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At least 19 recordsLinked to original sources
PubMed1992

Assignment of Listeria grayi and Listeria murrayi to a single species, Listeria grayi, with a revised description of Listeria grayi.

The genomic relatedness between Listeria grayi and Listeria murrayi was reevaluated by using DNA-DNA hybridization, multilocus enzyme electrophoresis, and rRNA restriction fragment length polymorphism techniques. The high levels of similarity observed between the strains of these two species confirmed the data published since 1973 and indicated that they should be considered members of a single species. On grounds of priority, the species should be named L. grayi.

DNA, Bacterial↗
PubMed1992

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.

DNA Fingerprinting↗
PubMed2006

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 result of deletions in all of the genes involved in virulence and of "fitness" genes required for intracellular survival, transcription factors, and LPXTG- and LRR-containing proteins as well as 55 genes involved in carbohydrate transport and metabolism. In total, 482 genes are absent from L. welshimeri relative to L. monocytogenes. Of these, 249 deletions are commonly absent in both L. welshimeri and L. innocua, suggesting similar genome evolutionary paths from an ancestor. We also identified 311 genes specific to L. welshimeri that are absent in the other two species, indicating gene expansion in L. welshimeri, including horizontal gene transfer. The species L. welshimeri appears to have been derived from early evolutionary events and an ancestor more compact than L. monocytogenes that led to the emergence of nonpathogenic Listeria spp.

Chromosomes, Bacterial↗
PubMed1994

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 synthetase genes. ORF B and prs were detected in all Listeria species and thus delimit the virulence region. This virulence gene cluster was detected exclusively in hemolytic Listeria species, Listeria ivanovii, an animal pathogen, and Listeria seeligeri, a nonpathogenic species.

Animals↗
PubMed1989

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 sequences, highly homologous listeriolysin genes were found to be present in the species L. monocytogenes, Listeria ivanovii, and Listeria seeligeri. Immunoblotting performed with affinity-purified antibody to listeriolysin allowed the detection of this protein in supernatants of all three species. This study demonstrates for the first time that listeriolysin is produced by L. seeligeri and documents the genetic homology between the various listeriolysins produced by Listeria spp. Sequences unique to the species L. monocytogenes were found to be located downstream of the listeriolysin gene. Furthermore, the restriction fragment length polymorphisms detected with probes flanking the hlyA gene may be useful epidemiological markers in identifying and distinguishing virulent Listeria strains from each other.

Bacterial Toxins↗
PubMed1993

Analysis of cytokine mRNA expression in Listeria-resistant C57BL/6 and Listeria-susceptible A/J mice during Listeria monocytogenes infection.

This laboratory previously reported that mRNA expression for many cytokines, as determined by reverse transcription-polymerase chain reaction analysis, is induced rapidly in the spleen during murine listeriosis. In the present study, the patterns of cytokine mRNA expression in spleens and livers of Listeria-resistant C57BL/6 and Listeria-susceptible A/J mice were compared. In addition, in situ hybridization was performed to evaluate the distributions of cytokine mRNA-expressing cells in these tissues. Listeria-resistant C57BL/6 mice demonstrated greater expression of gamma interferon (IFN-gamma) and granulocyte-macrophage colony-stimulating factor (GM-CSF) mRNAs in the spleen than Listeria-susceptible A/J mice. Greater numbers of cells expressing IFN-gamma and GM-CSF mRNAs were observed by in situ hybridization in the spleens of C57BL/6 mice than in those of A/J mice. C57BL/6 and A/J mice did not differ in their expression of IFN-gamma mRNA in the liver. Nor did C57BL/6 and A/J mice differ in their expression of tumor necrosis factor alpha, interleukin-1 alpha (IL-1 alpha), IL-2, IL-4, or IL-6 mRNA in the liver or spleen, as determined by reverse transcription-polymerase chain reaction and in situ hybridization. These results indicate that the greater resistance of C57BL/6 mice to Listeria monocytogenes infection is associated with greater expression of IFN-gamma and GM-CSF mRNAs in the spleen and GM-CSF mRNA in the liver.

