Vibrio Cholerae non-O1 Research Articles

Necrotizing Soft-Tissue Infections and Primary Sepsis Caused by Vibrio vulnificus and Vibrio cholerae non-O1

Vibrio species are a rare cause of necrotizing soft-tissue infections and primary septicemia, which are likely to occur in patients with hepatic disease, diabetes, adrenal insufficiency, and immunocompromised conditions. These organisms thrive in warm seawater and are often present in raw oysters, shellfish, and other seafood. This study examined fulminating clinical characteristics of Vibrio vulnificus and Vibrio cholerae non-O1 soft-tissue infections and identified outcome predictors. Thirty patients with necrotizing fasciitis and sepsis caused by Vibrio species were retrospectively reviewed. Twenty-eight patients had a history of contact with seawater or raw seafood. Eight patients had hepatic disease such as hepatitis or liver cirrhosis, and seven patients had diabetes mellitus. Nine patients had hepatic dysfunction combined with diabetes mellitus. Microbiology laboratory culture studies confirmed V. vulnificus in 23 patients and V. cholerae non-O1 in seven patients. Surgical debridement or immediate limb amputation was initially performed in all patients with necrotizing soft-tissue infections. Eleven patients (37%) died within several days of admission and 19 survived. The mortality of V. cholerae non-O1 group (57%) is higher than that of the V. vulnificus group (30%). A significantly higher mortality rate was noted in patients with initial presentations of a systolic blood pressure of < or =90 mm Hg, leukopenia, decreased platelet counts, and a combination of hepatic dysfunction and diabetes mellitus. Vibrio necrotizing soft-tissue infections should be suspected in patients with appropriate clinical findings and history of contact with seawater or seafood. V. cholerae non-O1 may cause bacteremia more often than V. vulnificus in patients with liver cirrhosis. Early fasciotomy and culture-directed antimicrobial therapy are aggressively recommended in patients with hypotensive shock, leukopenia, high band forms of white blood cells, decreased platelet counts, severe hypoalbuminemia, and underlying chronic illness, such as hepatic dysfunction and diabetes mellitus.

Vibrio cholerae non‐O1 infection in cirrhotics: case report and literature review

Vibrio species are ubiquitous in the marine environment and can cause severe infections in cirrhotic patients. Patients with liver disease should be warned about the potential dangers of consuming raw or undercooked seafood, and avoiding exposure of wounds to seawater. We report a case of severe sepsis from Vibrio cholerae non-O1 in a patient with cirrhosis awaiting orthotopic liver transplant. This case is aimed to advise clinicians about the importance of V. cholerae subtypes, and non-cholera Vibrio species infections in cirrhotic patients, highlighting the need to educate these patients to stay away from undercooked seafood.

Vibriocidal activity of certain medicinal plants used in Indian folklore medicine by tribals of Mahakoshal region of central India.

Objectives:Screening of the medicinal plants and determination of minimum inhibitory concentration (MIC) against Vibrio cholerae and Vibrio parahaemolyticus.Materials and Methods:A simple in vitro screening assay was employed for the standard strain of Vibrio cholerae, 12 isolates of Vibrio cholerae non-O1, and Vibrio parahaemolyticus. Aqueous and organic solvent extracts of different parts of the plants were investigated by using the disk diffusion method. Extracts from 16 medicinal plants were selected on account of the reported traditional uses for the treatment of cholera and gastrointestinal diseases, and they were assayed for vibriocidal activities.Results:The different extracts differed significantly in their vibriocidal properties with respect to different solvents. The MIC values of the plant extracts against test bacteria were found to be in the range of 2.5-20 mg/ml.Conclusions:The results indicated that Lawsonia inermis, Saraca indica, Syzygium cumini, Terminalia belerica, Allium sativum, and Datura stramonium served as broad-spectrum vibriocidal agents.

