Hello Microtwjc community!

This week we are going to have a discussion on a recent article I have published with Laura Bowater (@Lauramcbow) and Paul Hoskisson (@PaulHoskisson) on engaging students on STEM degrees with the Antimicrobial Resistance issue. Yes this is not something we have discussed before as we have generally focussed on research papers. However, all of us at some point do interact with students at all levels. We are also interested to see what you all have to say on this subject….

You can find the paper here:

Inspiring STEM undergraduates to tackle the AMR crisis.

Things to discuss:

  1. Can you think of other ways to engage students on this topic?
  2. Do you have specific examples that would also work as case examples?
  3. Can we improve our engagement of under and post-graduates on topical issues within the learning environment?

See you all on twitter at 8 PM Tomorrow night!


Hello alls,

In under a week we will be running session #2 of #microtwjc for the 2015 academic year. The paper I (@id_EATER) chose with input from @defectivebrayne is titled:

A 1,000-Year-Old Antimicrobial Remedy with Antistaphylococcal Activity

It’s a pretty straight forward paper which details the preparation of an ancient antimicrobial recipe and some studies on it’s antimicrobial efficacy. Some of the authors are on twitter (@friendlymicrobe, @sbi5ar and @stevediggle) which means we may have the opportunity to ask them questions directly.

Please keep the following discussion points/questions in mind when reading the paper and feel free to tweet to @microtwjc or comment below with any points/questions you might have during reading as well as any question you might have for the authors directly.

  1. How does the introduction support the research and (in addition to the discussion) help contextualize the findings in the field?
  2. What are the advantages and limitations of the experimental models chosen to study the antimicrobial effect of Bald’s eyesalve?
  3. Are the conclusions supported by the data (methods and results) in the paper?
  4. What have we learnt after reading the paper?
  5. Given what we have learnt, what future work would be of interest to conduct?

Here’s the abstract and hope to see you online!

Plant-derived compounds and other natural substances are a rich potential source of compounds that kill or attenuate pathogens that are resistant to current antibiotics. Medieval societies used a range of these natural substances to treat conditions clearly recognizable to the modern eye as microbial infections, and there has been much debate over the likely efficacy of these treatments. Our interdisciplinary team, comprising researchers from both sciences and humanities, identified and reconstructed a potential remedy for Staphylococcus aureus infection from a 10th century Anglo-Saxon leechbook. The remedy repeatedly killed established S. aureus biofilms in an in vitro model of soft tissue infection and killed methicillin-resistant S. aureus (MRSA) in a mouse chronic wound model. While the remedy contained several ingredients that are individually known to have some antibacterial activity, full efficacy required the combined action of several ingredients, highlighting the scholarship of premodern doctors and the potential of ancient texts as a source of new antimicrobial agents.

Hello everybody!

And welcome back to #microTwJC! We took some time off to re-organise our admins, but now we’re back and ready to discuss the latest in microbiology research. I will be tweeting from @Microtwjc, and you can follow the conversation using #microTwJC. All are welcome to join in, at 8pm BST on Tuesday 8th September.

This weeks paper was picked by new admin Frances @Mrs_FrancesJ and is being presented by myself – Stewart @stewart_barker, entitled “Distinct soil microbial diversity under long-term organic and conventional farming”. The paper can be accessed for free here!: http://www.nature.com/ismej/journal/v9/n5/full/ismej2014210a.html.