Animals↗
PubMed1990

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 immunoassays. Of the other 26 antibodies, 20 reacted with either L. monocytogenes Scott A or V7 and with some or all of the other six Listeria species but also cross-reacted with some or all of the non-Listeria bacteria tested. MAb P5C9 is of the immunoglobulin G1 murine subclass. In Western blot (immunoblot) analyses, this MAb reacted with a single antigen with a molecular weight of 18,500, and it is shared in common with all three reactive species, L. monocytogenes, L. innocua, and L. welshimeri. This antigen was extracted with detergent and appeared to be cell bound.

Animals↗
PubMed1975

[The occurrence of listeria encephalitis in cattle in a loose housing after the use of litter, infected with listeria bacteria, from a broiler farm. To what extent do listeria bacteria occur in the gut contents of broilers (author's transl)].

In a loose housing, four cows had to be slaughtered as an emergency measure within a few weeks because of symptoms of encephalitis. Listeria monocytogenes of type 4 b were isolated both from the brains of these cows and from the litter previously spread in the cow stables, which was obtained from a broiler farm. At the same time an investigation of the occurrence of Listeria bacteria in the faeces/gut contents of broilers was undertaken. From the contents of 2373 intestines, representing 0.1 per cent of about 2,300,000 broilers from 146 farms, Listeria monocytogenes were isolated in 4.1 per cent of the birds. The infection occurred on six broiler farms, two of them exhibited recidivation. Listeria monocytogenes of type 4 b were involved three times, type 1 was concerned on two farms, and one strain could not be typed.

Animals↗
PubMed1996

The use of listeriolysin O in an ELISA, a skin test and a lymphocyte blastogenesis assay on sheep experimentally infected with Listeria monocytogenes, Listeria ivanovii or Listeria innocua.

Purified listeriolysin O (LLO) was evaluated as a specific antigen to detect both humoral and cell mediated immune responses of sheep infected with Listeria monocytogenes. Six sheep (two in each group) were orally inoculated with 10(10) organisms of L. monocytogenes, L. ivanovii, or L. innocua. Only the L. monocytogenes inoculated sheep had an elevated temperature (> 42 degrees C) and after 15 days had anti-LLO antibodies as assessed by an ELISA. In a blastogenesis assay, only peripheral blood mononuclear cells (PBMC) from L. monocytogenes-infected sheep responded to LLO, while PBMC from all the sheep responded somewhat to heat-killed L. monocytogenes bacteria. In a skin test, only L. monocytogenes-infected sheep exhibited a positive reaction to injected LLO, while all the Listeria-infected sheep reacted to heat-killed bacteria. On day 120 postinfection, all of the sheep were orally inoculated with L. monocytogenes. Only the four that had not been previously given L. monocytogenes exhibited an elevated temperature (> 42 degrees C). 80 days later, sera from all of the animals were positive for anti-LLO antibodies. Thus, prior exposure to L. ivanovii or L. innocua does not protect against a L. monocytogenes challenge. These results suggest LLO is an excellent antigen for use in detecting Listeria infection in sheep. However, whether LLO will be useful in differentiating chronically infected animals from animals that have recovered, has yet to be investigated.

Animals↗
PubMed1993

Differentiation of Listeria monocytogenes and Listeria innocua by 16S rRNA genes and intraspecies discrimination of Listeria monocytogenes strains by random amplified polymorphic DNA polymorphisms.

