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Hi all

Zoonotica here posting this on Phil (@wragbags)’s behalf:

“I have had a few papers on my radar for my contribution the #microtwjc. In the end a paper that has changed my perspective on a number of things won. These include the impact MultiLocus Sequencing can have on diagnostics and the suggested costs of such tests. At our next meeting on July 30th we are going to discuss and dissect ‘Multilocus Sequence Typing as a Replacement for Serotyping in Salmonella enterica

Here is the Authors’ summary

Microbiologists have used serological and nutritional characteristics to subdivide pathogenic bacteria for nearly 100 years. These subdivisions in Salmonella enterica are called serovars, some of which are thought to be associated with particular diseases and epidemiology. We used MultiLocus Sequence-based Typing (MLST) to identify clusters of S. enterica isolates that are related by evolutionary descent. Some clusters correspond to serovars on a one to one basis. But many clusters include multiple serovars, which is of public health significance, and most serovars span multiple, unrelated clusters. Despite its broad usage, serological typing of S. enterica has resulted in confusing systematics, with a few exceptions. We recommend that serotyping for strain discrimination of S. enterica be replaced by a DNA-based method, such as MLST. Serotyping and other non-sequence based typing methods are routinely used for detecting outbreaks and to support public health responses. Moving away from these methods will require a major shift in thinking by public health microbiology laboratories as well as national and international agencies. However, a transition to the routine use of MLST, supplemented where appropriate by even more discriminatory sequence-based typing methods based on entire genomes, will provide a clearer picture of long-term transmission routes of Salmonella, facilitate data transfer and support global control measures.

Discussion Points

* Can this really replace traditional methods and when will that happen on the scale proposed?

* Where do you see this style of project going next?

* Was the presentation of such a complex subject done in an understandable manner?

* Experimentally would you have added anything to this story?”

We look forward to seeing/tweeting you all on Tues 31st July 🙂


This week the paper we will be discussing is:

The authors examined the effect of probiotics and antibiotics on intestinal homeostasis using a  a computer controlled model of the human large intestine. Antibiotic associated diarrhea (AAD) and Clostridium difficile infection (CDI) are complications in broad spectrum antibiotic therapy, probiotics have been suggested to be promising agents in the prevent of AAD and CDI. The authors suggest that mechanistic studies in vivo are difficult to perform due to sampling and ethical difficulties and the model simulates the colon to a high degree. The model is a unique tool as its able to study the stability, release, dissolution, absorption of nutrients, chemicals, bioactive compounds and pharmaceuticals in the gastrointestinal tract. They found that short chain fatty acids, ammonia, branched chain fatty acids and lactate were increased when using probiotic therapy compared to the controls and combination therapy (Clindamycin and probiotics).  Probiotics following antibiotic therpay did not help to recover the intestinal microbiota lost during the therapy. The main finding is that the simultaneous application of antibiotics and probiotics stablises the intestinal microbiota.  The authors conclude that probiotics could be a resonable strategy to prevent antibiotic associated disturbances of the gastrointestinal tract.

Discussion points

* How do you feel about the application of an in vitro model to study this?

* What  other experiments could be performed ?

* Do you think probiotics are useful in this application?

* What other data would be needed to convince you that probiotics work?

* Should we be using the probiotic mixture they described? What could the long term consequences be?

As ever please feel free to leave any other discussion points below.

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