Superoxide Dismutase and Catalase Activities in Vibrio Cholerae Non-O1 Strains

ABSTRACTAntioxidant enzymes are essential for living cells, producing protection from reactive oxygen species such as superoxide, which cause oxidative damage to cell structures. Superoxide dismutase (SOD) and catalase (CAT) activities were determined for three Vibrio strains (Vibrio cholerae non O1/29, V. cholerae non O1/29-T and V. cholerae non O1/26) aerobically grown at 30°C (optimal level) and 10 °C (cold stress). All strains tested expressed both antioxidant enzymes under normophysiological and stress conditions, but the cell response is more strain-dependent than dependent on temperature. Levels of SOD in cultures of V. cholerae non O1/26 grown at 30°C were about 2.5 to 9.5-times higher than those in the cultures grown at 10°C. In contrast, SOD activity in V. cholerae non O1/29 increased by 7.5-fold under stress conditions in comparison to that at optimal temperature. The strain V. cholerae non O1/29-T did not show any significant difference in the cell response depending on the growth temperature. CAT activity in cells of V. cholerae non O1/26 and V. cholerae non O1/29-T exhibited a similar tendency suggesting that this enzyme is not included in antioxidant response against cold stress. Contrary to the above observations, V. cholerae non 01/29 demonstrated higher CAT activity in response to temperature downshift. Only one SOD isoenzyme was detected in each of the three Vibrio strains by native PAGE analysis.

In Vitro Screening of the Antibacterial Activity and Identification of Bioactive Compounds From Plants against Selected Vibrio spp. Pathogens

In vitro investigation of the vibriocidal activity of acetone extracts of Saraca indica Linn (Caesalpinaceae) and Datura stramonium Linn (Solanaceae), and aqueous extracts of Allium sativum Linn (Liliaceae) showed that they have antibacterial activity against multidrug-resistant human pathogens. Disc diffusion assay showed that there was significant concentration-dependent antibacterial activity against standard strains of Vibrio cholerae, Vibrio parahaemolyticus, and 12 multidrug-resistant isolates of Vibrio cholerae non-O1. The crude plant extracts had zones of inhibition in the range of 7-27 mm against 1 or more test bacteria, with MIC ranging from 2.5 to 15 mg/ml. Acetone extracts of S. indica and D. stramonium, in most cases, had more potency (low MIC value) than ethanol and aqueous extracts; however, the aqueous extract of A. sativum was the most effective. Thin layer chromatography (TLC), bioautography, and high performance liquid chromatography (HPLC) analysis of the crude extracts revealed that saponin, tannin, scopolamine, atropine, and allicin were the active constituents.

Non-O1 Vibrio cholerae inguinal skin and soft tissue infection with bullous skin lesions in a patient with a penis squamous cell carcinoma

Vibrio spp. is a pathogen rarely isolated in cancer patients, and in most cases it is associated with haematological diseases. Cutaneous manifestations of this organism are even rarer. We report a case of Non-O1 Vibrio cholerae inguinal skin and soft tissue infection presenting bullous skin lesions in a young type II diabetic patient with a penis squamous cell carcinoma having a seawater exposure history.

A molecular survey on virulence associated genotypes of non-O1 non-O139 Vibrio cholerae in aquatic environment of Tehran, Iran

Thirty-seven Vibrio cholerae strains were isolated from surface water sources at 5 different locations in Tehran, Iran during 2006 and were identified as non-O1 and non-O139 isolates. PCR for SXT element and class 1 integron was positive for 19% and 5.4% of isolates, respectively. PCR for virulence associated-genes within the vibrio pathogenicity island (VPI) gene cluster showed the presence of LJ, int and RJ in 8, 59 and 30% of the isolates, respectively. None of the V. cholerae isolates contained the toxin encoding genes ( ace, zot, ctx) in the CTX genetic element. Biochemical fingerprinting using PhPlate system (PhP-RV) was able to type all strains and resulted in 8 common types (containing 78% of the isolates) and 8 single types (22%). Out of 37 isolates, only 26 isolates were typeable with pulsed-field gel electrophoresis (PFGE) producing banding patterns. The results presented in this study showed no genotyping correlation between the V. cholerae isolated from surface water and the clinical setting which had been reported previously by this laboratory. Furthermore, combination of PFGE and PhP-RV methods was proved beneficial for non-typeable V. cholerae isolates.

