-
Journal of Microbiology (Seoul, Korea) Nov 2023Listeria monocytogenes is an important food-borne pathogen that causes listeriosis and has a high case fatality rate despite its low incidence. Medicinal plants and...
Listeria monocytogenes is an important food-borne pathogen that causes listeriosis and has a high case fatality rate despite its low incidence. Medicinal plants and their secondary metabolites have been identified as potential antibacterial substances, serving as replacements for synthetic chemical compounds. The present studies emphasize two significant medicinal plants, Allium cepa and Zingiber officinale, and their efficacy against L. monocytogenes. Firstly, a bacterial isolate was obtained from milk and identified through morphology and biochemical reactions. The species of the isolate were further confirmed through 16S rRNA analysis. Furthermore, polar solvents such as methanol and ethanol were used for the extraction of secondary metabolites from A. cepa and Z. officinale. Crude phytochemical components were identified using phytochemical tests, FTIR, and GC-MS. Moreover, the antibacterial activity of the crude extract and its various concentrations were tested against L. monocytogenes. Among all, A. cepa in methanolic extracts showed significant inhibitory activity. Since, the A. cepa for methanolic crude extract was used to perform autography to assess its bactericidal activity. Subsequently, molecular docking was performed to determine the specific compound inhibition. The docking results revealed that four compounds displayed strong binding affinity with the virulence factor Listeriolysin-O of L. monocytogenes. Based on the above results, it can be concluded that the medicinal plant A. cepa has potential antibacterial effects against L. monocytogenes, particularly targeting its virulence.
Topics: Animals; Listeria monocytogenes; Onions; Zingiber officinale; Milk; RNA, Ribosomal, 16S; Molecular Docking Simulation; Anti-Infective Agents; Anti-Bacterial Agents; Plants, Medicinal; Plant Extracts; Phytochemicals
PubMed: 38048022
DOI: 10.1007/s12275-023-00086-w -
Food Chemistry Sep 2023This study aimed to investigate the synergistic effects of benzyl isothiocyanate (BITC) and resveratrol (RS) on Listeria monocytogenes and their application in chicken...
This study aimed to investigate the synergistic effects of benzyl isothiocyanate (BITC) and resveratrol (RS) on Listeria monocytogenes and their application in chicken meat preservation. BITC combined with RS (BR) significantly enhanced the antimicrobial activity and inhibited the growth of Listeria monocytogenes within 24 h compared to individual treatment, as well as suppressing bacterial swimming and swarming motility, reducing biofilm formation by 56.4%, increasing cell membrane disruption, and inducing intracellular ROS surges. Synergistic effects were associated with the inhibition of biofilm formation, cell membrane destruction, and ROS production. Biofilm removal facilitated the direct antimicrobial action of BR. RS disrupted cell membrane permeability, allowing more BITC into the cells, resulting in increased intracellular antibacterial levels, cell membrane hyperpolarization, and rapid ROS accumulation. Furthermore, BR visibly slowed the microbial growth in chicken flesh stored at 25 °C and 4 °C. Therefore, BR is expected to be a new strategy for food preservation.
Topics: Animals; Listeria monocytogenes; Chickens; Resveratrol; Meat; Reactive Oxygen Species; Food Preservation; Anti-Bacterial Agents; Food Microbiology; Colony Count, Microbial
PubMed: 37044056
DOI: 10.1016/j.foodchem.2023.135984 -
Cell Reports Aug 2023T-bet and FOXO1 are transcription factors canonically associated with effector and memory T cell fates, respectively. During an infectious response, these factors...
T-bet and FOXO1 are transcription factors canonically associated with effector and memory T cell fates, respectively. During an infectious response, these factors direct the development of CD8 T cell fates, where T-bet deficiency leads to ablation of only short-lived effector cells, while FOXO1 deficiency results in selective loss of memory. In contrast, following adjuvanted subunit vaccination in mice, both effector- and memory-fated T cells are compromised in the absence of either T-bet or FOXO1. Thus, unlike responses to challenge with Listeria monocytogenes, productive CD8 T cell responses to adjuvanted vaccination require coordinated regulation of FOXO1 and T-bet transcriptional programs. Single-cell RNA sequencing analysis confirms simultaneous T-bet, FOXO1, and TCF1 transcriptional activity in vaccine-elicited, but not infection-elicited, T cells undergoing clonal expansion. Collectively, our data show that subunit vaccine adjuvants elicit T cell responses dependent on transcription factors associated with effector and memory cell fates.
