| listeriolysin genes: complete sequence of ilo from listeria ivanovii and of lso from listeria seeligeri. | the complete dna sequences coding for the thiol-activated cytolysins from listeria ivanovii, ivanolysin o (ilo) and for seeligerolysin o (lso) from listeria seeligeri have been determined. the deduced amino acid sequences revealed that: (i) the primary translation products comprise 528 (ilo) and 530 (lso) amino acids, respectively, (ii) ilo contains two cysteines, lso has a substitution in the conserved cysteine motif. | 1992 | 1543752 |
| differentiation of listeria monocytogenes, listeria innocua, listeria ivanovii, and listeria seeligeri by pulsed-field gel electrophoresis. | clamped homogeneous electric field analysis of listeria dna with apai, asci, smai, or noti revealed species- and serotype-specific differences in genomic fingerprints. clamped homogeneous electric field analysis may prove useful, therefore, in epidemiologic studies. also, the summation of individually sized asci fragments of genomic dna from l. monocytogenes serotype 4b 101m and scott a indicated genome lengths of 2,925 and 3,046 kb, respectively. | 1992 | 1610193 |
| phosphatidylinositol-specific phospholipase c activity as a marker to distinguish between pathogenic and nonpathogenic listeria species. | in this study, 468 listeria strains were checked for the presence of phosphatidylinositol-specific phospholipase c (pi-plc) activity by using a simple assay that consisted of overlaying colonies formed on agar plates with l-alpha-phosphatidylinositol as substrate. in this assay, pi-plc-active colonies show turbid halos around the colonies as a result of the release of insoluble diacylglycerol from the substrate. this activity was detected only in the pathogenic species listeria monocytogenes and ... | 1991 | 1662937 |
| phylogenetic analysis of the genus listeria based on reverse transcriptase sequencing of 16s rrna. | the phylogenetic interrelationships of members of the genus listeria were investigated by using reverse transcriptase sequencing of 16s rrna. the sequence data indicate that at the intrageneric level the genus listeria consists of the following two closely related but distinct lines of descent: (i) the listeria monocytogenes group of species (including listeria innocua, listeria ivanovii, listeria seeligeri, and listeria welshimeri) and (ii) the species listeria grayi and listeria murrayi. at th ... | 1991 | 1713054 |
| sensitive and specific detection of listeria monocytogenes in milk and ground beef with the polymerase chain reaction. | a sensitive and specific method for detection of listeria monocytogenes in milk and ground-beef samples is described. it consists of culturing samples in listeria enrichment broth (leb) and subculturing them from leb to listeria plating media, followed by dna extraction and species-specific detection of the organism by using the polymerase chain reaction (pcr). in developing the l. monocytogenes pcr assay, five oligonucleotide primers complementary to the nucleotide sequence of the listeriolysin ... | 1991 | 1768130 |
| cloning, characterization, and expression in escherichia coli of a gene encoding listeria seeligeri catalase, a bacterial enzyme highly homologous to mammalian catalases. | a gene coding for catalase (hydrogen-peroxide:hydrogen-peroxide oxidoreductase; ec 1.11.1.6) of the gram-positive bacterium listeria seeligeri was cloned from a plasmid library of ecori-digested chromosomal dna, with escherichia coli dh5 alpha as a host. the recombinant catalase was expressed in e. coli to an enzymatic activity approximately 50 times that of the combined e. coli catalases. the nucleotide sequence was determined, and the deduced amino acid sequence revealed 43.2% amino acid seque ... | 1991 | 1860824 |
| taxonomy of the genus listeria by using multilocus enzyme electrophoresis. | seventy-three strains of the seven recognized listeria species were studied by performing a multilocus enzyme electrophoresis analysis of 18 enzyme loci. the mean number of alleles per locus was 9.5 and all of the loci were polymorphic. a total of 56 electrophoretic types were distinguished. cluster analysis of a matrix of the genetic distances between paired electrophoretic types revealed that there were six principal clusters at the species level (genetic distances between clusters greater tha ... | 1991 | 1899799 |
| evaluation of hybridization characteristics of a cloned prf106 probe for listeria monocytogenes detection and development of a nonisotopic colony hybridization assay. | an internal fragment (prf106 fragment, ca. 500 bp) of a gene (msp) coding for a 60-kda protein of listeria monocytogenes serotype 1/2a was used to develop a screening method to discriminate between l. monocytogenes and avirulent listeria spp. on primary isolation plates. the l. monocytogenes-derived probe fragment of prf106 hybridized to a 13-kb fragment of l. monocytogenes and a 3-kb fragment of one cheese isolate strain of listeria seeligeri under stringent hybridization conditions (mean therm ... | 1991 | 1903627 |
| production and characterization of neutralizing and nonneutralizing monoclonal antibodies against listeriolysin o. | listeriolysin o (llo) is a thiol-activated toxin secreted by the facultative intracellular pathogen listeria monocytogenes. llo is essential for the survival of the bacterium in the infected cell because it promotes lysis of the phagosome membrane and escape of the bacterium into the cytosol. llo was used as an antigen for the production of nine monoclonal antibodies (mabs) in mice. three of these could inhibit the hemolytic activity of llo. one of them inhibited binding of llo to erythrocyte me ... | 1991 | 1937824 |
| haematological reactions of rabbits infected intravenously with listeria strains of different virulence. | listeria strains of different virulence were injected intravenously into rabbits of both sexes (2-4 kg). the infectious dose was 10(8) cells/kg. blood samples were taken from the ear wein one day and immediately before the infection, then 3 h, 1, 2, 3, 6 and 10 days after it. total white blood cell counts and their changes were determined and the number of lysosomal granules in neutrophils were counted. a marked monocytic reaction was observed after the injection of virulent listeria monocytogen ... | 1990 | 2124767 |
