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Bioscience Reports Jun 2020In the present study, a total of 50 raw camel meat samples were analyzed for the presence of Listeria monocytogenes. The isolates were characterized via morphological...
In the present study, a total of 50 raw camel meat samples were analyzed for the presence of Listeria monocytogenes. The isolates were characterized via morphological and culture analyses; identification of isolates was confirmed by polymerase chain reaction (PCR) and sequencing of the listeriolysin O gene. The API Listeria system was used for further chemical identification and verification of the strains. L. monocytogenes was identified in eight raw camel meat samples, which was the highest incidence (16%) of contamination, followed by L. seeligeri 3(6%), L. innocua and L. welshimeri 2 (2% each), and L. grayi 1 (1%). According to Basic Local Alignment Search Tool (BLAST) analysis, isolated strains that were positive for the listeriolysin O gene were >99% similar to the published database sequences for L. monocytogenes strain LM850658 (sequence ID: CP009242.1). We studied the antibiotic resistance profile of the L. monocytogenes strains with common antibiotics used to treat human listeriosis and demonstrated that almost all strains tested were susceptible to the antibiotics.
Topics: Animals; Anti-Bacterial Agents; Bacterial Toxins; Camelus; DNA, Bacterial; Drug Resistance, Multiple, Bacterial; Food Microbiology; Foodborne Diseases; Heat-Shock Proteins; Hemolysin Proteins; Listeria monocytogenes; Listeriosis; Meat; Microbial Sensitivity Tests
PubMed: 32432315
DOI: 10.1042/BSR20201062 -
Virulence Dec 2019Thiol-disulfide glutaredoxin systems of bacterial cytoplasm favor reducing conditions for the correct disulfide bonding of functional proteins, and therefore were...
Thiol-disulfide glutaredoxin systems of bacterial cytoplasm favor reducing conditions for the correct disulfide bonding of functional proteins, and therefore were employed by bacteria to defend against oxidative stress. has been shown to encode a putative glutaredoxin, Grx (encoded by ), while the underlying roles remain unknown. Here we suggest an unexpected role of Grx in oxidative tolerance and intracellular infection. The recombinant Grx was able to efficiently catalyze the thiol-disulfide oxidoreduction of insulin in the presence of DTT as an election donor. Unexpectedly, the deletion of resulted in a remarkably increased tolerance and survival ability of this bacteria when exposed to various oxidizing agents, including diamide, and copper and cadmium ions. Furthermore, loss of significantly promoted bacterial invasion and proliferation in human epithelial Caco-2 cells and murine macrophages, as well as a notably increasing invasion but not cell-to-cell spread in the murine fibroblasts L929 cells. More importantly, lacking the glutaredoxin exhibited more efficient proliferation and recovery in the spleens and livers of the infected mice, and hence became more virulent by upregulating the virulence factors, InlA and InlB. In summary, we here for the first time demonstrated that glutaredoxin plays a counterintuitive role in bacterial oxidative resistance and intracellular infection, which is the first report to provide valuable evidence for the role of glutaredoxins in bacterial infection, and more importantly suggests a favorable model to illustrate the functional diversity of bacterial Grx systems during environmental adaption and host infection.
Topics: Animals; Bacterial Proteins; Caco-2 Cells; Cell Line; Cytoplasm; Epithelial Cells; Female; Fibroblasts; Gene Deletion; Glutaredoxins; Humans; Insulin; Listeria monocytogenes; Listeriosis; Macrophages; Mice; Mice, Inbred ICR; Oxidants; Oxidative Stress; Virulence Factors
PubMed: 31680614
DOI: 10.1080/21505594.2019.1685640 -
MSphere Aug 2021The foodborne pathogen Listeria monocytogenes can form proteinaceous organelles called bacterial microcompartments (BMCs) that optimize the utilization of substrates,...
