Persisters are a variant of bacteria responsible for non-inherited antibiotic resistance and tolerance.
Listeria monocytogenes
is a predominant food-borne pathogen causing listeriosis. Persister cell ...formation in
L. monocytogenes
population may be explained by the presence of toxin-antitoxin (TA) systems. Inhibition of TA complexes by antimicrobial peptides is suggested as a novel approach for fighting listeriosis. In this study, we used several valid servers to predict the protein models of three TA complexes and their regulatory Clp proteases in
L. monocytogenes
as well as their associated interactions following docking result analysis. Further, Peptiderive server was used to determine potential inhibitory peptides for toxin-antitoxin and antitoxin-ClpP interactions in
L. monocytogenes
. We studied the common toxin and ClpP residues with the antitoxin and with the derived peptide. These in silico-derived peptides would act as TA inhibitors paving the way for novel therapeutic developments to combat listeriosis infection.
•Sub-MICs of antibiotics can alter their physicochemical characteristics and the expression of bacterial virulence.•Toxin-antitoxin (TA) systems induce various responses to different stress ...conditions such as oxidative and antibiotic stress.•The various effects of TA systems depend on the type of stress.
Sub-inhibitory concentrations (sub-MICs) of antibiotics reflect the conditions that bacteria encounter in tissues and the natural environment. Sub-MICs of antibiotics can induce stress and alter the expression of different bacterial genes. Bacteria react to stress conditions using different mechanisms, one of which is the toxin-antitoxin (TA) system. This study investigated the expression of the TA system genes under oxidative and antibiotic stresses in Klebsiella pneumoniae (K. pneumoniae).
To determine the effects of sub-MICs of gentamicin, nalidixic acid, ceftazidime, and certain concentrations of H2O2 on bacterial survival and growth, colony forming units were quantitated and turbidity was assessed following the treatment of K. pneumoniae with ½ MICs of antibiotics and 5 mM H2O2 at different time intervals. The expression of TA system genes in K. pneumoniae was evaluated 1 h after treatment using the quantitative real-time PCR (qRT-PCR) method.
The results revealed reduced K. pneumoniae growth in the presence of sub-MICs of antibiotics and 5 mM H2O2 compared to the control. Furthermore, according to the results of the qRT-PCR assay, only the presence of gentamicin could increase the expression of TA system genes.
Although the exact role of the TA systems in response to stress is still unclear, this study provided information on the effect of the type II TA systems under oxidative and antibiotic stress conditions.
Human gastrointestinal tract harbors a variety of bacteria with vital roles in human health.
is considered one of the dominant constituents of gut microflora which can act as an opportunistic ...pathogen leading to various diseases, including colon cancer, diarrhea, uterine and intrathecal abscesses, septicemia, and pelvic inflammation. In this study, multiple locus variable number of tandem repeats analysis (MLVA) was performed to genetically differentiate 50
isolates.
Eight suitable tandem repeats (TRs) were selected by bioinformatics tools and were then subjected to PCR amplification using specific primers. Finally, MLVA profiles were clustered using BioNumerics 7.6 software package.
All VNTR loci were detected in all isolates using the PCR method. Overall,
isolates were differentiated into 27 distinct MLVA types. The highest diversity index was allocated to TR1, TR2, TR5, TR6, and TR8; with this taken into account, strain type 14 was the most prevalent with 12 strains belonging to this type. Clustering revealed three major clusters of A, B, and C. With regards to the pathogenicity of
and the outcomes of infections related to this microorganism, it is imperative to study this microorganism isolated from both patients and healthy individuals.
This study aimed at evaluating the efficiency of MLVA for the genetic differentiation of
. The results of this study indicate the promising efficiency of MLVA typing for cluster detection of this bacterium.
•Archaea have been established as abundant and prevalent microbial components of host microbiomes.•Not a single archaeal pathogen has yet been identified and archaeal microbiome components remain ...understudied.•Methanobrevibacter, is represented by two major species, which modulate the host’s nutrient break-down.•Methanosphaera is detected by the human immune system and might be involved in pathogenic processes.•The role of other host-associated archaea, remains to be further elucidated in future studies.
Since the introduction of Archaea as new domain of life more than 40 years ago, they are no longer regarded as eccentric inhabitants of extreme ecosystems. These microorganisms are widespread in various moderate ecosystems, including eukaryotic hosts such as humans.
Indeed, members of the archaeal community are now recognized as paramount constituents of human microbiome, while their definite role in disease or health is not fully elucidated and no archaeal pathogen has been reported. Here, we present a brief overview of archaea residing in and on the human body, with a specific focus on common lineages including Methanobrevibacter, Methanosphaeraand Methanomassilococcales.
This Review aims to coalesce existing knowledge on the human archaeome, a less-studied yet critical non-bacterial component of the human microbiome, with a focus on its interaction with the immune ...system. Despite a largely bacteria-centric focus in microbiome research, archaea present unique challenges and opportunities for understanding human health. We examine the archaeal distribution across different human body sites, such as the lower gastrointestinal tract (LGT), upper aerodigestive tract (UAT), urogenital tract (UGT), and skin. Variability in archaeal composition exists between sites; methanogens dominate the LGT, while Nitrososphaeria are prevalent on the skin and UAT. Archaea have yet to be classified as pathogens but show associations with conditions such as refractory sinusitis and vaginosis. In the LGT, methanogenic archaea play critical metabolic roles by converting bacterial end-products into methane, correlating with various health conditions, including obesity and certain cancers. Finally, this work looks at the complex interactions between archaea and the human immune system at the molecular level. Recent research has illuminated the roles of specific archaeal molecules, such as RNA and glycerolipids, in stimulating immune responses via innate immune receptors like Toll-like receptor 8 (TLR8) and 'C-type lectin domain family 4 member E' (CLEC4E; also known as MINCLE). Additionally, metabolic by-products of archaea, specifically methane, have demonstrated immunomodulatory effects through anti-inflammatory and anti-oxidative pathways. Despite these advancements, the mechanistic underpinnings of how archaea influence immune activity remain a fertile area for further investigation.
Bacterial co‐infections with SARS‐CoV‐2 Mirzaei, Rasoul; Goodarzi, Pedram; Asadi, Muhammad ...
IUBMB life,
October 2020, Letnik:
72, Številka:
10
Journal Article
Recenzirano
Odprti dostop
The pandemic coronavirus disease 2019 (COVID‐19), caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐CoV‐2), has affected millions of people worldwide. To date, there are no proven ...effective therapies for this virus. Efforts made to develop antiviral strategies for the treatment of COVID‐19 are underway. Respiratory viral infections, such as influenza, predispose patients to co‐infections and these lead to increased disease severity and mortality. Numerous types of antibiotics such as azithromycin have been employed for the prevention and treatment of bacterial co‐infection and secondary bacterial infections in patients with a viral respiratory infection (e.g., SARS‐CoV‐2). Although antibiotics do not directly affect SARS‐CoV‐2, viral respiratory infections often result in bacterial pneumonia. It is possible that some patients die from bacterial co‐infection rather than virus itself. To date, a considerable number of bacterial strains have been resistant to various antibiotics such as azithromycin, and the overuse could render those or other antibiotics even less effective. Therefore, bacterial co‐infection and secondary bacterial infection are considered critical risk factors for the severity and mortality rates of COVID‐19. Also, the antibiotic‐resistant as a result of overusing must be considered. In this review, we will summarize the bacterial co‐infection and secondary bacterial infection in some featured respiratory viral infections, especially COVID‐19.
