Publications

reconstitution of acetosyringone-mediated agrobacterium tumefaciens virulence gene expression in the heterologous host escherichia coli.	the ability to utilize escherichia coli as a heterologous system in which to study the regulation of agrobacterium tumefaciens virulence genes and the mechanism of transfer dna (t-dna) transfer would provide an important tool to our understanding and manipulation of these processes. we have previously reported that the rpoa gene encoding the alpha subunit of rna polymerase is required for the expression of lacz gene under the control of virb promoter (virbp::lacz) in e. coli containing a constit ...	2001	11371534
etiology of children's diarrhea in montevideo, uruguay: associated pathogens and unusual isolates.	we studied microorganisms associated with infant diarrhea in a group of 256 children admitted to a public pediatric hospital in montevideo, uruguay. diagnostic procedures were updated to optimize detection of potential pathogens, which were found in 63.8% of cases, and to be able to define their characteristics down to molecular or antigenic type. coinfection with two or more agents was detected in more than one-third of positive studies. escherichia coli enteric virotypes, especially enteropath ...	2001	11376047
effect of shiga toxin and shiga-like toxins on eukaryotic cells.	shigella dysenteriae and shiga-toxin-producing escherichia coli (stec) elaborate the ab holotoxins, shiga or shiga-like toxins (stx). stx play a major role in the pathogenesis of haemorrhagic colitis and haemolytic uremic syndrome. this review provides an overview of the mechanisms of action of stx and a model of the pathogenesis of stx-induced disease.	2001	11377211
attenuated shigella flexneri 2a delta guaba strain cvd 1204 expressing enterotoxigenic escherichia coli (etec) cs2 and cs3 fimbriae as a live mucosal vaccine against shigella and etec infection.	to construct a prototype hybrid vaccine against shigella and enterotoxigenic escherichia coli (etec), the genes encoding the production of etec cs2 and cs3 fimbriae were isolated and expressed in attenuated shigella flexneri 2a guaba strain cvd 1204. the cs2 cota to -d genes, isolated from etec strain c91f, and the cs3 csta to -h genes, subcloned from plasmid pcs100, were cloned into ~15-copy-number-stabilized pga1 behind the osmotically regulated ompc promoter, resulting in high expression of b ...	2001	11292735
high pressure increases bactericidal activity and spectrum of lactoferrin, lactoferricin and nisin.	we have studied the inactivation of a panel of eight test bacteria (two escherichia coli strains, salmonella enteritidis, salmonella typhimurium, shigella sonnei, shigella flexneri, pseudomonas fluorescens and staphylococcus aureus) by high pressure in the presence of bovine lactoferrin (500 microg/ml), pepsin hydrolysate of lactoferrin (500 microg/ml), lactoferricin (20 microg/ml) and nisin (100 iu/ml). none of these compounds, at the indicated dosage, were bactericidal when applied at atmosphe ...	2001	11294354
microbial growth modelling with artificial neural networks.	there is a growing interest in modelling microbial growth as an alternative to time-consuming, traditional, microbiological enumeration techniques. several statistical models have been reported to describe the growth of different microorganisms, but there are accuracy problems. an alternate technique 'artificial neural networks' (ann) for modelling microbial growth is explained and evaluated. published data were used to build separate general regression neural network (grnn) structures for model ...	2001	11294356
a synaptojanin-homologous region of salmonella typhimurium sigd is essential for inositol phosphatase activity and akt activation.	the ser-thr kinase akt is activated in epithelial cells by salmonella enterica serovar typhimurium. the bacterial effector sigd, which is translocated into host cells via the specialized type iii secretion system, is essential for akt activation. here, we investigated the inositol phospholipid substrate preferences of sigd. recombinant sigd preferentially dephosphorylated phosphatidylinositol 3,5-biphosphate and phosphatidylinositol 3,4,5-triphosphate over other phosphatidylinositol lipids. phos ...	2001	11311241
a weighted composite dose-response model for human salmonellosis.	this article describes the development of a weighted composite dose-response model for human salmonellosis. data from previously reported human challenge studies were categorized into two different groups representing low and moderately virulent/pathogenic salmonella strains based on a disease end point. because epidemiological data indicate that some salmonella strains are particularly pathogenic, and in the absence of human feeding study data for such strains, shigella dysenteriae was used as ...	2001	11414538
tetracycline antibiotics: mode of action, applications, molecular biology, and epidemiology of bacterial resistance.	tetracyclines were discovered in the 1940s and exhibited activity against a wide range of microorganisms including gram-positive and gram-negative bacteria, chlamydiae, mycoplasmas, rickettsiae, and protozoan parasites. they are inexpensive antibiotics, which have been used extensively in the prophlylaxis and therapy of human and animal infections and also at subtherapeutic levels in animal feed as growth promoters. the first tetracycline-resistant bacterium, shigella dysenteriae, was isolated i ...	2001	11381101
characterization of monoclonal antibodies with specificity for the core oligosaccharide of shigella lipopolysaccharide.	monoclonal antibodies (mabs) were prepared against different strains of shigella, following immunization of balb/c mice with a heat-killed preparation of shigella. antibody-producing hybridomas were screened in an indirect enzyme-linked immunoadsorbent assay (elisa) and epitope specificity determined using chemically defined lipopolysaccharide, lipid, and kdo fragments. five mabs were characterized and the following specificities identified: 2c32e6 and 4d64b9 (reactive to s. flexneri and s. boyd ...	2001	11394534
the shus protein of shigella dysenteriae is a heme-sequestering protein that also binds dna.	the ability of shigella dysenteriae to utilize heme as an iron source is dependent on the iron-regulated expression of a number of genes including the outermembrane receptor shua and the cytoplasmic protein shus. the shus protein has no sequence homology with any proteins of known function and its role in heme acquisition has not been determined. in this paper we describe the purification and characterization of shus. the soluble oligomeric protein (650 kda) is composed of a single type of subun ...	2001	11368175