| revision of the validity of camp tests for listeria identification. proposal of an alternative method for the determination of haemolytic activity by listeria strains. | the validity of camp tests with staphylococcus aureus and rhodococcus (corynebacterium) equi as defined for listeria identification was revised. this characterization method appeared to be unreliable for two reasons: first, a positive camp test with r. equi is not specific for listeria ivanovii as listeria monocytogenes (and listeria seeligeri) give also a clear positive reaction; second, doubtful reactions could be observed with s. aureus when assaying haemolytic and non-haemolytic listeria str ... | 1990 | 2270739 |
| the place of listeria among gram-positive bacteria. | the genus listeria, containing the species listeria monocytogenes, listeria innocua, listeria seeligeri, listeria welshimeri, listeria ivanovii, listeria grayi and listeria murrayi is a well circumscribed taxon. numerical taxonomic and chemical studies indicate a very close phenetic similarity to the genus brochothrix and a more distant, but close, similarity to a number of other genera such as lactobacillus, streptococcus, lactococcus, enterococcus, staphylococcus, kurthia and bacillus. recent ... | 1988 | 2458321 |
| taxonomy of the genus listeria. | according to dna homology values as well as to 16s rrna cataloguing results, the genus listeria presently contains two groups of closely related species: one is constitued by listeria gravi and listeria murrayi, the other by listeria monocytogenes, listeria ivanovii, listeria innocua, listeria welshimeri, and listeria seeligeri. among these seven species, only two are pathogenic for humans and animals: listeria monocytogenes and listeria ivanovii. listeria denitrificans was recently excluded fro ... | 1988 | 2458322 |
| cloning of a gene encoding a major secreted polypeptide of listeria monocytogenes and its potential use as a species-specific probe. | a gene, designated msp, that encodes a major secreted polypeptide with a molecular mass of approximately 60 kilodaltons (kda) was cloned from listeria monocytogenes 10403. dna hybridization analysis indicated that the msp gene was highly conserved among 15 independent l. monocytogenes isolates and that each of 5 isolates tested secreted a 60-kda polypeptide that was immunologically related to the msp gene product. dna sequences related to msp were not detected in any other listeria species or in ... | 1989 | 2508555 |
| production of thiol-dependent haemolysins by listeria monocytogenes and related species. | twenty-six strains belonging to the five main species of the genus listeria were examined for production of thiol-dependent exotoxins. all strains of l. monocytogenes cultured in charcoal-treated broth secreted a haemolytic factor at a level ranging from 200 to 800 haemolytic units (hu) ml-1, except for the strain egd (1500 hu ml-1) and the type strain cip 82110t (10 hu ml-1). the haemolytic activity reached a maximum level by 8-10 h and then rapidly declined as soon as bacterial exponential gro ... | 1989 | 2516113 |
| specific gene probe for detection of biotyped and serotyped listeria strains. | a total of 284 strains of listeria, including all known serovars and biovars together with listeria grayi and listeria murrayi, were biotyped and serotyped. biotyping and serotyping could be done in 2 days. a gene probe encoding a delayed hypersensitivity factor (dth) was used in the detection of pathogenic biotypes and serotypes of the tested strains. the gene was found in all 117 tested listeria monocytogenes strains of serogroups 1/2a, 1/2b, 1/2c, 3a, 3b, 3c, 4c, 4d, 4e, 4ab, and 7. it was al ... | 1989 | 2658807 |
| detection of listeriolysin, the thiol-dependent hemolysin in listeria monocytogenes, listeria ivanovii, and listeria seeligeri. | the listeriolysin gene from a weakly hemolytic but virulent strain of listeria monocytogenes serotype 1/2a was cloned in escherichia coli k-12. recombinants were identified on the basis of their cross-reactivities to hyperimmune antisera raised against streptolysin o and listeriolysin. low levels of hemolytic activity were detected in crude lysates of strains harboring the listeriolysin gene. in dna hybridization studies with five dna probes that encoded the listeriolysin gene and surrounding se ... | 1989 | 2744850 |
| microplate technique to determine hemolytic activity for routine typing of listeria strains. | because the hemolysis produced by listeria monocytogenes and listeria seeligeri on blood agar is frequently difficult to interpret, we developed a microplate technique for the routine determination of hemolytic activity with erythrocyte suspensions. this microtechnique is a simple and reliable test for distinguishing clearly between hemolytic and nonhemolytic strains and could be used instead of the camp (christie-atkins-munch-petersen) test with staphylococcus aureus in the routine typing of li ... | 1986 | 3088037 |
| carriage of listeria monocytogenes and related species in pregnant and non-pregnant women in aberdeen, scotland. | the faecal, cervico-vaginal and oropharyngeal carriage of listeria species in 54 healthy pregnant women and 60 healthy non-pregnant women was investigated. samples were cold-enriched at 4 degrees c and subcultured on selective media containing acriflavin, nalidixic acid and potassium thiocyanate. listeria monocytogenes was isolated from the faeces of one pregnant woman (2%) and two non-pregnant women (3.4%). listeria innocua was isolated from the faeces of one pregnant woman (2%) and one non-pre ... | 1986 | 3093591 |
| in vitro model of penetration and intracellular growth of listeria monocytogenes in the human enterocyte-like cell line caco-2. | penetration and replication of listeria monocytogenes within intestinal epithelial cells were studied by infecting the human enterocyte-like cell line caco-2. entry was due to directed phagocytosis, as suggested by the inhibiting effect of cytochalasin d on bacterial entry and by electron microscopy showing bacteria inside membrane-limiting vacuoles at the early stage of infection. only bacteria from pathogenic species (l. monocytogenes and listeria ivanovii) were able to induce their own phagoc ... | 1987 | 3117693 |
