Clinical manifestations of halophilic non-cholera Vibrio infections

Development of quantitative real-time polymerase chain reaction for the detection of Vibrio vulnificus based on hemolysin (vvhA) coding system

OBJECTIVE

To establish a TaqMan real-time fluorescent quantitative PCR to detect Vibrio vulnificus based on the hemolysin gene (vvhA) coding cytolysin.

METHODS

Primers and probes in the conserved region of the vvhA gene sequence were designed for the TaqMan real-time PCR to detect 100 bp amplicon from V. vulnificus DNA. Recombinant plasmid pMD19-vvhA100 was constructed and used as a positive control during the detection. Minimal amplification cycles (Ct value) and fluorescence intensity enhancement (DeltaRn value) were used as observing indexes to optimize the reaction conditions of TaqMan real-time PCR. The TaqMan assay for the detection of Vbirio vulnificus was evaluated in pure culture, mice tissue which artificially contaminated Vibrio vulnificus and clinical samples.

RESULTS

The established TaqMan real-time PCR showed positive results only for Vibrio vulnificus DNA and pMD19-vvhA100. The standard curve was plotted and the minimum level of the vvhA target from the recombinant plasmid DNA was 10(3) copies with a Ct value of 37.94+/-0.19, as the equivalent of 0.01 ng purified genomic DNA of Vibrio vulnificus. The results detected by TaqMan PCR were positive for the 16 clinical samples and all the specimens of peripheral blood and subcutaneous tissue of mice which were infected with Vibrio vulnificus.

CONCLUSION

TaqMan real-time PCR is a rapid, effective, and quantitative tool to detect Vibro vulnificus, and can be used in clinical laboratory diagnosis of septicemia and wound infection caused by Vibrio vulnificus.

A case of Vibrio vulnificus infection

Vibrio vulnificus, a recently described strain of the halophilic Vibrio species, was isolated from the blood of a 73-year-old man, who developed rapidly progressive wound infection and fatal septicemia. Twenty-one patients with Vibrio vulnificus infection have been reported in the Japanese literature. Vibrio vulnificus most frequently causes primary septicemia and necrotising cellulitis after the eating of raw fish or shellfish or after exposure to seawater. The infection is characterized by its occurring during the warm months of the year, in patients with underlying diseases, especially liver diseases, and the mortality rate is surprisingly high. Clinicians should therefore consider the possibility of Vibrio vulnificus infection in the differential diagnosis of severe wound infections. Early surgical intervention and intensive antibiotic therapy are recommended for preventing the progress of the septicemia.

Acute hepatic failure precipitated in a patient with subclinical liver disease by vibrionic and clostridial septicemia

A case of fatal septicemia caused by Vibrio vulnificus and Clostridium bifermentans in a patient with subclinical liver disease is described. The patient appeared to recover from the infection initially after antibiotic therapy but finally succumbed to rapidly developing hepatic failure. Postmortem examination revealed hemochromatosis. The pathogenesis of the polymicrobial septicemia and hepatic failure is discussed in the light of the published literature.

Bacteriology of the marine environment: implications for clinical therapy

Ocean water and tissue samples were obtained from a variety of sources with phylogenetic and geographic diversity. Purified bacterial colonies were isolated and identification procedures were performed. A total of 67 isolates were recovered. Thirty-eight isolates belonged to the genus Vibrio and included six species. Twenty-four non-fermentative bacteria and four Gram-positive isolates were recovered. Antibiotic susceptibility testing showed that while the non-fermentative marine bacteria generally were susceptible to the antibiotics tested, marine Vibrio species were relatively resistant to a wide variety of antimicrobials. Antibiotics effective against all species included imipenem, trimethoprim/sulfamethoxazole, and chloramphenicol. Further recommendations for treatment are based on sensitivity in culture. Some isolates failed to grow in the medium used for susceptibility testing. Because commercial test kits may not yield accurate identifications of bacteria, the acquisition of antimicrobial susceptibility data gains added importance.