Topics: Animals; Mice; Adjuvants, Vaccine; CD8-Positive T-Lymphocytes; Cell Differentiation; Immunologic Memory; Listeria monocytogenes; Mice, Inbred C57BL; Transcription Factors
PubMed: 37516968
DOI: 10.1016/j.celrep.2023.112911 -
Microbiology Spectrum Sep 2023is ubiquitously found in nature and can easily enter food-processing facilities due to contaminations of raw materials. Several countermeasures are used to combat...
is ubiquitously found in nature and can easily enter food-processing facilities due to contaminations of raw materials. Several countermeasures are used to combat contamination of food products, for instance, the use of disinfectants that contain quaternary ammonium compounds, such as benzalkonium chloride (BAC) and cetyltrimethylammonium bromide (CTAB). In this study, we assessed the potential of the commonly used wild-type strain EGD-e to adapt to BAC and CTAB under laboratory growth conditions. All BAC-tolerant suppressors exclusively carried mutations in , encoding a TetR-like transcriptional regulator, or its promoter region, likely resulting in the overproduction of the efflux pump FepA. In contrast, CTAB tolerance was associated with mutations in , which regulates the expression of the efflux pumps SugE1 and SugE2. strains lacking either FepA or SugE1/2 could still acquire tolerance toward BAC and CTAB. Genomic analysis revealed that the overproduction of the remaining efflux system could compensate for the deleted one, and even in the absence of both efflux systems, tolerant strains could be isolated, which all carried mutations in the diacylglycerol kinase-encoding gene (). DgkB converts diacylglycerol to phosphatidic acid, which is subsequently reused for the synthesis of phospholipids, suggesting that alterations in membrane composition could be the third adaptation mechanism. IMPORTANCE Survival and proliferation of in the food industry are ongoing concerns, and while there are various countermeasures to combat contamination of food products, the pathogen still successfully manages to withstand the harsh conditions present in food-processing facilities, resulting in reoccurring outbreaks, subsequent infection, and disease. To counteract the spread of , it is crucial to understand and elucidate the underlying mechanism that permits their successful evasion. We present various adaptation mechanisms of to withstand two important quaternary ammonium compounds.
PubMed: 37695041
DOI: 10.1128/spectrum.01441-23 -
Microorganisms May 2024() poses a significant threat to food safety due to its ability to cause severe human illness and its resistance to various antibiotics and environmental conditions....
() poses a significant threat to food safety due to its ability to cause severe human illness and its resistance to various antibiotics and environmental conditions. This study investigated the prevalence, serotype distribution, virulence gene profiles, and antimicrobial resistance patterns of in ready-to-eat (RTE) food products from Romania. A total of 8151 samples were analyzed, including various processed dairy, bovine, poultry, pork, and fish products. Bacterial isolation was conducted using the classical standard method, followed by confirmation through biochemical and molecular testing. Among the isolated strains, serotypes 1/2a, 1/2b, and 1/2c were identified, with a prevalence of 75% for serotype 1/2a. Additionally, virulence genes specific to listeriolysin O (A) and regulatory factor A (A) were detected in all isolates. Antimicrobial susceptibility testing revealed varying resistance patterns among the strains. Trimethoprim-sulfamethoxazole and oxacillin showed the highest prevalence of resistance at 26.92% and 23.07%, respectively. However, all strains remained susceptible to ciprofloxacin, levofloxacin, and moxifloxacin. Notably, 23.07% of the isolates exhibited multidrug resistance, with the most common pattern being resistance to oxacillin, penicillin, and tetracycline. Analysis of antimicrobial resistance genes identified tetracycline resistance genes, particularly (C), (M), and (K), in a significant proportion of isolates. The presence of C and D genes was also notable, indicating potential mechanisms of resistance. These results emphasize the necessity for ongoing surveillance of in RTE foods and emphasize the importance of thorough monitoring of antimicrobial resistance to guide public health strategies within the European Union.
PubMed: 38792784
DOI: 10.3390/microorganisms12050954 -
BMC Genomic Data Jan 2024Listeriosis caused by Listeria monocytogenes often poses a significant threat to vulnerable populations. Dairy products have been implicated in outbreaks of listeriosis...