| microcalorimetric investigations on listeria. | sixty-one listeria strains--listeria monocytogenes (35 strains), listeria ivanovii (8), listeria innocua (7), listeria welshimeri (6) and listeria seeligeri (5)--were tested microcalorimetrically for their heat production upon growth in columbia broth. listeria ivanovii and listeria seeligeri displayed different and quite characteristic thermograms. listeria welshimeri, listeria innocua and all but one of the listeria monocytogenes strains showed similar microcalorimetric curves, which differed ... | 1988 | 3134766 |
| pathogenicity of listeria monocytogenes in comparison to other listeria species. | in different mouse models the pathogenicity of various strains of listeria monocytogenes and of other listeria spp. was evaluated. although quantitative differences of virulence among strains of l. monocytogenes are found, all isolates have to be regarded pathogenic unless essential virulence factors, such as protein composition of the cell wall or hemolysin production, are lacking. besides l. monocytogenes, only listeria ivanovii is able to multiply in the murine host, though definitely to a le ... | 1988 | 3138187 |
| hemolysin from listeria--biochemistry, genetics and function in pathogenesis. | thiol-activated hemolysins (listeriolysins) from listeria monocytogenes (sv4b) and listeria ivanovii were purified to homogeneity. the n-terminal amino acid sequences of the 58 kda listeriolysin of l. ivanovii and of a 24 kda protein which may represent the camp-factor of l. ivanovii were determined. antibodies raised against the l. ivanovii listeriolysin and anti-streptolysin o antibodies were used in western blot analyses to detect listeriolysin(s) in virulent and avirulent listeria strains. i ... | 1988 | 3138189 |
| [new species of the genus listeria: listeria seeligeri]. | listeria seeligeri is a recently described species which shares 28% to 1% dna relatedness with the other species of the genus listeria. g + c% content of the type strain is 36. peptidoglycan type (variation a1 gamma) as well as teichoic acids are identical to those found in l. monocytogenes. l. seeligeri can be easily distinguished from the other species using the following markers: hemolysis (camp-tests with staphylococcus aureus and rhodococcus equi) and acid production from d-xylose, l-rhamno ... | 1987 | 3313216 |
| [isolation of listeria seeligeri and l. welshimeri bacteriophages. lysotyping of l. monocytogenes, l. ivanovii, l. innocua, l. seeligeri and l. welshimeri]. | recent taxonomic reexamination of listeria monocytogenes strains as defined in the 8th edition of bergey's manual of determinative bacteriology allowed to distinguish 5 species among these strains: l. monocytogenes, l. innocua, l. ivanovii, l. welshimeri, and l. seeligeri. as till now only the behaviour of the species l. monocytogenes, l. innocua, and l. ivanovii towards bacteriophages was characterized, the present study aimed at the search for phages occurring on these two new species and to d ... | 1985 | 4050196 |
| [isolation of micro-organisms of the species listeria from raw milk intended for human consumption]. | refrigerated mixtures of raw milk provided by a dairy which was supplied by farms from west and central spain were tested for the presence of listeria microorganisms. a total of 95 samples were taken at regular intervals over a 16-month period. listeria grayi was isolated from 89.5% of the samples, listeria monocytogenes s. str. from 45.3%, listeria innocua from 15.8%, listeria welshimeri from 3.1%, and listeria seeligeri from 1.05%. listeria ivanovii, listeria murrayi, and listeria denitrifican ... | 1985 | 4063881 |
| interactions with lectins and agglutination profiles of clinical, food, and environmental isolates of listeria. | on the basis of preliminary trials with 14 collection strains of listeria, five lectins (canavalia ensiformis, concanavalin a; griffonia simplicifolia lectin i; helix pomatia agglutinin; ricinus communis agglutinin; and triticum vulgaris wheat germ agglutinin) were selected to set up a microtiter agglutination assay. the lectin agglutination profiles of 174 clinical, food, and environmental strains of listeria monocytogenes, listeria innocua, and listeria seeligeri were investigated. data on the ... | 1994 | 7883879 |
| the virulence gene cluster of listeria monocytogenes is also present in listeria ivanovii, an animal pathogen, and listeria seeligeri, a nonpathogenic species. | most known listeria monocytogenes virulence genes cluster within a 9.6-kb chromosomal region. this region is flanked on one end by two uncharacterized open reading frames (orf a and orf b) and ldh, an orf presumably encoding the l. monocytogenes lactate dehydrogenase (j.-a. vazquez-boland, c. kocks, s. dramsi, h. ohayon, c. geoffroy, j. mengaud, and p. cossart, infect. immun. 60:219-230, 1992). we report here that the other end is flanked by prs, and orf homologous to phosphoribosyl ppi syntheta ... | 1994 | 8039927 |
| distribution of listeria spp. in confectioners' pastries from western france: comparison of enrichment methods. | three hundred samples of pastry from 100 different suppliers in western france, including butter-cream, whipped dairy cream and custard filled cakes from each supplier, were collected and tested for the occurrence of listeria spp. in 25 g samples. listeria spp. were detected in 21.7% of he samples: listeria monocytogenes in 13.7%, listeria innocua in 10% and listeria seeligeri in 2.3%. thirteen samples were contaminated with two species simultaneously. the frequency of contaminated samples was n ... | 1993 | 8347428 |