Report of a wound infection caused by Vibrio parahaemolyticus and Vibrio vulnificus

The present case describes a foot wound caused by a clam shell from which both Vibrio parahaemolyticus and Vibrio vulnificus were recovered. Although extraintestinal infections associated with Vibrio parahaemolyticus have been reported previously, the simultaneous isolation of two marine vibrios from our case suggests that these organisms may coexist in mixed infections from a common source.

Identification of Vibrio vulnificus by indirect immunofluorescence

A rapid, sensitive, and specific indirect immunofluorescence (IIF) procedure is described for identifying Vibrio vulnificus. Reference antisera were prepared by vaccinating rabbits with surface antigen preparations of V. vulnificus, and the antisera were examined for the ability to react with and serologically group 85 isolates of V. vulnificus grown in heart infusion broth, and to detect V. vulnificus in tissue specimens from mice experimentally infected with a virulent isolate of the bacterium. The antisera detected 100% of the V. vulnificus isolates examined and gave false-positive results in approximately 0.9% of 445 IIF tests performed with non-V. vulnificus clinical isolates. V. vulnificus also was detected in frozen tissue sections from infected mice; however, the most easily observed positive results were obtained by examining V. vulnificus from lesion specimens and blood cultured briefly in heart infusion broth. The bacteria in 2-hr-old cultures of local lesions fluoresced brilliantly and were easily detectable. The IIF procedure could be of value in rapidly diagnosing fulminating and potentially fatal human disease caused by V. vulnificus.

Purification and characterization of an extracellular cytolysin produced by Vibrio vulnificus

An extracellular cytolytic toxin produced by the halophilic bacterium Vibrio vulnificus was isolated free of detectable contamination with medium constituents and other bacterial products by sequential ammonium sulfate precipitation, gel filtration with Sephadex G-75, hydrophobic interaction chromatography with phenyl-Sepharose CL-4B, and isoelectric focusing in an ethylene glycol density gradient. The cytolysin is a heat-labile, hydrophobic protein that is inhibited by large amounts of cholesterol, is partially inactivated by proteases and trypan blue, has a molecular weight (estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by amino acid analysis) of ca. 56,000, and has an isoelectric point of ca. 7.1. The first 10 amino-terminal amino acid residues of the cytolysin are Gln-Glu-Tyr-Val-Pro-Ile-Val-Glu-Lys-Pro. Lysis of mouse erythrocytes by the purified cytolysin is a multi-hit, at least two-step process consisting of a temperature-independent, toxin-binding step, followed by a temperature-dependent, membrane-perturbation step(s). In addition to possessing cytolytic activity against erythrocytes from 17 animal species and against Chinese hamster ovary cells in tissue culture, the purified cytolysin preparation was lethal for mice (ca. 3 micrograms/kg, intravenous 50% lethal dose) and had vascular permeability factor activity in guinea pig skin.

Demonstration of a common antigen in sonicated cells for identification of Vibrio vulnificus serotypes

Ouchterlony immunodiffusion of sonicated Vibrio vulnificus cells illustrated a single major precipitation line with antiserum prepared from whole cells of the same species. Antigenic analysis by two-dimensional immunoelectrophoresis verified the presence of a single dominant precipitation line. Tandem two-dimensional immunoelectrophoretic analyses of V. vulnificus antigens from various strains revealed one fused precipitation line of identity. No fused precipitation lines were seen with other Vibrio species tested. This dominant antigen, designated VVA, was not dialyzable, lost antigenicity by heating at 100 degrees C but not at 70 degrees C, and was precipitated by 70%, but not by 50%, saturated ammonium sulfate. VVA was not present in concentrated (20X) spent culture medium. VVA is possibly an intracellular protein specific to V. vulnificus species and may be useful in the serological identification of this important human pathogen.

Necrotising fasciitis caused by Vibrio vulnificus

A case of necrotising fasciitis caused by Vibrio vulnificus is described. The need for early recognition and aggressive surgical treatment are highlighted, and the necrotising infections due to V vulnificus described in the published work are reviewed.

