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PloS One 2014A loop-mediated isothermal amplification (LAMP) assay for rapid and sensitive detection of the L. ivanovii strains had been developed and evaluated in this study....
A loop-mediated isothermal amplification (LAMP) assay for rapid and sensitive detection of the L. ivanovii strains had been developed and evaluated in this study. Oligonucleotide primers specific for L. ivanovii species were designed corresponding to smcL gene sequences. The primers set comprise six primers targeting eight regions on the species-specific gene smcL. The LAMP assay could be completed within 1 h at 64°C in a water bath. Amplification products were directly observed by the Loopamp Fluorescent Detection Reagent (FD) or detected by agarose gel electrophoresis. Moreover, the LAMP reactions were also detected by real-time measurement of turbidity. The exclusivity of 77 non-L. ivanovii and the inclusivity of 17 L. ivanovii were both 100% in the assay. Sensitivity of the LAMP assay was 250 fg DNA and 16 CFU per reaction for detection of L. ivanovii in pure cultures and simulated human stool. The LAMP assay was 10 and 100-fold more sensitive than quantitative PCR (qPCR) and conventional PCR assays,respectively. When applied to human stool samples spiked with low level (8 CFU/0.5 g) of L. ivanovii strains, the new LAMP assay described here achieved positive detection after 6 hours enrichment. In conclusion, the new LAMP assay in this study can be used as a valuable, rapid and sensitive detection tool for the detection of L. ivanovii in field, medical and veterinary laboratories.
Topics: Base Sequence; Feces; Genes, Bacterial; Humans; Listeria; Listeriosis; Molecular Sequence Data; Nucleic Acid Amplification Techniques; Sensitivity and Specificity; Virulence Factors
PubMed: 25549337
DOI: 10.1371/journal.pone.0115868 -
Applied and Environmental Microbiology Feb 2021is a major human and animal foodborne pathogen. However, data from environmental reservoirs remain scarce. Here, we used whole-genome sequencing to characterize...
is a major human and animal foodborne pathogen. However, data from environmental reservoirs remain scarce. Here, we used whole-genome sequencing to characterize species isolates recovered over 1 year from wild animals in their natural habitats in Spain. Three different spp. ( [ = 19], subsp. [ = 4], and [ = 3]) were detected in 23 animal tonsils (9 deer, 14 wild boars) and 2 feeding troughs. No species was detected in feces. was detected in tonsils of 44.4% (8 out of 18) of deer and 40.7% (11 out of 27) of wild boars. isolates belonged to 3 different core genome multilocus sequence typing (cgMLST) types (CTs) of 3 distinct sublineages (SL1, SL387, and SL155) from lineages I and II. While cgMLST type L1-SL1-ST1-CT5279 (IVb; clonal complex 1 [CC1]) occurred only in one animal, types L1-SL387-ST388-CT5239 (IVb; CC388) and L2-SL155-ST155-CT1170 (IIa; CC155) were retrieved from multiple animals. In addition, L1-SL387-ST388-CT5239 (IVb; CC388) isolates were collected 1 year apart, revealing their long-term occurrence within the animal population and/or environmental reservoir. The presence of identical strains in deer and wild boars suggests contamination from a common food or environmental source, although interhost transmission cannot be excluded. Pathogenicity islands LIPI-1, LIPI-3, and LIPI-4 were present in 100%, 5%, and 79% of the isolates, respectively, and all lineage II isolates ( = 3) carried SSI-1 stress islands. This study highlights the need for monitoring environmental contamination and the importance of tonsils as a possible intrahost reservoir. is a foodborne bacterial pathogen responsible for listeriosis. Whole-genome sequencing has been extensively used in public health and food industries to characterize circulating isolates, but genomic data on isolates occurring in natural environments and wild animals are still scarce. Here, we show that wild animals carry pathogenic and that the same genotypes can be found at different time points in different host species. This work highlights the need of species monitoring of environmental contamination and the importance of tonsils as a possible intrahost reservoir.
Topics: Animals; Deer; Feces; Genome, Bacterial; Listeria; Listeriosis; Multilocus Sequence Typing; Palatine Tonsil; Phylogeny; Sus scrofa; Whole Genome Sequencing
PubMed: 33397708
DOI: 10.1128/AEM.02651-20 -
Microbial Biotechnology Nov 2022Expressing heterologous antigens by plasmids may cause antibiotic resistance. Additionally, antigen expression via plasmids is unstable due to the loss of the plasmid....
