Listeriolysin S: A bacteriocin from epidemic Listeria monocytogenes strains that targets the gut microbiota

Listeria monocytogenes is a Gram-positive food-borne pathogen that in humans may traverse the intestinal, placental and blood/brain barriers, causing gastroenteritis, abortions and meningitis. Crossing of these barriers is dependent on the bacterial ability to enter host cells, and several L. monocytogenes surface and secreted virulence factors are known to facilitate entry and the intracellular lifecycle. The study of L. monocytogenes strains associated to human listeriosis epidemics has revealed the presence of novel virulence factors. One such factor is Listeriolysin S, a thiazole/oxazole modified microcin that displays bactericidal activity and modifies the host microbiota during infection. Our recent results therefore highlight the interaction of L. monocytogenes with gut microbes as a crucial step in epidemic listeriosis. In this article, we will discuss novel implications for this family of toxins in the pathogenesis of diverse medically relevant microorganisms

Listeriolysin S: A bacteriocin from epidemic Listeria monocytogenes strains that targets the gut microbiota.

Addendum to: Quereda JJ, Dussurget O, Nahori M-A, Ghozlane A, Volant S, Dillies M-A, Régnault B, Kennedy S, Mondot S, Villoing B, Cossart P, Pizarro-Cerdá J. Bacteriocin from epidemic Listeria strains alters the host intestinal microbiota to favor infection. Proc Nat Acad Sci USA 2016; 113:5706-11.International audienceListeria monocytogenes is a Gram-positive food-borne pathogen that in humans may traverse the intestinal, placental and blood/brain barriers, causing gastroenteritis, abortions and meningitis. Crossing of these barriers is dependent on the bacterial ability to enter host cells, and several L. monocytogenes surface and secreted virulence factors are known to facilitate entry and the intracellular lifecycle. The study of L. monocytogenes strains associated to human listeriosis epidemics has revealed the presence of novel virulence factors. One such factor is Listeriolysin S, a thiazole/oxazole modified microcin that displays bactericidal activity and modifies the host microbiota during infection. Our recent results therefore highlight the interaction of L. monocytogenes with gut microbes as a crucial step in epidemic listeriosis. In this article, we will discuss novel implications for this family of toxins in the pathogenesis of diverse medically relevant microorganisms

Efficacy and safety of two whole IgG polyvalent antivenoms, refined by caprylic acid fractionation with or without β-propiolactone, in the treatment of Bothrops asper bites in Colombia

The efficacy and safety of two whole IgG polyvalent antivenoms (A and B) were compared in a randomised, blinded clinical trial in 67 patients systemically envenomed by Bothrops asper in Colombia. Both antivenoms were fractionated by caprylic acid precipitation and had similar neutralising potencies, protein concentrations and aggregate contents. Antivenom B was additionally treated with β-propiolactone to lower its anticomplementary activity. Analysing all treatment regimens together, there were no significant differences between the two antivenoms (A = 34 patients; B = 33 patients) in the time taken to reverse venom-induced bleeding and coagulopathy, to restore physiological fibrinogen concentrations and to clear serum venom antigenaemia. Blood coagulability was restored within 6–24 h in 97% of patients, all of whom had normal coagulation and plasma fibrinogen levels 48 h after the start of antivenom treatment. Two patients (3.0%) had recurrent coagulopathy and eight patients suffered recurrence of antigenaemia within 72 h of treatment. None of the dosage regimens of either antivenom used guaranteed resolution of venom-induced coagulopathy within 6 h, nor did they prevent recurrences. A further dose of antivenom at 6 h also did not guarantee resolution of coagulopathy within 12–24 h in all patients. The incidence of early adverse reactions (all mild) was similar for both antivenoms (15% and 24%; P > 0.05).Instituto Colombiano para el Desarrollo de la Ciencia y la Tecnología Francisco José de Caldas//COLCIENCIAS/ColombiaUniversidad de Antioquia/[206PI0281]/CYTED/ColombiaUniversidad de Costa Rica//UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP