Publications

[a dried nutrient medium for the isolation of vibrio cholerae].	a dried differential nutrient medium for the isolation of v. cholerae has been developed. the medium is sufficiently sensitive, has pronounced differentiating properties and greatly inhibits the appearance of microbial associations. during the cultivation of v. cholerae with the use of this medium the cultural, morphological and agglutination properties of the initial strains are retained.	2000	10808569
differential activation of the tcpph promoter by aphb determines biotype specificity of virulence gene expression in vibrio cholerae.	vibrio cholerae strains of the classical biotype express the genes encoding cholera toxin (ct) and toxin-coregulated pilus (tcp) under a variety of environmental conditions in vitro, whereas el tor biotype strains express these genes only under specialized culture conditions. we show here that a single base-pair difference at positions -65 and -66 of the classical and el tor tcpph promoters, respectively, is responsible for the differential regulation of virulence gene expression in these two di ...	2000	10809704
nhaa, an na(+)/h(+) antiporter involved in environmental survival of vibrio cholerae.	vibrio cholerae, the agent of cholera, is a normal inhabitant of aquatic environments, in which it survives under a wide range of conditions of ph and salinity. in this work, we identified the nhaa gene in a wild-type epidemic strain of v. cholerae o1. nhaa encodes a protein of 382 amino acids that is very similar to the proteins nhaa of vibrio parahaemolyticus, vibrio alginolyticus ( approximately 87% identity), and escherichia coli (56% identity). v. cholerae nhaa complements an e. coli nhaa m ...	2000	10781565
bacteremic cellulitis caused by non-01, non-0139 vibrio cholerae: report of a case in a patient with hemochromatosis.	we report a case of bacteremia associated with hemorrhagic bullous skin lesions on the leg caused by non-01, non-0139 vibrio cholerae in a 66-year-old man with hemochromatosis developed in an inland region. the organism was isolated from blood and bullae fluid. the patient was treated successfully with cefotaxime and doxycycline. this report emphasizes the potential of this organism to produce bacteremic cellulitis in people with underlying illness in the absence of usual epidemiological risk fa ...	2000	10794945
genomic diversity among vibrio cholerae o139 strains isolated in bangladesh and india between 1992 and 1998.	in order to assess the extent of genomic diversity among vibrio cholerae o139 strains, restriction fragment length polymorphisms in two genetic loci, rrn and ctx, were studied. analysis of 144 strains isolated from different regions of bangladesh and india between 1992 and 1998 revealed the presence of at least six distinct ribotypes (b-i through b-vi) of which three were new ribotypes, and one of these was represented by a nontoxigenic o139 strain. strains of ribotypes b-i through b-v shared 11 ...	2000	10713434
isolation and characterization of vich, encoding a new pleiotropic regulator in vibrio cholerae.	during the last decade, the hns gene and its product, the h-ns protein, have been extensively studied in escherichia coli. h-ns-like proteins seem to be widespread in gram-negative bacteria. however, unlike in e. coli and in salmonella enterica serovar typhimurium, little is known about their role in the physiology of those organisms. in this report, we describe the isolation of vich, an hns-like gene in vibrio cholerae, the etiological agent of cholera. this gene was isolated from a v. cholerae ...	2000	10715012
mobilization of plasmids and chromosomal dna mediated by the sxt element, a constin found in vibrio cholerae o139.	the vibrio cholerae sxt element encodes resistance to multiple antibiotics and is a conjugative, self-transmissible, and chromosomally integrating element (a constin). excision and self-transfer of the sxt element require an element-encoded integrase. we now report that the sxt element can also mobilize the plasmids rsf1010 and clodf13 in trans as well as chromosomal dna in an hfr-like manner. sxt element-mediated mobilization of plasmids and chromosomal dna, unlike its self-transfer, is not dep ...	2000	10715015
food handlers and foodborne diseases: knowledge, attitudes, and reported behavior in italy.	the purpose of this study was to evaluate knowledge, attitudes, and behavior concerning foodborne diseases and food safety issues among food handlers in italy. face-to-face interviews were conducted within a random sample using a structured questionnaire. of the 411 food handlers responding, 48.7% knew the main foodborne pathogens (salmonella spp., staphylococcus aureus, vibrio cholerae or other vibrio spp., clostridium botulinum, hepatitis a virus), and this knowledge was significantly greater ...	2000	10716569
[the determination of the optimal conditions for the production of a number of pathogenicity factors in vibrio cholerae].	conditions for the cultivation of v. cholerae of different sero- and biovars on tryptone medium, ensuring the maximum production of cholera toxin (ct), dermonecrotic factor (dnf), hemorrhagic factor (hf) and new cholera toxin (nct) have been determined. the lack of coincidence in the optimum conditions ensuring the maximum production of ct, dnf and hf has been established, which may be indicative of different nature of these toxic substances. nct, produced by vct- strains, is similar to cn in bi ...	2000	10876885
[noncapsular mutants of vibrio cholerae serogroup o139: their isolation, identification and use for the preparation of an o139 diagnostic antiserum].	on the basis of v. cholerae strain p16064, serogroup o139, spontaneous and transposon mutants with the stable lose of the capacity for producing the polysaccharide capsule, but retaining antigen o139, have been obtained. as revealed in this study, capsular and noncapsular strains differ in their sensitivity to cholera phages 20 and inaba, as well as in agglutination with o139-antiserum. these data make it possible to use of bacteriophages for the differentiation of capsular and noncapsular strai ...	2000	10876889
identification of a cho cell-elongating factor produced by vibrio cholerae o1.	vibrio cholerae strains with all known toxin genes deleted or inactivated still cause diarrhoea in some volunteers, suggesting the presence of an unknown virulence factor or factors. lysozyme-edta treated cells of jbk70, a genetically manipulated cholera toxin negative strain of vibrio cholerae o1, biotype el tor, release a factor that causes elongation of chinese hamster ovary (cho) cells. cho cell-elongating toxin (cef) was purified by fplc chromatography (anion exchange; q sepharose high perf ...	2000	10873485
detection and analysis of gene expression during infection by in vivo expression technology.	many limitations associated with the use of in vitro models for study of bacterial pathogenesis can be overcome by the use of technologies that detect pathogen gene expression during the course of infection within an intact animal. in vivo expression technology (ivet) accomplishes this with versatility: it has been developed with a variety of reporter systems which allow for either in vivo selection or ex vivo screening. selectable gene fusion systems generally allow for the complementation of a ...	2000	10874732
virulence gene regulation inside and outside.	much knowledge about microbial gene regulation and virulence is derived from genetic and biochemical studies done outside of hosts. the aim of this review is to correlate observations made in vitro and in vivo with two different bacterial pathogens in which the nature of regulated gene expression leading to virulence is quite different. the first is vibrio cholerae, in which the concerted action of a complicated regulatory cascade involving several transcription activators leads ultimately to ex ...	2000	10874738
cloning, sequencing and expression of the gene encoding the extracellular metalloprotease of aeromonas caviae.	a gene (apk) encoding the extracellular protease of aeromonas caviae ae6 has been cloned and sequenced. for cloning the gene, the dna genomic library was screened using skim milk lb agar. one clone harboring plasmid pkk3 was selected for sequencing. nucleotide sequencing of the 3.5 kb region of pkk3 revealed a single open reading frame (orf) of 1,785 bp encoding 595 amino acids. the deduced polypeptide contained a putative 16-amino acid signal peptide followed by a large propeptide. the n-termin ...	2000	10888351
tnaraout, a transposon-based approach to identify and characterize essential bacterial genes.	identification of genes that encode essential products provides a promising approach to validation of new antibacterial drug targets. we have developed a mariner-based transposon, tnaraout, that allows efficient identification and characterization of essential genes by transcriptionally fusing them to an outward-facing, arabinose-inducible promoter, pbad, located at one end of the transposon. in the absence of arabinose, such tnaraout fusion strains display pronounced growth defects. of a total ...	2000	10888841
endotoxin and antiendotoxin antibodies in patients with acute pancreatitis.	to elucidate the time course of endotoxaemia and antiendotoxin antibodies in patients with acute pancreatitis.	2000	10890542
conversion of vibrio eltor mak757 to classical biotype: role of phage ps166.	temperate phage ps166 infection of vibrio eltor mak757 resulted in complete changes in all biotype-specific determinants. about 10% of the ps166 lysogens of mak757 lost their eltor-specific determinants, namely, the ability to produce soluble hemolysin, cell-associated hemagglutinin for chicken erythrocytes, and resistance to polymyxin b, as well as resistance to mukherjee's group iv phage and sensitivity to eltor phage e4. these lysogens were found to have acquired the properties of classical s ...	2000	10891405
mechanism of phage ps166-mediated biotype conversion in vibrio cholerae: role of the hlya locus.	temperate phage ps166 lysogens of vibrio eltor mak757 biotype eltor belong to two major categories. seventy percent of the lysogens acquire auxotrophy for glycine and histidine and maintain their parental biotype. about 10% of the lysogens become cys(-) or cys(-) met(-) and are converted to the classical biotype with complete changes in all biotype-specific determinants. pcr and rflp analysis revealed that in the latter lysogens, the phage genome integrated at the hlya locus, whereas the same lo ...	2000	10891406
crystal structure of an anti-carbohydrate antibody directed against vibrio cholerae o1 in complex with antigen: molecular basis for serotype specificity.	the crystal structure of the murine fab s-20-4 from a protective anti-cholera ab specific for the lipopolysaccharide ag of the ogawa serotype has been determined in its unliganded form and in complex with synthetic fragments of the ogawa o-specific polysaccharide (o-sp). the upstream terminal o-sp monosaccharide is shown to be the primary antigenic determinant. additional perosamine residues protrude outwards from the ab surface and contribute only marginally to the binding affinity and specific ...	2000	10880560
ctxphi contains a hybrid genome derived from tandemly integrated elements.	ctxphi is a filamentous, temperate bacteriophage whose genome includes ctxab, the genes that encode cholera toxin. in toxigenic isolates of vibrio cholerae, tandem arrays of prophage dna, usually interspersed with the related genetic element rs1, are integrated site-specifically within the chromosome. we have discovered that these arrays routinely yield hybrid virions, composed of dna from two adjacent prophages or from a prophage and a downstream rs1. coding sequences are always derived from th ...	2000	10880564
enterotoxin adjuvants have direct effects on t cells and antigen-presenting cells that result in either interleukin-4-dependent or -independent immune responses.	in an in vitro study, escherichia coli heat-labile toxin (lt) was shown to directly affect activated cd4(+) t cells and support interleukin (il)-5 production in il-4-deficient (il-4(-/-)) mice, whereas cholera toxin (ct) did not. both lt and ct enhanced b7-2 expression on b cells and macrophages. these effects were not influenced by cd40-cd40 ligand cosignaling. addition of lt- or ct-treated antigen-presenting cells to anti-cd3-triggered cd4(+) t cells resulted in the induction of t cell prolife ...	2000	10882596
host-pathogen interactions in emerging and re-emerging infectious diseases: a genomic perspective of tuberculosis, malaria, human immunodeficiency virus infection, hepatitis b, and cholera.	on exposure to a pathogen, a host may resist infection, become subclinically infected, or progress through several stages from mild to severe infection. chronic sequelae may or may not occur. host factors, particularly host genes, influence many of these stages. we have used a model of the continuum of pathogenesis of infectious diseases to consider the effect of host genes on five pathogens of significant public health burden: mycobacterium tuberculosis, plasmodium species, human immunodeficien ...	2000	10884944
development of a direct viable count procedure for the investigation of vbnc state in listeria monocytogenes.	a viable but non-culturable (vbnc) bacterial state was originally detected in studies in environmental microbiology. in particular, this state has been demonstrated for a number of human pathogens (escherichia coli, salmonella enteritidis, vibrio cholerae, legionella pneumophila and campylobacter jejuni). the presence of vbnc cells poses a major public health problem since they cannot be detected by traditional culturing methods and the cells remain potentially pathogenic under favourable condit ...	2000	10886620