Differences in the 16S rRNA genes (16S rDNA) which can be used to discriminate Listeria monocytogenes from Listeria innocua have been detected. The 16S rDNA were amplified by polymerase chain reaction with a set of oligonucleotide primers which flank a 1.5-kb fragment. Sequence differences were observed in the V2 region of the 16S rDNA both between L. monocytogenes Scott A and L. innocua and between different L. monocytogenes serotypes. Although L. monocytogenes SLCC2371 had the same V2 region sequence as L. innocua, the two species were different within the V9 region at nucleotides 1259 and 1292, in agreement with previous studies (R.-F. Wang, W.-W. Cao, and M.G. Johnson, Appl. Environ. Microbiol. 57:3666-3670, 1991). Intraspecies discrimination of L. monocytogenes strains was achieved by using the patterns generated by random amplified polymorphic DNA primers. Although some distinction can be made within the L. monocytogenes species by their 16S rDNA sequence, a far greater discrimination within species could be made by generating random amplified polymorphic DNA patterns from chromosomal DNA. By using a number of 10-bp primers, unique patterns for each isolate which in all cases examined differentiate between various L. monocytogenes serotypes, even though they may have the same 16S rRNA sequences, could be generated.

Base Sequence↗
PubMed2004

Carrier status for Listeria monocytogenes and other Listeria species in free range farm and market healthy indigenous chickens and ducks.

BACKGROUND: Listeria organisms are documented to be zoonotic; one of the sources of infection is the domestic fowl where it could occur as in apparent infection. The carriage of Listeria monocytogenes and other Listeria in indigenous birds has not been documented in Kenya. OBJECTIVE: To establish whether healthy looking indigenous chickens and ducks could be carriers of Listeria monocytogenes and other Listeria species. DESIGN: Field survey of indigenous chickens and ducks in three districts of Kenya. SETTING: Embakasi and Dagoreti divisions in Nairobi district; Athi river division in Machakos district; and Ngong division in Kajiado district, in Kenya. SUBJECTS: One hundred and thirty six indigenous chickens and 39 ducks reared under free range scavenging system in Nairobi, Machakos and Kajiado districts, in Kenya, were sampled. METHODS: In surveying the birds, the cloacal and pharyngeal swabs were taken from each bird separately using sterile cotton--tipped applicator swabs. The swabs in saline were transported in a coolbox to the laboratory for bacterial isolation and characterization. INTERVENTIONS: None (only compared farmed and the traded birds). MAIN OUTCOME MEASURES: Isolation of Listeria species and pathogenicity of Listeria isolates. RESULTS: Two Listeria monocytogenes and seven other Listeria species were recovered from the oropharyngeal swab samples of farm and market chickens but none from respective cloacal swabs. No Listeria was recovered from either oropharyngeal or cloacal swabs of farmed duck and slaughter chickens. Traded chickens yielded more Listeria isolates as compared to farmed chickens. CONCLUSION: This study shows that indigenous chickens in Kenya are carriers of Listeria monocytogenes and other Listeria species.

Animals↗
PubMed1969

Specificity of Acquired Resistance Produced by Immunization with Listeria monocytogenes and Listeria Fractions.

Mice were immunized with 1.0 mg of an attenuated strain of Listeria monocytogenes to determine the period of protection afforded by this strain when the mice were challenged intravenously with 5 MLD of listeria. Protection appeared 2 days after immunization and was still apparent 4 weeks after immunization. If the challenge dose was decreased to 1 MLD, protection was apparent at 10 weeks. Mice immunized with a comparable dose of mycobacterial cells and challenged intravenously with 1 MLD of listeria showed no protection at 10 weeks. The magnitude of the immune response to listeria challenge was not increased in mice immunized with the same virulent strain as that used for challenge. It was also found that resistance to listeria challenge appeared early after listeria immunization if the immunizing dose was large. As the immunizing dose was decreased and the challenge dose increased, resistance appeared later. Listeria killed by heat or ultraviolet irradiation, living but nonmultiplying streptomycin-dependent listeria, or listeria ribosomal fraction gave no protection against listeria challenge. The magnitude of the immune responses after listeria immunization to listeria challenge and to mycobacteria challenge were compared. It was found that protection after listeria challenge was of longer duration. In addition, a 100-fold larger vaccinating dose was required to give comparable protection against tuberculous infection.

Journal Article↗
PubMed2006

Evaluation of BBL CHROMagar Listeria agar for the isolation and identification of Listeria monocytogenes from food and environmental samples.