| in vitro conjugative transfer of vana vancomycin resistance between enterococci and listeriae of different species. | in a study designed to gain data on the in vitro transferability of vancomycin resistance from enterococci of the vana phenotype to listeriae of different species, three clinical enterococcus isolates-enterococcus faecium ls10, enterococcus faecalis ls4, and enterococcus faecalis a3208, all harboring a plasmid that strongly hybridized with a vana probe-were used as donors in transfer experiments. strains of five listeria species were used as recipients. from enterococcus faecium ls10, glycopepti ... | 1996 | 8641304 |
| comparative analysis of 16s and 23s rrna sequences of listeria species. | in order to establish the taxonomic value of 16s rrna and 23s rrna for distinguishing listeria species, the complete 23s rrna sequences for all listeria species were determined by using the type strains. we designed and experimentally validated a universal 23s rrna sequencing method, which included pcr amplification of the rdna gene and direct cycle sequencing of the amplicon with eubacterial primers. the results of our sequence comparison indicated that the genus listeria can be divided into tw ... | 1996 | 8782674 |
| genus- and species-specific detection of listeria monocytogenes using polymerase chain reaction assays targeting the 16s/23s intergenic spacer region of the rrna operon. | in this study, the 16s/23s rrna intergenic spacer (igs) regions of six listeria species were examined. dna bands of 590 and 340 bp were observed following polymerase chain reaction (pcr) amplification of dna from listeria monocytogenes, listeria innocua, listeria seeligeri, listeria welshimeri, and listeria ivanovii strains with generic rrna igs oligonucleotide primers. for strains of listeria grayi subspp. grayi and murrayi, dna band sizes of 550 and 340 bp were observed with this primer pair. ... | 1996 | 8941989 |
| occurrence of listeria monocytogenes and other listeria spp. in raw caprine milk. | samples of caprine milk from bulk tanks of 405 farms in central spain were analyzed for listeria spp. once per season over a 1-yr period. listeria monocytogenes and listeria innocua were detected in 2.56 and 1.73% of the 1445 samples, respectively. listeria ivanovii (0.21% samples) and listeria seeligeri (0.07% samples) were rarely isolated. only 6 milk samples were contaminated by more than one listeria species. most farms (92.59%) produced milk that was apparently free from l. monocytogenes th ... | 1996 | 8961100 |
| complementation of listeria seeligeri with the plca-prfa genes from l. monocytogenes activates transcription of seeligerolysin and leads to bacterial escape from the phagosome of infected mammalian cells. | infection experiments have shown that the avirulent species listeria seeligeri invaded the enterocyte-like cell line caco-2 with low efficiency but was unable to escape from the phagosome. introduction of the listeriolysin gene (hly) from l. monocytogenes into l. seeligeri via a recombinant plasmid did not change these characteristics. no measurable transcription of this gene or of the structurally intact chromosomal seeligerolysin gene (lso) was detected. transformation with a plasmid carrying ... | 1997 | 9011051 |
| [listeriosis in a rabbitry]. | an enzootic of listeriosis in a rabbitry is reported. listeria monocytogenes serotype 1/2a was isolated from the organs of a doe, which had died of septic metritits. from aborted fetuses of two other does listeria monocytogenes serotype 1/2b and 4b were cultured, respectively. in feed samples of the rabbitry listeria monocytogenes strains of the serotypes 1/2b and 4b besides the apathogenic listeria species listeria seeligeri and listeria innocua were detected. serological studies with agglutina ... | 1996 | 9081819 |
| prevalence of listeria sp. in droppings from urban rooks (corvus frugilegus). | droppings from 112 urban rooks (corvus frugilegus) were cultured for the presence of listeria sp. overall, 46% of rooks sampled harboured one or more listeria species. of all birds examined, 33%, 24% and 8%, respectively, were infected with listeria monocytogenes, listeria innocua and listeria seeligeri. differentiation of l. monocytogenes and l. seeligeri carried out by several phenotypic typing methods proved the diversity of strains and the major role of rooks which widely contribute to sprea ... | 1997 | 9172407 |
| phylogenetic relationships among prokaryotic and eukaryotic catalases. | seventy-four catalase protein sequences, including 29 bacterial, 8 fungal, 7 animal, and 30 plant sequences, were compiled, and 70 were used for phylogenetic reconstruction. the core of the resulting tree revealed unique, separate groups of plant and animal catalases, two groups of fungal catalases, and three groups of bacterial catalases. the only overlap of kingdoms occurred within one branch and involved fungal and bacterial large-subunit enzymes. the other fungal branch was closely linked to ... | 1997 | 9287428 |
| comparison of different selective methods for detection of listeria species in surface water. | tests were carried out to evaluate the efficiency of various combinations of selective enrichment and plating techniques using pure cultures of listeria monocytogenes, listeria seeligeri and listeria innocua in suspension and samples of surface water. the best yields for the various listeria spp. were obtained after a single passage in leb (oxoid) or leb buffered (oxoid) and after using palcam and oxford agar (oxoid). palcam agar was, however, shown to be the most efficient means of detecting th ... | 1995 | 9353532 |
| unstable expression and thermal instability of a species-specific cell surface epitope associated with a 66-kilodalton antigen recognized by monoclonal antibody em-7g1 within serotypes of listeria monocytogenes grown in nonselective and selective broths. | conditions that resulted in unstable expression and heat instability of a cell surface epitope associated with a 66-kda antigen in listeria monocytogenes serotypes were identified with the probe monoclonal antibody (mab) em-7g1 in an enzyme-linked immunosorbent assay. this epitope appeared to be absent in three serotypes (serotypes 3b, 4a, and 4c), which did not react with mab em-7g1 irrespective of the enrichment broth tested. the remaining 10 serotypes were detected by mab em-7g1 only when cel ... | 1998 | 9687476 |
