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?-Toxin Induces Platelet Aggregation and Liver Injury during Staphylococcus aureus Sepsis.

ABSTRACT: During sepsis, small blood vessels can become occluded by large platelet aggregates of poorly understood etiology. During Staphylococcal aureus infection, sepsis severity is linked to the bacterial ?-toxin (?-hemolysin, AT) through unclear mechanisms. In this study, we visualized intravascular events in the microcirculation and found that intravenous AT injection induces rapid platelet aggregation, forming dynamic micro-thrombi in the microcirculation. These aggregates are retained in the liver sinusoids and kidney glomeruli, causing multi-organ dysfunction. Acute staphylococcal infection results in sequestration of most bacteria by liver macrophages. Platelets are initially recruited to these macrophages and help eradicate S. aureus. However, at later time points, AT causes aberrant and damaging thrombosis throughout the liver. Treatment with an AT neutralizing antibody (MEDI4893?) prevents platelet aggregation and subsequent liver damage, without affecting the initial and beneficial platelet recruitment. Thus, AT neutralization may represent a promising approach to combat staphylococcal-induced intravascular coagulation and organ dysfunction.

SUBMITTER: Surewaard BGJ

PROVIDER: S-EPMC6295203 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

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α-Toxin Induces Platelet Aggregation and Liver Injury during Staphylococcus aureus Sepsis.

Surewaard Bas G J BGJ Thanabalasuriar Ajitha A Zeng Zhutian Z Tkaczyk Christine C Cohen Taylor S TS Bardoel Bart W BW Jorch Selina K SK Deppermann Carsten C Bubeck Wardenburg Juliane J Davis Rachelle P RP Jenne Craig N CN Stover Kendall C KC Sellman Bret R BR Kubes Paul P

Cell host & microbe 20180719 2

During sepsis, small blood vessels can become occluded by large platelet aggregates of poorly understood etiology. During Staphylococcal aureus infection, sepsis severity is linked to the bacterial α-toxin (α-hemolysin, AT) through unclear mechanisms. In this study, we visualized intravascular events in the microcirculation and found that intravenous AT injection induces rapid platelet aggregation, forming dynamic micro-thrombi in the microcirculation. These aggregates are retained in the liver ...[more]

PMID: 30033122

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Project description:The majority of bacteria detected in the nostril microbiota of most healthy adults belong to three genera: Propionibacterium, Corynebacterium, and Staphylococcus. Among these staphylococci is the medically important bacterium Staphylococcus aureus. Almost nothing is known about interspecies interactions among bacteria in the nostrils. We observed that crude extracts of cell-free conditioned medium from Propionibacterium spp. induce S. aureus aggregation in culture. Bioassay-guided fractionation implicated coproporphyrin III (CIII), the most abundant extracellular porphyrin produced by human-associated Propionibacterium spp., as a cause of S. aureus aggregation. This aggregation response depended on the CIII dose and occurred during early stationary-phase growth, and a low pH (~4 to 6) was necessary but was not sufficient for its induction. Additionally, CIII induced plasma-independent S. aureus biofilm development on an abiotic surface in multiple S. aureus strains. In strain UAMS-1, CIII stimulation of biofilm depended on sarA, a key biofilm regulator. This study is one of the first demonstrations of a small-molecule-mediated interaction among medically relevant members of the nostril microbiota and the first description of a role for CIII in bacterial interspecies interactions. Our results indicate that CIII may be an important mediator of S. aureus aggregation and/or biofilm formation in the nostril or other sites inhabited by Propionibacterium spp. and S. aureus. Importance: Very little is known about interspecies interactions among the bacteria that inhabit the adult nostril, including Staphylococcus aureus, a potential pathogen that colonizes about a quarter of adults. We demonstrated that coproporphyrin III (CIII), a diffusible small molecule excreted by nostril- and skin-associated Propionibacterium spp., induces S. aureus aggregation in a manner dependent on dose, growth phase, and pH. CIII also induces S. aureus to form a plasma-independent surface-attached biofilm. This report is the first description of a role for CIII in bacterial interspecies interactions at any human body site and a novel demonstration that nostril microbiota physiology is influenced by small-molecule-mediated interactions.

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Dataset Information

?-Toxin Induces Platelet Aggregation and Liver Injury during Staphylococcus aureus Sepsis.

Publications

α-Toxin Induces Platelet Aggregation and Liver Injury during Staphylococcus aureus Sepsis.

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