Dear Colleagues,

This Special Issue is the continuation of our previous Special Issue: "Gram Positive Toxins Producing Organisms".

Many bacteria produce toxins that are essential in the medical field. Vaccines have been developed for some toxin-mediated diseases (e.g., tetanus, diphtheria) and continue to play a significant role in the prevention of disease. Over the past few decades, great strides have been made in our understanding of the structure and function of bacterial toxins and their role in diseases. These advances reflect the productive interactions of disciplines, such as protein chemistry and crystallography, molecular genetics, molecular biology, genomics, immunology, neurobiology, pharmacology, and biophysics. Remarkable progress has been made in the elucidation of the molecular mechanisms of a wide range of toxins with increasing numbers found to have enzymatic activities, including those that ADP-ribosylate (e.g., diphtheria toxin) and glycosylate novel targets, as well as Zn-proteinases with exquisite specificities (e.g., botulinum A neurotoxin and SNAP-25).    The host immune system is not only the primary defense against colonization and sometimes invasion by toxigenic bacteria, but it also constitutes a major target for bacterial toxins that can act either directly via cytotoxicity to immune effector cells, or indirectly via the deregulation of cytokine production.

Toxin genes and other virulence determinants are frequently encoded by mobile genetic elements, which are located on pathogenicity islands and/or on mobilizable genetic elements, such as plasmids, transposons, and bacteriophages. These genetic elements have the capacity to be spread by horizontal gene transfer, contributing to the rapid evolution of bacterial pathogens as the rearrangement, excision and acquisition of large genomic regions creates new pathogenic variants. The occurrence of toxin-encoding genes on various interdepending genetic elements, their ability to delete from and integrate into chromosomal DNA and the existence of toxin families among a wide variety of bacterial species demonstrate that toxigenic pathogen evolution is connected to the transfer of foreign DNA harboring toxin determinants.

The aim of this Special Issue is to provide a collection of articles that highlights research on bacterial toxins. The editors chose to focus this Special Issue on Gram-positive bacterial toxins. We welcome submissions reflecting all aspects of toxin research from applied (novel diagnostics, countermeasures, vaccines) to more basic research areas related to the biology of the toxin, genomics, and pathogenesis.  Gram-positive toxins include, but are not limited to, tetanus toxin, botulinum toxins, staphylococcal toxins, diphtheria toxin, streptococcal toxins, Listeria toxin, anthrax toxins, Bacillus cereus toxins, pneumolysin, enterococcal toxins, and other clostridial toxins (e.g., perfringolysin O). Each of these toxins has a unique story to tell but needs a storyteller. We hope you will be able to contribute to this Special Issue on Gram-positive toxins. 

Dr. Shashi Sharma
Dr. Stephen A. Morse
Dr. Sabine Pellett
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Microorganisms is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.