Listeriosis is a serious infection linked to the consumption of food contaminated with Listeria monocytogenes. Outbreaks and mortality rates associated with this infection make it a significant ...public health concern. As biocontrol agents, probiotics such as Lactobacillus plantarum had been of interest for the promotion of antilisterial activities. However, a recent bacteriocin from epidemic L. monocytogenes strains called listeriolysin S (LLS) has been identified with the ability to target the prokaryotic cells that may hinder the anti-listerial properties of L. plantarum. The present study was designed to investigate the interplay between serotypes 4b (lineage I, LLS-producing strain) and 1/2a (NCTC7973, lineage II, non LLS-producing strain) L. monocytogenes and L. plantarum ATCC13643. According to the results of the co-culture assay, L. plantarum significantly reduced the growth of LLS- L. monocytogenes. However, there was a significant reduction in the growth of L. plantarum when co-cultured with LLS + L. monocytogenes. Moreover, according to the results of the culture assay using Caco-2 cell line, there was a significant reduced intracellular count of LLS- L. monocytogenes after L. plantarum exposure, whereas, no major differences were observed in the intracellular count of LLS + L. monocytogenes. These results suggest that L. plantarum may be unable to inhibit infections caused by LLS-producing L. monocytogenes. Also, phylogenetic studies showed the presence of LLS-like proteins in several environmental isolates including L. innocua which suggests a role for LLS in survival and bacterial colonization in harsh conditions. In overall, the ability of LLS to target certain bacterial cells should be taken into consideration during the development of anti-listerial probiotics. Future experiments are required to elucidate the exact mechanisms by which LLS achieves bacterial killing.
•LLS, a streptolysin S (SLS)-like virulence factor, belongs to the family of thiazole/oxazole-modified microcins (TOMMs).•L. plantarum is able to inhibit LLS-negative but not LLS-positive L. monocytogenes in vitro.•The RT-qPCR Results showed the significant expression of llsA at 4, 8, and 18 h post-inoculation.•Intracellular count of LLS+ L. monocytogenes is not affected by L. plantarum.•These data indicate the potential of LLS to target prokaryotic cells and combat the probiotic effects of L. plantarum.
Biofilms are microbial communities established in the self‐produced extracellular substances that include up to 80% of associated microbial infections. During biofilm formation, bacterial cells shift ...from the planktonic forms to aggregated forms surrounded by an extracellular polymeric substance. The bacterial biofilm shows resistance against immune reactions as well as antibiotics and is potentially able to cause disorders by both device‐related and nondevice‐related infections. The nondevice‐related bacterial biofilm infections include dental plaque, urinary tract infections, cystic fibrosis, otitis media, infective endocarditis, tonsillitis, periodontitis, necrotizing fasciitis, osteomyelitis, infectious kidney stones, and chronic inflammatory diseases. In this review, we will summarize and examine the literature about bacterial biofilm infections unrelated to indwelling devices.
Staphylococcus aureus is known as a common pathogen that colonizes 30% of healthy humans. Additionally, this bacterium can cause a number of serious infections, that is, endocarditis, bacteremia, ...pneumonia, wound, skin infections, and tissue abscesses. A variety of cellular and molecular pathways and targets are involved in response against S. aureus. Among them, microRNAs (miRNAs) have crucial roles in response against S. aureus. In this regard, it has been shown that these molecules exert their regulatory roles via modulating a wide range of events, such as inflammatory reactions, host innate, and adaptive immunity. Current works have provided insight into the crucial involvement of miRNAs in immune defense toward Staphylococcal infections. Herein, we highlighted the current findings on the deregulation of different miRNAs in S. aureus‐infected cells. Moreover, we summarized the mechanisms and targets of miRNAs in S. aureus infections.
•Currently, no proven effective therapies or preventive vaccines for SARAS-CoV-2 exist.•Effective vaccines against COVID-19 are urgently required to overcome the SARAS-CoV-2.•Several approaches are ...underway for vaccines developed against SARS-CoV-2.•Some clinical trials are launched in several countries.
Coronavirus disease 2019 (COVID-19) is a pandemic infectious disease caused by the novel coronavirus called SARS-CoV-2. There is a gap in our understanding regarding the immunopathogenesis of COVID-19. However, many clinical trials are underway across the world for screening effective drugs against COVID-19. Nevertheless, currently, no proven effective therapies for this virus exists. The vaccines are deemed as a significant part of disease prevention for emerging viral diseases, since, in several cases, other therapeutic choices are limited or non‐existent, or that diseases result in such an accelerated clinical worsening that the efficacy of treatments is restricted. Therefore, effective vaccines against COVID-19 are urgently required to overcome the tremendous burden of mortality and morbidity correlated with SARS-CoV-2. In this review, we will describe the latest evidence regarding outstanding vaccine approaches and the challenges for vaccine production.
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