A fatal case of Vibrio vulnificus meningoencephalitis

Vibrio vulnificus meningoencephalitis in a patient with thalassemia and a splenectomy

Vibrio vulnificus usually causes wound infection, gastroenteritis, and septicemia. However, it is a rare conditional pathogen causing meningoencephalitis. We report a case of a young, immunocompromised man presenting with severe sepsis after exposure to sea water and consumption of seafood. The patient subsequently developed meningoencephalitis, and Vibrio vulnificus was isolated from his blood culture. The sequence was confirmed by Next-generation sequencing of a sample of cerebrospinal fluid, as well as from a bacteria culture. After the pathogen was detected, the patient was treated with ceftriaxone, doxycycline, and moxifloxacin for 6 weeks, which controlled his infection. In this case, we acquired his clinical and dynamic MRI presentations, which were never reported. Physicians should consider Vibrio vulnificus infections when they see a similar clinical course, brain CT and MRI findings, susceptibility factors and recent seafood ingestion or exposure to seawater. Due to high mortality, the early diagnosis and treatment of Vibrio vulnificus infections are crucial. Next-generation sequencing was found to be useful for diagnosis.

Vibrio vulnificus infection and liver cirrhosis: a potentially lethal combination

We present a case of a 40-year-old man with decompensated alcoholic liver cirrhosis presenting with atraumatic cellulitis of one extremity and severe sepsis that rapidly progressed to compartment syndrome despite broad-spectrum antibiotics. Local cultures following debridement revealed Vibrio vulnificus, and subsequent history revealed consumption of raw oysters 48 h before presentation. Our case points out the unique susceptibility of those with cirrhosis and elevated iron saturation to Vibrio septicaemia, as well as the rapidity and severity of the disease progression.

Vibrio vulnificus MO6-24/O lipopolysaccharide stimulates superoxide anion, thromboxane B₂, matrix metalloproteinase-9, cytokine and chemokine release by rat brain microglia in vitro

Although human exposure to Gram-negative Vibrio vulnificus (V. vulnificus) lipopolysaccharide (LPS) has been reported to result in septic shock, its impact on the central nervous system's innate immunity remains undetermined. The purpose of this study was to determine whether V. vulnificus MO6-24/O LPS might activate rat microglia in vitro and stimulate the release of superoxide anion (O₂⁻), a reactive oxygen species known to cause oxidative stress and neuronal injury in vivo. Brain microglia were isolated from neonatal rats, and then treated with either V. vulnificus MO6-24/O LPS or Escherichia coli O26:B6 LPS for 17 hours in vitro. O₂⁻ was determined by cytochrome C reduction, and matrix metalloproteinase-2 (MMP-2) and MMP-9 by gelatinase zymography. Generation of cytokines tumor necrosis factor alpha (TNF-α), interleukin-1 alpha (IL-1α), IL-6, and transforming growth factor-beta 1 (TGF-β1), chemokines macrophage inflammatory protein (MIP-1α)/chemokine (C-C motif) ligand 3 (CCL3), MIP-2/chemokine (C-X-C motif) ligand 2 (CXCL2), monocyte chemotactic protein-1 (MCP-1)/CCL2, and cytokine-induced neutrophil chemoattractant-2alpha/beta (CINC-2α/β)/CXCL3, and brain-derived neurotrophic factor (BDNF), were determined by specific immunoassays. Priming of rat microglia by V. vulnificus MO6-24/O LPS in vitro yielded a bell-shaped dose-response curve for PMA (phorbol 12-myristate 13-acetate)-stimulated O₂⁻ generation: (1) 0.1-1 ng/mL V. vulnificus LPS enhanced O₂⁻ generation significantly but with limited inflammatory mediator generation; (2) 10-100 ng/mL V. vulnificus LPS maximized O₂⁻ generation with concomitant release of thromboxane B2 (TXB2), matrix metalloproteinase-9 (MMP-9), and several cytokines and chemokines; (3) 1000-100,000 ng/mL V. vulnificus LPS, with the exception of TXB2, yielded both attenuated O₂⁻ production, and a progressive decrease in MMP-9, cytokines and chemokines investigated. Thus concentration-dependent treatment of neonatal brain microglia with V. vulnificus MO6-24/O LPS resulted in a significant rise in O₂⁻ production, followed by a progressive decrease in O₂⁻ release, with concomitant release of lactic dehydrogenase (LDH), and generation of TXB2, MMP-9, cytokines and chemokines. We hypothesize that the inflammatory mediators investigated may be cytotoxic to microglia in vitro, by an as yet undetermined autocrine mechanism. Although V. vulnificus LPS was less potent than E. coli LPS in vitro, inflammatory mediator release by the former was clearly more efficacious. Finally, we hypothesize that should V. vulnificus LPS gain entry into the CNS, it would be possible that microglia might become activated, resulting in high levels of O₂⁻ as well as neuroinflammatory TXB2, MMP-9, cytokines and chemokines.

Structure of the lipopolysaccharide core of Vibrio vulnificus type strain 27562

The structure of the lipopolysaccharide core of Vibrio vulnificus type strain 27562 is presented. LPS hydrolysis gave two oligosaccharides, OS-1 and OS-2, as well as lipid A. NMR spectroscopic data corresponded to the presence of one Kdo residue, one beta-glucopyranose, three heptoses, one glyceric acid, one acetate, three PEtN, and one 5,7-diacylamido-3,5,7,9-tetradeoxynonulosonic acid residue (pseudaminic acid, Pse) in OS1. OS2 differed form OS 1 by the absence of glyceric acid, acetate, and Pse residues. Lipid A was analyzed for fatty acid composition and the following fatty acids were found: C14:0, C12:0-3OH, C16:0, C16:1, C14:0-3OH, C18:0, C18:1 in a ratio of 1:3:3:1:2.5:0.6:0.8.

Vibrio vulnificus endophthalmitis occurring after ingestion of raw seafood

Ocular Vibrio vulnificus infections are quite rare, and all previously reported cases have been associated with exposure to seafood and seawater. Here, we report a case of endogenous endophthalmitis caused by V. vulnificus, occurring after the ingestion of raw seafood. This case was not associated with any cutaneous or other severe systemic manifestations.