Putative type II toxin-antitoxin systems in Listeria monocytogenes isolated from clinical, food, and animal samples in Iran

Kalani, Behrooz Sadeghi; Irajian, Gholamreza; Lotfollahi, Lida; Abdollahzadeh, Esmail; Razavi, Shabnam

doi:10.1016/j.micpath.2018.06.003

Cited by 30 publications

(21 citation statements)

References 24 publications

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“…Similarly, lipid metabolism is important for intracellular life cycle, for example, to make use of host lipids as energy sources and to modulate host immune responses (65). Recent studies found existence of several type II toxin-antitoxin systems in L. monocytogenes connected to stress conditions (66,67), though their role in virulence needs further investigation. Two competence genes (lmo2189 and lmo1397) were positively correlated, while one (lmo1346) was negatively correlated to virulence level.…”

Section: Figmentioning

confidence: 99%

Exploring Listeria monocytogenes Transcriptomes in Correlation with Divergence of Lineages and Virulence as Measured in Galleria mellonella

Lee

Garmyn

Gal

et al. 2019

Appl Environ Microbiol

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As for many opportunistic pathogens, the virulence potential of Listeria monocytogenes is highly heterogeneous between isolates and correlated, to some extent, with phylogeny and gene repertoires. In sharp contrast with copious data on intraspecies genome diversity, little is known about transcriptome diversity despite the role of complex genetic regulation in pathogenicity. The current study implemented RNA sequencing to characterize the transcriptome profiles of 33 isolates under optimal in vitro growth conditions. Transcript levels of conserved single-copy genes were comprehensively explored from several perspectives, including phylogeny, in silico-predicted virulence category based on epidemiological multilocus sequence typing (MLST) data, and in vivo virulence phenotype assessed in Galleria mellonella. Comparing baseline transcriptomes between isolates was intrinsically more complex than standard genome comparison because of the inherent plasticity of gene expression in response to environmental conditions. We show that the relevance of correlation analyses and their statistical power can be enhanced by using principal-component analysis to remove the first level of irrelevant, highly coordinated changes linked to growth phase. Our results highlight the major contribution of transcription factors with key roles in virulence to the diversity of transcriptomes. Divergence in the basal transcript levels of a substantial fraction of the transcriptome was observed between lineages I and II, echoing previously reported epidemiological differences. Correlation analysis with in vivo virulence identified numerous sugar metabolism-related genes, suggesting that specific pathways might play roles in the onset of infection in G. mellonella. IMPORTANCE Listeria monocytogenes is a multifaceted bacterium able to proliferate in a wide range of environments from soil to mammalian host cells. The accumulated genomic data underscore the contribution of intraspecies variations in gene repertoire to differential adaptation strategies between strains, including infection and stress resistance. It seems very likely that the fine-tuning of the transcriptional regulatory network is also a key component of the phenotypic diversity, albeit more difficult to investigate than genome content. Some studies reported incongruity in the basal transcriptome between isolates, suggesting a putative relationship with phenotypes, but small isolate numbers hampered proper correlation analyses with respect to their characteristics. The present study is the embodiment of the promising approach that consists of analyzing correlations between transcriptomes and various isolate characteristics. Statistically significant correlations were found with phylogenetic groups, epidemiological evidence of virulence potential, and virulence in Galleria mellonella larvae used as an in vivo model.

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Section: Figmentioning

confidence: 99%

Exploring Listeria monocytogenes Transcriptomes in Correlation with Divergence of Lineages and Virulence as Measured in Galleria mellonella

Lee

Garmyn

Gal

et al. 2019

Appl Environ Microbiol

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“…L. monocytogenes causes human listeriosis, a rare disease associated with high rates of hospitalization and mortality [6,7]. The infection is mainly linked to the consumption of contaminated ready-to-eat foods, such as cheese and other dairy products, processed meats, salads, seafood, and raw eggs [8,9]. Another bacterium, S. aureus, which belongs to the Gram-positive Micrococcaceae family, is considered to be one of the most common causes of foodborne disease in the world [10].…”