a putative heat-labile enterotoxin expressed by strains of aeromonas media.	fifteen isolates of aeromonas media (seven from diarrhoeal stools, four from water and four from superficial skin ulcers of catfish) were examined for enterotoxin production. ten of these isolates (six diarrhoeal, one from water and three from fish) caused accumulation of fluid in the initial rabbit ileal loop (ril) tests. isolates from diarrhoeal stools and fish caused relatively more fluid accumulation than those from water. those strains that caused little or no fluid accumulation in the init ...	2000	10933251
vaccines for the future: problems and potential solutions from the countries that need them.		2000	10934500
effect of iron on the survival of vibrio cholerae in water.	effect of iron in the form of ferric oxide (fe2o3) on the survival of v. cholerae o1 was studied. v. cholerae o1 survived for 8 days in plain water whereas in presence of fe2o3 it survived up to 15 days. presence of organic material in the water further promoted the bacterial survival by at least 4 days. there was no difference between the behaviour of el tor and classical biotype. these results indicate that the presence of iron in water could promote the survival of v. cholerae o1 in water and ...	2000	10935316
entry into and release of solvents by escherichia coli in an organic-aqueous two-liquid-phase system and substrate specificity of the acrab-tolc solvent-extruding pump.	growth of escherichia coli is inhibited upon exposure to a large volume of a harmful solvent, and there is an inverse correlation between the degree of inhibition and the log p(ow) of the solvent, where p(ow) is the partition coefficient measured for the partition equilibrium established between the n-octanol and water phases. the acrab-tolc efflux pump system is involved in maintaining intrinsic solvent resistance. we inspected the solvent resistance of delta acrab and/or delta tolc mutants in ...	2000	10940021
development of hyperfimbriated strains of vibrio cholerae o1.	the vibrio cholerae o1 and o139 fimbrillin genes (fima or msha) were amplified by polymerase chain reaction and cloned into an escherichia coli pcr vector. these clones were sequenced. the fima sequences were found to be identical between v cholerae o1 and o139. one of the plasmids was digested with ecor i and inserted into the ecor i site of pgex-3x. the plasmid pvpp thus obtained was transferred into strains of wild-type v cholerae o1 bgd17 (classical in biotype) and its fimbriated strain by e ...	2000	10941926
vibrio cholerae ace stimulates ca(2+)-dependent cl(-)/hco(3)(-) secretion in t84 cells in vitro.	ace, accessory cholera enterotoxin, the third enterotoxin in vibrio cholerae, has been reported to increase short-circuit current (i(sc)) in rabbit ileum and to cause fluid secretion in ligated rabbit ileal loops. we studied the ace-induced change in i(sc) and potential difference (pd) in t84 monolayers mounted in modified ussing chambers, an in vitro model of a cl(-) secretory cell. ace added to the apical surface alone stimulated a rapid increase in i(sc) and pd that was concentration dependen ...	2000	10942706
evaluation of oral hypo-osmolar glucose-based and rice-based oral rehydration solutions in the treatment of cholera in children.	in a randomized controlled clinical trial, the efficacy of a low-sodium low-glucose oral rehydration solution (ors) and a low-sodium rice-based ors was compared with standard who glucose ors in the treatment of severe cholera in children aged 2-10y. in total, 120 children were evaluated for the study, of whom 58 patients were positive for vibrio cholerae and were included in the study. of these 58 cases, 19 received rice-based hypo-osmolar ors, 20 received who-ors and 19 received glucose-based h ...	2000	10943958
altered expression of the toxr-regulated porins ompu and ompt diminishes vibrio cholerae bile resistance, virulence factor expression, and intestinal colonization.	the transmembrane transcriptional activators toxr and tcpp modulate expression of vibrio cholerae virulence factors by exerting control over toxt, which encodes the cytoplasmic transcriptional activator of the ctx, tcp, and acf virulence genes. however, toxr, independently of tcpp and toxt, activates and represses transcription of the genes encoding two outer-membrane porins, ompu and ompt. to determine the role of toxr-dependent porin regulation in v. cholerae pathogenesis, the toxr-activated o ...	2000	10944196
prevalence and virulence properties of vibrio cholerae non-o1, aeromonas spp. and plesiomonas shigelloides isolated from cambé stream (state of paraná, brazil).	the incidence of vibrio cholerae, aeromonas spp. and plesiomonas shigelloides was determined in water samples from cambé stream. the samples were collected from seven different sites. the serogroups, virulence markers and drug resistance profiles were also evaluated. twelve aer. hydrophila, 12aer. caviae, eight aer. sobria, seven ple. shigelloides and two v. cholerae non-o1 were isolated. they belonged to different serogroups and all produced haemolysis in different assays. five of the aeromonas ...	2000	10945781
nontoxigenic vibrio cholerae o1 bacteremia: case report and review.		2000	10947231
phagocytic cell killing mediated by secreted cytotoxic factors of vibrio cholerae.	vibrio cholerae strain vb1 secretes a number of enzymes into the outside medium that utilize atp as a substrate. such enzymes are found in the outside medium during the mid-log phase of growth, when the optical density at 650 nm is about 0.4, and they demonstrate nucleoside diphosphate kinase (ndk), 5' nucleotidase, and adenylate kinase (ak) activities. we report that the filtered growth medium of v. cholerae, as well as the flowthrough fraction of a green sepharose column during fractionation o ...	2000	10948107
vibrio cholerae o139 conjugate vaccines: synthesis and immunogenicity of v. cholerae o139 capsular polysaccharide conjugates with recombinant diphtheria toxin mutant in mice.	epidemiologic and experimental data provide evidence that a critical level of serum immunoglobulin g (igg) antibodies to the surface polysaccharide of vibrio cholerae o1 (lipopolysaccharide) and of vibrio cholerae o139 (capsular polysaccharide [cps]) is associated with immunity to the homologous pathogen. the immunogenicity of polysaccharides, especially in infants, may be enhanced by their covalent attachment to proteins (conjugates). two synthetic schemes, involving 1-ethyl-3-(3-dimethylaminop ...	2000	10948122
treasure trove for cholera research.		2000	10952295
dna sequence of both chromosomes of the cholera pathogen vibrio cholerae.	here we determine the complete genomic sequence of the gram negative, gamma-proteobacterium vibrio cholerae el tor n16961 to be 4,033,460 base pairs (bp). the genome consists of two circular chromosomes of 2,961,146 bp and 1,072,314 bp that together encode 3,885 open reading frames. the vast majority of recognizable genes for essential cell functions (such as dna replication, transcription, translation and cell-wall biosynthesis) and pathogenicity (for example, toxins, surface antigens and adhes ...	2000	10952301
