| 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 |
| evaluation of an enzymatic method for fast identification of listeria spp. in cheese and meat products. | listeria-tek elisa was compared with conventional cultural procedure of fil/idf (federation international de laiterie/international dairy federation) modified by us. the elisa assay is able to detect listeria innocua, listeria monocytogenes, listeria murrayi and listeria welshimeri, after 48 h in artificially contaminated cheeses. no specific reactions, no false positive or negative were detected and the assay has a high correlation with the conventional method used in this research. we also ana ... | 1991 | 1750966 |
| 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 |
| 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 |
| monoclonal antibody specific for listeria monocytogenes, listeria innocua, and listeria welshimeri. | eight hundred fifty-nine murine hybridomas were produced from eight fusions, and 27 were characterized for secretion of antibodies reactive to listeria monocytogenes. one monoclonal antibody (mab), p5c9, reacted with all test strains of l. monocytogenes (31 of 31), l. innocua (3 of 3), and l. welshimeri (1 of 1) but not with any strains of the other four listeria species or with any of 22 gram-positive or 11 gram-negative species of bacteria when tested in microtiter and dot blot enzyme immunoas ... | 1990 | 2116762 |
| 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 |
| 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 |
| 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 |
| [virulence of listeria welshimeri]. | the species l. welshimeri consists of non-pathogenic bacteria. 16 different strains which were characterized biochemically were unable to multiply within adult nmri mice after injection of a high dose of about 10(7) bacteria. even macrophage depleted animals, which were obtained by treatment with highmolecular dextran sulfate, could eliminate l. welshimeri. 5 day old baby mice were resistant against l. welshimeri. l. innocua was as avirulent as l. welshimeri, whereas l. monocytogenes was virulen ... | 1986 | 3097990 |
| 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 |
| [first isolation of listeria welshimeri in a human]. | listeria welshimeri has been up to now isolated only from the environment and from rare animal sources. this note mentions the first isolation from a human source: a faecal carrier. | 1987 | 3604501 |
| [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 |
| study of the prevalence of listeria spp. in surface water. | the quantity of listeria species was determined in 49 samples of various types of water (river, brackish water, urban wastewater). twenty nine strains of listeria were isolated. these were mainly identified as listeria monocytogenes (72,4%), but listeria innocua, listeria grayi, listeria ivanohovii and listeria welshimeri were also present. with the exception of water taken from the estuary, 74.4% of samples contained listeria in mean concentrations of between 2 mpn/100 ml and 1320 mpn/100 ml in ... | 1994 | 7848499 |
| expression of superoxide dismutase in listeria monocytogenes. | the nature and expression of superoxide dismutase (sod; ec 1.15.1.1) in the gram-positive food-borne pathogen listeria monocytogenes were examined. metal depletion and reconstitution studies and resistance to h2o2 and potassium cyanide inactivation indicated that l. monocytogenes has a single sod which utilizes manganese as a metal cofactor. the specific activity of sod was unchanged in cells exposed to a heat shock at 42 degrees c or grown in the presence of paraquat-generated superoxide anion ... | 1994 | 8074517 |
| 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 |
| influence of lipoteichoic acid structure on recognition by the macrophage scavenger receptor. | lipoteichoic acids (ltas) belong to the immunostimulatory class of molecules of gram-positive bacteria (gpb). previous investigations showed that the macrophage scavenger receptor (sr), a glycosylated trimeric transmembrane protein, binds directly to many gpb, possibly via lta. sr binding to other ligands is dependent upon the spatial characteristics of the repeating negative charge of the ligand. we therefore investigated sr recognition of lta species with various charge densities and distribut ... | 1996 | 8757870 |
| 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 |
| 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 |
| incidence of listeria monocytogenes in cheese produced in rio de janeiro, brazil. | the present study evaluated the incidence of listeria spp. in some brazilian cheeses obtained from retail stores in rio de janeiro, of 103 samples of various types of cheese examined as recommended in the listeria isolation protocol of the health protection branch of canada, 11 (10.68%) were contaminated by listeria monocytogenes, 13 (12.62%) by listeria innocua, 6 (5.83%) by listeria grayi, and 1 (0.97%) by listeria welshimeri. a higher incidence of l. monocytogenes as observed mainly in the ho ... | 1998 | 9708310 |