| polar lipids of four listeria species containing l-lysylcardiolipin, a novel lipid structure, and other unique phospholipids. | the membrane lipids of listeria innocua, listeria monocytogenes, listeria seeligeri and listeria welshimeri were fractionated on deae-cellulose and purified by chromatography on silica gel and/or preparative tlc. the lipid structures were elucidated by chemical and chromatographic means. the polar lipid composition of the four listeria species was similar. phospholipids predominated. they consisted of phosphatidylglycerol, l-lysylphosphatidylglycerol, cardiolipin [bis(phosphatidyl)glycerol] and ... | 1999 | 10408878 |
| temperature gradient gel electrophoresis of the amplified product of a small 16s rrna gene fragment for the identification of listeria species isolated from food. | the development of a rapid method for the identification of listeria spp. is described. it is based on the polymerase chain reaction amplification of a small fragment from the 16s rrna gene followed by temperature gradient gel electrophoresis. forty-five strains of listeria spp. (listeria monocytogenes, listeria innocua, listeria ivanovii, listeria seeligeri, and listeria welshimeri) were used for the optimization of the protocol. no differences were observed between the results of the identific ... | 2000 | 10826726 |
| listeria species in raw and ready-to-eat foods from restaurants. | from september 1999 to march 2000, meat (pork, beef, and chicken), fish (salmon, hake, and sole), vegetable (lettuce and spinach), and spanish potato omelette samples obtained at restaurants were collected and tested for the occurrence of listeria spp. listeria monocytogenes was isolated from 3 (2.9%) out of 103 studied samples. other species isolated were listeria grayi (13.6%), listeria innocua (1.9%), listeria ivanovii (5.8%), listeria seeligeri (3.9%), and listeria welshimeri (1.9%). listeri ... | 2001 | 11307896 |
| incidence and characterization of listeria spp. from foods available in korea. | a total of 410 domestic korean food samples were analyzed for the presence of listeria spp. by the conventional u.s. department of agriculture protocol, and presumptive strains were identified by morphological, cultural and biochemical tests according to bergey's manual and confirmed by api-listeria kit. among the total 410 food samples, 46 samples (11.2%) were found to be contaminated with listeria species. among the 46 strains of listeria spp. isolates, 8 strains (17.42%) for listeria monocyto ... | 2001 | 11307897 |
| antibiotic resistance among listeria, including listeria monocytogenes, in retail foods. | in the past eight to 10 years, reports of antibiotic resistance in food-borne isolates in many countries have increased, and this work examined the susceptibility of 1001 food isolates of listeria species. | 2001 | 11309061 |
| crystallization and preliminary x-ray analysis of clade i catalases from pseudomonas syringae and listeria seeligeri. | haem-containing catalases are homotetrameric molecules that degrade hydrogen peroxide. phylogenetically, the haem-containing catalases can be grouped into three main lines or clades. the crystal structures of seven catalases have been determined, all from clades ii and iii. in order to obtain a structure of an enzyme from clade i, which includes all plant, algae and some bacterial enzymes, two bacterial catalases, catf from pseudomonas syringae and kat from listeria seeligeri, have been crystall ... | 2001 | 11468413 |
| comparison of the efficacy of different techniques, culture media, and sources of blood in determining the hemolytic activity of listeria spp.. | hemolytic activity is a fundamental criterion for the differentiation of listeria species; therefore, a simple and inexpensive procedure to clearly distinguish hemolytic strains from each other and from nonhemolytic strains would be of great aid. we compared the efficacy of several techniques, culture media, and types of blood in demonstrating the hemolysis of listeria spp. the hemolytic activities of listeria monocytogenes and listeria seeligeri were more easily detected with a red blood cell t ... | 2001 | 11547885 |
| difference in cholesterol-binding and cytolytic activities between listeriolysin o and seeligeriolysin o: a possible role of alanine residue in tryptophan-rich undecapeptide. | we have constructed recombinant listeriolysin o (rllo) and seeligeriolysin o (rlso) from listeria monocytogenes and listeria seeligeri, respectively. in hemolysis and cholesterol-binding assays, the specific activity of recombinant toxin was lower for lso as compared to llo. to understand the molecular basis of this difference, in particular with respect to the conserved trp-rich undecapeptide, a naturally occurring ala to phe substitution in lso was introduced into rllo. the rllo:a488f hemolysi ... | 2001 | 11583846 |
| prevalence and contamination levels of listeria monocytogenes in smoked fish and pâté sold in spain. | from march to november 2000, 170 samples of smoked fish and 182 samples of pâté for sale in retail outlets and supermarkets in the nine provinces of castilla and león (spain) were analyzed for the prevalence of listeria monocytogenes and other listeria spp. l. monocytogenes was isolated from 38 (22.3%) of the 170 samples of smoked fish analyzed. twenty of these positive samples contained l. monocytogenes at >100 cfu/g. other listeria spp., such as listeria innocua (26 isolates), listeria grayi ( ... | 2001 | 11770642 |
| bacteriocin-producing lactobacillus sake as starter culture in dry sausages. | one hundred and fifty-two strains of lactobacillus spp and micrococcus spp, isolated from dry sausages, were screened for inhibitory activity. two of the strains assayed of the genus lactobacillus showed bactericidal activity. they were able to inhibit listeria monocytogenes, listeria seeligeri, listeria innocua, lactobacillus alimentarius and lactobacillus bavaricus. the strains of escherichia coli, salmonella bradford and salmonella newlands, staphylococcus aureus, bacillus cereus, pseudomonas ... | 2002 | 11837390 |
