Dual function of a bacterial protein as an adhesin and extracellular effector of host GTPase signaling

Sargasso Sea Vibrio bacteria: Underexplored potential pathovars in a perturbed habitat

We fully sequenced the genomes of 16 Vibrio cultivars isolated from eel larvae, plastic marine debris (PMD), the pelagic brown macroalga Sargassum, and seawater samples collected from the Caribbean and Sargasso Seas of the North Atlantic Ocean. Annotation and mapping of these 16 bacterial genome sequences to a PMD-derived Vibrio metagenome-assembled genome created for this study showcased vertebrate pathogen genes closely-related to cholera and non-cholera pathovars. Phenotype testing of cultivars confirmed rapid biofilm formation, hemolytic, and lipophospholytic activities, consistent with pathogenic potential. Our study illustrates that open ocean vibrios represent a heretofore undescribed group of microbes, some representing potential new species, possessing an amalgam of pathogenic and low nutrient acquisition genes, reflecting their pelagic habitat and the substrates and hosts they colonize.

Vibrio parahaemolyticus Epidemiology and Pathogenesis: Novel Insights on an Emerging Foodborne Pathogen

The epidemiological dynamics of V. parahaemolyticus´ infections have been characterized by the abrupt appearance of outbreaks in remote areas where these diseases had not been previously detected, without knowing the routes of entry of the pathogens in the new area. However, there are recent studies that show the link between the appearance of epidemic outbreaks of Vibrio and environmental factors such as oceanic transport of warm waters, which has provided a possible mechanism for the dispersion of Vibrio diseases globally. Despite this evidence, there is little information on the possible routes of entry and transport of infectious agents from endemic countries to the entire world. In this sense, the recent advances in genomic sequencing tools are making it possible to infer possible biogeographical patterns of diverse pathogens with relevance in public health like V. parahaemolyticus. In this chapter, we will address several general aspects about V. parahaemolyticus, including their microbiological and genetic detection, main virulence factors, and the epidemiology of genotypes involved in foodborne outbreaks globally.

Nosocomial Infections: Pathogenicity, Resistance and Novel Antimicrobials

Background. The fight against the spread of infectious diseases creates the problem of resistance to pathogens and the most resistant of them – the propagators of nosocomial infections – are formed in hospitals because of a number of reasons. The solution of the problem lies in different areas, but the search of new effective means for the treatment of such diseases remains relevant right today. The shortest way to do this is to find the "pain points" of the pathogens themselves, i.e. the factors of their pathogenicity and resistance to which the action of novel antiseptics should be directed. Objective. We aimed to analyse and evaluate the main factors of pathogenicity and resistance of pathogens of nosocomial infections to determine modern approaches to the development of novel antimicrobials. Methods. Search and systematization of new scientific data and results concerning pathogenic factors of microbial pathogens that can be used as targets for the action of drugs. Results. Over the last 10–20 years, due to the development of new research methods in biology, it has become possible to clarify the features and additional conditions for the detection of pathogenic factors of nosocomial infections. Additional mechanisms of manifestation of resistance, adhesiveness, invasiveness, transmission of signs, secretion of toxins by pathogens are shownthat determines the general increase of their resistance to the action of currently used means. The general idea of ​​creating antiseptics that will not increase the resistance of pathogens can now be implemented by using substances with multidirectional or indirect mechanisms of action that minimally affect the metabolism of the cell and significantly reduce its resistance and pathogenicity. Conclusions. Factors of pathogenicity of propagators of nosocomial infections and mechanisms of their implementation can be considered as the main targets for the action of novel antiseptics that will inhibit the spread of pathogens without increasing their resistance. The promising substances for such drugs, among other things, are bacteriophages and their modifications, enzybiotics, immunobiotics, autoinducer inhibitors, quorum sensing-system inhibitors, b-lactamase inhibitors and others. Some of these substances in combination with the new generation of antibiotics significantly enhance their effectiveness and together they are able to overcome the resistance of even multidrug-resistant pathogens.

