Kanagawa hemolysin (KH), an exotoxin produced from Kanagawa phenomenon-positive Vibrio parahemolyticus, has been shown to possess various biological activities including hemolysis, enterotoxicity, cytotoxicity, and cardiotoxicity. The aim of this study was to investigate the effect of KH on the cardiovascular system and its mechanism, employing in vivo and in vitro experiments of the rat. Intracerebroventricular (icv) administration of 100 mHU KH produced a marked and continuous pressor effect (icv KH-pressor effect), and the icv pressor effect was not repeatable. However, intravenous (iv) injection of the same dose of KH induced a prominent depressor effect (iv KH-depressor effect). The icv KH-pressor effect was inhibited by acid-denaturation, while the iv KH-depressor effect was not. Simultaneous icv administration of the three agents (ouabain, diltiazem, or bumetanide: 10ng/kg each) significantly reduced the pressor effect. The icv KH-pressor effect was inhibited by treatment with iv phentolamine or chlorisondamine, but was not affected by iv candesartan. The iv KH-depressor effect was repeatable and was attenuated by treatment with iv NAME or methylene blue. In vitro experiments using isolated thoracic aorta, 10(-6) M phenylephrine (PE) and 50 mM KCl produced a sustained contraction. In rings contracted with either agents, KH showed relaxant responses in a concentration- dependent fashion and the relaxation (KH-vasorelaxation) was not dependent on the existence of the endothelium. The KH-vasorelaxation in the endothelium-intact rings contracted by PE was abolished by methylene blue treatment. In summary, the present findings suggest that in the icv KH-pressor effect the cation leak-inducing action of KH is implicated, which leads to the increased central sympathetic tone, that the iv KH-depressor effect results from the vasorelaxation via NO-guanylate cyclase system, and that the KH-vasorelaxation is independent of the endothelium and the guanylate cyclase system is involved in it. In conclusion, the mechanism of KH producing the icv pressor effect may not be identical to that of KH producing the iv depressor effect.
Animals ; Aorta ; Aorta, Thoracic ; Blood Pressure* ; Bumetanide ; Cardiovascular System ; Chlorisondamine ; Diltiazem ; Endothelium ; Exotoxins ; Guanylate Cyclase ; Hemolysis ; Ion Transport ; Methylene Blue ; Phentolamine ; Phenylephrine ; Rats* ; Relaxation ; Vasodilation ; Vibrio

BACKGROUND: Panton-Valentine leukocidin (PVL) is a pore-forming toxin secreted by some Staphylococcus aureus strains and associated with skin and soft tissue infections; these strains are epidemiologically associated with current outbreaks of community-acquired methicillin-resistant S. aureus (MRSA) and with necrotizing pneumonia in healthy adults in USA and Europe. This study was performed to investigate the presence of PVL-positive S. aureus and the significant infections known to be caused by this organism. METHODS: A total of 573 strains of S. aureus blood isolates at university-affiliated hospital during 2002 to 2005 were selected. The presence of PVL was investigated using PCR. Additional 12 staphylococcal toxin genes were also examined in PVL-positive S. aureus strains, and MRSA isolates were typed for the staphylococcal cassette chromosome mec (SCCmec). RESULTS: PVL genes were detected in 5 (0.9%) of 573 S. aureus strains, including 1 MRSA and 4 MSSA. The PVL-positive MRSA isolate was SCCmec type IV, and no other staphylococcal toxins were detected. The median age of the patients infected with PVL-positive S. aureus was 36 yr. Three cases of bacteremia were preceded by skin and soft-tissue infections. CONCLUSIONS: Bacteremia caused by PVL-positive S. aureus strain were detected in 5 patients in Korea, and some of the patients were associated with severe skin and soft-tissue infections. In addition, the PVL-positive MRSA strain of SCCmec type IV, a characteristic of community-acquired MRSA isolates in USA and Europe, also exists in Korea, and can cause the severe infections known to be associated with this organism.
Adult ; Bacteremia/*microbiology ; Bacterial Proteins/genetics ; Bacterial Toxins/*blood ; Exotoxins/*blood ; Female ; Humans ; Korea ; Leukocidins/*blood ; Male ; Methicillin/pharmacology ; Methicillin Resistance/drug effects ; Middle Aged ; Polymerase Chain Reaction/methods ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/genetics/*isolation & purification

BACKGROUND: Panton-Valentine leukocidin (PVL) is a pore-forming toxin secreted by some Staphylococcus aureus strains and associated with skin and soft tissue infections; these strains are epidemiologically associated with current outbreaks of community-acquired methicillin-resistant S. aureus (MRSA) and with necrotizing pneumonia in healthy adults in USA and Europe. This study was performed to investigate the presence of PVL-positive S. aureus and the significant infections known to be caused by this organism. METHODS: A total of 573 strains of S. aureus blood isolates at university-affiliated hospital during 2002 to 2005 were selected. The presence of PVL was investigated using PCR. Additional 12 staphylococcal toxin genes were also examined in PVL-positive S. aureus strains, and MRSA isolates were typed for the staphylococcal cassette chromosome mec (SCCmec). RESULTS: PVL genes were detected in 5 (0.9%) of 573 S. aureus strains, including 1 MRSA and 4 MSSA. The PVL-positive MRSA isolate was SCCmec type IV, and no other staphylococcal toxins were detected. The median age of the patients infected with PVL-positive S. aureus was 36 yr. Three cases of bacteremia were preceded by skin and soft-tissue infections. CONCLUSIONS: Bacteremia caused by PVL-positive S. aureus strain were detected in 5 patients in Korea, and some of the patients were associated with severe skin and soft-tissue infections. In addition, the PVL-positive MRSA strain of SCCmec type IV, a characteristic of community-acquired MRSA isolates in USA and Europe, also exists in Korea, and can cause the severe infections known to be associated with this organism.
Adult ; Bacteremia/*microbiology ; Bacterial Proteins/genetics ; Bacterial Toxins/*blood ; Exotoxins/*blood ; Female ; Humans ; Korea ; Leukocidins/*blood ; Male ; Methicillin/pharmacology ; Methicillin Resistance/drug effects ; Middle Aged ; Polymerase Chain Reaction/methods ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/genetics/*isolation & purification

