Scientists track evolution of pathogens across the skin's surface

 

A new analysis reveals how Staphylococcus aureus gains mutations that allow it to colonize eczema patches. The findings provide direct evidence of adaptive evolution in the skin microbiome.

 

Scientists from Massachusetts Institute of Technology have discovered that Staphylococcus aureus can rapidly evolve within a single person's microbiome. With people with eczema, S. aureus tends to evolve to a variant with a mutation in a specific gene that helps it grow faster on the skin.

 

While human skin is home to millions of microbes, S. aureus is found on many people as an opportunistic pathogen that can invade patches of skin affected by eczema (atopic dermatitis).

 

It is estimated that between 30 and 60 percent of people carry S. aureus in their nostrils. Here it is usually harmless. However, for people with eczema, S. aureus often spreads to eczema patches and infects the skin by finding a niche where the bacterium can grow and replicate.

 

Upon infection, S. aureus evolves to a variant with a mutation in a specific gene that helps it grow faster on the skin. Such bacteria contribute to the pathology because they secrete toxins and recruit immune cells, and this immune reaction further damages the skin barrier.

 

Data was gathered from samples taken of patients aged 5 to 15 who were being treated for moderate to severe eczema, across nine months. Samples were taken from the backs of the knees and inside of the elbows (the most common sites affected by eczema), the forearms, which are usually not affected, and the nostrils.

 

The researchers sequenced the cells' genomes. This yielded nearly 1,500 unique colonies, enabling observations about the bacterial cells' evolution to be made. This showed that most patients maintained a single lineage of S. aureus (hence it was very uncommon for a new strain to come in from the environment or another person and replace the existing S. aureus strain). Yet within each lineage, mutation and evolution occurred during the nine months of the study.

 

Many of these mutations arose in a gene called capD, which encodes an enzyme necessary for synthesizing the capsular polysaccharide -- a coating that protects S. aureus from recognition by immune cells. In two out of six deeply sampled patients, cells with capD mutations took over the entire S. aureus skin microbiome population.

 

Mutations to capD allowed S. aureus to grow faster than S. aureus strains with a normal capD gene. This is because synthesizing the capsular polysaccharide requires a lot of energy, so when cells do not have to make it, they have more fuel to power their own growth. It is also hypothesized that loss of the capsule may allow the bacteria to stick to the skin better because proteins that allow them to adhere to the skin are more exposed.

 

The researchers later analyzed nearly 300 publicly available genomes of bacteria isolated from people with and without eczema and found that people with eczema were much more likely to have S. aureus variants that could not produce the capsular polysaccharide than people without eczema.

The findings could help researchers develop potential treatments that would soothe the symptoms of eczema by targeting variants of S. aureus that have this type of mutation.

 

Reference:

 

Felix M. Key, Veda D. Khadka, Carolina Romo-González, et al. On-person adaptive evolution of Staphylococcus aureus during treatment for atopic dermatitis. Cell Host & Microbe, 2023; 31 (4): 593 DOI: 10.1016/j.chom.2023.03.009 

 

Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)

Tips for Sourcing Supplies for Your Medical Lab

 

As the owner of a medical laboratory, you know that sourcing supplies is an essential part of running your business. Finding the right suppliers can be a daunting task; it’s important to find reputable companies that offer reliable products and services. In this article, we will provide some tips and advice on how to source supplies for your medical lab.

Do Your Research

Before selecting a supplier, it’s important to do your research. Make sure you understand the company’s reputation and track record for delivering quality products in a timely manner. Read customer reviews and ask other laboratory owners for their feedback and recommendations. Additionally, take a look at the supplier’s website and social media accounts to get an idea of their level of engagement with customers.

 

By Emma Sturgis 

Know What You Need

 

It’s also important to have a clear understanding of what type of supplies you need before contacting potential suppliers. Take the time to compile a list of all the supplies you require, including any specific materials or components that may be necessary for your lab operations. This will make it easier when comparing different suppliers as you will be able to quickly assess which ones are capable of meeting your needs. For example, if you need medical kits laboratory kitting services will be the best option for you.

Negotiate Prices

 

Once you have identified several potential suppliers, you should contact them directly for price quotes. This is where negotiating skills come in handy—try to get the best possible deal by discussing payment terms, delivery arrangements, and discounts available for bulk orders. It’s also worth asking if they offer any special deals or incentives; many suppliers are willing to work with customers who demonstrate loyalty over time by offering discounts on future orders or free shipping options.

 

With these tips in mind, sourcing supplies for your medical lab should be much easier. Do your research on potential suppliers, know exactly what type of products you need, and don’t forget to negotiate prices whenever possible. These simple steps will help ensure that you find reliable vendors at competitive rates while avoiding any unpleasant surprises down the line.

 

Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)

Cultivating microbial communities in a permanently stable manner

 

The capabilities of complex microbial communities are used for numerous biotechnological processes. This requires special compositions of the microbial communities. However, these are often unstable and susceptible to disruption.

 

Scientists from Helmholtz Centre for Environmental Research have developed a so-called 'mass transfer method with a loop' that can stabilize microbial communities in the long term.

 

A minor random event can give rise to a completely different microbial community. This can happen rather quickly when microorganisms grow exponentially. In addition, there is constant flow or mass transfer in bioreactors, which can be disastrous for some microorganisms.

 

In microbial communities, there are also microorganisms that are present only in comparatively small numbers and which multiply slowly. For example, the methane-forming microorganisms used in biogas production. These organisms have slower growth rates and come into play only at later stages.

 

If the crucial microorganisms are inadvertently lost from the system, everything ultimately comes to a standstill.

 

In order to prevent this, a research team has proposed a new method called "mass transfer with a loop". This would be the type of loop is built into the bioreactor system in order to stabilise the microbial community and prevent microbial groups from being lost from the system altogether.

 

The researchers created five bioreactors, each with identical microbial communities. They then investigated whether and to what extent the composition of these communities changed over time. To do this, they used high-throughput flow cytometry to quickly examine single cells and characterise them in detail.

 

Various parameters of the bacteria such as cell size, cell density, and DNA content can be determined. A sample with 200,000 bacterial cells can thus be displayed as precisely as a fingerprint within just a few minutes.

 

Using special computer methods, the research team analysed the huge amounts of data generated and was thus able to detect changes in the microbial composition. It was found that the microbial communities in the five bioreactors developed quite differently despite the identical conditions.

 

The researchers then introduced a loop into the system. This sixth bioreactor was connected to each of the five reactors via inflow and outflow. As a result, a constant exchange or mass transfer took place between the bioreactors

 

This showed that the microbial communities in the bioreactors were synchronised with each other by the loop and that their composition and functions were permanently stabilised. In addition, the survival probability of micro-organisms with a low growth rate was considerably increased. This rescue effect can be crucial for many biotechnological processes.

 

The microbiologists were able to show for the first time that the principle of mass transfer with a loop can stabilise microbial communities in the long term.

 

See:  Shuang Li, Nafi'u Abdulkadir, Florian Schattenberg, Ulisses Nunes da Rocha, Volker Grimm, Susann Müller, Zishu Liu. Stabilizing microbial communities by looped mass transfer. Proceedings of the National Academy of Sciences, 2022; 119 (17) DOI: 10.1073/pnas.2117814119
 

 Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)