Expressing heterologous antigens by plasmids may cause antibiotic resistance. Additionally, antigen expression via plasmids is unstable due to the loss of the plasmid. Here, we developed a balanced-lethal system. The Listeria monocytogenes (LM) balanced-lethal system has been previously used as an antigen carrier to induce cellular immune response. However, thus far, there has been no reports on Listeria ivanovii (LI) balanced-lethal systems. The dal and dat genes from the LI-attenuated LIΔatcAplcB (LIΔ) were deleted consecutively, resulting in a nutrient-deficient LIΔdd strain. Subsequently, an antibiotic resistance-free plasmid carrying the LM dal gene was transformed into the nutrient-deficient strain to generate the LI balanced-lethal system LIΔdd:dal. The resultant bacterial strain retains the ability to proliferate in phagocytic cells, as well as the ability to adhere and invade hepatocytes. Its genetic composition was stable, and compared to the parent strain, the balanced-lethal system was substantially attenuated. In addition, LIΔdd:dal induced specific CD4 /CD8 T-cell responses and protected mice against LIΔ challenge. Similarly, we constructed an LM balanced-lethal system LMΔdd:dal. Sequential immunization with different recombinant Listeria strains will significantly enhance the immunotherapeutic effect. Thus, LIΔdd:dal combined with LMΔdd:dal, or with other balanced-lethal systems will be more promising alternative for vaccine development.
Topics: Mice; Animals; Listeria; Tuberculosis Vaccines; Listeria monocytogenes; Vaccines, Attenuated; Anti-Bacterial Agents
PubMed: 36069650
DOI: 10.1111/1751-7915.14137 -
Frontiers in Microbiology 2022(LM) induces efficient and specific T-cell immune responses in the host. Listeriolysin O (LLO) is the main virulence protein of LM. LLO helps LM escape from the...
(LM) induces efficient and specific T-cell immune responses in the host. Listeriolysin O (LLO) is the main virulence protein of LM. LLO helps LM escape from the lysosome. However, the pronounced pathogenicity of LM limits its practical application as a live bacterial vector. (LI) also displays intracellular parasitic abilities, cell to cell transfer, and other LM properties, with an elevated biosafety relative to LM. We have confirmed that LI can be used as a viable bacterial vaccine vector. However, we have also observed that LI vector vaccine candidates survive in the immune organ (spleen) for a shorter time compared with the survival time of LM and elicit weaker immune responses compared with LM. Studies have confirmed that hemolysin correlates with some important biological properties of , including cell invasion, intracellular proliferation, and the ability to induce immune responses. We speculated that the weaker immunogenicity of LI compared to LM may be related to the function of ivanolysin O (ILO). Here, we established a hemolysin gene deletion strain, LIΔ, and a modified strain, LIΔ:, whose was replaced by . The hemolysin-modified strain was attenuated; however, it led to significantly improved invasive and proliferative activities of antigen-presenting cells, including those of RAW 264.7 macrophages, compared with the effects of LI. Mice immunized twice with LIΔ: showed higher cytokine levels and better challenge protection rates than LI-immunized mice. This is the first description in carrier vaccine research of the modification of LI hemolysin to obtain a better vaccine carrier than LI. The recombinant strain LIΔ: showed good biosafety and immunogenicity, and thus appears to be a good vector strain for vaccine development.
PubMed: 35935244
DOI: 10.3389/fmicb.2022.962326 -
Infection and Immunity Jun 1996The surface-bound ActA polypeptide of the intracellular bacterial pathogen Listeria monocytogenes acts as a nucleator protein, generating the actin cytoskeleton around...
The surface-bound ActA polypeptide of the intracellular bacterial pathogen Listeria monocytogenes acts as a nucleator protein, generating the actin cytoskeleton around intracellularly motile bacteria. In this work, we examined the functional similarity of ActA from Listeria ivanovii (iActA) ATCC 19119 to its L. monocytogenes counterpart. The amino acid sequence of iActA predicts a molecular mass of 123 kDa and harbors eight proline-rich repeats. For functional analysis, various iActA derivatives and hybrid constructs of L. ivanovii and L. monocytogenes ActA polypeptides were transiently expressed in epithelial cells and examined for recruitment of host microfilament proteins by a mitochondrial targeting assay. As has been demonstrated with ActA, iActA also spontaneously inserted into the surface of mitochondria and induced recruitment of actin, alpha-actinin, and the vasodilator-stimulated phosphoprotein (VASP) to these subcellular organelles. By comparison of amino-terminally truncated iActA derivatives for their ability to recruit cytoskeletal proteins, a region essential for actin filament accumulation was identified between amino acid residues 290 and 325. Such derivatives, however, retained their ability to bind VASP. Replacement of the proline-rich repeats in ActA with those of iActA also resulted in VASP recruitment. Hence, despite the limited overall sequence homology between ActA and iActA, the two molecules consist of at least two similar domains: a highly positively charged N-terminal domain that is directly involved in actin filament recruitment and a proline-rich repeat region required for VASP binding.
