Chlamydia-like obligate parasite of free-living amoebae

Root colonization by Pseudomonas putida: love at first sight

“…Previous reports on new chlamydial organisms were from clinical samples (2,4,8,12,14,15), and environmental isolates concerned exclusively new phylotypes of parachlamydiae (9)(10)(11). Our data and those of Bowman et al (3) indicated that new distinct chlamydial lineages exist in natural environments as different as Antarctic marine salinity lake sediments and European freshwater ponds.…”

“…These activities and their potential use in agriculture have prompted an increasing interest in the study of mutualistic plant-Pseudomonas interactions. One of the most relevant aspects is the process of bacterial establishment in the rhizosphere, since an effective biocontrol depends on the efficiency of root colonization (2). Most studies of factors potentially involved in root colonization efficiency draw their conclusions from looking at wellestablished populations, i.e.…”

“…Among the new lineages the family Parachlamydiaceae that includes endosymbionts of amoebae of the group AcanthamoebaHartmannella is of interest. Parachlamydiae have been identified in various strains of amoebae isolated from soil, water conduit systems, sewage sludge, corneal\contact lens samples and nasal mucosa of healthy individuals (1, 9, 11), and there is evidence for their implication in human respiratory infections (2,4). 16S rDNA analyses showed that this group of chlamydiae is very rich, probably including several species and genera (10).…”

Predator or prey? Chlamydophila abortus infections of a free-living amoebae, Acanthamoeba castellani 9GU

“…abortus to infect animals. This suggestion is consistent with the absence of reports of disease outbreaks of members of the Chlamydiaceae from water sources and is in stark contrast to well-documented cases of disease outbreaks caused by amoebae-resistant bacteria such as Legionella [24] and even Chlamydia-like organisms such as P. acanthamoebae [25,26]. The lack of evidence linking growth and survival of the classical members of the Chlamydiaceae in free-living amoeba is also consistent with the failure to isolate any member of this family from environmental sources, compared to the successful recovery of a variety of intracellular bacteria using amoebal co-culture [16,27,28].…”

Discovery of New Intracellular Pathogens by Amoebal Coculture and Amoebal Enrichment Approaches

“…Free-living amoebae likely represent an important potential reservoir for intracellular bacteria that have yet not been discovered. This led our group to implement in Lausanne two main techniques, called amoebal coculture and amoebal enrichment, which allowed different groups to isolate several new obligate intracellular microorganisms from various environmental samples [9][10][11][12][13][14][15] .…”