A Case of Non-O1 and Non-O139 &lt;i&gt;Vibrio cholerae&lt;/i&gt; Septicemia with Endophthalmitis in a Cirrhotic Patient

Septicemia of Vibrio spp. such as non-O1 Vibrio cholerae presented with diarrhea, fasciitis, cellulitis or otitis media are common in cirrhotic patients (Lin, C.-J., Chiu, C.-T., Lin, D.-Y., et al., Am. J. Gastroenterol., 91, 336-340, 1996). It may result from a lower C3/C4 level, a lower serum ferritin level or opsonophagocytosis dysfunction. High mortality in such cases has been noted. However, endophthalmitis is rare in such patients, and has never been reported. We present a cirrhotic patient of non-O1 and non-O139 V. cholerae septicemia complicated with endophthalmitis.

Extraintestinal Vibrio infections in Mauritius

Few extraintestinal Vibrio infections have been reported in the African region. We report 3 cases from Mauritius: one case of Vibrio alginolyticus otitis externa; one case of soft tissue infection caused by non-O1 Vibrio cholerae and Vibrio parahaemolyticus; and one fatal case of non-O1 V. cholerae cellulitis and septicaemia.

해수에서 분리한 Vibrio cholerae non-O1 CT가 생산하는 용혈독소의 생화학적인 특징

The hemolysin of Vibrio cholerae non-O1 CT isolated from sea water was purified and characterized. The purified hemolysin displayed an optimum at <TEX>$37^{\circ}C$</TEX> and exhibited more than 70% of residual hemolytic activity after incubation at <TEX>$45^{\circ}C$</TEX> for 120 min. However, the activity dropped dramatically at temperature above <TEX>$55^{\circ}C$</TEX>. The purified protein showed the highest hemolytic activity at pH 7.0, while the activity was completely lost outside of the pH ranges of 5.0 and 10.0. The activity of hemolysin was inactivated by addition of divalent cations, such as <TEX>$Cu^{2+},\;Fe^{2+},\;Hg^{2+},\;Mn^{2+},\;and\;Zn^{2+}$</TEX>, however, the activity was not completely inhibited by additions of <TEX>$Ca^{2+},\;Mg^{2+},\;K^+,\;Na^+,\;and\;Li^+$</TEX>.

Functional independence of a variant LuxOPL91 from a non-O1 non-O139 Vibrio cholerae over the activity of CsrA and Fis

Functional independence of a variant LuxOPL91 from a non-O1 non-O139 Vibrio cholerae over the activity of CsrA and Fis.

Bactericidal effect of lactoferrin and lactoferrin chimera against halophilic Vibrio parahaemolyticus

Infections caused by Vibrio parahaemolyticus, an halophilic member of the genus Vibrio, have increased globally in the last 5 years. Diarrhea caused by V. parahaemolyticus results from eating raw or undercooked seafood. The aim of this work was to investigate whether lactoferrin and some lactoferrin-peptides have bactericidal activity against Vibrio parahaemolyticus ATCC 17802, the pandemic strain O3:K6, and the multidrug resistant isolate 727, as well as against Vibrio cholerae strains O1 and non-O1. Whereas both peptides lactoferricin (17–30) and lactoferrampin (265–284) did not have bactericidal activity, 40 μM of lactoferrin chimera (a fusion of the two peptides) inhibited the growth of all Vibrio tested to the same extent as the antibiotic gentamicin. The cidal effect of LFchimera showed a clear concentration response in contrast to bovine lactoferrin which showed higher inhibition at 10 μM than at 40 μM. FITC-labeled LFchimera bound to the bacterial membranes. Moreover LFchimera permeabilized bacterial cells and membranes were seriously damaged. Finally, in experiments with the multidrug resistant isolate 727, sub-lethal doses of LFchimera strongly reduced the concentrations of ampicillin, gentamicin or kanamicin needed to reach more than 95% growth inhibition, suggesting synergistic effects. These data indicate that LFchimera is a potential candidate to combat the multidrug resistant pathogenic Vibrio species.