cytochrome c-mediated caspase-9 activation triggers apoptosis in streptococcus pyogenes-infected epithelial cells.	epithelial cells are the initial sites of host invasion by group a streptococcus pyogenes (gas), and their infection of epithelial cells has been suggested to induce apoptosis. however, the mechanism responsible for bacteria-host interaction and the induction of apoptosis has not been clearly understood. we demonstrate here that human pharyngeal epithelial hep-2 cells became apoptotic with dna fragmentation by invasion of gas strains jrs4 (m6+, f1+) and jrs145 (m6-, f1+ mutant of jrs4), whereas ...	2001	11422082
glutamate decarboxylase genes as a prescreening marker for detection of pathogenic escherichia coli groups.	the enzyme glutamate decarboxylase (gad) is prevalent in escherichia coli but few strains in the various pathogenic e. coli groups have been tested for gad. using pcr primers that amplify a 670-bp segment from the gada and gadb genes encoding gad, we examined the distribution of the gadab genes among enteric bacteria. analysis of 173 pathogenic e. coli strains, including 125 enterohemorrhagic e. coli isolates of the o157:h7 serotype and its phenotypic variants and 48 isolates of enteropathogenic ...	2001	11425729
microarray analysis of microbial virulence factors.	hybridization with oligonucleotide microchips (microarrays) was used for discrimination among strains of escherichia coli and other pathogenic enteric bacteria harboring various virulence factors. oligonucleotide microchips are miniature arrays of gene-specific oligonucleotide probes immobilized on a glass surface. the combination of this technique with the amplification of genetic material by pcr is a powerful tool for the detection of and simultaneous discrimination among food-borne human path ...	2001	11425749
phenotypic variability of beta-glucoside utilization and its correlation to pathogenesis process in a few enteric bacteria.	utilization of beta-glucosides is markedly variable in the members of the family enterobacteriaceae. the results presented here provide molecular clues for evolutionary events that resulted in the phenotypic variability seen amongst the members of these species. the genomic hybridization of selected enterobacteriaceae members with the escherichia coli bgl and cel genes resulted in detection of a complete homolog of the bgl and cel operons in shigella sonnei, a member that is evolutionarily close ...	2001	11377874
type iii secretion systems and pathogenicity islands.	some bacterial pathogens have evolved by acquiring pathogenicity islands (pis), which are clusters of genes encoding virulence traits. pis encoding the secretion of effector molecules via type iii secretion (tts) systems have been discovered in several gram-negative pathogens. tts systems are involved in contact-dependent secretion of virulence factors and can facilitate delivery of toxins directly into target cells. the expanding list of bacteria found to contain clusters of tts genes includes ...	2001	11211218
a colony blot immunoassay to detect enteroinvasive escherichia coli and shigella in water samples.	the aim of the study was to develop a colony blot immunoassay to detect shigella and enteroinvasive escherichia coli (eiec) in water.	2001	11168726
structure and composition of the shigella flexneri "needle complex", a part of its type iii secreton.	type iii secretion systems (ttsss or secretons), essential virulence determinants of many gram-negative bacteria, serve to translocate proteins directly from the bacteria into the host cytoplasm. electron microscopy (em) indicates that the ttsss of shigella flexneri are composed of: (1) an external needle; (2) a transmembrane domain; and (3) a cytoplasmic bulb. em analysis of purified and negatively stained parts 1, 2 and a portion of 3 of the ttss, together termed the "needle complex" (nc), pro ...	2001	11169106
secretion of predicted inc proteins of chlamydia pneumoniae by a heterologous type iii machinery.	chlamydia spp. are strictly intracellular pathogens that grow inside a vacuole, called an inclusion. they possess genes encoding proteins homologous to components of type iii secretion machineries, which, in other bacterial pathogens, are involved in delivery of bacterial proteins within or through the membrane of eukaryotic host cells. inc proteins are chlamydial proteins that are associated with the inclusion membrane and are characterized by the presence of a large hydrophobic domain in their ...	2001	11169118
rational protocols for testing faeces in the investigation of sporadic hospital-acquired diarrhoea.	many recent studies have demonstrated that routine examination of faeces for conventional enteric pathogens such as salmonella, shigella, campylobacter and parasites in patients who develop sporadic hospital-acquired diarrhoea is unnecessary and wasteful. in this paper the advantages and disadvantages of a restricted testing protocol in patients with hospital-acquired diarrhoea are reviewed. practical issues for safe implementation of such a protocol are also discussed.	2001	11170768
microbes and microbial toxins: paradigms for microbial-mucosal interactions iii. shigellosis: from symptoms to molecular pathogenesis.	interaction of shigella flexneri with epithelial cells includes contact of bacteria with the cell surface and release of ipa proteins through a specialized type iii secreton. a complex signaling process involving activation of small gtpases of the rho family and c-src causes major rearrangements of the subcortical cytoskeleton, thereby allowing bacterial entry by macropinocytosis. after entry, shigellae escape to the cell cytoplasm and initiate intracytoplasmic movement through polar nucleation ...	2001	11171613
the insect endosymbiont sodalis glossinidius utilizes a type iii secretion system for cell invasion.	sodalis glossinidius is a maternally transmitted secondary endosymbiont residing intracellularly in tissues of the tsetse flies, glossina spp. in this study, we have used tn5 mutagenesis and a negative selection procedure to derive a s. glossinidius mutant that is incapable of invading insect cells in vitro and is aposymbiotic when microinjected into tsetse. this mutant strain harbors tn5 integrated into a chromosomal gene sharing high sequence identity with a type iii secretion system invasion ...	2001	11172045
salmonella-induced cell death: apoptosis, necrosis or programmed cell death?	over the past several years, it has become apparent that enteropathogens activate cell death programs. for salmonella and shigella species, the induction of cell death is required for pathogenesis, and the mechanisms by which these bacteria induce cell death is an area of intense investigation. although initial studies suggested that salmonella induce cell death through an apoptotic pathway, recent studies demonstrate that cell death occurs through a unique caspase 1-dependent mechanism.	2001	11173244