Low-input agricultural systems aim at reducing the use of synthetic fertilizers and pesticides in order to improve sustainable production and ecosystem health. Despite the integral role of the soil microbiome in agricultural production, we still have a limited understanding of the complex response of microbial diversity to organic and conventional farming. Here we report on the structural response of the soil microbiome to more than two decades of different agricultural management in a long-term field experiment using a high-throughput pyrosequencing approach of bacterial and fungal ribosomal markers. Organic farming increased richness, decreased evenness, reduced dispersion and shifted the structure of the soil microbiota when compared with conventionally managed soils under exclusively mineral fertilization. This effect was largely attributed to the use and quality of organic fertilizers, as differences became smaller when conventionally managed soils under an integrated fertilization scheme were examined. The impact of the plant protection regime, characterized by moderate and targeted application of pesticides, was of subordinate importance. Systems not receiving manure harboured a dispersed and functionally versatile community characterized by presumably oligotrophic organisms adapted to nutrient-limited environments. Systems receiving organic fertilizer were characterized by specific microbial guilds known to be involved in degradation of complex organic compounds such as manure and compost. The throughput and resolution of the sequencing approach permitted to detect specific structural shifts at the level of individual microbial taxa that harbours a novel potential for managing the soil environment by means of promoting beneficial and suppressing detrimental organisms.


1. Is this paper well written and easy to understand?

2. Does the introduction set the scene for the research presented?

3. Do the methods appear reliable and are they well explained?

4. Do the results and discussion make sense?

5. What (if any) future work could lead on from this?

Hope to see you at 8 pm BST, Tuesday 8th September! Use #microTwJC to follow the conversation.


Stewart and Frances

We will be back in September with a whole new modding team. Stay tuned, don’t panic, and stay science-y. More Microbiology is on the way. Mark down September 8th in your calendars.

Hi all

Sorry for the brief hiatus but hopefully we are back up and running and on Tues we will be looking at this paper

Ståhl A-l, Arvidsson I, Johansson KE, Chromek M, Rebetz J, et al. (2015) A Novel Mechanism of Bacterial Toxin Transfer within Host Blood Cell-Derived Microvesicles. PLoS Pathog 11(2): e1004619. doi: 10.1371/journal.ppat.1004619


Shiga toxin (Stx) is the main virulence factor of enterohemorrhagic Escherichia coli, which are non-invasive strains that can lead to hemolytic uremic syndrome (HUS), associated with renal failure and death. Although bacteremia does not occur, bacterial virulence factors gain access to the circulation and are thereafter presumed to cause target organ damage. Stx was previously shown to circulate bound to blood cells but the mechanism by which it would potentially transfer to target organ cells has not been elucidated. Here we show that blood cell-derived microvesicles, shed during HUS, contain Stx and are found within patient renal cortical cells. The finding was reproduced in mice infected with Stx-producing Escherichia coliexhibiting Stx-containing blood cell-derived microvesicles in the circulation that reached the kidney where they were transferred into glomerular and peritubular capillary endothelial cells and further through their basement membranes followed by podocytes and tubular epithelial cells, respectively. In vitro studies demonstrated that blood cell-derived microvesicles containing Stx undergo endocytosis in glomerular endothelial cells leading to cell death secondary to inhibited protein synthesis. This study demonstrates a novel virulence mechanism whereby bacterial toxin is transferred within host blood cell-derived microvesicles in which it may evade the host immune system.

Author Summary

Shiga toxin-producing enterohemorrhagic Escherichia coli are non-invasive bacteria that, after ingestion, cause disease by systemic release of toxins and other virulence factors. These infections cause high morbidity, including hemolytic uremic syndrome with severe anemia, low platelet counts, renal failure, and mortality. The most common clinical isolate is E. coli O157:H7. In 2011 an E. coli O104:H4 strain caused a large outbreak in Europe with high mortality. After Shiga toxin damages intestinal cells it comes in contact with blood cells and thus gains access to the circulation. In this study we have shown that the toxin is released into circulating host blood cell-derived microvesicles, in which it retains its toxicity but evades the host immune response. Our results suggest that these microvesicles can enter target organ cells in the kidney and transfer toxin into these cells as well as between cells. Such a mechanism of virulence has not been previously described in bacterial infection.

Discussion Points

  1. Is the paper well/clearly written?
  2. Were the experiments appropriate?  Were there any extras you would like to see in the paper?  Were any stats used appropriate?
  3. What impact will the results have on a wider field?  Where else might you look for this mechanism?
  4. Any other further experiments you would like to do?
  5. Any other comments?

Hope to see you there…


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