The foodborne pathogen Listeria monocytogenes can form proteinaceous organelles called bacterial microcompartments (BMCs) that optimize the utilization of substrates, such as 1,2-propanediol, and confer an anaerobic growth advantage. Rhamnose is a deoxyhexose sugar abundant in a range of environments, including the human intestine, and can be degraded in anaerobic conditions into 1,2-propanediol, next to acetate and lactate. Rhamnose-derived 1,2-propanediol was found to link with BMCs in some human pathogens such as Salmonella enterica, but the involvement of BMCs in rhamnose metabolism and potential physiological effects on L. monocytogenes are still unknown. In this study, we first test the effect of rhamnose uptake and utilization on anaerobic growth of L. monocytogenes EGDe without or with added vitamin B, followed by metabolic analysis. We show that vitamin B-dependent activation of stimulates metabolism and anaerobic growth of L. monocytogenes EGDe on rhamnose via 1,2-propanediol degradation into 1-propanol and propionate. Transmission electron microscopy of -induced cells shows that BMCs are formed, and additional proteomics experiments confirm expression of BMC shell proteins and enzymes. Finally, we discuss the physiological effects and energy efficiency of L. monocytogenes BMC-driven anaerobic rhamnose metabolism and the impact on competitive fitness in environments such as the human intestine. Listeria monocytogenes is a foodborne pathogen causing severe illness and, as such, it is crucial to understand the molecular mechanisms contributing to its survival strategy and pathogenicity. Rhamnose is a deoxyhexose sugar abundant in a range of environments, including the human intestine, and can be degraded in anaerobic conditions into 1,2-propanediol. In our previous study, the utilization of 1,2-propanediol () in L. monocytogenes was proved to be metabolized in bacterial microcompartments (BMCs), which are self-assembling subcellular proteinaceous structures and analogs of eukaryotic organelles. Here, we show that the vitamin B-dependent activation of stimulates metabolism and anaerobic growth of L. monocytogenes EGDe on rhamnose via BMC-dependent 1,2-propanediol utilization. Combined with metabolic and proteomics analysis, our discussion on the physiological effects and energy efficiency of BMC-driven rhamnose metabolism shed new light to understand the impact on L. monocytogenes competitive fitness in ecosystems such as the human intestine.
Topics: Anaerobiosis; Bacterial Proteins; Humans; Intestines; Listeria monocytogenes; Metabolic Networks and Pathways; Propylene Glycols; Proteomics; Rhamnose; Vitamin B 12
PubMed: 34287006
DOI: 10.1128/mSphere.00434-21 -
FEMS Microbiology Letters Sep 2021Listeria monocytogenes is the causative agent of the highly fatal foodborne disease listeriosis and can persist in food production environments. Recent research...
Listeria monocytogenes is the causative agent of the highly fatal foodborne disease listeriosis and can persist in food production environments. Recent research highlights the involvement of L. monocytogenes plasmids in different stress response mechanisms, which contribute to its survival in food production facilities. Ultraviolet (UV) light in the UVC spectrum (200-280 nm) is used in food production to control microbial contamination. Although plasmid-encoded UV resistance mechanisms have been described in other bacteria, no research indicates that L. monocytogenes plasmids contribute to the UV stress response. The plasmids of L. monocytogenes strains 6179, 4KSM and R479a are genetically distinct and were utilized to study the roles of plasmids in the UV response. Wild-type and plasmid-cured variant cells were grown to logarithmic or late-stationary phase, plated on agar plates and exposed to UVC for 60 or 90 s, and colony-forming units (CFUs) were determined. CFUs of 6179 and 4KSM, bearing pLM6179 and p4KSM, respectively, were significantly (P-value < 0.05) higher than those of the plasmid-cured strains in both logarithmic and stationary phases. No difference in survival was observed for the R479a strain. Our data show for the first time that certain L. monocytogenes plasmids contribute to the survival of UVC light stress.
Topics: Food Microbiology; Humans; Listeria monocytogenes; Listeriosis; Plasmids; Stress, Physiological; Ultraviolet Rays
PubMed: 34498664
DOI: 10.1093/femsle/fnab123 -
MicrobiologyOpen Oct 2022Recent research demonstrated that some Listeria monocytogenes plasmids contribute to stress survival. However, only a few studies have analyzed gene expression patterns...
Recent research demonstrated that some Listeria monocytogenes plasmids contribute to stress survival. However, only a few studies have analyzed gene expression patterns of L. monocytogenes plasmids. In this study, we identified four previously published stress-response-associated transcriptomic data sets which studied plasmid-harboring L. monocytogenes strains but did not include an analysis of the plasmid transcriptomes. The four transcriptome data sets encompass three distinct plasmids from three different L. monocytogenes strains. Differential gene expression analysis of these plasmids revealed that the number of differentially expressed (DE) L. monocytogenes plasmid genes ranged from 30 to 45 with log fold changes of -2.2 to 6.8, depending on the plasmid. Genes often found to be DE included the cadmium resistance genes cadA and cadC, a gene encoding a putative NADH peroxidase, the putative ultraviolet resistance gene uvrX, and several uncharacterized noncoding RNAs (ncRNAs). Plasmid-encoded ncRNAs were consistently among the highest expressed genes. In addition, one of the data sets utilized the same experimental conditions for two different strains harboring distinct plasmids. We found that the gene expression patterns of these two L. monocytogenes plasmids were highly divergent despite the identical treatments. These data suggest plasmid-specific gene expression responses to environmental stimuli and differential plasmid regulation mechanisms between L. monocytogenes strains. Our findings further our understanding of the dynamic expression of L. monocytogenes plasmid-encoded genes in diverse environmental conditions and highlight the need to expand the study of L. monocytogenes plasmid genes' functions.