Risk of bacteremia in bleeding and nonbleeding gastric varices after endoscopic injection of cyanoacrylate

Bacteremia is common in cirrhosis with gastrointestinal bleeding, including variceal bleeding. Elective esophageal sclerotherapy and banding have been reported to cause bacteremia. The risk associated with therapeutic endoscopy in patients with gastric varices has not yet been reported. This study was conducted to compare the risk of bacteremia between patients with active gastric variceal bleeding and those with gastric varices that were not actively bleeding who underwent N-butyl-2-cyanoacrylate injection. Patients were categorized into three groups: group I, patients with bleeding gastric varices who underwent cyanoacrylate injection for hemostasis (n = 20); group II, patients who underwent elective cyanoacrylate injection for further obliteration of gastric varices (n = 18); and group III, patients with cirrhosis who underwent endoscopic surveillance for varices, and patients with gastric varices who presented for a follow-up endoscopy without a requirement for treatment (n = 17). Blood culture was obtained before and 5 minutes and 3 hours after endoscopy. Needle tips were also sent for culture. Before procedures, blood cultures were positive in 4 patients (20 %) from group I. The number of positive blood cultures in group I at 5 minutes and 3 hours after the procedure were 3 (15 %) and 2 (10 %) respectively. The identified organisms were: Klebsiella pneumoniae (2), Escherichia coli (1), Vibrio cholerae non-O1 (1). No patient from group II had a positive culture at any point of blood drawn. Only one in group III had a positive culture, for Streptococcus mitis at 5 minutes. No clinical evidence of infections occurred in any patient. Needle-tip cultures grew mainly organisms from the oral and gastrointestinal tracts. Elective cyanoacrylate injection for nonbleeding gastric varices is not associated with significant bacteremia or infection. For this reason, prophylactic antibiotics may not be needed in this patient group. By contrast, prophylactic antibiotics are strongly recommended for patients with bleeding gastric varices undergoing cyanoacrylate injection.

Non-O1 Vibrio cholerae Epidural Brain Infection in a 12-Year-Old Boy After a Depressed Skull Fracture

To the Editors: Non-01 Vibrio cholerae is ubiquitous in the marine environment. It is morphologically identical to Vibrio cholerae, the causative agent of epidemic cholera, but lacks the O1 antigen. Infection typically causes self-limited gastroenteritis after consumption of raw shellfish in adults. We present the first report of central nervous system (CNS) infection in a pediatric patient after trauma sustained in a marine habitat. A 12-year-old boy in the Marshall Islands (equatorial Pacific) was climbing a coconut tree directly over shallow water. He fell an estimated 10–30 feet, sustaining an 8 cm deep scalp laceration with underlying depressed skull fracture. The laceration was primarily closed with staples, and he was urgently evacuated to our tertiary healthcare facility in Hawaii. During air-evacuation, he had decreased movements of his left upper and lower extremities. Intravenous dexamethasone was administered for presumed cerebral edema. Upon arrival, 2 days after the injury, no antibiotics had been administered. Physical examination demonstrated lethargy and decreased movement of the left upper and lower extremities. Computed tomography revealed a depressed 6 cm × 1.5 cm right parietal skull fracture, air in brain parenchyma, cortical contusions, and mild mass effect. Emergent surgical debridement and bone fragment removal was performed. Aerobic cultures of bone fragments yielded pure growth of Gram negative rods identified by the Hawaii Department of Health as Vibrio cholerae non-O1, non-0139. The organism was susceptible to all beta-lactams and cephalosporins. The patient received cephalexin 250 mg QID for 15 days and phenytoin for seizure prophylaxis. Over the next 2 weeks, he received physical therapy and demonstrated increased movement of the left extremities. At discharge, he was able to walk. Six months later, the patient returned for cranioplasty without evidence of postinfectious sequelae. Vibrio species are motile Gram-negative rods that are ubiquitous in salt and brackish waters. Non-O1 V. cholerae is found worldwide, with documented infections in North America, Europe, Africa, and the Pacific. The organism rarely causes illness in humans but can be associated with a wide spectrum of presentations including wound infections, gastrointestinal tract infections, secondary septicemia, and CNS infections. We identified 5 pediatric cases of non-O1 V. cholerae CNS infections: all were in neonates.1–5 Sources of infection were not definitely established, but freshwater exposures, either primary or secondary, were identified. In 1 instance, a feeding bottle was stored in the same cooler as live crabs.3 In another, a family member cleaned fish in the sink where the neonate received daily baths.4 All previous cases of CNS infection caused by non-01 V. cholerae were also associated with septicemia. These infections have been successfully treated with cephalosporins (cefotaxime, cefazolin, ceftriaxone), and amoxicillin/clavulanate. The fluoroquinolones and tetracyclines may be useful in older children or adults. In summary, we present the first case of non-O1 V. cholerae CNS infection in a pediatric patient resulting from head trauma in a marine environment. Physicians who care for patients injured in or near sea water should consider the marine Vibrio organisms in the differential diagnosis of ensuing infections and administer empirical antibiotics with activity against Vibrio species. The views expressed in this letter are those of the authors and do not reflect the official policy or position of the Department of the Army, Department of Defense, or the U.S. Government. Michael V. Arnett, MD Tripler Army Medical Center Honolulu, HI Susan L. Fraser, MD Walter Reed Army Medical Center Washington, DC Phyllis E. McFadden Tripler Army Medical Center Honolulu, HI