Topics: Amino Acid Sequence; Bacterial Proteins; Base Sequence; Binding Sites; Cell Adhesion Molecules; Listeria; Listeria monocytogenes; Membrane Proteins; Microfilament Proteins; Molecular Sequence Data; Phosphoproteins
PubMed: 8675289
DOI: 10.1128/iai.64.6.1929-1936.1996 -
Journal of Advanced Veterinary and... Mar 2022The work aimed to assess the safety and quality of broiler meat in experimental listeriosis changes in storage.
OBJECTIVE
The work aimed to assess the safety and quality of broiler meat in experimental listeriosis changes in storage.
MATERIALS AND METHODS
Ross Cobb 500 chickens (40) were divided into 4 groups of 10 animals each. Chickens from three experimental groups were infected by , , and . Meat samples were stored for 5 days at 0°C-4°C. Meat samples were kept in the refrigerator for 3, 4, and 5 days. Microbiological and laboratory indicators of meat freshness were found on these days as well.
RESULTS
After the slaughter of chickens with experimental listeriosis, pathological changes in muscles and organs were noted against the background of fattening carcasses with a high slaughter yield. By bacterial contamination, 1 day after slaughter, the meat of chickens of the experimental groups (, , and ) outperformed the control group by almost 1.9, 13.9, and 24.7 times, respectively ( < 0.05). The same trend is observed for the third, fourth, and fifth days of meat storage. To keep chicken meat fresh for 5 days, only samples from the control group stayed fresh.
CONCLUSION
According to the total bacterial contamination, the meat of chickens of the groups and was dangerous to human health after 5 and 4 days of storage, respectively. From the first day after the chickens were killed, the meat of chickens that had been infected with did not meet the requirements (up to 100 CFU/gm) and was not safe to store or eat.
PubMed: 35445111
DOI: 10.5455/javar.2022.i580 -
Infection and Drug Resistance 2021Listeriosis is one of the globally distributed foodborne diseases with the highest fatality rate. The objectives of this study were to isolate and identify species,...
PURPOSE
Listeriosis is one of the globally distributed foodborne diseases with the highest fatality rate. The objectives of this study were to isolate and identify species, assess factors for contamination of beef, and antibiogram of in Ambo and Holeta towns, Central Ethiopia.
MATERIALS AND METHODS
A total of 450 meat samples were collected from abattoirs (n=150), butchers (n=150), and restaurants (n=150) for isolation and identification of species. Logistic regression analysis was used to assess the association between the occurrence of species in meat and potential risk factors. The antimicrobial susceptibility test was done using the Kirby Bauer test.
RESULTS
The overall occurrence of species in Ambo and Holeta towns was 28.4% (128/450; 95% confidence interval [CI]: 24.3-32.9%). The isolation rate of was 4.4%, 2.2%, 1.8%, 3.8%, 6.2%, and 10.2%. The probability of contamination of meat in butchers and restaurants was higher in Holeta than Ambo [OR=3.4; 95%; p=0.001], in dry than wet season [OR=5.2; p=0.009], and where the hygiene of cutting boards was poor (OR=7.7; p=0.008). Of the 20 isolates, 80%, 70%, 60%, and 55% were resistant to oxacillin, amikacin, and nalidixic acid, chloramphenicol, and tetracycline, respectively. The isolates were 95%, 90%, and 85% susceptible to amoxicillin, vancomycin, and clindamycin, respectively. About 95% of isolates were multidrug-resistant. One isolate (5%) had developed resistance to 10 classes of antimicrobial drugs.
CONCLUSION
species are widespread and study towns, season, and hygiene of cutting boards are independent predictors of isolation of species. Multidrug resistance among was very high. Therefore, adequate cooking of meat, regular training of beef handlers, prudent use of drugs, and further molecular studies on species are important.