characterization of vibrio cholerae o1 antigen as the bacteriophage k139 receptor and identification of is1004 insertions aborting o1 antigen biosynthesis.	bacteriophage k139 was recently characterized as a temperate phage of o1 vibrio cholerae. in this study we have determined the phage adsorption site on the bacterial cell surface. phage-binding studies with purified lipopolysaccharide (lps) of different o1 serotypes and biotypes revealed that the o1 antigen serves as the phage receptor. in addition, phage-resistant o1 el tor strains were screened by using a virulent isolate of phage k139. analysis of the lps of such spontaneous phage-resistant m ...	2000	10960093
predicted highly expressed genes of diverse prokaryotic genomes.	our approach in predicting gene expression levels relates to codon usage differences among gene classes. in prokaryotic genomes, genes that deviate strongly in codon usage from the average gene but are sufficiently similar in codon usage to ribosomal protein genes, to translation and transcription processing factors, and to chaperone-degradation proteins are predicted highly expressed (phx). by these criteria, phx genes in most prokaryotic genomes include those encoding ribosomal proteins, trans ...	2000	10960111
ramón y cajal, microbiologist.		2000	10963336
development and validation of a detection system for wild-type vibrio cholerae in genetically modified cholera vaccine.	orochol, a live oral cholera vaccine licensed in switzerland and in other countries, is based on the genetically modified vibrio cholerae strain cvd103-hgr. this strain is derived from the wild-type o1 strain inaba 569b by deletion of a fragment internal to the ctxa gene encoding the a1 subunit of cholera toxin and by replacement of an internal fragment of the hlya gene with a fragment carrying the mer operon mediating mercury resistance. in this study we describe a polymerase chain reaction (pc ...	2000	10964441
virulence genes in environmental strains of vibrio cholerae.	the virulence of a pathogen is dependent on a discrete set of genetic determinants and their well-regulated expression. the ctxab and tcpa genes are known to play a cardinal role in maintaining virulence in vibrio cholerae, and these genes are believed to be exclusively associated with clinical strains of o1 and o139 serogroups. in this study, we examined the presence of five virulence genes, including ctxab and tcpa, as well as toxr and toxt, which are involved in the regulation of virulence, i ...	2000	10966424
molecular studies of the intestinal mucosal barrier physiopathology using cocultures of epithelial and immune cells: a technical update.	peyer's patch lymphocytes cocultured with caco-2 cells trigger the phenotypic conversion of enterocytes into cells that express morphological and functional m-cell properties. we report a technical update for setting up this model, which will enable the study of m-cell biology, the identification by biochemical approaches of molecules involved in the interaction of microorganisms with m cells, and the development of vectors that would efficiently target the mucosal immune system.	2000	10967292
a cytotoxin-producing strain of vibrio cholerae non-o1, non-o139 as a cause of cholera and bacteremia after consumption of raw clams.	we report a case of a cholera-like gastroenteritis subsequent with bacteremia in a healthy man following consumption of raw clams. although we failed to recover the organism from the patient's stool culture, his blood culture was positive for a non-cholera toxin-producing yet cytotoxin-producing non-o1 and non-o139 vibrio cholerae.	2000	10970422
lipid peroxidation during experimental cholera intoxication.	cholera intoxication in albino mice was induced by intraperitoneal injection of endotoxin in doses of ld(16), ld(25), and ld(50) and combination of endo- and enterotoxin in doses equivalent to ld(25). dose-dependent activation of superoxide dismutase, phasic changes in the contents of mda and conjugated trienes and dienes, and modulatory influence of enterotoxin on catalase activity in the blood were observed during intoxication.	2000	10977911
the o139 serogroup of vibrio cholerae comprises diverse clones of epidemic and nonepidemic strains derived from multiple v. cholerae o1 or non-o1 progenitors.	sixty-four representative strains of vibrio cholerae o139 were analyzed, to re-examine the origin of this serogroup. ribotyping differentiated the strains into 3 hindiii and 7 bgli ribotypes. one hindiii and 5 bgli ribotypes were shared by all toxigenic o139 strains. of 6 nontoxigenic o139 strains, 3 shared ribotypes with the toxigenic strains, carried genes encoding toxin coregulated pilus, and were susceptible to the cholera toxin-converting bacteriophage ctxphi. the remaining 3 strains belong ...	2000	10979913
evidence for specificity in type 4 pilus biogenesis by enteropathogenic escherichia coli.	type 4 fimbriae (pili) are surface appendages that are expressed by many species of gram-negative bacteria. previous studies have demonstrated that pseudomonas aeruginosa can express and assemble pilin subunits from several unrelated species, indicating a common mechanism for biogenesis of type 4 pili whereby structural subunits from one system may be interchanged with those of another. in this study, an isogenic mutant of enteropathogenic escherichia coli (epec) was constructed containing the e ...	2000	10746776
distribution of vibrio cholerae virulence genes among different vibrio species isolated in sardinia, italy.	the members of the genus vibrio include harmless aquatic strains as well as strains capable of causing epidemics of cholera. diarrhoea caused by vibrio cholerae is attributed to cholerae enterotoxin (ct) codified by the ctx operon and regulated by a number of virulence genes such as toxt, toxr and toxs. fifty-two vibrio strains were isolated from different aquatic environments in and around sardinia and searched by pcr for the presence of ctxa, zot, ace, toxr, toxs, toxt, tcpa and vpi virulence ...	2000	10747228
mucosal and systemic antibody responses after peroral or intranasal immunization: effects of conjugation to enterotoxin b subunits and/or of co-administration with free toxin as adjuvant.	the mucosa-binding molecules cholera toxin (ct) from vibrio cholerae and heat-labile enterotoxin (lt) from escherichia coli have previously been used as mucosal adjuvants and carriers for many types of antigen. however, since these molecules are toxic and cannot be used in human vaccines, it is important to study whether their non-toxic mucosa-binding b subunits, ctb and ltb, can be used as alternative safe mucosal adjuvants and/or carrier molecules. we have as a model protein antigen used human ...	2000	10752686
