Salmonella has resistance to different types of antibiotics

Salmonella has resistance to different types of antibiotics https://i0.wp.com/www.eresviral.com/wp-content/uploads/2018/11/La-salmonela-posee-resistencia-a-diferentes-tipos-de-antibióticos.jpg?fit=174%2C146&ssl=1

Salmonella has resistance to different types of antibiotics







Between 2000 and 2015, the Ministry of Health of Brazil registered 11,524 outbreaks of foodborne diseases throughout the country: there were 219,909 patients and 167 deaths. The main causal agent of the outbreaks of alimentary infections, diarrhea and gastroenteritis is the bacteria, and the most frequent are those of the genus Salmonella, with 31.7 thousand cases diagnosed (14.4% of the total), followed by Staphylococcus aureus. (7.4%) and Escherichia coli (6.1%).



Another study, carried out by the Ministry of Social Development of Brazil, indicates that 42.5% of the food outbreaks confirmed in the laboratory in the country between 1999 and 2009 had bacteria of the genus Salmonella as etiological agents.



The genomic research of the main bacteria involved in acute diarrheal diseases is the subject of research by a group of scientists from the University of São Paulo headed by Juliana Pfrimer Falcão, a professor at the Faculty of Pharmaceutical Sciences of Ribeirão Preto - FCFRP (in State of São Paulo, Brazil).



In a paper published in the journal PLOS ONE, the biomedical Amanda Aparecida Seribelli and Fernanda Almeida, from the Pfrimer Falcão group, sequenced and studied the genome of 90 samples (or strains) of a specific serovar of Salmonella enterica called Salmonella Typhimurium. (the abbreviation of Salmonella enterica subspecies 1 serotype Typhimurium).







Electron microscope image of 'Salmonella typhimurium' infecting human cells. (Photo: DICYT)



The 90 samples were isolated between 1983 and 2013 at the Adolfo Lutz Institute in Ribeirão Preto and at the Oswaldo Cruz Foundation (Fiocruz) in Rio de Janeiro. And they provide a portrait of the epidemiology of salmonellosis in Brazil over the past 30 years, since they come from all regions of the country. They were taken from patients affected by food infections, or were taken in contaminated food such as meat from poultry and swine, including sausages, or vegetables, lettuce and others.



"Regarding humans, we received blood samples, brain abscesses and diarrheal fecal matter," Seribelli said.



When testing the action of antibiotics in each of the 90 strains, it was discovered that the vast majority of them were resistant to different types of antibiotics that are part of the arsenal of medicine. The study also resulted in the identification of 39 genes responsible for antibiotic resistance.



Fiocruz researchers from the Faculty of Agricultural and Veterinary Sciences of the Universidade Estadual Paulista (Unesp) and the Adolfo Lutz Institute are participating in this work. The sequencing of the 90 strains of Salmonella Typhimurium was carried out under the auspices of the Food and Drug Administration (FDA), the US federal agency in charge of quality control of food and medicines in that country, during Fernanda Almeida's sandwich doctorate .



The comparative analysis of the genome, the transcriptome and the phenotypic characterization of lineages of Salmonella Typhimurium isolated in humans and in food in Brazil was supported by the Support Foundation for Scientific Research of the State of São Paulo - FAPESP, of the FDA and of the Coordination of Improvement of Higher Level Personnel - Capes, of Brazil.



Salmonella is a highly heterogeneous genus, composed of two species: Salmonella bongori and Salmonella enterica. The latter is the main responsible for cases of food infection in Brazil and in the world. The intestinal tract of men and animals is the main natural reservoir of this pathogen, and foods of avian and porcine origin are important transmission routes.



There are six subspecies of the bacterium Salmonella enterica, which in turn are subdivided into another 2.6 thousand serovars. The serovarieties are variants within the same species, which is the characterization of a microorganism according to the identification of its antigens.



Among the subspecies of Salmonella enterica, the most important from the epidemiological point of view is S. enterica subspecies enterica, which causes a food infection called salmonellosis. The symptoms are diarrhea, fever, abdominal cramps and vomiting.



S. enterica subspecies enterica is the main responsible for the 31.7 thousand cases of salmonellosis recorded in Brazil between 2000 and 2015. Among its various serovars, those that have been isolated most frequently are S. Typhimurium and S. Enteritidis.



S. Enteritidis is one of the main serovars that cause salmonellosis and spread from a pandemic that began in Europe in the 1990s. Meanwhile, S. Typhimurium was the serovar that prevailed before that pandemic, but not because of This stopped causing infections.



Almeida says that the total of the 90 samples analyzed in the framework of this study belong to the bacteria of the S. Typhimurium serovar. In the same laboratory of Clinical, Toxicological and Bromatological Analysis of the FCFRP, another researcher is currently carrying out the sequencing and analysis of samples of the S. Enteritidis serovar.