Vibrio hand infections: a case report and review of the literature

A case of Vibrio vulnificus infection of the hand is presented. The role of Vibrio species as primary pathogens in infections associated with exposure to a marine environment is discussed.

Vibrio vulnificus infection. Case report and update since 1970

Vibrio vulnificus infections is being reported with increasing frequency in coastal regions of the United States. Raw seafood consumption, particularly raw oysters, and wounds acquired in a marine environment predispose to infection. Patients with advanced liver disease are at increased risk of developing septicemia. V. vulnificus is a virulent pathogen producing significant morbidity and mortality; its virulence relates in part to the production of exotoxin. Skin lesions occur early in the clinical course of infection and provide means of specific diagnosis. The patient and the consulting physician are well served by the dermatologist capable of recognizing this infectious disease.

Marine bacteria complicating seawater near-drowning and marine wounds: a hypothesis

Of the hundreds of species of bacteria in seawater, in marine sediments, and associated with marine organisms, more than 20 are known human pathogens. Based on published data, wherein a variety of marine bacteria have been cultured from open wounds (eg, coral cuts) and from near-drowning pneumonias, it is hypothesized that these bacteria can provide a primary infectious inoculation of open marine wounds and of the respiratory tract of near-drowners.

The distribution of Vibrio parahaemolyticus serotypes in Kenyan seafish, shellfish, marine water and sediment

Vibrio parahaemolyticus was recovered from 74 of 912 marine samples screened for the organism. Of 74 isolates of V. parahaemolyticus obtained from marine fish, crustacean shellfish (prawns, lobster, crabs), and molluscan shellfish (oysters), and from water and sediment collected off the coast of Kenya, only 33 were positively identified. The isolates were only from seafish and shellfish. The main serotypes were 0,3:K37; 0,3:K40; 0,8:39; 0,10:23; 0,10:K52; and 0,11:K40. All the serotypes were Kanagawa-negative. The rest of the samples, mainly marine sediment and water, revealed what was described as untypable Vibrios. This is the first report of the organism in this part of the world where no clinical disease is reported.

Vibrio parahaemolyticus and related halophilic Vibrios

Approximately 30 years have elapsed since Dr. Fujino's original discovery that Vibrio parahaemolyticus (then termed Pasteurella parahemolytica) was the cause of "summer diarrhea" in Japan. Since that finding, V. parahaemolyticus has been established as a cause of gastroenteritis in numbers and places approaching global proportions. It has been isolated in marine and estuarine areas almost worldwide and despite its halophilic nature, V. parahaemolyticus has been isolated from saline-free waters. The relationship of this organism to the environment reveals a close association with other marine organisms especially copepods on which the Vibrios depend for survival in winter months and growth in summer months. There is a uniquely provocative disparity between human strains of V. parahaemolyticus which are Kanagawa phenomenon (KP) positive and the environmental strains which to a large extent are KP negative, the significance being that pathogenicity is measured according to the Kanagawa phenomenon (hemolytic activity) reaction. The hemolysin of the pathogenic strains is a thermostable, cardiotoxic protein, which thus far has not been implicated in the mechanism(s) which causes human gastroenteritis. The interest in this organism has been widened in recent years by the finding that similar organisms, V. alginolyticus, lactose positive vibrios and group F vibrios also cause serious disease in humans.

Detection of extracellular toxin(s) produced by Vibrio vulnificus

Conditions are described for the production, in high titers, a heat-labile, antigenic, extracellular toxin(s) by Vibrio vulnificus, a recently recognized human pathogen. Bacteriologically sterile culture filtrate preparations obtained from mid-logarithmic-phase cultures of the bacterium possessed cytolytic activity against mammalian erythrocytes, cytotoxic activity for Chinese hamster ovary cells, vascular permeability factor activity in guinea pig skin, and lethal activity for mice. The specific activity of toxin preparations from cultures of a virulent strain of the bacterium was ca. 25-fold more than that of toxin preparations obtained from cultures of a weakly virulent strain. The four toxic activities were inseparable by gel filtration with Sephadex G-100; however, two components, which had markedly different elution behavior but which possessed the four activities mentioned above, were obtained. The major (ca. 88% of the recovered activity) and minor components had apparent molecular weights of ca. 38,500 and greater than 150,000, respectively.

