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“Omics” Technologies in Vaccine Research
Published in Mesut Karahan, Synthetic Peptide Vaccine Models, 2021
Moriel et al. (2010) compared the genomes of pathogenic and non-pathogenic strains of extraintestinal pathogenic Escherichia coli (ExPEC) reporting 19 genomic islands and 230 antigens only found in the pathogenic strain. These proteins were produced recombinantly and used for the vaccination of mice. They found that nine proteins conferred protection against bacterial challenge in mice.
Gateways of Pathogenic Bacterial Entry into Host Cells—Salmonella
Published in K. Balamurugan, U. Prithika, Pocket Guide to Bacterial Infections, 2019
Balakrishnan Senthilkumar, Duraisamy Senbagam, Chidambaram Prahalathan, Kumarasamy Anbarasu
PagN, a 26 KDa outer membrane protein. has been identified as the important protein involved in Salmonella invasion mechanism (Lambert and Smith 2008). The gene, pagN, is located on the seventh centisome genomic island and is broadly scattered among Salmonella enterica serotypes (Folkesson et al. 1999). The pagN open reading frame was primarily identified during a TnphoA random-insertion screening in S. Typhimurium performed to discover PhoP-activated genes (Belden and Miller 1994). In general, PagN is similar to both the Tia and Hek invasions of E. coli and represents 39% and 42% similarity in amino acids with these two invasions, respectively. Tia and Hek are predicted to have eight transmembrane regions, four long exposed extracellular loops, and three short periplasmic turns (Mammarappallil and Elsinghorst 2000; Fagan et al. 2008). Thus, PagN probably adopts a similar conformation as that of Hek and Tia.
Vibrio
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Interestingly, genome comparison of V. parahaemolyticus pandemic strain RIMD 2210633 and a nonpandemic O3:K6 isolate AQ3810 indicates that genomic islands VPaI-1–VPaI-7 (in particular, VPaI-1 and VPaI-4–VPaI-6) are present in the pandemic strain but are absent or partially missing in the nonpandemic isolate. BLAST analysis suggests that V. parahaemolyticus VPaI-1 encodes a protein with homology to that of V. cholera; V. parahaemolyticus VPaI-3 is similar to a region in V. harveyi; and V. parahaemolyticus VPaI-5 and VPaI-6 resemble ORFs in Shewanella spp. These data provide evidence for the likely acquisition of genomic islands by nonpandemic O3:K6 clone through horizontal gene transfer (HGT) in its evolution to become a pandemic strain [9,10].
The ancestral stringent response potentiator, DksA has been adapted throughout Salmonella evolution to orchestrate the expression of metabolic, motility, and virulence pathways
Published in Gut Microbes, 2022
Helit Cohen, Boaz Adani, Emiliano Cohen, Bar Piscon, Shalhevet Azriel, Prerak Desai, Heike Bähre, Michael McClelland, Galia Rahav, Ohad Gal-Mor
Salmonella speciation and the development of its pathogenicity have been fundamentally shaped by the horizontal acquisition of discrete genomic islands that encode new virulence capabilities including host cell invasion and intracellular pathogenesis.3,9 Many of the pan-Salmonella virulence genes are clustered within 23 horizontally acquired accessory genetic elements, known as Salmonella pathogenicity islands (SPIs).10 SPIs, like pathogenicity islands in other bacterial pathogens, are often located adjacent to tRNA genes and have been characterized as a “molecular toolbox” for bacterial virulence.11 The key acquisition of the Salmonella pathogenicity island 1 (SPI-1) prior to the divergence of S. bongori and S. enterica confers invasion ability into non-phagocytic host cells, via a type three secretion system (T3SS) and an associated array of secreted effectors encoded within and outside of SPI-1.12,13S. enterica speciation was marked by the acquisition of SPI-2 that encodes a second T3SS, required for survival in professional phagocytes and long-term persistence in the host.14,15 Throughout S. enterica evolution, additional horizontally acquired SPIs have further shaped Salmonella virulence and host-specificity.
Lactic acid bacteria and bifidobacteria deliberately introduced into the agro-food chain do not significantly increase the antimicrobial resistance gene pool
Published in Gut Microbes, 2022
Vita Rozman, Petra Mohar Lorbeg, Primož Treven, Tomaž Accetto, Majda Golob, Irena Zdovc, Bojana Bogovič Matijašić
Systematic screening for MGEs in the genetic environment of predicted ARGs (15 coding sequences (CDSs) upstream and downstream) was conducted with BLAST (parameters -evalue 1e-10, -max_target_seqs 10, query coverage ≥ 80%, similarity cutoff ≥ 80%) and a custom MGEs database.9 Genomic islands (chromosomal regions acquired by horizontal gene transfer) and their insertion sites were traced using multiple genome alignments generated by progressiveMauve.69 Additional BLAST alignments were performed to eliminate the redundancy and to uncover known MGEs published in the literature as well as putative novel elements whose labels were assigned in-house. Protein domain analysis was performed using hmmsearch (–noali -E 1e-10)70 and the Pfam database 33.1.
Antimicrobial resistance in enteric bacteria: current state and next-generation solutions
Published in Gut Microbes, 2020
M. J. Wallace, S. R. S. Fishbein, G. Dantas
Another enteropathogenic species within the Enterobacteriaceae family is Salmonella enterica. The serovars of S. enterica are divided into typhoidal and non-typhoidal Salmonella (NTS), and encompass a group of bacteria that occupy digestive tracts of both animals and humans (Figure 1a).59 Although borne from the same species, the clinical manifestations and the associated immune responses are distinct among serovars. The GI distress associated with typhoid fever is due to the typhoid toxin and the damage it inflicts upon the GI epithelium. Typhoid fever is almost always treated with antibiotics.25,59 This disease is more common to developing countries, while NTS is common to both developed and developing countries. NTS infections present with gastroenteritis and diarrhea.59 NTS is usually self-limiting, and antibiotics are typically avoided since they may induce prolonged shedding of infectious NTS after treatment.59 Inappropriate antibiotic use is a key driver of AMR in Salmonella, and resistant infections often worsen clinical outcomes.1,25,60Salmonella is notorious for its genomic islands, including Salmonella genomic island 1 (SGI1) carrying the ACSSuT region, encoding MDR (Table 1).26 More recently, some NTS serovars have evolved a novel genomic island encoding streptomycin and azithromycin resistance, which is concerning given that azithromycin is a second-line agent.61 Since Salmonella continues to be a major source of enteric infection, it will likely continue to present severe human health burdens without serious interventions.