the suckling mouse model of cholera.	vibrio cholerae colonization of the suckling mouse intestine is a commonly used animal model for the human diarrheal disease cholera. this model has a number of advantages as well as disadvantages, and has been extremely useful in the identification and characterization of proven and putative virulence factors involved in human cholera.	2000	10754579
vibrio cholerae o139 in calcutta, 1992-1998: incidence, antibiograms, and genotypes.	we report results of surveillance for cholera caused by vibrio cholerae o139 from september 1992, when it was first identified, to december 1998. v. cholerae o139 dominated as the causative agent of cholera in calcutta during 1992-93 and 1996- 97, while the o1 strains dominated during the rest of the period. dramatic shifts in patterns of resistance to cotrimoxazole, neomycin, and streptomycin were observed. molecular epidemiologic studies showed clonal diversity among the o139 strains and conti ...	2000	10756147
vibrio cholerae o2 as a cause of a skin lesion in a tourist returning from tunisia.	isolates of vibrio cholerae other than o1 and o139 (non o1 vibrio cholerae) are associated with sporadic diarrheal disorders, and limited outbreaks of diarrhea, and have often been reported in association with extraintestinal infections. the majority of cases of non o1 vibrio cholerae infection involve immunocompromised patients with hematologic malignancies or cirrhosis. in italy, very few cases of gastrointestinal and extraintestinal infections due to non o1 vibrio cholerae have been described ...	2000	10759577
convergence of the secretory pathways for cholera toxin and the filamentous phage, ctxphi.	virulence of vibrio cholerae depends on secretion of cholera toxin (ct), which is encoded within the genome of a filamentous phage, ctxphi. release of ct is mediated by the extracellular protein secretion (eps) type ii secretion system. here, the outer membrane component of this system, epsd, was shown to be required for secretion of the phage as well. thus, epsd plays a role both in pathogenicity and in horizontal transfer of a key virulence gene. genomic analysis suggests that additional filam ...	2000	10764646
classical and el tor biotypes of vibrio cholerae differ in timing of transcription of tcpph during growth in inducing conditions.	two protein pairs in vibrio cholerae, toxrs and tcpph, are necessary for transcription from the toxt promoter and subsequent expression of cholera virulence genes. we have previously shown that transcription of tcpph in classical strains of v. cholerae is activated at mid-log-phase growth in toxr-inducing conditions, while transcription of tcpph in el tor strains is not. in this study, we showed that while transcription of tcpph differs at mid-log-phase growth in toxr-inducing conditions between ...	2000	10769005
[radiosensitivity of vibrio cholerae o1 incorporated in oysters, to (60)co].	evaluate the effect of ionizing irradiation by 60co on vibrio cholerae o1, el-tor, ogawa, non-toxigenic, incorporated in live oysters crassostrea brasiliana.	2000	10769357
novel beta-lactamase genes from two environmental isolates of vibrio harveyi.	two ampicillin-resistant (amp(r)) isolates of vibrio harveyi, w3b and hb3, were obtained from the coastal waters of the indonesian island of java. strain w3b was isolated from marine water near a shrimp farm in north java while hb3 was from pristine seawater in south java. in this study, novel beta-lactamase genes from w3b (bla(vhw-1)) and hb3 (bla(vhh-1)) were cloned and their nucleotide sequences were determined. an open reading frame (orf) of 870 bp encoding a deduced protein of 290 amino aci ...	2000	10770767
distribution and content of class 1 integrons in different vibrio cholerae o-serotype strains isolated in thailand.	in this study, 176 clinical and environmental vibrio cholerae strains of different o serotypes isolated in thailand from 1982 to 1995 were selected and studied for the presence of class 1 integrons, a new group of genetic elements which carry antibiotic resistance genes. using pcr and dna sequencing, we found that 44 isolates contained class 1 integrons harboring the aadb, aada2, blap1, dfra1, and dfra15 gene cassettes, which encode resistance to gentamicin, kanamycin, and tobramycin; streptomyc ...	2000	10770768
survival of vibrio cholerae o1 in ceviche and its reduction by heat pretreatment of raw ingredients.	the survival of vibrio cholerae o1 serotypes inaba and ogawa was determined in ceviche prepared from inoculated ground fish. ground mackerel purchased from a seafood distribution center was inoculated with v. cholerae and stored at 8 or 20 degrees c. counts of v. cholerae decreased in 2.6 to 2.7 log10 cfu/g during 96 h of storage at 8 degrees c or 2.5 to 2.6 log10 cfu/g during 24 h at 20 degrees c. survival studies indicated that serotype inaba decreased its number following a linear or retarded ...	2000	10772208
[bacteremia by vibrio cholera no 01, two cases].		2000	10721567
the role of probiotic cultures in the control of gastrointestinal health.	the use of probiotics to enhance intestinal health has been proposed for many years. probiotics are traditionally defined as viable microorganisms that have a beneficial effect in the prevention and treatment of specific pathologic conditions when they are ingested. there is a relatively large volume of literature that supports the use of probiotics to prevent or treat intestinal disorders. however, the scientific basis of probiotic use has been firmly established only recently, and sound clinic ...	2000	10721914
molecular evidence of clonality amongst vibrio cholerae o1 biotype el tor during an outbreak in malaysia.	forty-three clinical strains of v. cholerae o1 biotype e1 tor were isolated between 3 may and 10 june 1998 during an outbreak in the metropolitan area of kuala lumpur and its suburbs. with the exception of three inaba strains that were restricted to three members of a family, all the others belonged to the ogawa serotype. the strains were analysed for clonality using ribotyping and pulsed-field gel electrophoresis (pfge). two ribotypes, v/b21a and b27, were identified among 40 ogawa isolates usi ...	2000	10722126
cell vacuolation, a manifestation of the el tor hemolysin of vibrio cholerae.	culture supernatants of nontoxigenic nonepidemic clinical strains of vibrio cholerae belonging to diverse serogroups were found to induce vacuolation of nonconfluent hela cells. the vacuoles became prominent 18 h after introduction of culture supernatant, and vacuolated cells survived for 48 h and then died. only a fraction of the vacuolated cells took up neutral red dye, implying that there were differences in the vacuolar microenvironment. further tests showed that the factor responsible for v ...	2000	10722584
