Vibrio vulnificus infection and liver cirrhosis: a potentially lethal combination

Characteristic Metabolic Changes in Skeletal Muscle Due to Vibrio vulnificus Infection in a Wound Infection Model

Vibrio vulnificus is a bacterium that inhabits warm seawater or brackish water environments and causes foodborne diseases and wound infections. In severe cases, V. vulnificus invades the skeletal muscle tissue, where bacterial proliferation leads to septicemia and necrotizing fasciitis with high mortality. Despite this characteristic, information on metabolic changes in tissue infected with V. vulnificus is not available. Here, we elucidated the metabolic changes in V. vulnificus-infected mouse skeletal muscle using capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS). Metabolome analysis revealed changes in muscle catabolites and energy metabolites during V. vulnificus infection. In particular, succinic acid accumulated but fumaric acid decreased in the infected muscle. However, the virulence factor deletion mutant revealed that changes in metabolites and bacterial proliferation were abolished in skeletal muscle infected with a multifunctional-autoprocessing repeats-in-toxin (MARTX) mutant. On the other hand, mice that were immunosuppressed via cyclophosphamide (CPA) treatment exhibited a similar level of bacterial counts and metabolites between the wild type and MARTX mutant. Therefore, our data indicate that V. vulnificus induces metabolic changes in mouse skeletal muscle and proliferates by using the MARTX toxin to evade the host immune system. This study indicates a new correlation between V. vulnificus infections and metabolic changes that lead to severe reactions or damage to host skeletal muscle. IMPORTANCE V. vulnificus causes necrotizing skin and soft tissue infections (NSSTIs) in severe cases, with high mortality and sign of rapid deterioration. Despite the severity of the infection, the dysfunction of the host metabolism in skeletal muscle triggered by V. vulnificus is poorly understood. In this study, by using a mouse wound infection model, we revealed characteristic changes in muscle catabolism and energy metabolism in skeletal muscle associated with bacterial proliferation in the infected tissues. Understanding such metabolic changes in V. vulnificus-infected tissue may provide crucial information to identify the mechanism via which V. vulnificus induces severe infections. Moreover, our metabolite data may be useful for the recognition, identification, or detection of V. vulnificus infections in clinical studies.

Vibrio vulnificus, an Underestimated Zoonotic Pathogen

V. vulnificus, continues being an underestimated yet lethal zoonotic pathogen. In this chapter, we provide a comprehensive review of numerous aspects of the biology, epidemiology, and virulence mechanisms of this poorly understood pathogen. We will emphasize the widespread role of horizontal gene transfer in V. vulnificus specifically virulence plasmids and draw parallels from aquaculture farms to human health. By placing current findings in the context of climate change, we will also contend that fish farms act as evolutionary drivers that accelerate species evolution and the emergence of new virulent groups. Overall, we suggest that on-farm control measures should be adopted both to protect animals from Vibriosis, and also as a public health measure to prevent the emergence of new zoonotic groups.

Vibrio vulnificus induces mTOR activation and inflammatory responses in macrophages

Vibrio vulnificus (V. vulnificus), a Gram-negative marine bacterium, can cause life-threatening primary septicemia, especially in patients with liver diseases. How V. vulnificus affects the liver and how it acts on macrophages are not well understood. In this report, we demonstrated that V. vulnificus infection causes a strong inflammatory response, marked expansion of liver-resident macrophages, and liver damage in mice. We demonstrated further that V. vulnificus activates mTOR in macrophages and inhibition of mTOR differentially regulates V. vulnificus induced inflammatory responses, suggesting the possibility of targeting mTOR as a strategy to modulate V. vulnificus induced inflammatory responses.

Vibrio vulnificus septic shock due to a contaminated tattoo

We present a case of Vibrio vulnificus septic shock and cellulitis in a patient with chronic liver disease that occurred after obtaining a leg tattoo with subsequent seawater exposure in the Gulf of Mexico. Initial suspicion for V. vulnificus was high and he was started on empiric doxycycline and ceftriaxone at admission. Blood and wound cultures grew oxidase positive and comma-shaped Gram-negative rods ultimately confirmed to be V. vulnificus. Despite aggressive initial treatment, the patient developed septic shock and died. This case highlights the association of chronic liver disease and high mortality associated with infections of V. vulnificus Health providers should remain vigilant for V. vulnificus infections in patients with chronic liver disease and raw oyster ingestion or seawater exposure.