| seeligeriolysin o, a cholesterol-dependent cytolysin of listeria seeligeri, induces gamma interferon from spleen cells of mice. | seeligeriolysin o (lso), one of the cholesterol-dependent cytolysins produced by listeria seeligeri, shows 80% homology to listeriolysin o (llo) produced by listeria monocytogenes at the amino acid sequence level. in addition to cytolytic activity, llo has been shown to exhibit cytokine-inducing activity. in order to determine whether lso is also capable of exhibiting these two different activities, we constructed a recombinant full-length lso (rlso530) and a noncytolytic truncated derivative wi ... | 2003 | 12496171 |
| polymerase chain reaction detection of listeria monocytogenes on frankfurters using oligonucleotide primers targeting the genes encoding internalin ab. | a polymerase chain reaction (pcr) assay targeting the genes encoding internalin ab (inlab) was developed for detecting listeria monocytogenes in pure cell cultures and on artificially contaminated frankfurters. four sets of oligonucleotide primers were evaluated. the set targeting a 902-bp region of the inlab gene was the most specific. this pcr product was detected in 51 l. monocytogenes strains belonging to four different serogroups (1/2a, 1/2b, 1/2c, and 4b). in contrast, the pcr product was ... | 2003 | 12597483 |
| bacteriocin-like substance (bls) production in aeromonas hydrophila water isolates. | 30 aeromonas hydrophila water isolates were tested for bacteriocin-like substance (bls) production using a target panel of closely related microorganisms and other gram-positive and gram-negative bacteria, including food-borne pathogens. a. hydrophila showed antibacterial activity against one or more indicator microorganisms, but the activity emerged only with non-phylogenetically related genera or species. in particular all a. hydrophila showed antibacterial activity against one or more of the ... | 2003 | 12644237 |
| rapid identification of listeria species by using restriction fragment length polymorphism of pcr-amplified 23s rrna gene fragments. | a molecular method based on restriction fragment length polymorphism (rflp) of pcr-amplified fragments of the 23s rrna gene was designed to rapidly identify listeria strains to the species level. two fragments (s1, 460 bp, and s2, 890 bp) were amplified from boiled dna. s2 was cut with the restriction enzymes xmni or cfoi and, if needed, s1 was digested by either alui or clai. this method was first optimized with six reference strains and then applied to 182 isolates collected from effluents of ... | 2003 | 14602590 |
| species-specific pcr determination of listeria seeligeri. | listeria seeligeri is a non-pathogenic bacterium coming under the genus listeria. as this bacterium resembles other listeria species such as l. monocytogenes and l. ivanovii that are pathogenic to man and animals, it is important that rapid and precise identification techniques be available for l. seeligeri in cases where such determination is desirable. a specific molecular test on the basis of a uniquely present gene region in l. seeligeri will be of particular value under the circumstances. i ... | 2004 | 15501651 |
| evolutionary history of the genus listeria and its virulence genes. | the genus listeria contains the two pathogenic species listeria monocytogenes and listeria ivanovii and the four apparently apathogenic species listeria innocua, listeria seeligeri, listeria welshimeri, and listeria grayi. pathogenicity of the former two species is enabled by an approximately 9 kb virulence gene cluster which is also present in a modified form in l. seeligeri. for all listeria species, the sequence of the virulence gene cluster locus and its flanking regions was either determine ... | 2005 | 15709360 |
| effect of ph on the inhibition of listeria spp. by vanillin and vanillic acid. | the antimicrobial effects of vanillin and vanillic acid were verified against several species and strains of listeria monocytogenes, listeria innocua, listeria grayi, and listeria seeligeri in a laboratory medium adjusted to ph values ranging from 5.0 to 8.0. medium ph had little influence on the mic of vanillin as determined by a broth dilution assay, and growth of all test strains was inhibited by concentrations ranging from 23 to 33 mm. in contrast, none of the strains were inhibited by 100 m ... | 2005 | 16013390 |
| seeligeriolysin o, a protein toxin of listeria seeligeri, stimulates macrophage cytokine production via toll-like receptors in a profile different from that induced by other bacterial ligands. | seeligeriolysin o (lso), a member of cholesterol-dependent cytolysins of listeria seeligeri, exhibits cytokine-inducing activity. in this study, we examined the profile of cytokines expressed in macrophages of mice after stimulation with full-length form of recombinant lso (rlso530), c-terminal-truncated protein (rlso483) and two authentic cytokine-inducing toll-like receptor (tlr) ligands from bacteria, peptidoglycan (pgn) and lps. both rlso530 and rlso483 were able to induce il-12 p40 and il-1 ... | 2005 | 16291660 |
| monoclonal antibodies binding to the cell surface of listeria monocytogenes serotype 4b. | serotype 4b strains of the food-borne pathogen listeria monocytogenes are responsible for a large portion of sporadic listeric infections and all major food-borne listeriosis outbreaks in humans. hybridomas were produced from three fusions with lymphocytes of nd4 mice immunized either with the insoluble antigens of l. monocytogenes serotype 4b or with formalin-killed bacterial cells and screened for monoclonal antibodies (mabs) reactive to l. monocytogenes serotype 4b. a set of 35 mabs was ident ... | 2006 | 16476793 |
| discovery of natural atypical nonhemolytic listeria seeligeri isolates. | we found seven listeria isolates, initially identified as isolates with the xyl(+) rha(-) biotype of listeria welshimeri by phenotypic tests, which exhibited discrepant genotypic properties in a well-validated listeria species identification oligonucleotide microarray. the microarray gives results of these seven isolates being atypical hly-negative l. seeligeri isolates, not l. welshimeri isolates. the aberrant l. seeligeri isolates were d-xylose fermentation positive, l-rhamnose fermentation ne ... | 2006 | 16597942 |