Listeriosis caused by Listeria monocytogenes often poses a significant threat to vulnerable populations. Dairy products have been implicated in outbreaks of listeriosis worldwide. In Ethiopia, studies have identified Listeria spp. and L. monocytogenes in various dairy products, but the genetic diversity and phylogenetic relationships of these bacteria remain largely unknown in the low- and middle-income countries. Therefore, we conducted whole-genome sequencing on 15 L. monocytogenes and 55 L. innocua isolates obtained from different levels of the dairy supply chains across three regions in Ethiopia. Genomes were assembled and used for MLST genotyping and single nucleotide polymorphism (SNP) analysis to infer phylogenetic relationships. We identified a total of 3 L. monocytogenes (i.e., 2, 145, and 18) and 12 L. innocua (i.e., 1489, 1619, 603, 537, 1010, 3186, 492, 3007, 1087, 474, 1008, and 637) MLST sequence types among the studied isolates. Some of these sequence types showed region-specific occurrence, while others were broadly distributed across regions. Through high-quality SNP analysis, we found that among 13 L. monocytogenes identified as ST 2, 11 of them were highly similar with low genetic variation, differing by only 1 to 10 SNPs, suggesting potential selection in the dairy food supply chain. The L. innocua isolates also exhibited low intra-ST genetic variation with only 0-10 SNP differences, except for the ST 1619, which displayed a greater diversity.
Topics: Humans; Animals; Listeria monocytogenes; Milk; Multilocus Sequence Typing; Ethiopia; Phylogeny; Listeria; Listeriosis; Genomics
PubMed: 38297216
DOI: 10.1186/s12863-024-01195-0 -
Clinical Immunology (Orlando, Fla.) Dec 2023Innate immune response is critical for the control of Listeria monocytogenes infection. Here, we identified developmentally regulated GTP-binding protein 2 (DRG2) in...
Innate immune response is critical for the control of Listeria monocytogenes infection. Here, we identified developmentally regulated GTP-binding protein 2 (DRG2) in macrophages as a major regulator of the innate immune response against L. monocytogenes infection. Both whole-body DRG2 knockout (KO) mice and macrophage-specific DRG2 KO mice had low levels of IL-6 during early infection and increased susceptibility to L. monocytogenes infection. Following an initial impaired inflammatory response of macrophages upon i.p. L. monocytogenes infection, DRG2 mice showed delayed recruitment of neutrophils and monocytes into the peritoneal cavity, which led to elevated bacterial burden, inflammatory cytokine production at a late infection time point, and liver micro-abscesses. DRG2 deficiency decreased the transcriptional activity of NF-κB and impaired the inflammatory response of both bone marrow-derived and peritoneal macrophages upon L. monocytogenes stimulation. Our findings reveal that DRG2 in macrophages is critical for the initial inflammatory response and protection against L. monocytogenes infection.
Topics: Animals; Mice; Immunity, Innate; Listeria monocytogenes; Listeriosis; Macrophages; Mice, Knockout; Monocytes; GTP-Binding Proteins
PubMed: 37918467
DOI: 10.1016/j.clim.2023.109819 -
International Journal of Food... Jul 2023Root vegetables, which are in close contact with soil, are particularly vulnerable to soil contamination or decay as they can be contaminated from multiple sources,...
Simulation of contamination and elimination of Escherichia coli, Listeria monocytogenes, and Murine norovirus 1 (MNV-1) from the washing process when handling of potatoes.
Root vegetables, which are in close contact with soil, are particularly vulnerable to soil contamination or decay as they can be contaminated from multiple sources, including primary production and processing. This study investigated effective washing conditions to reduce the microbial contamination of potatoes by using soaking and shaking in the washing process. The reduction of Escherichia coli, Listeria monocytogenes, and Murine norovirus 1 (MNV-1) in four washing processes (soaking only, shaking only, combined soaking-shaking I, and combined soaking-shaking I-shaking II) were compared. The numbers of E. coli and L. monocytogenes decreased by 0.55 and 0.49 log CFU/g after shaking only, 1.96 and 1.80 log CFU/g after soaking, 2.07 and 1.67 log CFU/g after soaking-shaking I, and 2.42 and 1.90 log CFU/g after soaking-shaking I-shaking II, respectively. The combined process reduced the microbial contamination more efficiently than shaking only. The reduction of E. coli in the washing process was higher than that of L. monocytogenes by approximately 0.5 logs. MNV-1 showed a reduction in the soaking and shaking steps by 1.34 and 1.98 log GC/100 g, with no significant reduction observed after the combination process. A combined process of soaking-shaking I-shaking II was effective to eliminate E. coli, L. monocytogenes, and MNV-1 from potatoes during the handling and washing process.