mutations in the extracellular protein secretion pathway genes (eps) interfere with rugose polysaccharide production in and motility of vibrio cholerae.	vibrio cholerae is the causal organism of the diarrheal disease cholera. the rugose variant of v. cholerae is associated with the secretion of an exopolysaccharide. the rugose polysaccharide has been shown to confer increased resistance to a variety of agents, such as chlorine, bioacids, and oxidative and osmotic stresses. it also promotes biofilm formation, thereby increasing the survival of the bacteria in the aquatic environments. here we show that the extracellular protein secretion system ( ...	2000	10722590
high-efficiency passive elution of bacterial lipopolysaccharides from polyacrylamide gels.	we recently described a method for recovering polyacrylamide-gel-separated bacterial lipopolysaccharides (lps) based on the sensitive on-gel lps detection (1-10 ng/band) with zinc-imidazole followed by passive elution from 32 microm average size gel microparticles into water. with this procedure, the recovery of rough- or semismooth-type lps after 3 h elution is about 70-80%, while that of smooth lps is only about 10%. here we evaluated whether a simple replacement of water with other eluents wo ...	2000	10726753
antibodies (igg) to lipopolysaccharide of vibrio cholerae o1 mediate protection through inhibition of intestinal adherence and colonisation in a mouse model.	an antiserum raised against purified lipopolysaccharide (lps) of a vibrio cholerae o1 strain (co366) induced passive protection against challenge with the parent as well as other o1 organisms but not against o139 or non-o1/non-o139 organisms. a considerable level of protection against o1 strains was also observed with the igg fraction of the antiserum which inhibited intestinal adherence and colonisation. the monovalent fab(igg) fragment, on the other hand, showed only a low level of protection. ...	2000	10731603
identification of an operon required for ferrichrome iron utilization in vibrio cholerae.	mutagenesis of vibrio cholerae with tnphoa, followed by screening for fusions that were activated under low-iron conditions, led to the identification of seven independent fusion strains, each of which was deficient in the ability to utilize ferrichrome as a sole iron source for growth in a plate bioassay and had an insertion in genes encoding products homologous to escherichia coli fhua or fhud. expression of the gene fusions was independent of irgb but regulated by fur. we report here a map of ...	2000	10735886
effect on systemic antibody concentrations of topical application of choleratoxin to skin of sheep.	to examine the ability of a vaccine formulation combining choleratoxin with an experimental antigen to induce a systemic antibody response when applied topically on unbroken skin of sheep.	2000	10736674
surveillance of bacterial pathogens associated with acute diarrhea in lima, peru.	a study was conducted in lima, peru, from january to april 1995, to determine the bacterial pathogens associated with acute diarrhea in adults, their susceptibility to common antimicrobials, the risk factors involved in cholera transmission, and the best clinical predictors of cholera.	2000	10737846
efficacy trial of single-dose live oral cholera vaccine cvd 103-hgr in north jakarta, indonesia, a cholera-endemic area.	a randomized, double-blind, placebo-controlled efficacy trial of one dose of cvd 103-hgr live oral cholera vaccine was performed in indonesia from 1993 to 1997. 67,508 persons aged 2-41 years ingested vaccine or placebo and were followed for four years, detecting cholera cases using hospital-based surveillance. a nested reactogenicity study (538 vaccinees, 535 controls) revealed no vaccine-attributable side effects. a nested immunogenicity study (n=657) showed vibriocidal seroresponses in 64-70% ...	2000	10738097
determination of biological toxins using capillary electrokinetic chromatography with multiphoton-excited fluorescence.	we report a highly sensitive and rapid strategy for characterizing biological toxins based on capillary electrokinetic chromatography with multiphoton-excited fluorescence. in this approach, aflatoxins b1, b2, and g1 and the cholera toxin a-subunit are fractionated in approximately 80 s in a narrow-bore electrophoretic channel using the negatively charged pseudostationary phase, carboxymethyl-beta-cyclodextrin. the aflatoxins--highly mutagenic multiple-ringed heterocycles produced by aspergillus ...	2000	10740883
characterization of a putative virulence island in the chromosome of uropathogenic escherichia coli possessing a gene encoding a uropathogenic-specific protein.	this study was initiated to search for a homologue of the vibrio cholerae zot gene in uropathogenic escherichia coli (upec) using a specific dna probe. the faint signal obtained at low stringency with some upec strains associated with prostatitis cases prompted us to examine upec strains by pcr using primers designed from the conserved regions of the proteins of the zot group of putative ntpases containing the classical ntp binding motif. this led to the discovery of a dna fragment in upec strai ...	2000	10702359
distribution of is1358 and linkage to rfb-related genes in vibrio anguillarum.	the insertion sequence is1358 is linked to the rfb regions of both vibrio cholerae o1 and o139, and its location was suggestive of a role in generating new combinations of rfb genes. this provoked an examination of the distribution and localization of is1358 in vibrio anguillarum. s11358 was widely distributed in a number of v. anguillarum serogroups. in particular, when cosmid clones of v. anguillarum o1 were screened with is1358 and subsequently subcloned and sequenced, it was found that rfb-l ...	2000	10708371
lowering of the electric potential on the membrane as a possible signal modulating the expression of virulence factors in vibrio cholerae.		2000	10652109
pandemic spread of an o3:k6 clone of vibrio parahaemolyticus and emergence of related strains evidenced by arbitrarily primed pcr and toxrs sequence analyses.	vibrio parahaemolyticus o3:k6 strains responsible for the increase in the number of cases of diarrhea in calcutta, india, beginning in february 1996 and those isolated from southeast asian travelers beginning in 1995 were shown to belong to a unique clone characterized by possession of the tdh gene but not the trh gene and by unique arbitrarily primed pcr (ap-pcr) profiles (j. okuda, m. ishibashi, e. hayakawa, t. nishino, y. takeda, a. k. mukhopadhyay, s. garg, s. k. bhattacharya, g. b. nair, an ...	2000	10655349
helicobacter pylori and epidemic vibrio cholerae o1 infection in peru.	in a cross-sectional study of the 1991 peruvian cholera epidemic, vibrio cholerae o1 infection was associated with helicobacter pylori infection, particularly in young children. these data support the hypothesis that hypochlorhydria induced by h. pylori is important in the pathogenesis of diarrhoeal disease.	2000	10665561