PubMed: 33907427
DOI: 10.2147/IDR.S304871 -
Genome Announcements May 2014We present the complete de novo assembled genome sequences of Listeria monocytogenes strains WSLC 1001 (ATCC 19112) and WSLC 1042 (ATCC 23074) and Listeria ivanovii WSLC...
We present the complete de novo assembled genome sequences of Listeria monocytogenes strains WSLC 1001 (ATCC 19112) and WSLC 1042 (ATCC 23074) and Listeria ivanovii WSLC 3009, three strains frequently used for the propagation and study of bacteriophages because they are presumed to be free of inducible prophages.
PubMed: 24786957
DOI: 10.1128/genomeA.00404-14 -
Research in Microbiology 2020Listeria ivanovii is one of the two pathogenic species within the genus Listeria, the other being Listeria monocytogenes. In this study, we generated a stable pediocin...
Listeria ivanovii is one of the two pathogenic species within the genus Listeria, the other being Listeria monocytogenes. In this study, we generated a stable pediocin resistant mutant Liv-r1 of a L. ivanovii strain, compared phenotypic differences between the wild-type and the mutant, localised the pediocin-induced mutations in the chromosome, and analysed the mechanisms behind the bacteriocin resistance. In addition to pediocin resistance, Liv-r1 was also less sensitive to nisin. The growth of Liv-r1 was significantly reduced with glucose and mannose, but less with cellobiose. The cells of Liv-r1 adsorbed less pediocin than the wild-type cells. Consequently, with less pediocin on the cell surface, the mutant was also less leaky, as shown as the release of intracellular lactate dehydrogenase to the supernatant. The surface of the mutant cells was more hydrophobic than that of the wild-type. Whole genome sequencing revealed numerous changes in the Liv-r1 chromosome. The mutations were found e.g., in genes encoding sigma-54-dependent transcription regulator and internalin B, as well as in genes involved in metabolism of carbohydrates such as glucose and cellobiose. Genetic differences observed in the mutant may be responsible for resistance to pediocin but no direct evidence is provided.
Topics: Antimicrobial Cationic Peptides; Carbohydrate Metabolism; Drug Resistance, Bacterial; Genome, Bacterial; Genomics; Listeria; Listeriosis; Microbial Sensitivity Tests; Pediocins; Whole Genome Sequencing
PubMed: 32119904
DOI: 10.1016/j.resmic.2020.02.004 -
Veterinary World Feb 2020This study was undertaken to isolate (.) species from raw meats sold in markets in Enugu State, Southeast Nigeria, and to determine the antibacterial resistance profile.
AIM
This study was undertaken to isolate (.) species from raw meats sold in markets in Enugu State, Southeast Nigeria, and to determine the antibacterial resistance profile.
MATERIALS AND METHODS
Twenty-five grams of beef (n=144), chicken meat (n=144), and pork (n=144) were collected randomly from supermarkets and general markets in Enugu State. Isolation of was done using half and full Fraser broths, and polymyxin acriflavine lithium chloride ceftazidime aesculin mannitol agar. Identification of isolates was done using an analytical profile index kit specific for . Confirmation of the genus was done by a polymerase chain reaction. The resistance of the isolates was determined using the disk diffusion method.
RESULTS
was isolated from 39/144 (27.1%) chicken meat, 19/144 (13.2%) pork, and 66/144 (45.8%) beef samples cultured. was the predominant species in chicken meat (52.6%) and beef (81.8%) samples. , , and were also isolated from the beef and chicken meat samples. More than 65% of the isolates were resistant to penicillin, rifampicin, ciprofloxacin, sulfamethoxazole-trimethoprim, and cephalothin. All the isolates from beef and pork samples and 23 (92%) from chicken meat samples, were resistant to ≥3 classes of antibacterial agents. Mean multiple antibiotic resistance index (MARI) was 0.77 (range=0.42-1.00), 0.58 (range=0.25-0.83), and 0.79 (range=0.58-0.92) for the isolates from beef, chicken meat, and pork samples, respectively. All the isolates had MARI >0.2.
CONCLUSION
Multidrug-resistant strains contaminate raw beef, pork, and chicken meats marketed in Enugu State, Southeast Nigeria.
PubMed: 32255974
DOI: 10.14202/vetworld.2020.317-325