Topics: Listeria monocytogenes; Transcriptome; Plasmids; Cadmium
PubMed: 36314750
DOI: 10.1002/mbo3.1315 -
Journal of Bacteriology Apr 2020The capacity of to adapt to environmental changes is facilitated by a large number of regulatory proteins encoded by its genome. Among these proteins are the...
The capacity of to adapt to environmental changes is facilitated by a large number of regulatory proteins encoded by its genome. Among these proteins are the uncharacterized LysR-type transcriptional regulators (LTTRs). LTTRs can work as positive and/or negative transcription regulators at both local and global genetic levels. Previously, our group determined by comparative genome analysis that one member of the LTTRs (NCBI accession no. WP_003734782) was present in pathogenic strains but absent from nonpathogenic strains. The goal of the present study was to assess the importance of this transcription factor in the virulence of strain F2365 and to identify its regulons. An strain lacking (the F2365Δ strain) displayed significant reductions in cell invasion of and adhesion to Caco-2 cells. In plaque assays, the deletion of resulted in a 42.86% decrease in plaque number and a 13.48% decrease in average plaque size. Furthermore, the deletion of also attenuated the virulence of in mice following oral and intraperitoneal inoculation. The analysis of transcriptomics revealed that the transcript levels of 139 genes were upregulated, while 113 genes were downregulated in the F2365Δ strain compared to levels in the wild-type bacteria. -repressed genes included ABC transporters, important for starch and sucrose metabolism as well as glycerolipid metabolism, flagellar assembly, quorum sensing, and glycolysis/gluconeogenesis. Conversely, activated the expression of genes related to fructose and mannose metabolism, cationic antimicrobial peptide (CAMP) resistance, and beta-lactam resistance. These data suggested that contributed to virulence by broad impact on multiple pathways of gene expression. is the causative agent of listeriosis, an infectious and fatal disease of animals and humans. In this study, we have shown that contributes to pathogenesis and replication in cell lines. We also highlight the importance of in regulating the transcription of genes involved in different pathways that might be essential for the growth and persistence of in the host or under nutrient limitation. Better understanding pathogenesis and the role of various virulence factors is necessary for further development of prevention and control strategies.
Topics: Animals; Bacterial Proteins; Caco-2 Cells; Female; Gene Expression Regulation, Bacterial; Humans; Listeria monocytogenes; Listeriosis; Mice; Mice, Inbred BALB C; Regulon; Transcription Factors; Virulence
PubMed: 32179628
DOI: 10.1128/JB.00087-20 -
Molecular Microbiology Apr 2020CodY is a global transcriptional regulator that controls, directly or indirectly, the expression of dozens of genes and operons in Listeria monocytogenes. We used in...
CodY is a global transcriptional regulator that controls, directly or indirectly, the expression of dozens of genes and operons in Listeria monocytogenes. We used in vitro DNA affinity purification combined with massively parallel sequencing (IDAP-Seq) to identify genome-wide L. monocytogenes chromosomal DNA regions that CodY binds in vitro. The total number of CodY-binding regions exceeded 2,000, but they varied significantly in their strengths of binding at different CodY concentrations. The 388 strongest CodY-binding regions were chosen for further analysis. A strand-specific analysis of the data allowed pinpointing CodY-binding sites at close to single-nucleotide resolution. Gel shift and DNase I footprinting assays confirmed the presence and locations of several CodY-binding sites. Surprisingly, most of the sites were located within genes' coding regions. The binding site within the beginning of the coding sequence of the prfA gene, which encodes the master regulator of virulence genes, has been previously implicated in regulation of prfA, but this site was weaker in vitro than hundreds of other sites. The L. monocytogenes CodY protein was functionally similar to Bacillus subtilis CodY when expressed in B. subtilis cells. Based on the sequences of the CodY-binding sites, a model of CodY interaction with DNA is proposed.
