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Microorganisms Aug 2022and , are the only pathogenic species of the genus and share many virulence factors and mechanisms of pathogenicity. shows host tropism towards small ruminants and... (Review)
Review
and , are the only pathogenic species of the genus and share many virulence factors and mechanisms of pathogenicity. shows host tropism towards small ruminants and rodents and much lower virulence for humans compared to . However, severe infections caused by , resulting in bacteremia, abortion and stillbirth, occasionally occurred in immunocompromised persons and in pregnant women, while in immunocompetent hosts can cause gastroenteritis. In this review, the updated knowledge on virulence aspects and distribution of in the environment and in food is summarized. Recent research on its virulence characters at genome level gave indications on how pathogenicity evolved in this bacterial species. As for , infections occurred after the ingestion of contaminated food, so an overview of reports regarding its distribution in food products was carried out to obtain indications on the categories of foods exposed to contamination by . It was found that a wide variety of food products can be a source of this microorganism and that, like , is able to persist in the food production environment. Studies on its ability to grow in enrichment and isolation media suggested that its occurrence in nature might be underestimated. Moreover, virulence varies among strains for differences in virulence character regulation, presence/absence of genetic regions and the possible instability of a pathogenicity genomic island, LIPI-2, which is unique to . We can conclude that , as a possible pathogen for animals and humans, requires more focused investigations regarding its occurrence in the environment and in food and on intra-species variability of pathogenic potential.
PubMed: 36014096
DOI: 10.3390/microorganisms10081679 -
Frontiers in Veterinary Science 2020subsp. is an intracellular bacterium distributed widely in nature, causing the listeriosis in ruminants and humans. Previous researches had isolated 116 strains of...
subsp. is an intracellular bacterium distributed widely in nature, causing the listeriosis in ruminants and humans. Previous researches had isolated 116 strains of subsp. from wild rodents and pikas of different regions in China, and the predominant sequence types were ST1 and ST2. In this study, we first investigated the biological characteristics and virulence of these two clonal strains including motility, metabolism and virulence in cells and mouse model. The results demonstrated the ST1 strains exhibited motility, wide metabolic activity and hypervirulence, whereas the ST2 strains showed non-motility, relative lower metabolic activity and virulence. Considering the transmissible ability from wild rodents and pikas to ecological environment, the subsp. with potential pathogenicity to humans and ruminants should be monitored.
PubMed: 32161763
DOI: 10.3389/fvets.2020.00088 -
Microbial Genomics Jul 2022() is a bacterial pathogen that causes listeriosis in immunocompromised individuals, particularly pregnant women. Several virulence factors support the intracellular...
() is a bacterial pathogen that causes listeriosis in immunocompromised individuals, particularly pregnant women. Several virulence factors support the intracellular lifecycle of and facilitate cell-to-cell spread, allowing it to occupy multiple niches within the host and cross-protective barriers, including the placenta. One family of virulence factors, internalins, contributes to pathogenicity by inducing specific uptake and conferring tissue tropism. Over 25 internalins have been identified thus far, but only a few have been extensively studied. Internalins contain leucine-rich repeat (LRR) domains that enable protein-protein interactions, allowing to bind host proteins. Notably, other species express internalins but cannot colonize human hosts, prompting questions regarding the evolution of internalins within the genus . Internalin P (InlP) promotes placental colonization through interaction with the host protein afadin. Although prior studies of InlP have begun to elucidate its role in pathogenesis, there remains a lack of information regarding homologs in other species. Here, we have used a computational evolutionary approach to identify InlP homologs in additional species. We found that () and () encode InlP homologs. We also found InlP-like homologs in and the recently identified species . All newly identified homologs lack the full-length LRR6 and LRR7 domains found in 's InlP. These findings are informative regarding the evolution of one key virulence factor, InlP, and serve as a springboard for future evolutionary studies of pathogenesis as well as mechanistic studies of internalins.
Topics: Bacterial Proteins; Female; Humans; Listeria; Listeria monocytogenes; Listeriosis; Placenta; Pregnancy; Virulence Factors
PubMed: 35904424
DOI: 10.1099/mgen.0.000828 -
Biology Jun 2022A cross-sectional study was performed in 325 sheep and 119 goat dairy farms in Greece. Samples of bulk-tank milk were examined by standard microbiological techniques for...
Isolation of from Bulk-Tank Milk of Sheep and Goat Farms-From Clinical Work to Bioinformatics Studies: Prevalence, Association with Milk Quality, Antibiotic Susceptibility, Predictors, Whole Genome Sequence and Phylogenetic Relationships.