| occurrence of listeria monocytogenes in sewage sludge. | the search for salmonella is the only bacteriological index included in italian guidelines (in accordance with eu regulations) for the use of sewage sludge in agriculture. as a result, information regarding the presence of listeria monocytogenes is rather limited. we therefore decided to carry out an investigation of listeria in the sludge produced by the bologna (italy) treatment plant during the various phases of treatment. five different types of sludge were analysed (primary raw, activated, ... | 1998 | 9789361 |
| antibiotic resistance of salmonella spp. and listeria spp. isolates from traditionally made fresh sausages in greece. | sixty-five samples of traditionally made fresh sausages obtained from retail shops and butcher shops in northern greece were screened for the presence of salmonella spp. and listeria spp. salmonella spp. were found in 20% of the samples tested (54% salmonella typhimurium and 46% salmonella enteritidis). the prevalence of listeria spp. in the samples was 26% (12% listeria monocytogenes, 76% listeria innocua, and 12% listeria welshimeri). nine of 13 salmonella isolates were found to be resistant t ... | 1998 | 9798159 |
| 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 |
| cardiolipin, alpha-d-glucopyranosyl, and l-lysylcardiolipin from gram-positive bacteria: fab ms, monofilm and x-ray powder diffraction studies. | cardiolipin preparations from streptococcus b, listeria welshimeri, staphylococcus aureus, and a glucosyl and lysyl derivative of cardiolipin were analysed for fatty acid composition and fatty acid combinations. three different fatty acid patterns are described and up to 17 molecular species were identified in streptococcus b lipids by high resolution fab ms. the physicochemical properties of these lipids were characterised in the sodium salt form by monofilm experiments and x-ray powder diffrac ... | 2000 | 10675509 |
| behaviour of listeria spp. in naturally contaminated chorizo (spanish fermented sausage). | counts of listeria spp. were determined during the manufacture and drying of 21 lots of five chorizo varieties produced by three different manufacturers. presumptive listeria were not isolated from any of the batches produced in a large factory (f3) using starter, sorbate and controlled ripening at high temperatures. initial levels in factory 1 (f1), with no starter added, but controlled ripening at low temperatures, were ca 3.5 log10 cfu/g while those in factory 2 (f2), with no starter added an ... | 1999 | 10728617 |
| 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 |
| evaluation of batch and semicontinuous application of high hydrostatic pressure on foodborne pathogens in salsa. | the effects of high hydrostatic pressure (hpp; 545 mpa) on strains of escherichia coli o157:h7, listeria monocytogenes, enterotoxigenic staphylococcus aureus, and nonpathogenic microorganisms were studied in tomato-based salsa. products were evaluated for the survival of the inoculated pathogens following hpp treatment and after storage at 4 degrees c and 21 to 23 degrees c for up to 2 months. inoculated samples without hpp treatment, stored under the same conditions, were also evaluated to dete ... | 2000 | 11131896 |
| pulsed-field gel electrophoresis (pfge) typing of listeria strains isolated from a meat processing plant over a 2-year period. | as part of a hygiene monitoring program in a meat processing plant a total of 131 listeria isolates were detected by sampling different processing areas and meat products within a 2-year period. the isolates were differentiated by means of phenotypic characteristics. furthermore, the genomic apai and smai fragment patterns of all isolates were examined by pulsed-field gel electrophoresis (pfge). pfge using smai and apai yielded 15 (listeria monocytogenes), 20 (listeria innocua) and six (listeria ... | 2000 | 11139016 |
| 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 |
| 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 |
| specific identification of listeria welshimeri and listeria monocytogenes by pcr assays targeting a gene encoding a fibronectin-binding protein. | we have cloned and sequenced a listeria welshimeri dna fragment homologous to the previously described fibronectin-binding protein-encoding gene (fbp) of listeria monocytogenes (p. gilot, y. jossin, and j. content, j. med. microbiol., 49:887-896, 2000). this l. welshimeri dna fragment expresses a 24.8-kda protein that binds to human fibronectin. based on the fbp sequences, we developed novel pcr assays for the identification of l. welshimeri and l. monocytogenes. | 2002 | 11826001 |
| 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 |
| prevalence of listeria spp. in feces and carcasses at a lamb packing plant in brazil. | the objective of this work was to study the occurrence of listeria species in feces and on dressed and cooled carcasses of lambs at a packing plant in brazil. listeria spp. were recovered on oxford and palcam agars. the 35 fecal samples yielded listeria welshimeri (20%) and listeria innocua (8.6%). the 69 carcass samples yielded l. innocua (34.8%), listeria monocytogenes (4.3%), and listeria ivanovii (1.5%). more listeria spp. were recovered with two selective agars than with either agar alone. | 2003 | 12597497 |
| 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 |