| rabbit meat as a source of bacterial foodborne pathogens. | even though worldwide production of rabbit meat is >1,000,000 tons, little information is available for rabbit meat microbiology. this study provides data on the prevalence of salmonella, escherichia coli o157:h7, yersinia enterocolitica, listeria spp., motile aeromonas spp., and staphylococcus aureus on rabbit meat. a total of 24 rabbit carcasses from two abattoirs and 27 rabbit meat packages from supermarket displays were examined. in addition to culturing methods, associated virulence genes w ... | 2006 | 16715811 |
| species-specific differences in the activity of prfa, the key regulator of listerial virulence genes. | prfa, the master regulator of lipi-1, is indispensable for the pathogenesis of the human pathogen listeria monocytogenes and the animal pathogen listeria ivanovii. prfa is also present in the apathogenic species listeria seeligeri, and in this study, we elucidate the differences between prfa proteins from the pathogenic and apathogenic species of the genus listeria. prfa proteins of l. monocytogenes (prfa(lm) and prfa*(lm)), l. ivanovii (prfa(li)), and l. seeligeri (prfa(ls)) were purified, and ... | 2006 | 16980455 |
| dna fingerprinting by eric-pcr for comparing listeria spp. strains isolated from different sources in san luis, argentina. | in this study, a total of 24 listeria spp. strains were analyzed. twenty-two isolates were obtained in san luis (argentina) from human, animal, and food samples. two types of strains, listeria monocytogenes clip 22762 and listeria innocua clip 74915, were included as reference strains. all isolates were biochemically identified and characterized by serotyping, phage typing, and amplification of the flaa gene by polymerase chain reaction (pcr). repetitive intergenic consensus (eric) sequence-base ... | 2006 | 17037249 |
| genotypic characterization of listeria spp. isolated from fresh water fish. | a total of 200 samples (muscles and viscera, 100 of each) of fresh water fish, walking catfish (clarias batrachus) were screened for listeria spp. all the samples were subjected to a two-step enrichment followed by plating on selective media. confirmation of the isolates was on the basis of biochemical characters, haemolysis on blood agar and christie, atkins, munch petersen test. a total of 39 isolates of listeria spp. were recovered. of these 26 (67%), 8 (21%), 3 (8%) and 2 (5%) were listeria ... | 2007 | 17182144 |
| real-time pcr detection of 16s rrna genes speeds most-probable-number enumeration of foodborne listeria monocytogenes. | quantifying foodborne pathogens at concentrations of 0.1 to 1,000 cfu/g of food generally involves most-probable-number (mpn) enumeration, which takes at least 4 days. a real-time pcr assay (rti-pcr) was developed to accelerate mpn enumeration of foodborne listeria monocytogenes. foods were spiked from 70 to 110 cfu/g, and triplicate subportions from 0.0001 to 1 g were selectively enriched for 48 h at 30 degrees c. for standard mpn enumeration, the enrichments were subcultured on oxford agar (48 ... | 2007 | 17685338 |
| complete genome sequence of listeria seeligeri, a nonpathogenic member of the genus listeria. | we report the complete and annotated genome sequence of the nonpathogenic listeria seeligeri slcc3954 serovar 1/2b type strain harboring the smallest completely sequenced genome of the genus listeria. | 2010 | 20061480 |
| listeria seeligeri isolates from food processing environments form two phylogenetic lineages. | seven different acta subtypes forming two phylogenetic lineages could be distinguished by sequencing the acta gene of listeria seeligeri isolates from different habitats. isolates of the two lineages differ in hemolytic as well as phospholipase activities and in the arrangement of the virulence gene cluster. the presence of a serine protease gene resembling orf2110 of l. monocytogenes in some isolates further supports the hypothesis that l. seeligeri is subject to ongoing adaptation to changing ... | 2010 | 20228097 |
| antibiotic resistance in listeria species isolated from catfish fillets and processing environment. | to investigate the susceptibility of 221 listeria spp. (86 listeria monocytogenes, 41 listeria innocua and 94 listeria seeligeri-listeria welshimeri-listeria ivanovii) isolated from catfish fillets and processing environment to 15 antibiotics. | 2010 | 20406380 |
| prevalence and contamination patterns of listeria monocytogenes in catfish processing environment and fresh fillets. | catfish skins, intestines, fresh fillets, processing surfaces at different production stages, chiller water and non-food contact surfaces were sampled for listeria monocytogenes and other listeria species. among 315 samples, prevalence of l. monocytogenes, listeria innocua and a group of listeria seeligeri-listeria welshimeri-listeria ivanovii was 21.6, 13.0 and 29.5%, respectively. no listeria grayi was detected in this survey. while no l. monocytogenes strains were isolated from catfish skins ... | 2010 | 20510783 |
| complementation of listeria monocytogenes null mutants with selected listeria seeligeri virulence genes suggests functional adaptation of hly and prfa and considerable diversification of prfa regulation in l. seeligeri. | while listeria seeligeri and l. monocytogenes contain the main listeria virulence gene cluster, only l. monocytogenes is considered an intracellular pathogen. initial evolutionary analyses showed that the virulence genes prfa, hly, and plca are conserved in l. seeligeri, with specific hly and prfa amino acid residues showing evidence for positive selection in l. seeligeri. our data also show that temperature-dependent transcript patterns for prfa, which encodes a transcriptional regulator of vir ... | 2010 | 20543041 |
| rapid identification of listeria species and screening for variants by melting curve and high-resolution melting curve analyses of the intergenic spacer region of the rrna gene. | the presence of any listeria species in food may be an indicator of poor hygiene in food processing facilities. the biochemical identification of listeria species is laborious and time consuming. therefore, the development of novel identification methods that are rapid and simple to perform would be an asset. in this study, large intergenic spacer region amplicons of 343-374 bp were generated from 207 listeria isolates. the melting curve analysis of these amplicons specifically classified all is ... | 2010 | 20725130 |