Topics: Animals; Mice; Food Microbiology; Listeria monocytogenes; Solanum tuberosum; Food Handling; Norovirus; Escherichia coli O157; Colony Count, Microbial
PubMed: 37126887
DOI: 10.1016/j.ijfoodmicro.2023.110221 -
Frontiers in Microbiology 2023In this study, genetic variations and characteristics of isolates from enoki mushrooms (23), smoked ducks (7), and processed ground meat products (30) were examined...
In this study, genetic variations and characteristics of isolates from enoki mushrooms (23), smoked ducks (7), and processed ground meat products (30) were examined with respect to hemolysis, virulence genes, growth patterns, and heat resistance. The isolates that showed the highest pathogenicity and the lowest pathogenicity were analyzed to obtain the whole-genome sequence, and the sequences were further analyzed to identify genetic variations in virulence, low-temperature growth-related, and heat resistance-related factors. All isolates had -hemolysis and virulence genes (A, A, A, B, and B). At low temperatures, isolates with high growth ( strains SMFM 201803 SD 1-1, SMFM 201803 SD 4-2, and SMFM 201804 SD 5-3) and low growth ( strains SMFM 2019-FV43, SMFM 2019-FV42, and SMFM 2020-BT30) were selected. Among them, SMFM 201804 SD 5-3 showed the highest resistance at 60°C and 70°C. The strains SMFM 201804 SD 5-3 (high-risk) and SMFM 2019-FV43 (low-risk) harbored 45 virulence genes; 41 single nucleotide variants (SNVs) were identified between these two isolates. A comparison of 26 genes related to low-temperature growth revealed 18 SNVs between these two isolates; a comparison of the 21 genes related to heat resistance revealed 16 SNVs. These results indicate that the differences in the pathogenicity of SMFM 201804 SD 5-3 and SMFM 2019-FV43 are associated with the SNVs identified in virulence genes, low-temperature growth-related genes, and heat resistance-related genes.
PubMed: 37533826
DOI: 10.3389/fmicb.2023.1163841 -
Polish Journal of Veterinary Sciences Mar 2024Listeria monocytogenes is a ubiquitous microorganism that is isolated from a variety of sources such as soil, water, decaying vegetation, sewage, animal feeds, silage,...
Listeria monocytogenes is a ubiquitous microorganism that is isolated from a variety of sources such as soil, water, decaying vegetation, sewage, animal feeds, silage, farm environments and food-processing environments. This study aimed to determine the prevalence, serogroups, biofilm formation, virulence factor genes, and genetic relationships of L. monocytogenes strains isolated from beef meat and meat contact surfaces obtained from a slaughterhouse in Burdur, Turkey. In this study, a total of 179 beef meat and meat contact surface samples were analyzed for the presence of L. monocytogenes by polymerase chain reaction (PCR). Out of a total of 179 beef meat and meat contact surface samples, 83 (46.37%) were found to be contaminated with L. monocytogenes, with the highest incidence (53.01%) occurring in beef meat. In the present study, most of the isolated strains belonged to serogroups IIB and IVB (lineage I). The L. monocytogenes strain also contained monoA-B, prfA, plcA, plcB, mpl, hlyA, actA, gtcA, dltA, Fri, flaA, InlA, InlC, InlJ, and iap genes. Biofilm formation was not determined in the tested samples at pH 5.5 and different temperatures (4°C, 10°C, 25°C, and 37°C). However, strong biofilm formation was observed in 6.45% (2/31) of the strains at pH 7.0 after 48 h incubation at 37°C, and in 3.22% (1/31) of the strains at pH 7.0 after 48 h incubation at 4°C and 10°C. Pulsed-field gel electrophoresis (PFGE) results showed that L. monocytogenes isolates were clonally related, and cross-contamination was present. In addition, PFGE results also revealed that AscI had more distinguishing power than the ApaI restriction enzyme. These results indicate that L. monocytogenes detected from meat and meat contact surfaces in the slaughterhouse pose a potential risk to public health.
Topics: Cattle; Animals; Listeria monocytogenes; Virulence; Food Microbiology; Abattoirs; Meat
PubMed: 38511571
DOI: 10.24425/pjvs.2024.149329