The performance of BBL CHROMagar Listeria chromogenic agar for the detection of Listeria monocytogenes was evaluated for its ability to isolate and identify L. monocytogenes from food and environmental samples. The medium was compared to non-chromogenic selective agars commonly used for Listeria isolation: Oxford, Modified Oxford, and PALCAM. BBL CHROMagar Listeria had a sensitivity of 99% and 100% for the detection of L. monocytogenes from 200 natural and artificially inoculated food samples, respectively, with a colony confirmation rate of 100%. The sensitivity of non-chromogenic selective media for the detection of L. monocytogenes from these same samples was 97-99% with colony confirmation rates of 65-67.5%. From 93 environmental samples, BBL CHROMagar Listeria agar results correlated 100% with a Listeria spp. visual immunoassay (TECRA) performed on these same samples and the USDA-FSIS standard culture method for the isolation of L. monocytogenes. From environmental samples, the L. monocytogenes confirmation rate was 100% for BBL CHROMagar Listeria as compared to 50% for conventional agars tested. On BBL CHROMagar Listeria, L. monocytogenes forms a translucent white precipitation zone (halo) surrounding blue-pigmented colonies of 2-3 mm in diameter, with an entire border. BBL CHROMagar Listeria offers a high degree of specificity for the confirmation of suspect L. monocytogenes colonies, whereas non-chromogenic selective agars evaluated were not differential for L. monocytogenes from other Listeria species.

Agar↗
PubMed1969

Specificity of the anamnestic response produced by Listeria monocytogenes or Mycobacterium tuberculosis to challenge with Listeria monocytogenes.

When mice immunized with Listeria monocytogenes were given a second injection of listeria, they showed an anamnestic immune response to intravenous challenge with listeria, as measured by enumeration of the viable infecting organisms in the spleens of the infected animals. This response was independent of the effects of the challenge dose. When mice immunized with living or heat-killed attenuated mycobacterial cells were boosted with living H37Ra, there was also an accelerated response to listeria challenge. The response was greater in the mice given the primary immunization with living cells than in those immunized with heat-killed cells. The response to listeria challenge in mice immunized and boosted with mycobacteria was of less magnitude than that in the mice immunized and boosted with listeria. Growth of listeria in the mice immunized and boosted with mycobacteria was retarded only during the first 2 days of the infection, whereas the infecting listeria in mice immunized and boosted with listeria were permanently inactivated. Mice immunized with mycobacterial ribosomal fraction and restimulated with living mycobacterial cells showed no accelerated response to listeria challenge. It is evident from these results that resistance to these organisms is specifically evoked, but that once evoked it is not completely nonspecific in action. Also, the resistance produced by the mycobacterial ribosomal fraction to challenge with mycobacteria is completely specific in action. Therefore, it has been shown that there are two mechanisms involved in acquired immunity to facultative, intracellular parasites. One is nonspecific and mediated by activated macrophages. The other is specific and mediated by a mechanism as yet unknown.

Animals↗
PubMed1992

[The diagnosis of Listeria encephalitis in ruminants using cultural and immunohistological techniques. I. Comparison of different selective media and culture techniques for the detection of Listeria from ruminant brains].

The selective L-PALCAMY differential enrichment broth, the Listeria enrichment broth of the International Dairy Federation, Oxford Listeria selective agar, and PALCAM Listeria selective agar were comparatively examined in the cultural isolation of Listeria spp. from ten ruminant brains. The L-PALCAMY medium proved to be superior to the IDF broth in both selectivity and productivity for Listeria spp. in the brain samples, which were also contaminated with other bacteria. The Oxford and PALCAM agars corresponded in their productivity for Listeria spp. The latter, however, was more selective than the Oxford agar. Bacterial counts of up to 1.2 x 10(9) CFU/g of brain stem sample were made from Listeria monocytogenes (L.m.), and up to 6.2 x 10(4) CFU/g from Listeria innocua. A total of 164 brains from ruminants showing CNS disturbances and/or pathoanatomical CNS alterations were examined using L-PALCAMY medium, and Oxford and PALCAM agar. L.m. could be isolated from 29 of the brains, and Listeria innocua from five. Cultural isolation of both Listeria spp. occurred in one brain. Of 27 brains containing L.m., which were also examined using cold enrichment, L.m. was isolated in 59.3% of the cases with direct culture, in 81.5% of the cases using selective warm enrichment, and in 77.8% of the cases by means of selective cold enrichment. Five cases each were identified solely by cold or warm enrichment, respectively. In investigations of further 69 ruminant brains the number of brains shown to contain L.m. could be increased from seven to 13 by means of selective cold enrichment for three months.