Topics: Bacterial Proteins; Binding Sites; DNA, Bacterial; DNA-Binding Proteins; Gene Expression Regulation, Bacterial; Listeria monocytogenes; Protein Binding; Transcription Factors; Virulence Factors
PubMed: 31944451
DOI: 10.1111/mmi.14449 -
Current Opinion in Microbiology Apr 2022Listeria monocytogenes (Lm) is a foodborne pathogen and the etiological agent of listeriosis. This facultative intracellular Gram-positive bacterium has the ability to... (Review)
Review
Listeria monocytogenes (Lm) is a foodborne pathogen and the etiological agent of listeriosis. This facultative intracellular Gram-positive bacterium has the ability to colonize the intestinal lumen, cross the intestinal, blood-brain and placental barriers, leading to bacteremia, neurolisteriosis and maternal-fetal listeriosis. Lm is a model microorganism for the study of the interplay between a pathogenic microbe, host tissues and microbiota in vivo. Here we review how animal models permissive to Lm-host interactions allow deciphering some of the key steps of the infectious process, from the intestinal lumen to the crossing of host barriers and dissemination within the host. We also highlight recent investigations using tagged Lm and clinically relevant strains that have shed light on within-host dynamics and the purifying selection of Lm virulence factors. Studying Lm infection in vivo is a way forward to explore host biology and unveil the mechanisms that have selected its capacity to closely associate with its vertebrate hosts.
Topics: Animals; Bacterial Proteins; Female; Host-Pathogen Interactions; Listeria monocytogenes; Listeriosis; Placenta; Pregnancy
PubMed: 34923331
DOI: 10.1016/j.mib.2021.11.015 -
Journal of Applied Microbiology May 2022To reveal the antibacterial mechanism of the combination of thymol and cinnamaldehyde to Listeria monocytogenes ATCC 19115 on autoclaved chicken breast.
AIMS
To reveal the antibacterial mechanism of the combination of thymol and cinnamaldehyde to Listeria monocytogenes ATCC 19115 on autoclaved chicken breast.
METHODS AND RESULTS
In this study, L. monocytogenes ATCC 19115 on autoclaved chicken breast was exposed to the stress of 125 μg/ml thymol and 125 μg/ml cinnamaldehyde, and transcriptome analysis was used to reveal the crucial antibacterial mechanism. According to the results, 1303 significantly differentially expressed genes (DEGs) were identified. Treated by thymol and cinnamaldehyde in combination, pyrimidine and branched-chain amino acid biosynthesis of L. monocytogenes were thwarted which impairs its nucleic acid biosynthesis and intracellular metabolism. The up-regulated DEGs involved in membrane composition and function contributed to membrane repair. Besides, pyruvate catabolism and TCA cycle were restrained which brought about the disturbance of amino acid metabolism. ABC transporters were also perturbed, for instance, the uptake of cysteine, D-methionine, and betaine was activated, while the uptake of vitamin, iron, and carnitine was repressed. Thus, L. monocytogenes tended to activate PTS, glycolysis, glycerol catabolism, and pentose phosphate pathways to obtain energy to adapt to the hostile condition. Noticeably, DEGs involved in virulence factors were totally down-regulated, including genes devoted to encoding flagella, chemotaxis, biofilm formation, internalin as well as virulence gene clusters.
CONCLUSIONS
The combination of thymol and cinnamaldehyde is effective to reduce the survival and potential virulence of L. monocytogenes on autoclaved chicken breast.
SIGNIFICANCE AND IMPACT OF STUDY
This work contributes to providing theoretical information for the application and optimization of thymol and cinnamaldehyde in ready-to-eat meat products to inhibit L. monocytogenes.
Topics: Acrolein; Animals; Anti-Bacterial Agents; Chickens; Listeria monocytogenes; Thymol; Virulence
PubMed: 35178822
DOI: 10.1111/jam.15496 -
Frontiers in Immunology 2020is a Gram-positive foodborne bacterial pathogen capable of interacting and crossing the intestinal barrier, blood-brain barrier, and placental barrier to cause deadly... (Review)
Review
is a Gram-positive foodborne bacterial pathogen capable of interacting and crossing the intestinal barrier, blood-brain barrier, and placental barrier to cause deadly infection with high mortality. is an intracellular pathogen characterized by its ability to enter non-phagocytic cells. Expression of the cytolysin listeriolysin O has been shown to be the main virulence determinant and in mouse models. can also perform cell-to-cell spreading using actin-rich membrane protrusions to infect neighboring cells, which also constitutes an important strategy for infection. These events including entry into host cells, interaction between listeriolysin O and host plasma membrane, and bacterial cell-to-cell spreading have been demonstrated to implicate the cholesterol-rich lipid rafts or molecules in these microdomains in the host plasma membrane with tissue culture models. Here we review the contribution of lipid rafts on plasma membrane to infection.
Topics: Animals; Bacterial Toxins; Heat-Shock Proteins; Hemolysin Proteins; Host-Pathogen Interactions; Humans; Listeria monocytogenes; Listeriosis; Membrane Microdomains; Virulence
PubMed: 32849575
DOI: 10.3389/fimmu.2020.01666