Environmental pollutions impacts on the bacteriological and physicochemical quality of suburban and rural groundwater supplies in Marrakesh area (Morocco)

This study scrutinized bacteriological and chemical quality of groundwater supplies of Marrakesh (Morocco) within a year. It assessed the influence of some chemical factors on fecal and opportunistic pathogenic bacterial communities. The annual average densities of fecal coliforms, fecal streptococci and Pseudomonas aeruginosa were respectively: 1891 colony forming units (CFU)/100 mL, 1246 CFU/100 mL and 206 CFU/100 mL. The total occurrence of these bacteria during the period of study was 94%. Detectable non-O1 Vibrio cholerae was present in 81% of samples and the mean abundances ranged from 0 to 11100 MPN/100 mL. Significant correlations between fecal coliforms and streptococci and between fecal coliforms and non-O1 V. cholerae (p < 0.01) were found. Fecal coliforms can be used to detect the presence of non-O1 V. cholerae in this groundwater. These well waters were greatly mineralized, hard, salt with high concentrations of nitrogenous ions and major elements (Ca(2+), Na(+), Cl(-), SO(2-)(4) and K(+)). Most of chemical parameters were relatively steady with time except for calcium, ammonium, nitrites and organic matter which were seasonally influenced. The degree of correlation between chemical parameters and the abundances of isolated bacteria is heterogeneous. The concentrations of calcium and nitrites favored (p < 0.01) the abundance of fecal coliforms and streptococci, but reduced P. aeruginosa abundances. Calcium, salinity, chlorides, nitrites and nitrates tests can be used for screening in situ when the laboratory facilities are limited. This work is expected to assist local authorities in developing plans and actions to reduce the pollution to acceptable levels.