downregulation of bactericidal peptides in enteric infections: a novel immune escape mechanism with bacterial dna as a potential regulator.	antibacterial peptides are active defense components of innate immunity. several studies confirm their importance at epithelial surfaces as immediate barrier effectors in preventing infection. here we report that early in shigella spp. infections, expression of the antibacterial peptides ll-37 and human beta-defensin-1 is reduced or turned off. the downregulation is detected in biopsies from patients with bacillary dysenteries and in shigella- infected cell cultures of epithelial and monocyte or ...	2001	11175848
sonographic findings in shigella colitis.	we present a case of colitis caused by shigella sonnei in which abdominal sonography helped in the early diagnosis, leading to successful conservative management. sonography showed diffuse wall thickening and layer stratification in the descending and sigmoid colon. although shigella colitis is relatively rare, the possibility must be considered when patients have diffuse wall thickening with distinct layer stratification in the left colon.	2001	11180185
phyloproteomics: species identification of enterobacteriaceae using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.	to evaluate matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (maldi-tof ms) as a tool for rapid identification of common clinical bacterial isolates, we analyzed 25 carefully selected isolates of pathogenic escherichia coli (e. coli) and additional enterobacteriaceae members. organisms were prepared according to clinical microbiological protocols and analyzed with minimal additional processing. spectra were reproducible from preparation to preparation and comprised 40 ...	2001	11200222
etiology of bloody diarrhea among patients presenting to united states emergency departments: prevalence of escherichia coli o157:h7 and other enteropathogens.	escherichia coli o157:h7 and other shiga toxin-producing e. coli (stec) infections have been associated with bloody diarrhea. the prevalence of enteropathogens among patients with bloody diarrhea was determined by a prospective study at 11 us emergency departments. eligible patients had bloody stools, > or =3 loose stool samples per 24-h period, and an illness lasting <7 days. among 873 patients with 877 episodes of bloody diarrhea, stool samples for culture were obtained in 549 episodes (62.6%) ...	2001	11181120
parameters underlying successful protection with live attenuated mutants in experimental shigellosis.	because the use of live attenuated mutants of shigella spp. represents a promising approach to protection against bacillary dysentery (m. e. etherridge, a. t. m. shamsul hoque, and d. a. sack, lab. anim. sci. 46:61-66, 1996), it becomes essential to rationalize this approach in animal models in order to optimize attenuation of virulence in the vaccine candidates, as well as their route and mode of administration, and to define the correlates of protection. in this study, we have compared three s ...	2001	11160004
phylogenetic evidence for horizontal transfer of muts alleles among naturally occurring escherichia coli strains.	muts mutators accelerate the bacterial mutation rate 100- to 1,000-fold and relax the barriers that normally restrict homeologous recombination. these mutators thus afford the opportunity for horizontal exchange of dna between disparate strains. while much is known regarding the muts phenotype, the evolutionary structure of the muts(+) gene in escherichia coli remains unclear. the physical proximity of muts to an adjacent polymorphic region of the chromosome suggests that this gene itself may be ...	2001	11160094
shigellae control the gates of ll.		2001	11175842
a new target for shigellosis: rational design and crystallographic studies of inhibitors of trna-guanine transglycosylase.	eubacterial trna-guanine transglycosylase (tgt) is involved in the hyper-modification of cognate trnas leading to the exchange of g34 at the wobble position in the anticodon loop by preq1 (2-amino-5-(aminomethyl)pyrrolo[2,3-d]pyrimidin-4(3h)-one) as part of the biosynthesis of queuine (q). mutation of the tgt gene in shigella flexneri results in a significant loss of pathogenicity of the bacterium, revealing tgt as a new target for the design of potent drugs against shigellosis. the x-ray struct ...	2001	11178905
safety and immunogenicity of improved shigella o-specific polysaccharide-protein conjugate vaccines in adults in israel.	data suggest that the o-specific polysaccharide (o-sp) domain of the lipopolysaccharide (lps) of shigella species is both an essential virulence factor and a protective antigen and that a critical level of serum immunoglobulin g (igg) to this antigen will confer immunity to shigellosis. because covalent attachment of polysaccharides to proteins increases their immunogenicity, especially in infants and in young children, the o-sp of shigella species were bound to medically useful proteins, and th ...	2001	11179298
identification and characterization of an in vivo regulated d15/oma87 homologue in shigella flexneri using differential display polymerase chain reaction.	shigella genes expressed during infection likely contribute to adaptation and virulence in the host. using differential display pcr (ddpcr), a cdna fragment from shigella flexneri serotype 5 that showed enhanced expression in a murine model was identified, cloned and sequenced. enhanced expression was verified by rna dot blot. the full-length gene was cloned using pcr and sequenced. the complete gene sequence was blast searched against genbank, and exhibited strong homology to genes encoding hae ...	2001	11179681
periplasmic transit and disulfide bond formation of the autotransported shigella protein icsa.	the shigella outer membrane protein icsa belongs to the family of type v secreted (autotransported) virulence factors. members of this family mediate their own translocation across the bacterial outer membrane: the carboxy-terminal beta domain forms a beta barrel channel in the outer membrane through which the amino-terminal alpha domain passes. icsa, which is localized at one pole of the bacterium, mediates actin assembly by shigella, which is essential for bacterial intracellular movement and ...	2001	11208794
a sensitive seminested pcr method for the detection of shigella in spiked environmental water samples.	a rapid seminested polymerase chain reaction (pcr) method for the specific, sensitive detection of virulent shigella spp. in spiked environmental water samples was developed. a set of primers specific for the invasion plasmid antigen gene (ipah) of virulent shigella spp. and enteroinvasive escherichia coli produced a 620-bp fragment that was used as template for the seminested primer pair delineating a 401-bp fragment. by using agarose gel electrophoresis for detection of the seminested pcr-ampl ...	2001	11235881
computer identification of shigella species by rrna gene restriction patterns.	we describe a mlui ribotyping scheme for shigella which approaches correlation with serotyping. one hundred and seventeen reference strains and previously serotyped clinical isolates representing the 57 shigella serotypes and biotypes were included in this study. a total of 51 distinct ribotypes were obtained and a database was built with them. the number of bands composing each ribotype varied from 9 to 15. the fragments ranged in size from 1.6 to 18.8 kbp. one hundred and eleven clinical isola ...	2001	11281325
