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Microbiology Spectrum Jul 2018For nearly a century the use of antibiotics to treat infectious diseases has benefited human and animal health. In recent years there has been an increase in the... (Review)
Review
For nearly a century the use of antibiotics to treat infectious diseases has benefited human and animal health. In recent years there has been an increase in the emergence of antibiotic-resistant bacteria, in part attributed to the overuse of compounds in clinical and farming settings. The genus currently comprises 17 recognized species found throughout the environment. is the etiological agent of listeriosis in humans and many vertebrate species, including birds, whereas causes infections mainly in ruminants. is the third-most-common cause of death from food poisoning in humans, and infection occurs in at-risk groups, including pregnant women, newborns, the elderly, and immunocompromised individuals.
Topics: Aged; Animals; Animals, Domestic; Anti-Infective Agents; Drug Resistance, Bacterial; Farms; Female; Food Microbiology; Foodborne Diseases; Humans; Infant, Newborn; Interspersed Repetitive Sequences; Listeria; Listeria monocytogenes; Listeriosis; Pregnancy
PubMed: 30027884
DOI: 10.1128/microbiolspec.ARBA-0031-2017 -
Clinical Microbiology Reviews Jul 2001The gram-positive bacterium Listeria monocytogenes is the causative agent of listeriosis, a highly fatal opportunistic foodborne infection. Pregnant women, neonates, the... (Review)
Review
The gram-positive bacterium Listeria monocytogenes is the causative agent of listeriosis, a highly fatal opportunistic foodborne infection. Pregnant women, neonates, the elderly, and debilitated or immunocompromised patients in general are predominantly affected, although the disease can also develop in normal individuals. Clinical manifestations of invasive listeriosis are usually severe and include abortion, sepsis, and meningoencephalitis. Listeriosis can also manifest as a febrile gastroenteritis syndrome. In addition to humans, L. monocytogenes affects many vertebrate species, including birds. Listeria ivanovii, a second pathogenic species of the genus, is specific for ruminants. Our current view of the pathophysiology of listeriosis derives largely from studies with the mouse infection model. Pathogenic listeriae enter the host primarily through the intestine. The liver is thought to be their first target organ after intestinal translocation. In the liver, listeriae actively multiply until the infection is controlled by a cell-mediated immune response. This initial, subclinical step of listeriosis is thought to be common due to the frequent presence of pathogenic L. monocytogenes in food. In normal individuals, the continual exposure to listerial antigens probably contributes to the maintenance of anti-Listeria memory T cells. However, in debilitated and immunocompromised patients, the unrestricted proliferation of listeriae in the liver may result in prolonged low-level bacteremia, leading to invasion of the preferred secondary target organs (the brain and the gravid uterus) and to overt clinical disease. L. monocytogenes and L. ivanovii are facultative intracellular parasites able to survive in macrophages and to invade a variety of normally nonphagocytic cells, such as epithelial cells, hepatocytes, and endothelial cells. In all these cell types, pathogenic listeriae go through an intracellular life cycle involving early escape from the phagocytic vacuole, rapid intracytoplasmic multiplication, bacterially induced actin-based motility, and direct spread to neighboring cells, in which they reinitiate the cycle. In this way, listeriae disseminate in host tissues sheltered from the humoral arm of the immune system. Over the last 15 years, a number of virulence factors involved in key steps of this intracellular life cycle have been identified. This review describes in detail the molecular determinants of Listeria virulence and their mechanism of action and summarizes the current knowledge on the pathophysiology of listeriosis and the cell biology and host cell responses to Listeria infection. This article provides an updated perspective of the development of our understanding of Listeria pathogenesis from the first molecular genetic analyses of virulence mechanisms reported in 1985 until the start of the genomic era of Listeria research.
Topics: Animals; Bacterial Proteins; Humans; Listeria; Listeriosis; Virulence
PubMed: 11432815
DOI: 10.1128/CMR.14.3.584-640.2001 -
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 -
Vector Borne and Zoonotic Diseases... Jan 2019Listeria is ubiquitous in natural environments and can be isolated from animal hosts, including rodents. Listeria ivanovii and Listeria monocytogenes are the main...
Listeria is ubiquitous in natural environments and can be isolated from animal hosts, including rodents. Listeria ivanovii and Listeria monocytogenes are the main pathogenic species that can cause serious listeriosis in animals and human. In this study, we investigated the prevalence of Listeria in wild rodents from six regions in China, and analyzed the molecular characteristics and antibiotics resistance of the L. ivanovii isolates. A total of 702 fecal samples of 25 different species of wild rodents were examined, and 75 were Listeria positive, including 26 L. ivanovii strains, 2 L. monocytogenes strains, and 47 Listeria innocus strains. The 26 L. ivanovii isolates (including 2 subspecies) were divided into 5 different sequence types by multilocus sequence typing with ST6 being the dominant type, and 5 different pulsotypes by pulsed-field gel electrophoresis. The results of antimicrobial susceptibility revealed that all L. ivanovii isolates were sensitive to rifampin, chloramphenicol, gentamicin, erythromycin, tetracycline, vancomycin, penicillin G, imipenem, trimethoprim-sulfamethoxazole, but some isolates (including ST1, ST7, and ST8) were resistant to clindamycin. The results suggest that the prevalence of L. ivanovii (3.7%, 26/702) in wild rodents was higher in some regions, and the genetic diversity of L. ivanovii isolates in the wild rodents is relatively low and most belong to one lineage. These wild rodents may act as the natural host for L. ivanovii and possibly transmit the pathogen between wild animals and humans.
Topics: Animals; Listeria; Listeriosis; Phylogeny; Prevalence; Rodent Diseases; Rodentia
PubMed: 30570448
DOI: 10.1089/vbz.2018.2317 -
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 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 -
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 -
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 -
The Journal of Infection Sep 1994
Topics: Adult; Alcoholism; Ampicillin; Bacteremia; Humans; Listeria; Listeriosis; Male; Narcotics; Risk Factors; Substance Abuse, Intravenous
PubMed: 7806889
DOI: 10.1016/s0163-4453(94)90914-8 -
Food Microbiology Sep 2014It has been suggested that the rarity of human listeriosis due to Listeria ivanovii reflects not only host tropism factors but also the rare occurrence of this species...
It has been suggested that the rarity of human listeriosis due to Listeria ivanovii reflects not only host tropism factors but also the rare occurrence of this species in the environment, compared with Listeria monocytogenes. In the present study we evaluate the effects on the reference strain L. ivanovii ATCC 19119 behaviour of two combined stresses, low iron availability and acid environment, that bacteria can encounter in the passage from saprophytic life to the host. In these conditions, L. ivanovii evidenced a different behaviour compared to L. monocytogenes exposed to similar conditions. L. ivanovii was not able to mount an acid tolerance response (ATR) even if, upon entry into the stationary phase in iron-loaded medium, growth phase-dependent acid resistance (AR) was evidenced. Moreover, bacteria grown in iron excess and acidic pH showed the higher invasion value in Caco-2 cells, even though it was not able to efficiently multiply. On the contrary, low iron and acidic conditions improved invasion ability in amniotic WISH cells.
Topics: Acids; Caco-2 Cells; Humans; Hydrogen-Ion Concentration; Iron; Listeria; Listeriosis; Virulence
PubMed: 24929719
DOI: 10.1016/j.fm.2014.02.015