| interaction of a free-living soil nematode, caenorhabditis elegans, with surrogates of foodborne pathogenic bacteria. | free-living nematodes may harbor, protect, and disperse bacteria, including those ingested and passed in viable form in feces. these nematodes are potential vectors for human pathogens and may play a role in foodborne diseases associated with fruits and vegetables eaten raw. in this study, we evaluated the associations between a free-living soil nematode, caenorhabditis elegans, and escherichia coli, an avirulent strain of salmonella typhimurium, listeria welshimeri, and bacillus cereus. on an a ... | 2003 | 14503703 |
| 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 |
| identification of a gene encoding a putative phosphotransferase system enzyme iibc in listeria welshimeri and its application for diagnostic pcr. | to identify a listeria welshimeri-specific gene that can be used for identification of this species by pcr. | 2004 | 14746548 |
| prevalence and typing of listeria monocytogenes in ready-to-eat food products on the belgian market. | listeria monocytogenes is a major concern to producers of ready-to-eat foods because of the high mortality rate associated with listeriosis and the widespread nature of the organism. to investigate the prevalence of this pathogen in different ready-to-eat food products on the belgian market, a variety of 252 ready-to-eat food products, mainly fish and meat products, were analyzed. overall, l. monocytogenes was detected in 23.4% of the samples. the highest prevalence of l. monocytogenes was found ... | 2004 | 15553631 |
| 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 |
| does sporadic listeria gastroenteritis exist? a 2-year population-based survey in nova scotia, canada. | febrile gastroenteritis due to listeria monocytogenes (lm) has been primarily described in foodborne outbreaks. we decided to determine the incidence of sporadic, febrile gastroenteritis due to lm in a large, well-defined north american population over a 2-year period and to compare these cases to sporadic cases of campylobacter and salmonella infections occurring concurrently in the community. | 2005 | 16107973 |
| 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 |
| whole-genome sequence of listeria welshimeri reveals common steps in genome reduction with listeria innocua as compared to listeria monocytogenes. | we present the complete genome sequence of listeria welshimeri, a nonpathogenic member of the genus listeria. listeria welshimeri harbors a circular chromosome of 2,814,130 bp with 2,780 open reading frames. comparative genomic analysis of chromosomal regions between l. welshimeri, listeria innocua, and listeria monocytogenes shows strong overall conservation of synteny, with the exception of the translocation of an f(o)f(1) atp synthase. the smaller size of the l. welshimeri genome is the resul ... | 2006 | 16936040 |
| daily variability of listeria contamination patterns in a cold-smoked salmon processing operation. | an understanding of listeria transmission and contamination patterns in processing environments of ready-to-eat foods is critical for improving control of listeria monocytogenes. a cold-smoked fish processing operation was the site used to study variability in listeria contamination in a processing environment associated with a ready-to-eat food product throughout one production week (five consecutive days). intensive testing was conducted on finished products and environmental samples collected ... | 2006 | 16995514 |
| 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 |
| growth characteristics of listeria monocytogenes, listeria welshimeri and listeria innocua strains in broth cultures and a sliced bologna-type product at 4 and 7 degrees c. | the growth characteristics of meat processing plant-derived field strains of listeria monocytogenes, l. welshimeri and l. innocua were analyzed. the strains were inoculated in bhi broth cultures and incubated at 4 and 7 degrees c. growth curves were determined by colony counting for 28 days. significant variations were detected in the growth properties of these field-derived strains. in particular some of the l. monocytogenes strains displayed better cold stress tolerance. these discrepancies in ... | 2007 | 17367677 |
| 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 |
| biodiversity of the species listeria monocytogenes and the genus listeria. | this review describes the listeria monocytogenes genome sequences available today and their comparison with that of listeria innocua and listeria welshimeri by highlighting their characteristic features and common traits. the diversity present among them is analysed with emphasis on putative virulence and host-pathogen interaction related functions. then large-scale studies comparing gene content of listeria and how these studies contributed to typing applications will be discussed. finally, evo ... | 2007 | 17719817 |
| enumeration and growth of naturally occurring listeria spp. in unpackaged ham. | a total of 301 unpackaged retail ham samples were tested for the presence and number of listeria spp. after 7 days at 5 degrees c to simulate domestic storage. thirteen samples (4.3%) contained listeria monocytogenes, with the highest count being 1.6 x 10(3)cfu g(-1). thirteen samples contained other listeria spp. genotyping showed that only one l. monocytogenes isolate from the 14 tested was of a type previously identified in new zealand human cases. listeria-contaminated batches were incubated ... | 2008 | 18206784 |