Diarrhea in a Renal Allograft Recipient in the Tropics

Diarrhea is a common problem in developing countries (1). Renal allograft recipients can develop diarrhea as the result of community-acquired enteric pathogens, drugs such as mycophenolic acid (MPA), and opportunistic pathogens. This case report features an allograft recipient with diarrhea caused by Vibrio cholerae, where mycophenolate sodium and Cryptosporidium sp. were red herrings. CASE REPORT A 50-year-old Bhutanese male underwent a living-related renal transplantation from his six HLA-antigen matched sister. The immunosuppression administered to him included Basiliximab (Simulect, Novartis India Limited), prednisolone 20 mg (Wysolone, Wyeth Limited), mycophenolate sodium 900 mg bid (Renfor, Nicholas Piramal India Limited), and tacrolimus 2 mg bid (Pangraf, Panacea Biotech Limited). In the second week after transplantation, he developed acute watery diarrhea. Six hours extrapolated MPA area under the curve (AUC) was 24.1 mg.h/L. Because MPA-induced diarrhea is a common event in the immediate posttransplant setting, it was withheld. Tacrolimus trough concentration was adequate (20.1 ng/mL). Stool microscopy for intestinal parasites, cysts, and Vibrio cholerae were negative. PP65 test for cytomegalovirus proliferation was also negative. The diarrhea persisted despite stopping MPA. A fresh stool examination showed oocysts of cryptosporidium sp. On the third day, the stool culture grew Vibrio cholerae non-O1, non-O139. The patient was treated with doxycycline, and the diarrhea subsided. Mycophenolate sodium was restarted a week later, and the drug was tolerated without diarrhea. DISCUSSION MPA may cause diarrhea. This adverse effect is not related to the MPA AUC (2). The pathogenesis and pathology of diarrhea are unclear, although types of histolgy similar to Crohn's disease and graft versus host disease have been reported (3, 4). Cryptosporidium sp. is an intracellular parasite. In children with diarrhea, Cryptosporidium sp. alone accounts for 7.61% and was the third most common etiologic agent after rotavirus and Giardia sp. (5). Diarrhea, usually self limited, occasionally may be protracted in immunocompromised patients. Oocysts in the stool with specific stains aid diagnosis. Multiple specimens should be tested, as the examination of a single stool specimen identifies only 30% of intestinal cryptosporidial infections (6). Cholera is endemic water-borne infection in Indian subcontinent. Epidemics occur when sanitary measures fail after floods and other natural calamities. Vibrio cholerae serotypes O1 and O139 produce seasonal epidemics. The other serotypes, designated “non-O1, non-O139,” are endemic. More than 100 cases of culture proven cholera are reported at our center annually. The organism exists in a viable but noncultivable dormant state in the environment (7). In a study to ascertain the prevalence of vibrio in Vellore, India. it was found that non-O1, non-O139 strains of V. cholerae were detected in 41% of drinking water samples and 100% of water, sediment and plankton samples from test water bodies (8). Cytomegalovirus disease also causes diarrhea in immunosuppressed patients (9). Other potential causes of diarrhea in the immunocompromised host include antibiotic therapy, parasitic infestations due to Giardia, Isospora, bacterial infections such as campylobacter, salmonella, shigella and viral infections, illeocaecal tuberculosis and, rarely, posttransplant lymphoproliferative disorder involving the gut. The diagnosis of diarrhea in the immunocompromised host is a clinical challenge in the tropics. This patient illustrates how the various risk factors can coexist and shroud the true cause. Madhivanan Sundaram Department of Nephrology Christian Medical College Vellore, India Balaji Veeraraghavan Department of Microbiology Christian Medical College Vellore, India. George T. John Department of Nephrology Christian Medical College Vellore, India

Vibrio cholerae non‐O1, non‐O139 strains isolated before 1992 from Varanasi, India are multiple drug resistant, contain intSXT, dfr18 and aadA5 genes

In this study, we report the presence of the SXT element and Class I integron in Vibrio cholerae non-O1, non-O139 strains isolated from Varanasi, India. Isolates were resistant to cotrimoxazole, trimethoprim and/or streptomycin, furazolidone and ampicillin. None contained plasmids. Polymerase chain reaction (PCR) and DNA sequencing revealed the presence of antibiotic resistance gene cassettes, aadA1, aadA2, aadA5 and dfrA15, in the Class I integron and SXT, an integrative conjugative element containing dfr18, sulII and strAB, in three and six of the isolates respectively. Conjugation experiments, followed by PCR analysis of transconjugants, provided evidence for the transferable nature of intSXT and associated antibiotic resistance gene cassettes. This is the first report of the occurrence of SXT ICE, dfr18, sulII, strAB and aadA5 genes in environmental V. cholerae non-O1, non-O139 strains from Varanasi, India, that had been isolated before 1992.