Fulminating systemic infection caused by Vibrio cholerae species which does not agglutinate with 0-1 V. cholerae antiserum

A case of fatal septicaemia caused by Vibrio cholerae which did not agglutinate with 0 group 1 V. cholerae antiserum is presented. The illness occurred in a 64-year-old Aboriginal woman from Aurukun Mission in Cape York. The organism was isolated from multiple blood cultures and urine during life, and froma a large hepatic abscess found post mortem. The pathogenicity and epidemiology of the organism is discussed.

Disease caused by a marine Vibrio. Clinical characteristics and epidemiology

We studied the clinical characteristics and epidemiology of disease associated with a rare, unnamed halophilic lactose-fermenting Vibrio species in 39 persons from whom the organism had been isolated. Two distinct clinical presentations were seen. In the first, the illness began with septicemia, often within 24 hours after raw oysters had been eaten; 18 of 24 such patients had pre-existing hepatic disease, and 11 of the 24 died. In the second, there was a wound infection after exposure to seawater or an injury incurred during the handling of crabs; none of these persons had pre-existing hepatic disease, and one of 15 died. Most cases (85 per cent) occurred during relatively warm months (May to October) in men (90 per cent) 40 or more years of age (95 per cent). This Vibrio species is a pathogen and should be considered in the differential diagnosis of septicemia with secondary skin lesions and of wound infections after exposure to seawater.

Fulminating lactose-positive Vibrio septicemia

Recently cases of tissue invasion by as yet unnamed marine vibrios which were morphologically and biochemically similar to both Vibrio parahemolyticus and V. alginolyticus, but not identical with either of them, have been described. We have seen a patient who had serious widespread tissue infection with a halophilic, Gram-negative bacterium which was isolated from blood and leg lesions. The organism had the characteristics of the genus Vibrio, and lactose fermentation and ONPG reactions were positive. It also had a lower tolerance for sodium chloride in the nutrient broth compared with the above two vibrios. The isolate seems identical to the lactose positive (L+) Vibrio described by HOLLIS et al. (1976). Tissue infection resulting in severe necrotizing cellulitis and vasculitis was demonstrated at autopsy.

Experimental pathogenicity and mortality in ligated ileal loop studies of the newly reported halophilic lactose-positive Vibrio sp

Laboratory animals were challenged subcutaneously, intraperitoneally, and intravenously with the halophilic lactose-positive Vibrio. Intraperitoneal inocula of 10(8) organisms proved to be rapidly lethal in mice, rats, and hamsters. The 50% lethal doese in ICR strain mice was estimatd to be 8 X 10(5) live cells, injected intraperitoneally or subcutaneously. Subtaneous inocula in mice resulted in severe local infections, characterized by gross edema, and for those animals surviving longer than 48 h, tissue necrosis. Intravenous, intraperitoneal, and subcutaneous injections of 10(8) cells in mice resulted in death within 3 to 6 h. These animals rapidly developed Vibrio bacteremia after injections. V. parahaemolyticus, studied for comparative purposes, produced no morbidity or mortality when injected subcutaneously. Injections of live lactose-positive Vibrio into ligated ileal loops in rats and rabbits consistently proved to be lethal with a high-density bacteremia resulting.

Systemic vibriosis due to non-cholera vibrio

A case of extraintestinal vibriosis with septicaemia due to a non-cholera vibrio, from which the patient had recovered, is presented. Diagnostically useful clinical and laboratory data are described together with an outline of the combined medical and surgical treatment regimen which is employed. The association with excessive alcohol consumption and liver diseases is noted.