| a listeria monocytogenes mutant defective in bacteriophage attachment is attenuated in orally inoculated mice and impaired in enterocyte intracellular growth. | a listeria monocytogenes bacteriophage was used to identify a phage-resistant tn917 insertion mutant of the mouse-virulent listerial strain f6214-1. the mutant was attenuated when it was inoculated orally into female a/j mice and failed to replicate efficiently in cultured mouse enterocytes. phage binding studies indicated that the mutant had a cell surface alteration that precluded phage attachment. all phenotypes associated with the mutation could be complemented in trans by a single open read ... | 2008 | 18559424 |
| listeria marthii sp. nov., isolated from the natural environment, finger lakes national forest. | four isolates (fsl s4-120(t), fsl s4-696, fsl s4-710, and fsl s4-965) of gram-positive, motile, facultatively anaerobic, non-spore-forming bacilli that were phenotypically similar to species of the genus listeria were isolated from soil, standing water and flowing water samples obtained from the natural environment in the finger lakes national forest, new york, usa. the four isolates were closely related to one another and were determined to be the same species by whole genome dna-dna hybridizat ... | 2010 | 19667380 |
| the overgrowth of listeria monocytogenes by other listeria spp. in food samples undergoing enrichment cultivation has a nutritional basis. | the isolation of listeria monocytogenes from food is carried out using a double enrichment. in cases where multiple listeria species are present within the original sample, l. monocytogenes can be overgrown during enrichment by other species of listeria present in the original sample. from a practical perspective, this can result in a false negative or complicate the ability of public health investigators to match food and clinical isolates. we have further investigated this phenomenon by analys ... | 2010 | 19945759 |
| 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 |
| 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 |
| prevalence of listeria species in camel sausages from retail markets in aydin province in turkey and rapd analysis of listeria monocytogenes isolates. | samples were taken from 100 camel sausages from the different retail markets in aydin province in the south-west of turkey and they were tested for the presence of listeria spp by biochemical methods. samples were enriched using listeria enrichment broth and they were inoculated onto listeria selective agar. listeria monocytogenes was isolated from nine samples (9%), listeria innocua from 14 samples (14%) and listeria welshimeri from two samples(2%). a 701 bp fragment of listeriolysin o sequence ... | 2006 | 21851683 |
| control of listeria monocytogenes growth in a ready-to-eat poultry product using a bacteriophage. | a bacteriophage (phage) that infected strains of the species listeria monocytogenes as well as listeria ivanovii and listeria welshimeri, but not listeria grayi or listeria innocua, was isolated from sheep faeces. the phage had a contractile tail and an icosohedral head indicating that it was a myovirus, and was morphologically similar to phage a511. at 30 °c, phages added at 5.2 × 10⁷ pfu ml⁻¹ prevented the growth in broth of l. monocytogenes present at approximately twice this concentration fo ... | 2011 | 21925027 |
| trophosome of the deep-sea tubeworm riftia pachyptila inhibits bacterial growth. | the giant tubeworm riftia pachyptila lives in symbiosis with the chemoautotrophic gammaproteobacterium cand. endoriftia persephone. symbionts are released back into the environment upon host death in high-pressure experiments, while microbial fouling is not involved in trophosome degradation. therefore, we examined the antimicrobial effect of the tubeworm's trophosome and skin. the growth of all four tested gram-positive, but only of one of the tested gram-negative bacterial strains was inhibite ... | 2016 | 26730960 |
| cultivation to improve in vivo solubility of overexpressed arginine deiminases in escherichia coli and the enzyme characteristics. | overexpression of foreign genes in escherichia coli cells is an efficient means to obtain recombinant proteins. the technique is, however, often hampered by misfolding, degradation, aggregation and formation in inclusion bodies of products. | 2014 | 24908259 |
| isolation and lytic activity of the listeria bacteriophage endolysin lysz5 against listeria monocytogenes in soya milk. | the endolysin gene (lysz5) from the genome of the listeria monocytogenes phage fwllm3 was cloned in escherichia coli and characterized. comparative sequence analysis revealed that lysz5 resembled the murein hydrolase ply511 encoded by l. monocytogenes phage a511. the encoded protein lysz5 had a predicted molecular mass of 35.8 kda and was expressed in e. coli as an n-terminal fusion protein of 41.5 kda. addition of purified fusion protein to lawns of indicator bacteria showed that lysz5 could ly ... | 2012 | 22475951 |
| 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 |
| various ready-to-eat products from retail stores linked to occurrence of diverse listeria monocytogenes and listeria spp. isolates. | listeriosis outbreaks have been associated with a variety of foods. this study investigated the prevalence and diversity of listeria monocytogenes and listeria spp. in ready-to-eat (rte) products and evaluated the performance of a rapid detection method, the 3m molecular detection assay for l. monocytogenes (mda-lm), for detection of l. monocytogenes. assay results were compared with those obtained using the u.s. food and drug administration standard culture method described in the bacteriologic ... | 2016 | 26818984 |