Animals↗
PubMed1985

Killed Listeria-induced suppressor T cells involved in suppression of delayed-type hypersensitivity and protection against Listeria infection.

Pretreatment of mice by intravenous injection with killed Listeria provided neither delayed-type hypersensitivity to Listeria protoplasm nor protection against Listeria infection. Assuming that this suppression is due to suppressor cells, we attempted to clarify their induction and characterization. Pretreatment with killed BCG instead of killed Listeria suppressed the induction of DTH and protection in subsequent Listeria-immunized mice. Conversely, pretreatment with killed Listeria suppressed subsequent induction of DTH to PPD or protection from tuberculosis. Thus, these suppressions were induced antigen nonspecifically. Transfer of splenic non-adherent cells from killed Listeria-injected mice which had been treated with anti-BA theta serum plus complement, or had been passed through Sephadex G-10 columns, resulted in both afferent and efferent DTH suppression, suggesting that the DTH suppression is closely associated with suppressor T cells. Moreover, the splenic nonadherent cells from killed Listeria-injected mice showed suppression in vitro of listericidal activity of PEC from Listeria-immune mice in the presence of Listeria protoplasm.

Animals↗
PubMed1996

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 throughout the sampling period, and 88.40% produced milk that was apparently free from Listeria spp. Milk contamination by Listeria spp. was seasonal; incidence in autumn (9.33%) and winter (5.14%) samples was higher than incidence in spring (0.85%) and summer (0.85%) samples. Occurrence of Listeria spp. was lower in samples from mountain farms (1.25%) than in samples from plateau farms (7.03%).

Animals↗
PubMed1998

Reactivities of genus-specific monoclonal antibody EM-6E11 against Listeria species and serotypes of Listeria monocytogenes grown in nonselective and selective enrichment broth media.

Depending on the growth medium used for enrichment of bacterial cells prior to assay, the monoclonal antibody (MAb) EM-6E11 recognizing Listeria genus-specific epitope on 43 and 94 to 97 kDa cell-surface antigens (A. K. Bhunia and M. G. Johnson, Appl. Environ. Microbiol. 58:1924-1929, 1992) exhibited extensive variability in the detection of Listeria species. MAb EM-6E11 strongly detected live cells of all Listeria species and all serotypes of L. monocytogenes by ELISA when cells were grown in nonselective brain heart infusion (BHI) broth, in selective Listeria enrichment broth (LEB), or in Listeria repair broth (LRB). In contrast, EM-6E11 detected only four of the thirteen serotypes of L. monocytogenes (serotypes 1/2c, 3b, 4ab, and 7) when cells were grown in the UVM1 formulation of Listeria enrichment broth (UVM1) or Fraser broth (FRB). This MAb failed to react with live cells of four other Listeria species, including L. ivanovii, L. welshimeri, L. grayi, and L. murrayi cells grown in UVM1 or FRB. Heating of Listeria cells at 100 degrees C for 20 min, irrespective of the enrichment media used, led to large losses of MAb EM-6E11 reactivity in ELISA, suggesting that the specific cell-surface epitopes involved may not be heat stable. Our results confirm that MAb EM-6E11 is suitable for detection of live cells but not heat-killed cells of Listeria spp. and can be used in conjunction with an enrichment step in BHI, LEB, or LRB but not in UVM1 or FRB.

Antibodies, Monoclonal↗