Publications by authors named "Anamaria M P Dos Santos"

3 Publications

  • Page 1 of 1

Virulence genes identification and characterization revealed the presence of the Yersinia High Pathogenicity Island (HPI) in Salmonella from Brazil.

Gene 2021 Jun 20;787:145646. Epub 2021 Apr 20.

Molecular & Analytical Laboratory Center, Faculty of Veterinary, Department of Food Technology, Universidade Federal Fluminense, Niterói, Brazil; Chemistry Institute, Food Science Program, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; Center for Food Analysis (NAL-LADETEC), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; National Institute of Health Quality Control, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.

Salmonella spp. is one of the major agents of foodborne disease worldwide, and its virulence genes are responsible for the main pathogenic mechanisms of this micro-organism. The whole-genome sequencing (WGS) of pathogens has become a lower-cost and more accessible genotyping tool providing many gene analysis possibilities. This study provided an in silico investigation of 129 virulence genes, including plasmidial and bacteriophage genes from Brazilian strains' public Salmonella genomes. The frequency analysis of the four most sequenced serovars and a temporal analysis over the past four decades was also performed. The NCBI sequence reads archive (SRA) database comprised 1077 Salmonella public whole-genome sequences of strains isolated in Brazil between 1968 and 2018. Among the 1077 genomes, 775 passed in Salmonella in silico Typing (SISTR) quality control, which also identified 41 different serovars in which the four most prevalent were S. Enteritidis, S. Typhimurium, S. Dublin, and S. Heidelberg. Among these, S. Heidelberg presented the most distinct virulence profile, besides presenting Yersinia High Pathogenicity Island (HPI), rare and first reported in Salmonella from Brazil. The genes mgtC, csgC, ssaI and ssaS were the most prevalent within the 775 genomes with more than 99% prevalence. On the other hand, the less frequent genes were astA, iucBCD, tptC and shdA, with less than 1% frequency. All of the plasmids and bacteriophages virulence genes presented a decreasing trend between the 2000 s and 2010 s decades, except for the phage gene grvA, which increased in this period. This study provides insights into Salmonella virulence genes distribution in Brazil using freely available bioinformatics tools. This approach could guide in vivo and in vitro studies besides being an interesting method for the investigation and surveillance of Salmonella virulence. Moreover, here we propose the genes mgtC, csgC, ssaI and ssaS as additional targets for PCR identification of Salmonella in Brazil due to their very high frequency in the studied genomes.
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http://dx.doi.org/10.1016/j.gene.2021.145646DOI Listing
June 2021

Type three secretion system in Salmonella Typhimurium: the key to infection.

Genes Genomics 2020 05 28;42(5):495-506. Epub 2020 Feb 28.

Molecular and Analytical Laboratory Center, Faculty of Veterinary, Department of Food Technology, Universidade Federal Fluminense, Niterói, Brazil.

Background: Type Three Secretion Systems (T3SS) are nanomachine complexes, which display the ability to inject effector proteins directly into host cells. This skill allows for gram-negative bacteria to modulate several host cell responses, such as cytoskeleton rearrangement, signal transduction, and cytokine production, which in turn increase the pathogenicity of these bacteria. The Salmonella enterica subsp. enterica serovar Typhimurium (ST) T3SS has been the most characterized so far. Among gram-negative bacterium, ST is one of enterica groups predicted to have two T3SSs activated during different phases of infection.

Objective: To comprise current information about ST T3SS structure and function as well as an overview of its assembly and hierarchical regulation.

Methods: With a brief and straightforward reading, this review summarized aspects of both ST T3SS, such as its structure and function. That was possible due to the development of novel techniques, such as X-ray crystallography, cryoelectron microscopy, and nano-gold labelling, which also elucidated the mechanisms behind T3SS assembly and regulation, which was addressed in this review.

Conclusion: This paper provided fundamental overview of ST T3SS assembly and regulation, besides summarized the structure and function of this complex. Due to T3SS relevance in ST pathogenicity, this complex could become a potential target in therapeutic studies as this nanomachine modulates the infection process.
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http://dx.doi.org/10.1007/s13258-020-00918-8DOI Listing
May 2020

Virulence Factors in Salmonella Typhimurium: The Sagacity of a Bacterium.

Curr Microbiol 2019 Jun 21;76(6):762-773. Epub 2018 May 21.

Department of Food Technology, Faculty of Veterinary, Molecular & Analytical Laboratory Center, Universidade Federal Fluminense, Niterói, Brazil.

Currently, Salmonella enterica Typhimurium (ST) is responsible for most cases of food poisoning in several countries. It is characterized as a non-specific zoonotic bacterium that can infect both humans and animals and although most of the infections caused by this microorganism cause only a self-limiting gastroenteritis, some ST strains have been shown to be invasive, crossing the intestinal wall and reaching the systemic circulation. This unusual pathogenicity ability is closely related to ST virulence factors. This review aims to portray the main virulence factors in Salmonella Typhimurium, in order to better understand the strategies that this pathogen uses to reach the systemic circulation and increase its infectivity in humans and animals. Thus, the most studied Salmonella pathogenicity islands in Salmonella Typhimurium were detailed as to the functions of their encoded virulence factors. In addition, available knowledge on virulence plasmid was also compiled, as well as the chromosome regions involved in the virulence of this bacterium.
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http://dx.doi.org/10.1007/s00284-018-1510-4DOI Listing
June 2019