| chitosan improves anti-biofilm efficacy of gentamicin through facilitating antibiotic penetration. | antibiotic overuse is one of the major drivers in the generation of antibiotic resistant "super bugs" that can potentially cause serious effects on health. in this study, we reported that the polycationic polysaccharide, chitosan could improve the efficacy of a given antibiotic (gentamicin) to combat bacterial biofilms, the universal lifestyle of microbes in the world. short- or long-term treatment with the mixture of chitosan and gentamicin resulted in the dispersal of listeria monocytogenes (l ... | 2014 | 25479075 |
| 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 |
| consumer method to control salmonella and listeria species in shrimp. | the purpose of this study was to determine whether the current consumer method of boiling shrimp until floating and pink in color is adequate for destroying listeria and salmonella. shrimp samples were submerged in bacterial suspensions of listeria and salmonella for 30 min and allowed to air dry for 1 h under a biosafety cabinet. color parameters were then measured with a spectrophotometer programmed with the cielab system. twenty-four shrimp samples were divided into groups (days 0, 1, or 2) a ... | 2013 | 23317857 |
| 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 |
| antimicrobial-resistant listeria species from retail meat in metro detroit. | a total of 138 listeria isolates from retail meat, including 58 listeria welshimeri, 44 listeria monocytogenes, and 36 listeria innocua isolates, were characterized by antimicrobial susceptibility tests against nine antimicrobials. in addition, the 44 l. monocytogenes isolates were analyzed by serotype identification using pcr and genotyping using pulsed-field gel electrophoresis. resistance to one or two antimicrobials was observed in 32 listeria isolates (23.2%). no multidrug resistance was id ... | 2012 | 23212009 |
| occurrence and characterization of listeria spp. in ready-to-eat retail foods from vancouver, british columbia. | the occurrence of listeria spp. and listeria monocytogenes in retail rte meat and fish products in vancouver, british columbia (b.c.) was investigated. to assess potential consumer health risk, recovered l. monocytogenes isolates were subjected to genotypic and phenotypic characterization. conventional methods were used to recover listeria spp. from deli meat (n = 40) and fish (n = 40) samples collected from 17 stores. listeria spp. were recovered only from fish samples (20%); 5% harboured liste ... | 2012 | 22365350 |
| rugulactone and its analogues exert antibacterial effects through multiple mechanisms including inhibition of thiamine biosynthesis. | rugulactone is a dihydro-α-pyrone isolated from the plant cryptocarya rugulosa in 2009. it has been reported to display ikb kinase (ikk) inhibitory activity, as well as antibiotic activity in several strains of pathogenic bacteria. however, its biological targets and mode of action in bacteria have not yet been explored. here we present enantioselective syntheses of rugulactone and of some corresponding activity-based protein profiling (abpp) probes. we found that the abpp probes in this study a ... | 2012 | 22653914 |
| monitoring transmission routes of listeria spp. in smoked salmon production with repetitive element sequence-based pcr techniques. | various techniques have been used for tracing the transmission routes of listeria species and for the assessment of hygiene standards in food processing plants. the potential of repetitive element sequence-based pcr (rep-pcr) methods (gtg₅ and repi + ii) for the typing of listeria isolates (n = 116), including listeria monocytogenes (n = 46), was evaluated in a particular situation arising from the relocation of a company producing cold-smoked salmon. pulsed-field gel electrophoresis (pfge) usin ... | 2012 | 22410224 |
| microbiota of human breast tissue. | in recent years, a greater appreciation for the microbes inhabiting human body sites has emerged. in the female mammary gland, milk has been shown to contain bacterial species, ostensibly reaching the ducts from the skin. we decided to investigate whether there is a microbiome within the mammary tissue. using 16s rrna sequencing and culture, we analyzed breast tissue from 81 women with and without cancer in canada and ireland. a diverse population of bacteria was detected within tissue collected ... | 2014 | 24610844 |
| genetic stability and evolution of the sigb allele, used for listeria sensu stricto subtyping and phylogenetic inference. | sequencing of single genes remains an important tool that allows the rapid classification of bacteria. sequencing of a portion of sigb, which encodes a stress-responsive alternative sigma factor, has emerged as a commonly used molecular tool for the initial characterization of diverse listeria isolates. in this study, evolutionary approaches were used to assess the validity of sigb allelic typing for listeria for a data set of 4,280 isolates, sigb allelic typing showed a simpson's index of diver ... | 2017 | 28389543 |