Vibrio vulnificus is an estuarine bacterium which causes septicemia and serious wound infection. But the pathogenesis of Vibrio vulnificus infection is unknown. Among the exotoxins secreted by Vibrio vulnificus, cytolysin has been incriminated as one of the potent virulence determinants. In order to clarify the toxicity of cytolysin in mice, the morphological changes of various organs after the intravenous injection of cytolysin were observed. The pathological changes of mouse due to a single intravenous injection of Vibrio vulnificus cytolysin (8 hemolytic units) were as follows : Blood volume was decreased, and pleural effusion, vascular permeability of lungs, wet weight and volume of lungs were increased. And cytolysin was lead to patchy hemorrhage of pulmonary surface. The microscopic findings of mouse lung in experimental group were characterized by (1) extensive perivascular edema; (2) accumulation of intraalveolar fluid with electron dense particles; (3) narrowing of alveolar space; (4) leukocyte infiltration in perivascular and intraalveolar space; (5) vasodilatation of capillary; (6) damaged capillary endothelial cells and alveolar epithelial cells; (7) interstitial edema of interalveolar septa; (8) disorganization of collagen bundles. These results indicate that the lung may be an important target organ of cytolysin in the pathologenesis and lethal activity of Vibrio vulnificus infections.
Animals ; Blood Volume ; Capillaries ; Capillary Permeability ; Collagen ; Edema ; Endothelial Cells ; Epithelial Cells ; Exotoxins ; Hemorrhage ; Injections, Intravenous ; Leukocytes ; Lung ; Mice ; Perforin* ; Pleural Effusion ; Pulmonary Edema ; Sepsis ; Vasodilation ; Vibrio vulnificus* ; Vibrio* ; Virulence ; Wound Infection

OBJECTIVETo explore the pathogenesis of the damage to peripheral nerves induced by Campylobacter jejuni exotoxin (CJT).

METHODS(1) Animal models: (1) The CJT was extracted from PEN 19-CJ and injected perineurally and intravenously to Wistar rats. (2) The sera and the supernatants of peripheral blood mononuclear cells (PBMCs), taken from the rats immunized with the CJT, were injected perineurally at sciatic nerves of experimental rats and intravenously, respectively. (2) Histopathologic study of sciatic nerves: the animals were sacrificed and their sciatic nerves were examined for tease fibers, transverse section with toluidine blues staining and electron microscopy. (3) Immunohistochemistry: sections of sciatic nerves of either normal rats or human which were incubated with CJT and the sciatic nerves with pathological changes induced by CJT were obtained for observation of the binding capability of CJT with peripheral nerves by SABC and FITC-immunofluorescence methods, and nucleic acid hybridization techniques for detection of TNF-alpha mRNA expression in pathological sciatic nerves samples.

RESULTS(1) Remarkable peripheral neuropathies with axon degeneration and/or demyelination were found in the nerves induced by both CJT injection perineurally and intravenously. The axon degeneration was more obvious. Pathological changes were identified in 76.8% (2,763/3,600) of teasing fibers after perineural injection, but only 9.6% (230/2,400) of fibers were damaged in control group (P < 0.01). The peak severity of fiber damage was found on the 3rd day after CJT intravenous injection with the incidence of abnormal fibers was 19.5% (390/2,000), and abnormalities of 15.5% (310/2000) on the 14th day. However, no abnormal changes were demonstrated in control group (P < 0.01). So was in the groups injected with anti-CJT sera and the supernatants of PBMCs compared with control (P > 0.05). (2) Binding of CJT to the nerve was found dominant in the sciatic nerves taken from normal rats or human either incubated with CJT or in the pathological sciatic nerves induced by CJT to various degrees. The binding of CJT to all these nerves was determined. (3) After intravenous injection with CJT, no histopathologic change could be found in the other viscera of the rats, with the exception of remarkable pathological change in peripheral nerves.

CONCLUSIONS(1) CJT could remarkably damage the peripheral nerves in rats. Specific pathogenicity of CJT to peripheral nerves was well shown, because no histopathologic abnormalities could be found in the other viscera, such as brain, liver and kidney etc. although there was remarkable pathological change along the peripheral nerve in the animals. (2) No immunological pathogenicity of CJT could be demonstrated in the nerves of rats after immunization with CJT.

Animals ; Antibodies, Anti-Idiotypic ; blood ; Bacterial Toxins ; immunology ; toxicity ; Campylobacter jejuni ; immunology ; Exotoxins ; immunology ; toxicity ; Gene Expression ; drug effects ; Peripheral Nerves ; drug effects ; metabolism ; pathology ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Wistar ; Sciatic Nerve ; drug effects ; metabolism ; pathology ; Tumor Necrosis Factor-alpha ; genetics