In vitro response to chloramphenicol, tetracycline, ampicillin, gentamicin, and beta-lactamase production by halophilic Vibrios from human and environmental sources

Isolates of Vibrio parahaemolyticus and V. alginolyticus from human and environmental sources were examined for antibiotic susceptibility by the methods of minimal inhibitory concentration (MIC) in broth and agar diffusion. These strains were found to be almost uniformly susceptible to chloramphenicol and tetracycline within attainable serum levels. The relationships of zone sizes to MICs for these two antimicrobial agents and ampicillin conformed essentially to those obtained by standard methods with gram-negative rods. Most strains were resistant to ampicillin and exhibited beta-lactamase activity, which accounted for this resistance. Nine of 30 V. alginolyticus strains from environmental sources were ampicillin resistant but did not produce measurable amounts of beta-lactamase. Three strains exhibited multiresistance to high concentrations of chloramphenicol, tetracycline, and ampicillin, which suggests the presence of plasmids. Although the great majority of vibrios appeared to be susceptible to gentamicin by agar diffusion, susceptibility could not be measured by MIC because the added NaCl, required for growth by the halophilic vibrios, diminished gentamicin activity.

Vibrio alginolyticus infections in Hawaii

Clinical and bacteriological features of eight cases of Vibrio alginolyticus infections in Hawaii are presented. These isolates occurred in superficial sites, primarily related to infections caused by swimming.

A case of non-agglutinable vibrio gastroenteritis with anuria

A case of non-agglutinable vibrio (Heiberg Group II) gastroenteritis is presented. The patient, an alcoholic, acquired this infection in Australia and recovered fully. The need to use selective vibrio media when diarrhoeal stools are cultured is emphasized.

Halophilic Vibrio species isolated from blood cultures

The Special Bacteriology Section of the Center for Disease Control has received 38 cultures of a halophilic bacterium which apparently unnamed. On the basis of the minimal characteristics of Vibrio species proposed by Hugh and Sakazaki, this bacterium belongs to the genus Vibrio. The unnamed species can be differentiated from Vibro parahaemolyticus by a lower tolerance for sodium chloride (NaC1) and the fermentation of lactose. The failure to ferment sucrose is an additional characteristic which differentiates these organisms from V. alginolyticus. Of 33 unnamed species strains tested, all were sensitive to penicillin, ampicillin, carbenicillin, cephalothin, chlorapmphenicol, gentamicin, tetracycline, rifampin, nitrofurantoin, and sulfisoxazole by agar diffusion and agar dilution tests. The sources of isolation of the cultures of the unnamed species suggest that it is a clinically important organism. Twenty strains were isolated remaining cultures were isolated from localized infections of the extremities. In contrast, only 2 of 60 cultures of V. parahaemolyticus and V. alginolyticus received in our laboratory as human isolates from extra-intestinal sources were isolated from blood.

Bacteremia in suckling rabbits after oral challenge with Vibrio parahaemolyticus

Vibrio parahaemolyticus, a halophilic marine enteropathogen, produces diarrhea in man after ingestion of contaminated seafood. Only strains capable of producing beta-hemolysis (Kanagawa-positive strains) are enteropathogenic. Yet the majority of marine isolants are nonhemolytic and Kanagawa negative. Studies were initiated in suckling rabbits in an attempt to elucidate pathogenetic mechanisms. Fasting animals were infected orally with Kanagawa-positive and Kanagawa-negative strains of V. parahaemolyticus, V. cholerae, two enteropathogenic strains of Escherichia coli, Shigella flexneri, and strains of salmonellae. Seven hours postchallenge, cardiac blood, liver, and spleen cultures were obtained. V. parahaemolyticus strains failed to induce intestinal fluid accumulation during this study period. Bacteremia occurred in animals challenged with Kanagawa-positive V. parahaemolyticus, S. flexneri, and salmonella strains only. Animal passage increased the ability of V. parahaemolyticus to cause bacteremia. Liver and spleen cultures were positive in approximately 50% of animals challenged with the Kanagawa-positive strains of V. parphaemolyticus. The ability of this organism to penetrate the intestinal epithelium of suckling rabbits may represent a specific property that plays a role in pathogenesis.