shigella and salmonella strains isolated from children under 5 years in gaborone, botswana, and their antibiotic susceptibility patterns.	we isolated shigella from 43/221 (21%) and salmonella 8/221 (3%) rectal swabs from children under 5 years with diarrhoea, and found shigella in two of 100 specimens from children without diarrhoea. sh. boydii (13%) was the most prevalent shigella species followed by sh. flexneri (6%) and sh. sonnei (2%). the prevalence of various types of sh. boydii was type 7, 5%; type 9, 3%; type 12 and 16, 2%; and type 18, 1%. other shigella serotypes encountered were sh. flexneri type 6 (4%), type 4 (2%), wi ...	2001	11251896
increased nitrite and nitrate concentrations in sera and urine of patients with cholera or shigellosis.	nitric oxide (no) is an important regulator of cell function. in the intestine, no regulates blood flow, peristalsis, secretion, and is associated with inflammation and tissue injury. the objectives of this study were to assess and compare the role of no in cholera, a noninflammatory enteric infection, and in shigellosis, a bacterial inflammation of the colon.	2001	11232692
use of live bacterial vaccine vectors for antigen delivery: potential and limitations.	most infectious agents are restricted to the mucosal membranes or their transit through the mucosa constitutes a critical step in the infection process. therefore, the elicitation of an efficient immune response, not only at systemic, but also at mucosal level, after vaccination is highly desirable, representing a significant advantage in order to prevent infection. this goal can be only achieved, when the vaccine formulation is administered by the mucosal route. however, soluble antigens given ...	2001	11166877
frequency of triggering bacteria in patients with reactive arthritis and undifferentiated oligoarthritis and the relative importance of the tests used for diagnosis.	reactive arthritis (rea) triggered by chlamydia trachomatis or enteric bacteria such as yersinia, salmonella, campylobacter jejuni, or shigella is an important differential diagnosis in patients presenting with the clinical picture of an undifferentiated oligoarthritis (uoa). this study was undertaken to evaluate the best diagnostic approach.	2001	11247862
third-generation cephalosporin resistance in shigella sonnei, argentina.	shigella sonnei resistant to cefotaxime (but not to ceftazidime) was isolated for the first time in stool samples from a pediatric patient with vomiting and bloody diarrhea in northern argentina. microbiologic and biochemical tests confirmed the presence of an extended spectrum beta-lactamase displaying an apparent isoelectric point value of 8.2.	2001	11384523
prospective cohort studies of shigellosis during military field training.	epidemiological and clinical features of shigellosis occurring among cohorts of israeli recruits followed-up for 3-6 months during the summer field training of years 1993-1997 were studied. the incidence rate of culture-proven shigellosis was the highest (78 cases per 1,000 recruits) in 1996 and the lowest (13 cases per 1,000 recruits) in 1995. shigella sonnei (152 isolates) and shigella flexneri (151 isolates) were the most common species. fifty percent of the patients with shigellosis had feve ...	2001	11305466
vaccination with the glycoprotein d gene of pseudorabies virus delivered by nonpathogenic escherichia coli elicits protective immune responses.	attenuated intracellular bacteria, such as salmonella and shigella, have been exploited to act as gene delivery vectors. in this study, we report that nonpathogenic, live escherichia coli can be used for the delivery of dna vaccines in vivo, leading to generation of immune responses against plasmid-encoded foreign antigens. the pseudorabies virus (prv) dna vaccine carrying the glycoprotein d (gd) gene delivered by e. coli was able to induce protective immune responses in mice against a lethal pr ...	2001	11312026
shigella infection in a scid mouse-human intestinal xenograft model: role for neutrophils in containing bacterial dissemination in human intestine.	shigellae infect human intestine and cause intense inflammation and destruction of colonic and rectal mucosa. to model the interactions of shigella with human intestine in vivo, we have studied shigella infection in human intestinal xenografts in severe combined immunodeficient mice (scid-hu-int mice). inoculation of shigella into human intestinal xenografts caused severe inflammation and mucosal damage, which was apparent as soon as 4 h following infection. shigella infection was associated wit ...	2001	11292746
complete dna sequence and analysis of the large virulence plasmid of shigella flexneri.	the complete sequence analysis of the 210-kb shigella flexneri 5a virulence plasmid was determined. shigella spp. cause dysentery and diarrhea by invasion and spread through the colonic mucosa. most of the known shigella virulence determinants are encoded on a large plasmid that is unique to virulent strains of shigella and enteroinvasive escherichia coli; these known genes account for approximately 30 to 35% of the virulence plasmid. in the complete sequence of the virulence plasmid, 286 open r ...	2001	11292750
probiotic activities of lactobacillus casei rhamnosus: in vitro adherence to intestinal cells and antimicrobial properties.	the interest of probiotics as remedies for a broad number of gastrointestinal and other infectious diseases has gained wide interest over the last few years, but little is known about their underlying mechanism of action. in this study, the probiotic activities of a human isolate of lactobacillus casei subsp. rhamnosus strain (lcr35) were investigated. using intestinal caco-2 cell line in an in vitro model, we demonstrated that this strain exhibited adhesive properties. the inhibitory effects of ...	2001	11316370
pcr primers designed from malic acid dehydrogenase gene and their use for detection of escherichia coli in water and milk samples.	escherichia coli has been the appropriate focus for monitoring of potential enteric pathogens in water and foods. although several methods have been used for the detection or enumeration of e. coli cells in water and foods, the time and accuracy limitations of these methods suggest the need of a rapid and specific method. by comparison of the gene sequences coding for malic acid dehydrogenase (mdh) of e. coli and non-e. coli strains, two oligonucleotides were designed and their possible use as e ...	2001	11252491
