any antagonistic compound and was the only one able to strongly enhance L. pneumophila biofilm. Our results highlight that BLS production may contribute to determining the fate of L. pneumophila within ecological niches. The interactions observed in this study are important features of L. pneumophila ecology, which knowledge may lead to more effective measures to control the persistence of the germ in the environment.

Molecular Survey of the Occurrence of Legionella spp., Mycobacterium spp., Pseudomonas aeruginosa, and Amoeba Hosts in Two Chloraminated Drinking Water Distribution Systems

“…Specifically, one isolate of B. subtilis was able to reduce L. pneumophila numbers in either the absence or presence of amoebae by lysing Legionella cells or inhibiting internal replication in amoebae, respectively (69). Among members of one collection of aquatic bacteria, 66% inhibited L. pneumophila growth (35).…”

“…For example, the ecological niche of Legionella and mycobacteria overlaps with those of amoebae and protozoa (1,24) and infection of protozoan hosts can enhance reproduction and virulence in these and other pathogens (18,19). Certain aquatic bacteria have also been reported to exert a negative influence on L. pneumophila (35). Therefore, advancing understanding of the microbial ecology of multiple representative opportunistic pathogens is critical to developing appropriate guidance and controls to broadly limit their proliferation.…”

Bacterial Biodiversity in Midguts of Anopheles Mosquitoes, Malaria Vectors in Southeast Asia

“…The most striking result was the pair P. fluorescens / Serratia which never co-habited with Acinetobacter. Pseudomonas fluorescens is well known as a great anti-microbial and bacteriocin-like substances producer [71] exhibiting negative effect on diverse Gram-negative bacteria and biofilm formation [72]. The bacteriocins are narrow-spectrum toxins that typically kill bacteria related to the producing strain as is the case for P. fluorescens and Acinetobacter, which both belong to the order Pseudomonadales.…”

Airborne Legionella bacteria from pulp waste treatment plant: aerosol particles characterized as aggregates and their potential hazard

“…This further raises the question whether a mixed culture of bacteria and other organisms, in addition to various substances, may enhance infectivity of Legionella. Studies have shown that bacteriocin-like substances and Pseudomonas may affect the persistence of Legionella in aquatic ecological niches (Guerrieri et al 2007(Guerrieri et al , 2008.…”