Multiple High-affinity Iron-uptake Systems of Vibrio vulnificus

Vibrio vulnificus is a Gram-negative halophilic bacterium that causes necrotizing wound infections and fatal septicemia, which mainly occur in patients with elevated serum or tissue iron levels. Accumulated experimental data clearly show that V. vulnificus is a ferrophilic bacterium that requires more available iron for growth than other pathogenic bacteria, has multiple iron-uptake systems, which play important roles in the pathogenesis of the V. vulnificus infections. This review summarized the composition, regulation and significance of V. vulnificus iron-uptake systems. These iron-uptake systems may be attractive candidates for the development of V. vulnificus vaccine. Iron-chelating therapy can also be a promising modality for the prevention and treatment of V. vulnificus infections.

Vibrio vulnificus Cytolysin Forms Anion-selective Pores on the CPAE Cells, a Pulmonary Endothelial Cell Line

Cytolysin produced by Vibrio vulnificus has been incriminated as one of the important virulence determinants in V. vulnificus infection. Ion selectivity of cytolysin-induced pores was examined in a CPAE cell, a cell line of pulmonary endothelial cell, using inside-out patch clamp techniques. In symmetrical NaCl concentration (140 mM), intracellular or extracellular application of cytolysin formed ion-permeable pores with a single channel conductance of 37.5 4.0 pS. The pore currents were consistently maintained after washout of cytolysin. Replacement of Na in bath solution with monovalent ions (K, Cs or TEA ) or with divalent ions (Mg2, Ca2 ) did not affect the pore currents. When the NaCl concentration in bath solution was lowered from 140 to 60 and 20 mM, the reversal potential shifted from 0 to 11.8 and 28.2 mV, respectively. The relative permeability of the cytolysin pores to anions measured at 40 mV was Cl = NO2 > or = Br = I > SCN > acetate > isethionate > ascorbic acid > EDTA2, in descending order. The cytolysin-induced pore current was blocked by Cl channel blockers or nucleotides. These results indicate that V. vulnificus cytolysin forms anion-selective pores in CPAE cells.

Changes of Serum Cytokines ( TNF-alpha, IL-beta, IL-6 ) in Toxemic Mice Induced by Vibrio vulnificus Cytolysin / 대한피부과학회지

BACKGROUND: Cytokines such as TNF-a, and IL-1, 6, 8 are thought to mediate many host responses in patients with sepsis through the release of many kinds of inflammatory mediators. Vibrio vulnificus is a virulent, halophilic, marine, and Gram-negative bacterium causing wound infections or primary sepsis with fulminant course. It has been known to produce many exocellular factors, such as cytolysin and exozymes, which are possible causes of shock and tissue damage. OBJECTIVE: Our purpose was to investigate the changes of cytokines(TNF-a, Il-l p, and IL-6) after intravenous administration of V. vulnificus cytolysin which have known to be a major virulent factor for elucidating pathogenesis of septic shock. METHODS: After administration of V. vulnificus cytolysin(20 hemolytic units) and physiologic saline through a mouse tail vein, we obtained blood samples from the heart according to a time course(0, 30, 60, 90, 120, 240, and 360 minutes). We measured serum concentrations of circulating TNF- a, IL-1 p, and IL-6 using commercially available immunoassay kits. RESULTS: The serum concentration of TNF- a peaked at 60 min (1894 pg/ml, as compared with 829 pg/ml after saline administration), began to decrease at 90 min and fell to baseline at 360min. Concentration of IL-6 rose significantly at 90 min(>3,839 pg/ml) and began to decrease at 120 min, whereas the level of IL-1 0 increased slightly and the peaked around 90min(117 pg/ml) after the cytolysin injection. CONCLUSION: We conclude that the host response to cytolysin is associated with a brief pulse of circulating cytokines in the early stage of sepsis caused by V. vulnipcus infection.

Vibrio vulnificus Septicemia: Report of Four Cases

Vibrio vulnificus causes very severe infections. The organism is isolated, for the most part, from the blood, and skin lesions. Isolation from other sources, including the urine, is very rate. Four cases of V. vulnificus septicemia were bacteriologically diagnosed in 1984 and 1985 at Severance Hospital. All of the patients were men, 42 years and older, with preexisting liver disease. All of them showed hypotension and secondary skin lesions, and all expired. The organism was isolated from the blood in all patients, from the peritoneal fluid in one, and from skin lesions in two. From one patient, isolation from a urine speAmen was also accomplished. All of the isolates were typical in their characteristics such as in their forming green colonies on Thiosulfate citrate bile sucrose (TCBS) agar, delayed acid production from lactose, and growth in broth with 6% NaCl.

Vibrio vulnificus Septicemia in a Patient with Liver Cirrhosis

Vibrio vulnificus was isolated from a blood culture of a 41-year-old male patient with liver cirrhosis. He had eaten raw fish one day prior to the onset of clinical symptoms which included fever, chills, diarrhea and hypotension. He also developed cellulitis of the right leg which developed into a necrotic ulcer. The isolate was a slightly curved gram-negative bacillus and the colony morphology on a TCBS plate was similar to that of V. parabaemolyticus. Acid production from lactose was detected after 2 days of incubation. Other biochemical tests showed typical reactions of V vulnificus. The isolate was susceptible to all of the tested antibiotics except to clindamycin, colistin and penicillin G.