acetyl-coa synthetase from the amitochondriate eukaryote giardia lamblia belongs to the newly recognized superfamily of acyl-coa synthetases (nucleoside diphosphate-forming).	the gene coding for the acetyl-coa synthetase (adp-forming) from the amitochondriate eukaryote giardia lamblia has been expressed in escherichia coli. the recombinant enzyme exhibited the same substrate specificity as the native enzyme, utilizing acetyl-coa and adenine nucleotides as preferred substrates and less efficiently, propionyl- and succinyl-coa. n- and c-terminal parts of the g. lamblia acetyl-coa synthetase sequence were found to be homologous to the alpha- and beta-subunits, respectiv ...	2000	10681568
vibrio cholerae in victoria.		2000	10682025
gene replacement in gram-negative bacteria: the pmaksac vectors.		2000	10683723
evaluation of antibacterial activity of asparagus racemosus willd. root.	different concentrations (50, 100, 150 microg/ml) of the methanol extract of the roots of asparagus racemosus willd. showed considerable in vitro antibacterial efficacy against escherichia coli, shigella dysenteriae, shigella sonnei, shigella flexneri, vibrio cholerae, salmonella typhi, salmonella typhimurium, pseudomonas putida, bacillus subtilis and staphylococcus aureus. the effects produced by the methanol extract were compared with chloramphenicol.	2000	10685109
epidemic cholera in guinea-bissau: the challenge of preventing deaths in rural west africa.	an epidemiologic investigation was conducted to identify factors associated with cholera mortality in a rural african setting and interventions likely to prevent deaths in future epidemics.	2000	10689208
double-blind, randomized, placebo controlled pilot study evaluating efficacy and reactogenicity of an oral etec b-subunit-inactivated whole cell vaccine against travelers' diarrhea (preliminary report).	diarrhea caused by enterotoxigenic e.coli (etec) is an important health problem in developing countries and in travelers to these areas. in previous trials formulations of etec vaccines containing the b-subunit of cholera toxin, which is antigenically similar to the heat labile enterotoxin of etec, and the most prevalent colonization factor antigens of etec, were shown to stimulate relevant mucosal immune responses in volunteers from sweden and egypt.	2000	10689236
phosphorylation of the flagellar regulatory protein flrc is necessary for vibrio cholerae motility and enhanced colonization.	the human pathogen vibrio cholerae specifically expresses virulence factors within the host, including cholera toxin (ct) and the toxin co-regulated pilus (tcp), which allow it to colonize the intestine and cause disease. v. cholerae is a highly motile organism by virtue of a polar flagellum, and motility has been inferred to be an important aspect of virulence, yet the exact role of motility in pathogenesis has remained undefined. the two-component regulatory system flrb/flrc is required for po ...	2000	10692152
delineation of pilin domains required for bacterial association into microcolonies and intestinal colonization by vibrio cholerae.	the toxin-co-regulated pilus (tcp), a type 4 pilus that is expressed by epidemic strains of vibrio cholerae o1 and o139, is required for colonization of the human intestine. the tcp structure is assembled as a polymer of repeating subunits of tcpa pilin that form long fibres, which laterally associate into bundles. previous passive immunization studies have suggested that the c-terminal region of tcpa is exposed on the surface of the pilus fibre and has a critical role in mediating the colonizat ...	2000	10692166
vibrio cholerae vibf is required for vibriobactin synthesis and is a member of the family of nonribosomal peptide synthetases.	a 7.5-kbp fragment of chromosomal dna downstream of the vibrio cholerae vibriobactin outer membrane receptor, viua, and the vibriobactin utilization gene, viub, was recovered from a sau3a lambda library of o395 chromosomal dna. by analogy with the genetic organization of the escherichia coli enterobactin gene cluster, in which the enterobactin biosynthetic and transport genes lie adjacent to the enterobactin outer membrane receptor, fepa, and the utilization gene, fes, the cloned dna was examine ...	2000	10692380
ctxphi infection of vibrio cholerae requires the tolqra gene products.	ctxphi is a lysogenic filamentous bacteriophage that encodes cholera toxin. filamentous phages that infect escherichia coli require both a pilus and the products of tolqra in order to enter host cells. we have previously shown that toxin-coregulated pilus (tcp), a type iv pilus that is an essential vibrio cholerae intestinal colonization factor, serves as a receptor for ctxphi. to test whether ctxphi also depends upon tol gene products to infect v. cholerae, we identified and inactivated the v. ...	2000	10692381
neonatal septicemia caused by vibrio cholerae o:139.		2000	10694008
climate and infectious disease: use of remote sensing for detection of vibrio cholerae by indirect measurement.	it has long been known that cholera outbreaks can be initiated when vibrio cholerae, the bacterium that causes cholera, is present in drinking water in sufficient numbers to constitute an infective dose, if ingested by humans. outbreaks associated with drinking or bathing in unpurified river or brackish water may directly or indirectly depend on such conditions as water temperature, nutrient concentration, and plankton production that may be favorable for growth and reproduction of the bacterium ...	2000	10677480
in vitro and in vivo analyses of constitutive and in vivo-induced promoters in attenuated vaccine and vector strains of vibrio cholerae.	the optimal promoter for in vivo expression of heterologous antigens by live, attenuated vaccine vector strains of vibrio cholerae is unclear; in vitro analyses of promoter activity may not accurately predict expression of antigens in vivo. we therefore introduced plasmids expressing the b subunit of cholera toxin (ctxb) under the control of a number of promoters into v. cholerae vaccine strain peru2. we evaluated the tac promoter, which is constitutively expressed in v. cholerae, as well as the ...	2000	10678922
iha: a novel escherichia coli o157:h7 adherence-conferring molecule encoded on a recently acquired chromosomal island of conserved structure.	the mechanisms used by shiga toxin (stx)-producing escherichia coli to adhere to epithelial cells are incompletely understood. two cosmids from an e. coli o157:h7 dna library contain an adherence-conferring chromosomal gene encoding a protein similar to iron-regulated gene a (irga) of vibrio cholerae (m. b. goldberg, s. a. boyko, j. r. butterton, j. a. stoebner, s. m. payne, and s. b. calderwood, mol. microbiol. 6:2407-2418, 1992). we have termed the product of this gene the irga homologue adhes ...	2000	10678953