In relation to the S. Typhimurium serovar, Almeida was allowed to bring the 90 samples to the United States in 2015. "There, at the Food Safety and Applied Nutrition Center of the FDA, in Maryland, their genome was sequenced under the supervision of the researcher Marc W. Allard, "he said.



The genome of S. Typhimurium possesses 4.7 million base pairs. When doing the accounts, it can be perceived that this work generated a mountain of data. More specifically, they are 423 million bases corresponding to the sum of the 90 genomes.



Back in Ribeirão Preto, Almeida shared with Seribelli the task of shredding and comparing the genomes of the different strains in order to understand their diversity and the existing evolutionary relationship between them.



Almeida reports that the technique used was genotyping with SNPs (pronounced "snips", the acronym in English of "single nucleotide polymorphisms"). It is a process aimed at identifying the genetic composition (genotype) of each strain by examining its DNA sequence. SNPs are one of the most common types of genetic variation markers. The phylogenetic results separated the 90 strains of S. Typhimurium into two large groups: A and B.



"The group of samples collected in food differs from the group of samples taken from human patients. Dietary isolates were distributed in groups A and B in relatively similar numbers, suggesting that there is more than one subtype in circulation in Brazil. The isolates of humans were more prevalent in group B, which suggests the existence of a subtype probably more adapted between strains isolated in humans in the country, "said Seribelli.



Another important part of the research aimed to verify the degree of resistance to antibiotics of each of the 90 strains. According to this work, 65 (72.2%) of the 90 strains of S. Typhimurium were resistant to antibiotics of the sulfonamide class, 44 (48.9%) strains were resistant to streptomycin, 27 ( 30%) to tetracycline, 21 (23.3%) to gentamicin and seven (7.8%) were resistant to cephalosporins.



In the work with SNPs, a total of 39 genes of resistance to different types of antibiotics were identified, such as aminoglycosides, tetracyclines, sulfonamides, trimethoprim, beta-lactams, fluoroquinolones, phenicol and macrolides. The existence of point mutations in some of the genes was also confirmed, as in gyrA, gyrB, parC and parE.



"Draws attention to resistance of S. Typhimurium to antibiotics that can be applied in the treatment of the disease. They are drugs that are available to doctors to combat infections that are resistant. And they constitute the second line of defense, when microorganisms do not die due to the action of the patient's immune system, since normally salmonellosis is a self-limited disease and does not require the use of antibiotics. The biggest problem arises when this fails and the bacterium becomes invasive, "Seribelli said.



Another point that caught the attention of the scientists resided in the different degrees of resistance of the strains when they were distributed throughout the 30 years of collections.



"The samples of S. Typhimurium taken in the mid-1990s showed greater resistance to antibiotics than those that circulated among the population at the end of that period. The possible explanation for this lies in the emergence at the beginning of the 1990s of the S. Enteritidis serovar, which since then became one of the main agents in cases of salmonellosis, "said Seribelli.



Serovar S. Enteritidis is known since the 1950s, but it was responsible for a smaller number of cases in the overall epidemiology of Salmonella. This changed radically from the aforementioned S. Enteritidis pandemic in Europe, in the turn of the 1980s to the 1990s, when it spread around the world.



"Since then, S. Enteritidis is one of the most prevalent serovarieties in Brazil and in the world. Therefore, it is a serovar that can also be combated by the application of antibiotics, if necessary, "said Seribelli.



Almeida explains that S. Typhimurium are still one of the main isolated serovars of humans, animals and food in Brazil and in the world.



Since the pandemic of S. Enteritidis in the mid-1990s, the number of resistant strains apparently decreased with respect to strains before the 1990s, but it is not known whether the virulence of these strains increased so that they adapted to this strain. new niche



"The main result of this work was to discover the large amount of antimicrobial resistance genes found in the samples, considering that they are isolated samples in humans and in food. It can be seen that there is currently a very high risk of contamination in Brazil from foods with Salmonella strains that are resistant to antimicrobials, "said Almeida. (Source: AGENCIA FAPESP / DICYT)

        .

  !function(f,b,e,v,n,t,s)

  {if(f.fbq)return;n=f.fbq=function(){n.callMethod?

  n.callMethod.apply(n,arguments):n.queue.push(arguments)};

  if(!f._fbq)f._fbq=n;n.push=n;n.loaded=!0;n.version='2.0';

  n.queue=[];t=b.createElement(e);t.async=!0;

  t.src=v;s=b.getElementsByTagName(e)[0];

  s.parentNode.insertBefore(t,s)}(window, document,'script',

  'https://connect.facebook.net/en_US/fbevents.js');

  fbq('init', '369524843414444');

  fbq('track', 'PageView');

    .


SOURCE LINK ERESVIRAL.COM 
https://www.beviral.online