Ballast water: a review of the impact on the world public health

Since the nineteenth century ships have been using ballast water (BW) for safety, stability, propulsion and maneuverability, as well as to redress loss of fuel weight and water consumption, and to maintain structural stress at acceptable levels. Ballast water has been spreading many non-native species around the globe, but little is known about the extent and potential significance of ship-mediated transfer of microorganisms. The global movements of ballast water by ships create a long-distance dispersal mechanism for human pathogens that may be important in the worldwide distribution of microorganisms, as well as for the epidemiology of waterborne diseases. Only a few studies have been carried out on this subject, most of them involving ballast water containing crustacean larvae and phytoplankton. Specialized microbiological studies on these waters are necessary to avoid a repeat of what happened in 1991, when epidemic cholera was reported in Peru and rapidly spread through Latin America and Mexico. In July of 1992, Vibrio cholerae was found in the USA and the Food and Drug Administration (FDA) determined that it came from ballast water of ships whose last port of call was in South America. In Brazil, just a few studies about the subject have been performed. An exploratory study by the Brazilian National Health Surveillance Agency (Agência Nacional de Vigilância Sanitária - ANVISA) found in ballast water different microorganisms, such as fecal coliforms, Escherichia coli, Enterococcus faecalis, Clostridium perfringens, coliphages, Vibrio cholerae O1 and Vibrio cholerae non-O1. Until now, Brazil has been focusing only on organisms transported to its territory from other countries by ballast water, to avoid their establishment and dissemination in Brazilian areas. Studies that can assess the probability that water ballast carries pathogenic microorganisms are extremely important, as is the examination of ships that arrive in the country. Treatment of the human infections caused by BW exists but none is completely safe and efficient.

Foodborne disease outbreaks caused by sucrose-nonfermenting and β-galactosidase-deficient variants of Vibrio cholerae

We reported four foodborne disease outbreaks in Taiwan caused by sucrose-nonfermenting and by β-galactosidase-deficient variants of non-O1, non-O139 Vibrio cholerae. The sucrose-nonfermenting vibrios collected from three outbreaks were biochemically identified to be V. mimicus and the β-galactosidase-deficient vibrios from an outbreak to be V. alginolyticus. However, molecular methods including DNA–DNA hybridization, fatty acid profile analysis, and sequence analysis of 16S rRNA, oriC, pyrH, recA, and rpoA indicated that these vibrios should be V. cholerae. These V. cholerae variants carried two hemolysin genes, hlyA and hlx, but contained neither cholera toxin gene, ctx, V. mimicus hemolysin gene, vmh, nor thermo-directed hemolysin, tdh. The sucrose-nonfermenting variants of V. cholerae shared a high level of genetic relatedness; they could derive from a common clone. In our record from 1995 to date, this was the first time that V. cholerae variants were discovered as etiologic agents for foodborne disease outbreaks in Taiwan.

Molecular Cloning and Characterization of All RND‐Type Efflux Transporters in Vibrio cholerae Non‐O1

Resistance Nodulation cell Division (RND) efflux transporters are thought to be involved in mediating multidrug resistance in Gram-negative bacteria, including Vibrio cholerae non-O1. There are six operons for putative RND-type efflux transporters present in the chromosome of V. cholerae O1 including two operons, vexAB and vexCD, which had already been identified. All of the six operons were cloned from V. cholerae non-O1, NCTC4716 by the PCR method, introduced, and expressed in cells of drug hypersusceptible Escherichia coli KAM33 (DeltaacrAB, DeltaydhE). Only vexEF conferred elevated minimum inhibitory concentrations (MICs) of some antimicrobial agents in the E. coli cells. However, VexEF did not confer increased MIC of any drug tested in tolC-deficient E. coli KAM43 cells. On the other hand, when E. coli KAM43 was transformed with vexAB, vexCD or vexEF together with tolC(Vc) of V. cholerae NCTC4716, we observed elevated MICs of various antimicrobial agents. Among them, E. coli KAM43 expressing both VexEF and TolC(Vc) showed much higher MICs and much broader substrate specificity than the other two. We also observed ethidium efflux activity via VexEF-TolC(Vc), and the activity required Na(+). Thus, VexEF-TolC (Vc) is either a Na(+)-activated or a Na(+)-coupled transporter. To our knowledge, this is the first report on the requirement of Na(+) for an RND-type efflux transporter.