the virulence regulatory protein toxr mediates enhanced bile resistance in vibrio cholerae and other pathogenic vibrio species.	the transmembrane regulatory protein toxr is required for expression of virulence factors in the human diarrheal pathogen vibrio cholerae, including cholera toxin (ct) and the toxin coregulated pilus (tcp). toxr is necessary for transcription of the gene encoding a second regulatory protein, toxt, which is the direct transcriptional activator of ct and tcp genes. however, toxr, independent of toxt, directly activates and represses transcription of the outer membrane porins ompu and ompt, respect ...	2000	10678965
infectious ctxphi and the vibrio pathogenicity island prophage in vibrio mimicus: evidence for recent horizontal transfer between v. mimicus and v. cholerae.	vibrio mimicus differs from vibrio cholerae in a number of genotypic and phenotypic traits but like v. cholerae can give rise to diarrheal disease. we examined clinical isolates of v. mimicus for the presence of ctxphi, the lysogenic filamentous bacteriophage that carries the cholera toxin genes in epidemic v. cholerae strains. four v. mimicus isolates were found to contain complete copies of ctxphi. southern blot analyses revealed that v. mimicus strain pt5 contains two ctx prophages integrated ...	2000	10678967
cytotoxic cell vacuolating activity from vibrio cholerae hemolysin.	a vibrio cholerae cytotoxin, designated vcvac, was found to cause vacuolation in vero cells. it was originally detected in the pathogenic o1 amazonia variant of v. cholerae and later shown to be produced in environmental strains and some el tor strains. comparison of vcvac production in various strains suggested that hemolysin was responsible for the vacuolating phenotype. genetic experiments established a firm correlation between vacuolation and hemolysin production. the mammalian cell vacuolat ...	2000	10678992
novel approaches to monitor bacterial gene expression in infected tissue and host.	elucidating the complex and dynamic host-microbe interactions during infection requires, among other things, detailed knowledge of microbial gene expression in vivo. recently, advances in fluorescence and bioluminescence detection techniques, as well as recombinase-based in vivo expression technology, have rendered monitoring virulence gene expression in vivo a feasible task. these techniques have been adapted by several laboratories to study the spatial and temporal patterns of virulence gene e ...	2000	10679414
cloning and characterization of vuua, a gene encoding the vibrio vulnificus ferric vulnibactin receptor.	the ability of vibrio vulnificus to acquire iron from the host has been shown to correlate with virulence. many iron transport genes are regulated by iron, and in v. vulnificus, transcriptional regulation by iron depends on the fur gene. the n-terminal amino acid sequence of a 72-kda iron-regulated outer membrane protein purified from a v. vulnificus fur mutant had 53% homology with the first 15 amino acids of the mature protein of the vibrio cholerae vibriobactin receptor, viua. in this report, ...	2000	10639413
molecular characterization of a new variant of toxin-coregulated pilus protein (tcpa) in a toxigenic non-o1/non-o139 strain of vibrio cholerae.	a toxigenic non-o1/non-o139 strain of vibrio cholerae (10259) was found to contain a new variant of the toxin-coregulated pilus (tcp) protein gene (tcpa) as determined by pcr and southern hybridization experiments. nucleotide sequence analysis data of the new tcpa gene in strain 10259 (o53) showed it to be about 74 and 72% identical to those of o1 classical and el tor biotype strains, respectively. the predicted amino acid sequence of the 10259 tcpa protein shared about 81 and 78% identity with ...	2000	10639469
optimizing the germfree mouse model for in vivo evaluation of oral vibrio cholerae vaccine and vector strains.	the germfree mouse model of vibrio cholerae infection can be used to judge immune responses to v. cholerae vaccine and vector strains. in the original model, a single oral inoculation was administered on day 0, a booster oral inoculation was administered on day 14, and immune responses were analyzed with samples collected on day 28. unfortunately, immune responses in this model frequently were low level, and interanimal variability occurred. in order to improve this model, we evaluated various p ...	2000	10639476
use of lambda phage s and r gene products in an inducible lysis system for vibrio cholerae- and salmonella enterica serovar typhimurium-based dna vaccine delivery systems.	novel methods for adapting dna vaccine technology to the prevention of mucosal diseases are greatly needed. here we show that regulated expression of phage lambda lysis genes s and r causes dramatic lysis of both vibrio cholerae and salmonella enterica serovar typhimurium cells with concomitant release of plasmid dna into the surrounding media. we also used single and double dnase mutant strains to show that secreted v. cholerae dnases can adversely affect the integrity of dna molecules released ...	2000	10639478
the type 4 prepilin peptidases comprise a novel family of aspartic acid proteases.	type 4 prepilins or prepilin-like-proteins are secreted by a wide range of bacterial species and are required for a variety of functions including type 4 pilus formation, toxin and other enzyme secretion, gene transfer, and biofilm formation. a distinctive feature of these proteins is the presence of a specialized leader peptide that is cleaved off by a cognate membrane-bound type 4 prepilin peptidase (tfpp) during the process of secretion. in this report we show that the tfpps represent a novel ...	2000	10625704
a region of the transmembrane regulatory protein toxr that tethers the transcriptional activation domain to the cytoplasmic membrane displays wide divergence among vibrio species.	the virulence regulatory protein toxr of vibrio cholerae is unique in that it contains a cytoplasmic dna-binding-transcriptional activation domain, a transmembrane domain, and a periplasmic domain. although toxr and other transmembrane transcriptional activators have been discovered in other bacteria, little is known about their mechanism of activation. utilizing degenerate oligonucleotides and pcr, we have amplified internal toxr gene sequences from seven vibrio and photobacterium species and s ...	2000	10629204
molecular cloning and transcriptional regulation of ompt, a toxr-repressed gene in vibrio cholerae.	in pathogenic vibrio cholerae, at least 17 genes are co-ordinately regulated by toxr. most of these genes, including those that encode cholera toxin (ct), toxin co-regulated pilus (tcp), accessory colonization factor (acf) and ompu, are positively regulated. ompt is the only identified protein under negative regulation of toxr. to understand the molecular mechanism by which toxr represses ompt expression, we cloned ompt and characterized the ompt promoter and its interaction with toxr. sequence ...	2000	10632889