genetic organization of plasmid coljs, encoding colicin js activity, immunity, and release genes.	the 5.2-kb coljs plasmid of a colicinogenic strain of shigella sonnei (colicin type 7) was isolated and sequenced. pcoljs was partly homologous to pcole1 and to pesticin-encoding plasmid ppcp1, mainly in the rep, mob, and cer regions. a 1.2-kb unique region of pcoljs showed significantly different g+c content (34%) compared to the rest of pcoljs (53%). within the unique region, seven open reading frames (orfs) were identified. orf94 was shown to code for colicin js activity (cja), a 94-amino-aci ...	2001	11395458
the iron- and temperature-regulated cjrbc genes of shigella and enteroinvasive escherichia coli strains code for colicin js uptake.	a cosmid library of dna from colicin js-sensitive enteroinvasive escherichia coli (eiec) strain o164 was made in colicin js-resistant strain e. coli vcs257, and colicin js-sensitive clones were identified. sensitivity to colicin js was associated with the carriage of a three-gene operon upstream of and partially overlapping senb. the open reading frames were designated cjrabc (for colicin js receptor), coding for proteins of 291, 258, and 753 amino acids, respectively. tn7 insertions in any of t ...	2001	11395459
pulsenet standardized protocol for subtyping listeria monocytogenes by macrorestriction and pulsed-field gel electrophoresis.	pulsenet is a national network of pubic health and food regulatory laboratories established in the us to detect clusters of foodborne disease and respond quickly to foodborne outbreak investigations. pulsenet laboratories currently subtype escherichia coli o157:h7, non-typhoidal salmonella, and shigella isolates by a highly standardized 1-day pulsed-field gel electrophoresis (pfge), and exchange normalized dna "fingerprint" patterns via the internet. we describe a standardized molecular subtypin ...	2001	11322701
shv-type extended-spectrum beta-lactamase in a shigella flexneri clinical isolate.	a shigella flexneri isolate resistant to oxyimino-cephalosporins was recovered from a stool sample of a 16 month-old algerian child hospitalized in paris, france. this isolate harboured an shv-2 beta-lactamase gene located on a c. 80 kb self-transferable plasmid. this is the first report of an ambler class a extended-spectrum beta-lactamase from shigella spp.	2001	11328785
[immunologic properties of coli surface antigen 6(cs6) of enterotoxigenic escherichia coli and cholera toxin subunit b expressed in shigella flexneri 2a strain t32].	a host-plasmid balancing system composed with a delta asd mutant (fad) of an avirulent strain (t32) of shigella flexneri 2a and plasmid harboring asd gene was used to express enterotoxigenic e. coli surface antigen 6(cs6) and v. cholerae toxin subunit b (ctb). the results of western blotting and elisa showed that all of recombinant plasmids (pyx201, pyx202 and pyx203) could be maintained stably and expressed cs6 and ctb respectively in t32 without any antibiotic selection. all the recombinant ba ...	2001	11330183
[immunosuppressive effects of pathogenic gram-negative bacteria].	the review deals with the immunosuppressive effects of virulent gram-negative bacteria (salmonella, shigela, pseudomonas aeruginosa), with the importance of these effects for the bacteria to survive in the infected body. the above bacteria affect the immunity system in a different way, yet have common features. they are characterized by the occurrence of endotoxin shock, by the suppression of the phagocytic system and cell-mediated immunity. a significant role in suppressing a cellular immune re ...	2001	11338500
antimicrobial-resistant bacterial diarrhea in rural western kenya.	bacterial diarrheal diseases cause substantial morbidity and mortality in sub-saharan africa, but data on the epidemiology and antimicrobial susceptibility patterns of enteric bacterial pathogens are limited. between may 1997 and april 1998, a clinic-based surveillance for diarrheal disease was conducted in asembo, a rural area in western kenya. in total, 729 diarrheal specimens were collected, and 244 (33%) yielded >or=1 bacterial pathogen, as determined by standard culture techniques; 107 (44% ...	2001	11343224
genetic trees reveal disease origins.		2001	11352059
glutaraldehyde-induced colitis.	to describe the etiology and clinical course of acute colitis occurring after flexible endoscopy.	2001	11308232
cloning and characterization of aspergillus nidulans vpsa gene which is involved in vacuolar biogenesis.	in saccharomyces cerevisiae, vacuoles play very important roles in ph and osmotic regulation, protein degradation and storage of amino acids, small ions as well as polyphosphates. in filamentous fungi, however, little is known about vacuolar functions at a molecular level. in this paper, we report the isolation of the vpsa gene from the filamentous fungus aspergillus nidulans as a homologue of the vps1 gene of s. cerevisiae which encodes a dynamin-related protein. the vpsa gene encodes a polypep ...	2001	11368897
molecular characterization of global regulatory rna species that control pathogenicity factors in erwinia amylovora and erwinia herbicola pv. gypsophilae.	rsmb(ecc) specifies a nontranslatable rna regulator that controls exoprotein production and pathogenicity in soft rot-causing erwinia carotovora subsp. carotovora. this effect of rsmb(ecc) rna is mediated mostly by neutralizing the function of rsma(ecc), an rna-binding protein of e. carotovora subsp. carotovora, which acts as a global negative regulator. to determine the occurrence of functional homologs of rsmb(ecc) in non-soft-rot-causing erwinia species, we cloned the rsmb genes of e. amylovo ...	2001	11222584
elicitation of predictable immune responses by using live bacterial vectors.	there is an increasing need for novel vaccines able to stimulate efficient and long-lasting responses, which have also low production costs. to confer protective immunity following vaccination, the adequate type of response should be elicited. vaccines based on attenuated bacterial carriers have contained production and delivery costs, and are able to stimulate more potent immune responses than non-replicating formulations. the improved knowledge on carrier physiology and host response, the avai ...	2001	11222981
diversity in phagocytic signalling.		2001	11228148
molecular epidemiology of a shigella flexneri outbreak in a mountainous township in taiwan, republic of china.	an outbreak of shigellosis occurred in a township of nantou conuty in central taiwan from august to october in 1996. the infections extended to two neighboring townships and continued to the end of 1996. forty cases were confirmed during the period, in contrast to only one confirmed case in nantou county in 1996 before the outbreak. all of these 41 cases in 1996 were identified as infections with shigella flexneri serotype 2a. in order to trace the source of the infections, the 41 isolates recov ...	2001	11230426
etiology of acute diarrhea among children in ribeirão preto-sp, brazil.	to study the main enteropathogens causing diarrhea in the region of ribeirão preto regarding serogroups and serotypes, the feces of 1836 children under 10 years old, from both sexes, attack of acute gastroenteritis, were analysed during a period of 4 years in adolfo lutz institute - ribeirão preto, sp. the pathogens identified by standard methods were the following: escherichia coli, salmonella spp., shigella spp., campylobacter spp., yersinia spp., and cryptosporidium spp. positive samples were ...	2001	11246278