The Rho signalling pathway mediates the pathogenicity of AHPND-causing V. parahaemolyticus in shrimp

An emerging bacterial disease, acute hepatopancreatic necrosis disease (AHPND), is caused by strains of Vibrio parahaemolyticus with an additional AHPND-associated plasmid pVA1 encoding a virulent toxin (Pir^vp ) that damages the shrimp's hepatopancreas. Like other species of Vibrio, these virulent strains initially colonise the shrimp's stomach, but it is not yet understood how the bacteria or toxins are subsequently able to cross the epithelial barrier and reach the hepatopancreas. Here, by using transcriptomics and system biology methods, we investigate AHPND-induced changes in the stomach of AHPND-causing V. parahaemolyticus (5HP)-infected shrimp and identify host molecular mechanisms that might explain how the integrity of the stomach barrier is compromised. We found that the expression of 376 unique genes was differentially regulated by AHPND infection. Gene ontology, protein interaction, and gene-to-gene correlation expression interaction analyses indicated that in addition to the immune system, a number of these genes were involved in cytoskeleton regulation by Rho GTPase. The involvement of Rho pathway regulation during AHPND pathogenesis was further supported by experiments showing that while Rho inhibitor pretreatment delayed the infection, pretreatment with Rho activator enhanced the pathogenicity of 5HP, and both the bacteria and toxin were detected sooner in the hepatopancreas. Further, disruption of the stomach epithelial structure was found in both Rho preactivated shrimp and in 5HP-infected shrimp. Taken together, we interpret our results to mean that Rho signalling helps to mediate AHPND pathogenesis in shrimp.

Against the tide: the role of bacterial adhesion in host colonization

Evolving under the constant exposure to an abundance of diverse microbial life, the human body has developed many ways of defining the boundaries between self and non-self. Many physical and immunological barriers to microbial invasion exist, and yet bacteria have found a multitude of ways to overcome these, initiate interactions with and colonize the human host. Adhesion to host cells and tissues is a key feature allowing bacteria to persist in an environment under constant flux and to initiate transient or permanent symbioses with the host. This review discusses reasons why adhesion is such a seemingly indispensable requirement for bacteria–host interactions, and whether bacteria can bypass the need to adhere and still persist. It further outlines open questions about the role of adhesion in bacterial colonization and persistence within the host.

Vibrio Parahaemolyticus: A Review on Distribution, Pathogenesis, Virulence Determinants and Epidemiology

Vibrio parahaemolyticus is a Gram-negative, halophilic bacterium isolated from marine environments globally. After the consumption of contaminated seafood, V. parahaemolyticus causes acute gastroenteritis. To initiate infection, a wide range of virulence factors are required. A complex group of genes is known to participate in the pathogenicity of V. parahaemolyticus; however, to understand the full mechanism of infection, extensive research is yet required. V. parahaemolyticus has become the leading cause of seafood-related gastroenteritis in Japan, the United States and several other parts of the world. In addition, outbreaks caused by the pandemic clone of this organism are escalating and spreading universally. To minimize the risk of V. parahaemolyticus infection and warrant the safety of seafood, collaboration between governments and scientists is required. We herein provide an updated review of the pathogenicity determinants and distribution of V. parahaemolyticus to deliver a better understanding of the significance of V. parahaemolyticus and its host-pathogen interactions.

Displacement of Pathogens by an Engineered Bacterium Is a Multifactorial Process That Depends on Attachment Competition and Interspecific Antagonism

Pathogen attachment to host cells is a key process during infection, and inhibition of pathogen adhesion is a promising approach to the prevention of infectious disease. We have previously shown that multivalent adhesion molecules (MAMs) are abundant in both pathogenic and commensal bacterial species, mediate early attachment to host cells, and can contribute to virulence. Here, we investigated the efficacy of an engineered bacterium expressing a commensal MAM on its surface in preventing pathogen attachment and pathogen-mediated cytotoxicity in a tissue culture infection model. We were able to dissect the individual contributions of adhesion and interspecific antagonism on the overall outcome of infection for a range of different pathogens by comparison with the results obtained with a fully synthetic adhesion inhibitor. We found that the potential of the engineered bacterium to outcompete the pathogen is not always solely dependent on its ability to hinder host attachment but, depending on the pathogenic species, may also include elements of interspecific antagonism, such as competition for nutrients and its ability to cause a loss of fitness due to production of antimicrobial factors.