Section: Introductionmentioning

confidence: 99%

Towards understanding the antagonistic activity of phytic acid against common foodborne bacterial pathogens using a general linear model

et al. 2020

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The increasing challenge of antibiotic resistance requires not only the discovery of new antibiotics, but also the development of new alternative approaches. Therefore, in the present study, we investigated for the first time the antibacterial potential of phytic acid (myo-inositol hexakisphosphate, IP6), a natural molecule that is 'generally recognized as safe' (FDA classification), against the proliferation of common foodborne bacterial pathogens such as Listeria monocytogenes, Staphylococcus aureus and Salmonella Typhimurium. Interestingly, compared to citric acid, IP6 was found to exhibit significantly greater inhibitory activity (P<0.05) against these pathogenic bacteria. The minimum inhibitory concentration of IP6 varied from 0.488 to 0.97 mg/ml for the Gram-positive bacteria that were tested, and was 0.244 mg/ml for the Gram-negative bacteria. Linear and general models were used to further explore the antibacterial effects of IP6. The developed models were validated using experimental growth data for L. monocytogenes, S. aureus and S. Typhimurium. Overall, the models were able to accurately predict the growth of L. monocytogenes, S. aureus, and S. Typhimuriumin Polymyxin acriflavine lithium chloride ceftazidime aesculin mannitol (PAL-CAM), Chapman broth, and xylose lysine xeoxycholate (XLD) broth, respectively. Remarkably, the early logarithmic growth phase of S. Typhimurium showed a rapid and severe decrease in a period of less than one hour, illustrating the bactericidal effect of IP6. These results suggest that IP6 is an efficient antibacterial agent and can be used to control the proliferation of foodborne pathogens. It has promising potential for environmentally friendly applications in the food industry, such as for food preservation, food safety, and for prolonging shelf life.

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“…The following TAS pairs were identified mainly using in silico methods in the strain ATCC19117 (with their corresponding gene names in L. monocytogenes EGD-e): lmo0113-0114, lmo0887-0888, and lmo1301-1302, predicting their 3D structure and potential inhibitory peptides. This report also showed by qPCR that lmo0113 is upregulated upon heat stress [21,22]. Another report investigated the TAS lmo0887-888 of L. monocytogenes EGD-e in more detail, ruling out the classical MazF action, but without demonstrating the exact role of this TAS in L. monocytogenes [20].…”

Section: Introductionmentioning

confidence: 79%

“…In silico predictions using TADB2 reveal only two TASs in L. monocytogenes EGD-e: lmo0113-0114 and lmo0887-0888 [19]. There are a few studies investigating TAS systems in L. monocytogenes [20][21][22] focusing only on a few L. monocytogenes strains and a few TAS pairs. The following TAS pairs were identified mainly using in silico methods in the strain ATCC19117 (with their corresponding gene names in L. monocytogenes EGD-e): lmo0113-0114, lmo0887-0888, and lmo1301-1302, predicting their 3D structure and potential inhibitory peptides.…”

Section: Introductionmentioning

confidence: 99%

Large-Scale Comparison of Toxin and Antitoxins in Listeria monocytogenes

Agüero

Akarsu

Aguilar-Bultet

et al. 2020

Toxins

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Toxin–antitoxin systems (TASs) are widely distributed in prokaryotes and encode pairs of genes involved in many bacterial biological processes and mechanisms, including pathogenesis. The TASs have not been extensively studied in Listeria monocytogenes (Lm), a pathogenic bacterium of the Firmicutes phylum causing infections in animals and humans. Using our recently published TASmania database, we focused on the known and new putative TASs in 352 Listeria monocytogenes genomes and identified the putative core gene TASs (cgTASs) with the Pasteur BIGSdb-Lm database and, by complementarity, the putative accessory gene TAS (acTASs). We combined the cgTASs with those of an additional 227 L. monocytogenes isolates from our previous studies containing metadata information. We discovered that the differences in 14 cgTAS alleles are sufficient to separate the four main lineages of Listeria monocytogenes. Analyzing these differences in more details, we uncovered potentially co-evolving residues in some pairs of proteins in cgTASs, probably essential for protein–protein interactions within the TAS complex.

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Putative type II toxin-antitoxin systems in Listeria monocytogenes isolated from clinical, food, and animal samples in Iran

Cited by 30 publications

References 24 publications

Exploring Listeria monocytogenes Transcriptomes in Correlation with Divergence of Lineages and Virulence as Measured in Galleria mellonella

Exploring Listeria monocytogenes Transcriptomes in Correlation with Divergence of Lineages and Virulence as Measured in Galleria mellonella

Towards understanding the antagonistic activity of phytic acid against common foodborne bacterial pathogens using a general linear model

Large-Scale Comparison of Toxin and Antitoxins in Listeria monocytogenes

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