complete genomic sequence of the lytic bacteriophage phiyeo3-12 of yersinia enterocolitica serotype o:3.	phiyeo3-12 is a t3-related lytic bacteriophage of yersinia enterocolitica serotype o:3. the nucleotide sequence of the 39,600-bp linear double-stranded dna (dsdna) genome was determined. the phage genome has direct terminal repeats of 232 bp, a gc content of 50.6%, and 54 putative genes, which are all transcribed from the same dna strand. functions were assigned to 30 genes based on the similarity of the predicted products to known proteins. a striking feature of the phiyeo3-12 genome is its ext ...	2001	11222590
pathogen evolution: how good bacteria go bad.	recent findings suggest that dysentery-causing shigella strains have arisen several times from escherichia coli via plasmid acquisition and phenotypic convergence. similarly, three bacillus strains with distinct pathogenic properties are derivatives of a single species whose behavior is profoundly altered by acquired plasmids.	2001	11231141
spa33, a cell surface-associated subunit of the mxi-spa type iii secretory pathway of shigella flexneri, regulates ipa protein traffic.	the mxi-spa type iii secretion system of shigella flexneri directs the host cell contact-induced secretion of a set of invasins, referred to as ipas. in this study, we examined the role of spa33 in ipa secretion. a spa33-null mutant was both noninvasive and unable to translocate the ipas from inner membrane to outer membrane (om) positions of the mxi-spa transmembrane channel. spa33 was found to be a mxi-spa substrate that is translocated to the bacterial cell surface upon the induction of ipa s ...	2001	11254573
shigella spp. surveillance in indonesia: the emergence or reemergence of s. dysenteriae.	from june 1998 through november 1999, shigella spp. were isolated in 5% of samples from 3,848 children and adults with severe diarrheal illness in hospitals throughout indonesia. s. dysenteriae has reemerged in bali, kalimantan, and batam and was detected in jakarta after a hiatus of 15 years.	2001	11266305
antimicrobial activity of honokiol and magnolol isolated from magnolia officinalis.	the antimicrobial activity of honokiol and magnolol, the main constituents of magnolia officinalis was investigated. the antimicrobial activity was assayed by the agar dilution method using brain heart infusion medium and the minimum inhibitory concentration (mic) were determined for each compound using a twofold serial dilution assay. the results showed that honokiol and magnolol have a marked antimicrobial effect (mic = 25 microg/ml) against actinobacillus actinomycetemcomitans, porphyromonas ...	2001	11268114
synthesis of mannich bases of some 2,5-disubstituted 4-thiazolidinones and evaluation of their antimicrobial activities.	5-phenyl/methyl-5-morpholinomethyl/pyrrolidinomethyl-2-(5- aryl-1,3,4-oxadiazol-2-yl)imino]-4-thiazolidinones (5a-m) were synthesized by the reaction of 5-phenyl/methyl-2-[(5-aryl-1,3,4-oxadiazol -2-yl)imino]-4-thiazolidinones (4a-j) with formaldehyde and morpholine or pyrrolidine. the structures of the compounds were determined by analytical and spectral (ir, 1h-nmr, eims) methods. the antibacterial activities of the novel compounds against staphylococcus aureus atcc 6538, staphylococcus epider ...	2001	11268772
re-evaluating criteria for peritoneal dialysis in "classical" (d+) hemolytic uremic syndrome.	indications for peritoneal dialysis in children with post-dysenteric hemolytic uremic syndrome (d+ hus) have not been thoroughly evaluated. although early institution of dialysis may reduce mortality, the procedure has attendant complications.	2001	11269677
wip regulates n-wasp-mediated actin polymerization and filopodium formation.	induction of filopodia is dependent on activation of the small gtpase cdc42 and on neural wiskott-aldrich-syndrome protein (n-wasp). here we show that wasp-interacting protein (wip) interacts directly with n-wasp and actin. wip retards n-wasp/cdc42-activated actin polymerization mediated by the arp2/3 complex, and stabilizes actin filaments. microinjection of wip into nih 3t3 fibroblasts induces filopodia; this is inhibited by microinjection of anti-n-wasp antibody. microinjection of anti-wip an ...	2001	11331876
regulating cellular actin assembly.	cellular actin assembly is tightly regulated. the study of pathogen motility has led to the identification of several cellular factors that are critical for controlling this process. pathogens such as listeria require ena/vasp and arp2/3 proteins to translate actin polymerization into movement. recent work has extended these observations and uncovered some similarities and surprising differences in the way cells and pathogens utilize the actin cytoskeleton.	2001	11248549
type iv o antigen modification genes in the genome of shigella flexneri nctc 8296.	the genes encoding type iv o antigen glucosylation were characterized from both escherichia coli and shigella flexneri. the putative o antigen modification genes from e. coli, o120 o306 o443, were pcr-amplified and introduced into s. flexneri serotype y strain sfl124. immunogold labelling and phage sensitivity indicated the presence of both serotype y and serotype 4a o antigens on the cell surface of the resulting recombinant sfl124 strains, suggesting that only partial serotype conversion was c ...	2001	11283281
campylobacter jejuni infections: update on emerging issues and trends.	infection with campylobacter jejuni is one of the most common causes of gastroenteritis worldwide; it occurs more frequently than do infections caused by salmonella species, shigella species, or escherichia coli o157:h7. in developed countries, the incidence of campylobacter jejuni infections peaks during infancy and again during early adulthood. most infections are acquired by the consumption and handling of poultry. a typical case is characterized by diarrhea, fever, and abdominal cramps. obta ...	2001	11283810
chvd, a chromosomally encoded atp-binding cassette transporter-homologous protein involved in regulation of virulence gene expression in agrobacterium tumefaciens.	a yeast two-hybrid screen searching for chromosomally encoded proteins that interact with the agrobacterium tumefaciens virb8 protein was carried out. this screen identified an interaction candidate homologous to the partial sequence of a gene that had previously been identified in a transposon screen as a potential regulator of virg expression, chvd. in this report, the cloning of the entire chvd gene is described and the gene is sequenced and characterized. insertion of a promoterless lacz gen ...	2001	11344138