| microbiological quality of grey-mullet roe. | the greek grey-mullet roe is produced from the fully developed gonads of the female mullet (mugil cephalus) couth in lagoons during their reproductive migration. the traditional processing method of the roe includes, air drying, salting, shape formation and covering with multiple layers of natural beeswax for preservation and distribution. fish roe brands have been a staple in local diet and is increasingly becoming popular in the international market. as a ready-to-eat food it's microbial quali ... | 2011 | 21497664 |
| occurrence of escherichia coli o157:h7, listeria monocytogenes, salmonella and campylobacter spp. on beef carcasses in northern ireland. | a survey of beef carcasses was conducted in all 10 european community approved abattoirs in northern ireland to determine the incidence of escherichia coli o157:h7. analyses were based on excised samples of neck meat taken less than 48 h post-kill. overall, 780 carcasses were sampled and all were negative for e. coli o157:h7. a sub-set of samples was analysed for the presence of listeria monocytogenes (n=200), salmonella (n=200) and campylobacter spp.(n=100). l. monocytogenes was not detected bu ... | 2001 | 22062423 |
| incidence of listeria spp. in dairy cows feed and raw milk in latvia. | feed is a risk factor for poisoning the farm environment thus also fresh milk with pathogenic microorganisms of listeria genus species. listeria ivanovii, listeria innocua, and listeria seeligeri were isolated from 9.2%, but listeria monocytogenes from 20.0% of feed samples. most often different fodders (9.3%) and silage (4.7%) were contaminated with listeria monocytogenes. listeria genus species were isolated more often from feed prepared and used in organic dairy farm than from that used in co ... | 2012 | 23738125 |
| isolation, identification, and characterization of listeria spp. from various animal origin foods. | the present study was undertaken with the prime objective of isolating and identifying listeria spp. from various foods of animal origin sold at retail market outlets in the city of navsari, gujarat. | 2015 | 27065632 |
| effect of listeria seeligeri or listeria welshimeri on listeria monocytogenes detection in and recovery from buffered listeria enrichment broth. | the presence of multiple species of listeria in regulated food products is not uncommon and can complicate the recovery of listeria monocytogenes particularly on a non-differentiating medium. the potential complications of listeria seeligeri and listeria welshimeri on the recovery of l. monocytogenes from inoculated food test samples using the u.s. food and drug administration's (fda) selective enrichment procedure was investigated. post-enrichment enumeration, in the absence of food product, in ... | 2015 | 25475325 |
| listeria monocytogenes and listeria spp. contamination patterns in retail delicatessen establishments in three u.s. states. | postprocessing contamination in processing plants has historically been a significant source of listeria monocytogenes in ready-to-eat delicatessen meats, and therefore a major cause of human listeriosis cases and outbreaks. recent risk assessments suggest that a majority of human listeriosis cases linked to consumption of contaminated deli meats may be due to l. monocytogenes contamination that occurs at the retail level. to better understand the ecology and transmission of listeria spp. in ret ... | 2014 | 25364927 |
| identification of six listeria species by real-time pcr assay. | the listeria genus comprises 10 recognized species. listeria monocytogenes causes listeriosis in humans and other animals primarily via contaminated food or animal feed. listeria ivanovii causes listeriosis in animals and on rare occasions in humans. the identification of nonpathogenic species of listeria in foods indicates that conditions exist that support the growth of pathogenic strains and is used to facilitate the implementation of control and prevention measures. this study shows the deve ... | 2014 | 24461044 |
| prevalence and antimicrobial resistance of listeria species isolated from different types of raw meat in iran. | listeria and particularly listeria monocytogenes are important foodborne pathogens that can cause listeriosis and severe complications in immunocompromised individuals, children, pregnant women, and the elderly. the objective of this study was to determine the prevalence of listeria spp. in raw meat in iran. from july 2010 to november 2011, a total of 1,107 samples of various raw meats were obtained from randomly selected retail butcher shops. the results of conventional bacteriologic and pcr me ... | 2012 | 23212021 |
| reservoirs of listeria species in three environmental ecosystems. | soil and water are suggested to represent pivotal niches for the transmission of listeria monocytogenes to plant material, animals, and the food chain. in the present study, 467 soil and 68 water samples were collected in 12 distinct geological and ecological sites in austria from 2007 to 2009. listeria was present in 30% and 26% of the investigated soil and water samples, respectively. generally, the most dominant species in soil and water samples were listeria seeligeri, l. innocua, and l. iva ... | 2014 | 25002422 |
| diversity of listeria species in urban and natural environments. | a total of 442 listeria isolates, including 234 listeria seeligeri, 80 l. monocytogenes, 74 l. welshimeri, 50 l. innocua, and 4 l. marthii isolates, were obtained from 1,805 soil, water, and other environmental samples collected over 2 years from four urban areas and four areas representing natural environments. listeria spp. showed similar prevalences in samples from natural (23.4%) and urban (22.3%) environments. while l. seeligeri and l. welshimeri were significantly associated with natural e ... | 2012 | 22504820 |