The Impact of Protozoan Predation on the Pathogenicity of Vibrio cholerae

Abstract

In the aquatic environment, Vibrio spp. interact with many living organisms that can serve as a replication niche, including heterotrophic protists, or protozoa. Protozoa engulf bacteria and package them into phagosomes where the cells are exposed to low pH, antimicrobial peptides, reactive oxygen/nitrogen species, proteolytic enzymes, and low concentrations of essential metal ions such as iron. However, some bacteria can resist these digestive processes. For example, Vibrio cholerae and Vibrio harveyi can resist intracellular digestion. In order to survive intracellularly, bacteria have acquired and/or developed specific factors that help them to resist the unfavorable conditions encountered inside of the phagosomes. Many of these intra-phagosomal factors used to kill and digest bacteria are highly conserved between eukaryotic cells and thus are also expressed by the innate immune system in the gastrointestinal tract as the first line of defense against bacterial pathogens. Since pathogenic bacteria have been shown to be hypervirulent after they have passed through protozoa, the resistance to digestion by protist hosts in their natural environment plays a key role in enhancing the infectious potential of pathogenic Vibrio spp. This review will investigate the current knowledge in interactions of bacteria with protozoa and human host to better understand the mechanisms used by both protozoa and human hosts to kill bacteria and the bacterial response to them.

A Systematic Review of Intracellular Microorganisms within Acanthamoeba to Understand Potential Impact for Infection

“…The intracellular survival mechanisms of bacteria in the amoebal cytoplasm differ between species and this, coupled with analysis of phylogenetic lineages of intracellular bacteria, indicates the ability that has developed with time over the microbe’s evolution [ 33 ]. For instance, V. cholerae can escape degradation by applying an intricate neutralising program that effectively neutralises changes to the pH, digestive enzyme functions, and the production of reactive oxygen radicals that may otherwise destroy the bacteria [ 34 ]. On the other hand, L. pneumophila forms a membrane-enclosed microenvironment within the Acanthamoeba that is produced via the endoplasmic reticulum, membrane transporters, and fusion with other membrane-bound vesicles [ 35 , 36 ].…”

Metagenomic Insights Into Co-Proliferation of Vibrio Spp. and Dinoflagellates Prorocentrum During A Spring Algal Bloom in the Coastal East China Sea Near Xiamen

“…Spatial microaerobic or anoxic niches may also exist, such as in bio lms attached to particle surfaces, microbial aggregates, and intracellular spaces within zooplankton or phytoplankton where Vibrio spp. may be able to colonize [52,[54][55][56]. Rapid decay of algal carcass, and/or upwelling of hypoxic bottom water may also cause temporal anoxia that may not be captured by snapshots of DO measurement [57,58].…”

Evaluation of the occurrence of pathogenic free‐living amoeba and bacteria in 20 public indoor swimming pool facilities

“…Bacterial species such as Vibrio spp. (Espinoza-Vergara et al, 2020) or Pseudomonas spp. (Ilk et al, 2020) can form biofilms involving an infection hazard.…”