A cross-sectional study was performed in 325 sheep and 119 goat dairy farms in Greece. Samples of bulk-tank milk were examined by standard microbiological techniques for spp. was isolated from one (0.3%) and from three (0.9%) sheep farms. No associations between the isolation of or and milk quality were found. No resistance to antibiotics was identified. Three variables emerged as significant predictors of isolation of the organism: the presence of pigs, low average relative humidity and a high number of ewes on the farm. The three isolates were assessed in silico for identification of plasmids, prophages, antibiotic resistance genes, virulence factors, CRISPRs and CAS genes. Phylogenetic analysis using the core genome revealed that the three strains belonged to the subsp. branch and were especially close to the PAM 55 strain. All strains of the branch appeared to be very similar, with the distance between them being small.
PubMed: 35741392
DOI: 10.3390/biology11060871 -
Molecules (Basel, Switzerland) Dec 2022The main target of this work is to discover new protein fractions from natural resources with high antibacterial action. The 7S and 11S globulin fractions, as well as...
The main target of this work is to discover new protein fractions from natural resources with high antibacterial action. The 7S and 11S globulin fractions, as well as the basic subunit (BS), were isolated from lupine seeds (), chemically characterized, and screened for antibacterial activity against seven pathogenic bacteria. SDS-PAGE revealed molecular weights ranging from 55 to 75 kDa for 7S globulin, 20-37 kD for 11S globulin, and 20 kD for the BS. 11S globulin and the BS migrated faster on Urea-PAGE toward the cathode compared to 7S globulin. FTIR and NMR showed different spectral patterns between the 7S and 11S globulins but similar ones between 11S globulin and the BS. The MICs of the BS were in the range of 0.05-2 μg/mL against , , , , , , and compared to higher values for 11S globulin. The BS surpassed 11S globulin in antibacterial action, while 7S globulin showed no effect. The MICs of 11S globulin and the BS represented only 5% and 2.5% of the specific antibiotic against , respectively. Scanning electron microscopy (SEM) demonstrated different signs of cellular deformation and decay in the protein-treated bacteria, probably due to interaction with the bacterial cell wall and membranes. 11S globulin and the BS can be nominated as effective food biopreservatives.
Topics: Lupinus; Globulins; Vegetables; Anti-Bacterial Agents; Seeds
PubMed: 36615230
DOI: 10.3390/molecules28010035 -
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 -
Journal of Bacteriology Jul 2021Listeria ivanovii () is an intracellular Gram-positive pathogen that primarily infects ruminants but also occasionally causes enteric infections in humans. Albeit rare,...
Listeria ivanovii () is an intracellular Gram-positive pathogen that primarily infects ruminants but also occasionally causes enteric infections in humans. Albeit rare, this bacterium possesses the capacity to cross the intestinal epithelium of humans, similar to its more frequently pathogenic cousin, Listeria monocytogenes (). Recent studies in have shown that specific glycosyl modifications on the cell wall-associated glycopolymers (termed wall teichoic acid [WTA]) of are responsible for bacteriophage adsorption and retention of the major virulence factor internalin B (InlB). However, the relationship between InlB and WTA in remains unclear. Here, we report the identification of the unique gene , which encodes a putative glucosyltransferase in the polycistronic WTA gene cluster of the WSLC 3009 genome. We found that in-frame deletion of led to loss of the glucose substitution on WTA, as revealed by ultraperformance liquid chromatography-mass spectrometry (UPLC-MS) analysis. Interestingly, the glucose-deficient mutant became resistant to phage B025 infection due to an inability of the phage to adsorb to the bacterial surface, a binding process mediated by the receptor-binding protein B025_Gp17. As expected, deletion of led to loss of InlB retention on the bacterial cell wall, which corresponded to a drastic decrease in cellular invasion. Genetic complementation of restored the characteristic phenotypes, including glucose decoration, phage adsorption, and cellular invasion. Taken together, our data demonstrate that an interplay between phage, bacteria, and host cells also exists in Listeria ivanovii, suggesting that the trade-off between phage resistance and virulence attenuation may be a general feature in the genus . Listeria ivanovii is a Gram-positive bacterial pathogen known to cause enteric infection in rodents and ruminants and occasionally in immunocompromised humans. Recent investigations revealed that in its better-known cousin Listeria monocytogenes, strains develop resistance to bacteriophage attack due to loss of glycosylated surface receptors, which subsequently results in disconnection of one of the bacterium's major virulence factors, InlB. However, the situation in remains unclear. Here, we show that acquires phage resistance following deletion of a unique glycosyltransferase. This deletion also leads to dysfunction of InlB, making the resulting strain unable to invade host cells. Overall, this study suggests that the interplay between phage, bacteria, and the host may be a feature common to the genus .
Topics: Adsorption; Bacterial Proteins; Bacteriophages; Cell Wall; Glucose; Glycosylation; Host-Pathogen Interactions; Lipopolysaccharides; Listeria; Listeria monocytogenes; Membrane Proteins; Teichoic Acids; Virulence
PubMed: 34096780
DOI: 10.1128/JB.00136-21 -
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