Metabolites, antibiotimicrobials, and gut microbiome

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Salmonella Bacteria, Source: NIAID

In this article published by the National Hog Farmer, nutritionists and microbiome analysts from the University of Minnesota discuss what consequences antimicrobials can have on the gut microbiome.

What does microbiome mean?

Microbiome refers to all of the microbes present in an area. For example, gut microbiome is the entire population of microorganisms (most of the time bacteria) present in the intestinal tract.

The purpose of this research program is to study the effects antimicrobials can have on the bacterial populations present in the gut and how those changes influence the metabolites present in the pig.

What is a metabolite?

Metabolites are usually small molecules and are created by enzymatic reactions happening through the natural life of a cell or organism.

One of the effects of administering tylosin to pigs was the increased growth of bacteria producing short-chain fatty acids in the intestinal flora. The use of this antimicrobial also led to the development of Lactobacillus in the gut.

Relating changes in metabolites to the gut microbiome allows for a more complete understanding and investigation of the impact that antibiotics have in enhancing growth. Without completely understanding the mechanism of increased growth, antibiotic alternatives could be used inappropriately without much added benefit.

Link to the full paper

What does antimicrobial-resistant bacteria really mean?

Antimicrobial resistance is an expression that everyone in swine production has heard at least once but what does it really mean?  How are you as a producer or veterinarian affected?

Villalta NHF antimicrobial resistance 2017.gif

In this column for the National Hog Farmer, Dr. Carles Vilalta explains that beyond the definition of a bacterium that is not affected by an antimicrobial, there are two different approaches to think about resistance:

  • One is determined by the Minimal Inhibitory Concentration or MIC, which records the minimum medicine concentration required to stop the growth of the bacteria.
  • The other focuses on the presence of genes enabling the bacterium to counteract the effect of the antimicrobial.

These genes are usually present in a sub-population of bacteria called mutants. The video below created by Harvard Medical School shows how these mutants can develop, adapt, and survive the highest antimicrobial concentrations. (video length < 2min)

 

 

Ionophore intoxication in swine

In this month column of the National Hog Farmer, Dr. Albert Rovira from the University of Minnesota is reviewing the cases of intoxication due to ionophores, these antibiotics given through the feed to control bacterial and coccidial infections in swine.Clinical signs are non-specific. Indeed, pigs become weak and stop eating but do not have a fever. In more severe cases, neurological signs can be noted. However, histological lesions are striking with a dramatic change of the muscle structure as is shown in Figure 1 below.

ionophore-intoxication

There are three main causes of ionophore intoxication in swine:

  1. Dosage error in the diet: the optimal concentration is very small, between 15 and 30 parts per milliom.
  2. Mixing ionophore and tiamulin: Tiamulin prevents the ionophore from being excreted by the body, leading to toxic blood levels.
  3. Inclusion of ionophores designed for another species. Usually, the levels are incorporated at a concentration higher than the toxic level.

In conclusion although cases of ionophore intoxication are rare in swine, it may become more prevalent starting in 2017, with the approval of the only swine ionophore as a growth promotant.

Link to the full article

New swine virus identified in the US: introducing porcine sapelovirus

This past month, a team of swine pathologists including Dr. Albert Rovira from the University of Minnesota identified, thanks to funds from Swine Health Information Center’s Support for Diagnostic Fees program, a new swine virus called porcine sapelovirus.

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Histological lesion associated with infection by porcine sapelovirus

This virus is thought to induce atypical neurological signs in pigs and has previously been described in Korea. Videos of the clinical presentation can be been here.

Research is still on-going to prove Koch’s postulate and declare causality between the presence of the virus and the clinical presentation but it is a step forward in the identification and understanding of swine pathogens.

Full description of the porcine sapelovirus cases

One flu, many colors – Drs. Culhane and Rovira in the National Hog Farmer

One flu, many colors: that is the title of the latest article published in the National Hog Farmer by two faculty members from the University of Minnesota, Drs. Culhane and Rovira. If it is common to talk about one influenza especially in the One Health initiative which reminds us that human and animal health are intricately related, the authors also emphasize that there are “many variants of influenza A viruses [which] paint a complicated picture, sometimes with colors too numerous to grasp with quick glances.”

062716 Uof Mflu Figure3

Because influenza is common to swine, poultry, and human, there are many differences among the strains, enhanced by the variations found between and within geographic locations. This is why our experts recommend to characterize the virus, and go one step further than the one test common to all influenza A.

As they put it themselves, “Influenza A viruses are fascinating, challenging and dynamic” and it is important to determine their colors.

Link to the full article