identification and functional characterization of arylamine n-acetyltransferases in eubacteria: evidence for highly selective acetylation of 5-aminosalicylic acid.	arylamine n-acetyltransferase activity has been described in various bacterial species. bacterial n-acetyltransferases, including those from bacteria of the gut flora, may be involved in the metabolism of xenobiotics, thereby exerting physiopathological effects. we characterized these enzymes further by steady-state kinetics, time-dependent inhibition, and dna hybridization in 40 species, mostly from the human intestinal microflora. we report for the first time n-acetyltransferase activity in 11 ...	2001	11344150
espg, a novel type iii system-secreted protein from enteropathogenic escherichia coli with similarities to vira of shigella flexneri.	the function of the rorf2 gene located on the locus of enterocyte effacement (lee) pathogenicity island of enteropathogenic escherichia coli (epec) has not been described. we report that rorf2 encodes a novel protein, named espg, which is secreted by the type iii secretory system and which is translocated into host epithelial cells. espg is homologous with shigella flexneri protein vira, and the cloned espg (rorf2) gene can rescue invasion in a shigella vira mutant, indicating that these protein ...	2001	11349072
[clinical and biological study of acute diarrhea with mixed etiology in 48 patients].	the study of incidence, clinical manifestation and treatment of acute diarrhea with mixed etiology.	2001	12092189
expression of colonization factor antigen i of enterotoxigenic escherichia coli in shigella flexneri 2a t32.	a host-plasmid lethal balancing system was constructed based on asd gene in an avirulent strain of s.flexneri to express colonization factor antigen i(cfa-i) of enterotoxigenic escherichia coli.the results of western blotting suggested that avirulant strain of s.flexneri fwl01 expressed cfa-i steadily. examination of negatively-stained preparation of cultures by electron microscopy showed that s.flexneri fwl01 carrying the plasmid pzhy21 had thick pili on its surface. antibodies against cfa-i we ...	2001	12050785
survivability of shigella dysenteriae type 1 & s. flexneri 2a in laboratory conditions simulating aquatic environment.	information about the duration of survival of shigellae in water is speculative. the present study was undertaken to assess the duration of survival of shigella dysenteriae type 1 and s. flexneri type 2a in the laboratory conditions simulating the aquatic environment, their invasive property and the association of different physico-chemical parameters in the survival process.	2001	12040763
antimicrobial resistance of shigella spp isolated from diarrheal patients between 1989 and 1998 in vietnam.	shigellosis is an important cause of infectious diarrhea in vietnam, caused mainly by shigella flexneri. this study provides for the first time in the international literature, data on the development of antimicrobial resistance in shigella between 1988 to 1998, including data reported to the national program for surveillance of antimicrobial resistance (npsar). our studies show that about 80% of the shigella strains tested were resistant to ampicillin, chloramphenicol, oxytetracycline, trimetho ...	2001	12041563
tropical diarrhoea: new developments in traveller's diarrhoea.	traveller's diarrhoea is the most common illness acquired by visitors to developing countries, affecting 20-50% of the 35 million people who travel from industrialized countries each year. important risk factors include point of origin and destination of the traveller, host factors, and exposure to contaminated food and water. the most common causes of traveller's diarrhoea in adults in developing countries include infection with escherichia coli, shigella spp., salmonella spp., campylobacter sp ...	2001	11964874
epidemiological applications: a case report of a village epidemic of gastroenteritis.	this is a case report of an epidemic of gastroenteritis which was investigated and controlled by epidemiological methods only, before laboratory investigations could be done to confirm the original epidemiological conclusions--from contaminated home made ice-cubes. the case and process are reported in order to encourage similar uses of epidemiology by field public health practitioners, especially within the district or primary health care systems and particularly in places where laboratory suppo ...	2001	12017811
death from multi-resistant shigellosis in fiji islands.	death from shigellosis is rare in developed countries, however it causes over a million deaths in developing countries worldwide annually. death from shigellosis is rare in fiji. however, the global problem of emerging multidrug resistance raises some issues about the management of shigellosis in this country. within fiji, shigella is a notifiable disease. the fiji ministry of health recorded 68 cases of shigella in 1996, 173 cases in 1997 and 334 cases in 1998 (no data available for 1999). ther ...	2001	12017845
global aspects of antimicrobial-resistant enteric bacteria.	antibiotics have been considered to be safe and effective 'magic bullets', with no disadvantages to their widespread use. this has been proven to be a complacent attitude, with ever-increasing prevalences of resistance now evident. the present review covers aspects of the development, mechanisms and genetics of antimicrobial resistance in enteric commensals and pathogens.	2001	11964879
protozoan enteric infection in aids related diarrhea in thailand.	the aim of this study was to determine the prevalence of enteric protozoa and other pathogens in aids patients with diarrhea in bangkok, thailand. of 288 consecutive patients screened in the 10 month period between november 1999-august 2000 inclusive, 55 (19.2%) had cryptosporidium spp, 13 (4.5%) had isospora oocyst, 11 (3.8%) had giardia lamblia, 3 (0.9%) had entamoeba histolytica, and 1 (0.3%) had iodamoeba butschlii infection. the prevalence of microsporidia was 11% in this study. of 251 pati ...	2001	12041580
antibiotic resistance and sero-groups of shigella among paediatric out-patients in southwest ethiopia.	to determine the prevalence of shigella sero-groups and resistance pattern of isolates to commonly used antibiotics in jimma.	2001	12002106
salmonella, shigella and growth potential of other food-borne pathogens in ethiopian street vended foods.	to evaluate the bacteriological safety of food items sold by street vendors with regard to salmonella and shigella and to assess the growth potential of some foodborne pathogens in some street foods.	2001	12219962
the type iii secretion system of gram-negative bacteria: a potential therapeutic target?	several pathogenic gram-negative bacteria, including salmonella, shigella, yersinia, pseudomonas aeruginosa and enteropathogenic escherichia coli harbour a complex attack system called 'type iii secretion' which is, in every case, an essential virulence determinant. this system, activated by contact with an eukaryotic cell membrane, allows bacteria to inject bacterial proteins across the two bacterial membranes and the eukaryotic cell membrane, to reach the cell's cytosol and destroy or subvert ...	2001	12540268
