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An Overview of Parasite Diversity
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Among the bacteria are several intriguing and lesser known parasites. Bdellovibrio is a parasitoid that bores into and parasitizes the bodies of other bacteria (Figure 2.6). It has been considered a possible means to control antibiotic-resistant bacterial pathogens. Some bacteria colonize unicellular eukaryotes like the ciliate Paramecium and can interfere with host reproduction (Holospora) or confer on their host the ability to kill other Paramecium whilst simultaneously rendering their host immune from similar attacks (Caedibacter). Unicellular eukaryotes like freshwater amebas serve as reservoir hosts for over 20 species of bacteria that are human pathogens, including Legionella pneumophila that causes Legionnaires’ disease. Plants too suffer from bacterial infections as do invertebrates such as corals that are weakened by stressors like climate change and are thus more vulnerable to infections.
Control of the Large Bowel Microflora
Published in Michael J. Hill, Philip D. Marsh, Human Microbial Ecology, 2020
Bohumil S. Drasar, April K. Roberts
Many of the coliform bacteria found in the gut, when grown in vitro, liberate “colicines” that are able to kill other related bacteria and it is assumed that this must happen in the intestine. Studies by Branche et al.98 on five healthy individuals over a period of 6 months indicated that resident serotypes of E. coli produced colicine far more consistently than did transient serotypes, and that a greater variety of serotypes was present in the subjects whose strains produced relatively little colicine. Bacteriophage may also play a role in the mediation of bacteria/bacteria interaction. An interesting development is the recognition of a possible role for micropredators such as Bdellovibrio.99
Taxonomy and Grouping
Published in Paul Pumpens, Single-Stranded RNA Phages, 2020
The list of unclassified Leviviridae members includes the acinetophage AP205, the pseudomonaphages PP7 and LeviOr01, and the caulophage φCB5. The appearance of the entry “Bdellovibrio bacteriovirus” could be explained as an aftereffect of the misinterpretation connected with Bdellovibrio bacteriovorus phages which is described in the Dangerous similarity section in Chapter 1. The Leviviridae sp. directory contains sequences acquired metagenomically by Krishnamurthy et al. (2016) and therefore opens a way to novel species discovered by novel approaches and not by the traditional search for the infectious phage particles.
Isolation and cultivation of candidate phyla radiation Saccharibacteria (TM7) bacteria in coculture with bacterial hosts
Published in Journal of Oral Microbiology, 2020
Pallavi P. Murugkar, Andrew J. Collins, Tsute Chen, Floyd E. Dewhirst
The first roadblock was the assumption that Saccharibacteria were simply fastidious bacteria that were capable of axenic growth in a complex medium under the proper culture conditions. We now know that all Saccharibacteria isolated to date are obligate parasites that require the presence of live bacterial hosts. Thus, anyone using Koch’s approach of streaking for isolation and axenic culture was doomed to fail because it excludes the necessary bacterial host. The idea that obligate parasitic organisms require a host is an old concept in biology, but possibly under-appreciated by the microbiologists attempting to culture candidate phyla bacteria before the isolation of TM7x. It is well recognized that there are bacterial parasites of eukaryotic cells such as members of the genera Chlamydia and Mycoplasma, the insect endosymbiont Buchnera spp [51], and Vampirovibrio chlorellavorus, a small, 0.6-micron diameter, epi-parasite of the green alga Chorella vulgaris [52]. However, awareness of the fact that bacteria parasitize other bacteria was generally overlooked except for Bdellovibrio bacteriovorus and related bacteria [53]. Therefore, despite solid literature on specific prokaryotes being parasites on other prokaryotes, there are no reports that microbiologists attempted to culture CPR bacteria in binary coculture before the isolation of TM7x. It appears that most investigators attempted to obtain pure cultures directly following Koch’s approach.
Stenotrophomonas maltophilia biofilm: its role in infectious diseases
Published in Expert Review of Anti-infective Therapy, 2019
Samantha Flores-Treviño, Paola Bocanegra-Ibarias, Adrián Camacho-Ortiz, Rayo Morfín-Otero, Humberto Antonio Salazar-Sesatty, Elvira Garza-González
Biofilm formation by S. maltophilia can be disrupted by a bacterial predator such as Bdellovibrio exovorus [113]. This predator restricts its attack to the biofilm of Gram-negative pathogens and normally does not engage in interactions with either eukaryotic cells or Gram-positive bacteria, which could benefit from potential therapeutic use. In addition, B. exovorus can prey on biofilm in concentrations of ciprofloxacin up to 20 µg/mL. Subtherapeutic concentrations of ciprofloxacin significantly reduce S. maltophilia biofilm mass, whereas kanamycin reduces the effectiveness of B. exovorus. This represents a novel approach to combat bacterial infections in humans.