[laboratory diagnostics of acute enteric infections under the conditions of the work of the specialized epidemic brigade during liquidation of the consequences of the emergency situations].	the scheme of the complex microbiological diagnostics of cholera, dysentery, salmonellosis and escherichiosis has been developed. the scheme includes the introduction of material taken from a patient with acute enteric infection into 1% peptone water (ph 8.0), followed by inoculation into endo medium (ph 7.4-8.0) and the selection of colonies on mc-agar with the subsequent final identification of bacteria with the use of biochemical, serological and genetic methods of investigation. this scheme ...	2001	12718172
rapid detection, identification, and enumeration of escherichia coli cells in municipal water by chemiluminescent in situ hybridization.	a new chemiluminescent in situ hybridization (cish) method provides simultaneous detection, identification, and enumeration of culturable escherichia coli cells in 100 ml of municipal water within one working day. following filtration and 5 h of growth on tryptic soy agar at 35 degrees c, individual microcolonies of e. coli were detected directly on a 47-mm-diameter membrane filter using soybean peroxidase-labeled peptide nucleic acid (pna) probes targeting a species-specific sequence in e. coli ...	2001	11133438
identification of functional regions within invasion plasmid antigen c (ipac) of shigella flexneri.	shigella flexneri causes bacillary dysentery with symptoms resulting from the inflammation that accompanies bacterial entry into the cells of the colonic epithelium. the effectors of s. flexneri invasion are the ipa proteins, particularly ipab and ipac, which are secreted at the host-pathogen interface following bacterial contact with a host cell. of the purified ipa proteins, only ipac has been shown to possess quantifiable in vitro activities that are related to cellular invasion. in this stud ...	2001	11123692
resistance to antimicrobial agents in mediterranean countries.		2001	11137644
shigella flexneri luxs quorum-sensing system modulates virb expression but is not essential for virulence.	quorum-sensing systems regulate the expression of virulence factors in a wide variety of plant and animal pathogens, including members of the enterobacteriaceae. studies of shigella virulence gene expression have demonstrated that maximal expression of genes encoding the type iii secretion system and its substrates and maximal activity of this virulence organelle occur at high cell density. in these studies, we demonstrate that the expression of ipa, mxi, and spa invasion operons is maximal in s ...	2001	11119484
molecular and phenotypic characterization of potentially new shigella dysenteriae serotype.	from september 1997 to november 1998, the french national center for salmonella and shigella received 22 shigella isolates recovered from 22 different patients suffering from dysentery. none of these isolates reacted with any of the antisera used to identify established shigella serotypes, but all of them agglutinated in the presence of antisera to a previously described potentially new shigella dysenteriae serotype (represented by strain 96-204) primarily isolated from stool cultures of importe ...	2001	11158117
genetic organization of the she pathogenicity island in shigella flexneri 2a.	in this study we report the complete nucleotide sequence and genetic organization of the she pathogenicity island (pai) of shigella flexneri 2a strain ysh6000t. the 46 603 bp she pai is situated adjacent to the 3' terminus of the phev trna gene and includes an imperfect direct repeat of the 3'-terminal 22 bp of the phev gene at the right boundary of the pai. the she pai carries a bacteriophage p4-like integrase gene within the phev -proximal boundary of the pai, intact and truncated mobile genet ...	2001	11162180
inactivation of gram-negative bacteria by lysozyme, denatured lysozyme, and lysozyme-derived peptides under high hydrostatic pressure.	we have studied the inactivation of six gram-negative bacteria (escherichia coli, pseudomonas fluorescens, salmonella enterica serovar typhimurium, salmonella enteritidis, shigella sonnei, and shigella flexneri) by high hydrostatic pressure treatment in the presence of hen egg-white lysozyme, partially or completely denatured lysozyme, or a synthetic cationic peptide derived from either hen egg white or coliphage t4 lysozyme. none of these compounds had a bactericidal or bacteriostatic effect on ...	2001	11133464
structure-function analysis of the shigella virulence factor ipab.	infection by the gram-negative bacterium shigella flexneri results in dysentery, an acute inflammatory disease of the colon. essential events in the pathogenesis of shigella infections include bacterial invasion of epithelial cells, escape from the phagosome, and induction of apoptosis in macrophages. the shigella virulence factor invasion plasmid antigen b (ipab) is required for all of these processes. induction of apoptosis is dependent on ipab binding to the cysteine protease caspase-1 (casp- ...	2001	11157939
conserved regulatory elements of the promoter sequence of the gene rpoh of enteric bacteria.	the rpoh regulatory region of different members of the enteric bacteria family was sequenced or downloaded from genbank and compared. in addition, the transcriptional start sites of rpoh of yersinia frederiksenii and proteus mirabilis, two distant members of this family, were determined. sequences similar to the sigma(70) promoters p1, p4 and p5, to the sigma(e) promoter p3 and to boxes dnaa1, dnaa2, camp receptor protein (crp) boxes crp1, crp2 and box cytr present in escherichia coli k12, were ...	2001	11139607
surfing pathogens and the lessons learned for actin polymerization.	a number of unrelated bacterial species as well as vaccinia virus (ab)use the process of actin polymerization to facilitate and enhance their infection cycle. studies into the mechanism by which these pathogens hijack and control the actin cytoskeleton have provided many interesting insights into the regulation of actin polymerization in migrating cells. this review focuses on what we have learnt from the actin-based motilities of listeria, shigella and vaccinia and discusses what we would still ...	2001	11146296
microbiological survey of retail herbs and spices from mexican markets.	in the present study, 304 samples of herbs and spices (garlic powder, cumin seeds, black pepper, oregano, and bay leaves) widely used in mexico were analyzed for the presence of bacillus cereus, salmonella typhi, shigella dysenteriae, escherichia coli, total and fecal coliforms, total mesophilic aerobic organisms, and fungi. samples were nonpackaged or packaged in polyethylene bags or glass containers. high levels (10(5) to 10(7) cfu/g) of mesophilic aerobic microorganisms were found in most of ...	2001	11198448