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Nature Reviews. Microbiology Aug 2017Many bacteria can infect and persist inside their hosts for long periods of time. This can be due to immunosuppression of the host, immune evasion by the pathogen and/or... (Review)
Review
Many bacteria can infect and persist inside their hosts for long periods of time. This can be due to immunosuppression of the host, immune evasion by the pathogen and/or ineffective killing by antibiotics. Bacteria can survive antibiotic treatment if they are resistant or tolerant to a drug. Persisters are a subpopulation of transiently antibiotic-tolerant bacterial cells that are often slow-growing or growth-arrested, and are able to resume growth after a lethal stress. The formation of persister cells establishes phenotypic heterogeneity within a bacterial population and has been hypothesized to be important for increasing the chances of successfully adapting to environmental change. The presence of persister cells can result in the recalcitrance and relapse of persistent bacterial infections, and it has been linked to an increase in the risk of the emergence of antibiotic resistance during treatment. If the mechanisms of the formation and regrowth of these antibiotic-tolerant cells were better understood, it could lead to the development of new approaches for the eradication of persistent bacterial infections. In this Review, we discuss recent developments in our understanding of bacterial persisters and their potential implications for the treatment of persistent infections.
Topics: Anti-Bacterial Agents; Bacteria; Bacterial Infections; Drug Resistance, Multiple, Bacterial; Humans
PubMed: 28529326
DOI: 10.1038/nrmicro.2017.42 -
Journal of Clinical Laboratory Analysis Jan 2022A variety of bacteriocins originate from lactic acid bacteria, which have recently been modified by scientists. Many strains of lactic acid bacteria related to food... (Review)
Review
A variety of bacteriocins originate from lactic acid bacteria, which have recently been modified by scientists. Many strains of lactic acid bacteria related to food groups could produce bacteriocins or antibacterial proteins highly effective against foodborne pathogens such as Staphylococcus aureus, Pseudomonas fluorescens, P. aeruginosa, Salmonella typhi, Shigella flexneri, Listeria monocytogenes, Escherichia coli O157:H7, and Clostridium botulinum. A wide range of bacteria belonging primarily to the genera Bifidobacterium and Lactobacillus have been characterized with different health-promoting attributes. Extensive studies and in-depth understanding of these antimicrobials mechanisms of action could enable scientists to determine their production in specific probiotic lactic acid bacteria, as they are potentially crucial for the final preservation of functional foods or for medicinal applications. In this review study, the structure, classification, mode of operation, safety, and antibacterial properties of bacteriocins as well as their effect on foodborne pathogens and antibiotic-resistant bacteria were extensively studied.
Topics: Animals; Anti-Bacterial Agents; Bacteria; Bacteriocins; Foodborne Diseases; Gastrointestinal Microbiome; Humans; Lactobacillales; Mice
PubMed: 34851542
DOI: 10.1002/jcla.24093 -
Microbiological Research Apr 2019Endophytic bacteria are the plant beneficial bacteria that thrive inside plants and can improve plant growth under normal and challenging conditions. They can benefit... (Review)
Review
Endophytic bacteria are the plant beneficial bacteria that thrive inside plants and can improve plant growth under normal and challenging conditions. They can benefit host plants directly by improving plant nutrient uptake and by modulating growth and stress related phytohormones. Indirectly, endophytic bacteria can improve plant health by targeting pests and pathogens with antibiotics, hydrolytic enzymes, nutrient limitation, and by priming plant defenses. To confer these benefits, the bacteria have to colonize the plant endosphere after colonizing the rhizosphere. The colonization is achieved using a battery of traits involving motility, attachment, plant-polymer degradation, and evasion of plant defenses. The diversity of endophytic colonizers depends on several bacteria, plant and environment specific factors. Some endophytic bacteria can have a broad host range and can be used as bioinoculants in developing a safe and sustainable agriculture system. This review elaborates the factors affecting diversity of bacterial endophytes, their host specificity and mechanisms of plant growth promotion. The review also accentuates various methods used to study endophytic communities, wild plants as a source of novel endophytic bacteria, and innovative approaches that may improve plant-endophyte association. Moreover, bacterial genes expressed in planta and challenges to study them are also discussed.
Topics: Bacteria; Endophytes; Host Specificity; Plant Development; Plant Roots; Plants; Rhizosphere; Symbiosis
PubMed: 30825940
DOI: 10.1016/j.micres.2019.02.001 -
The Journal of Clinical Investigation Feb 2022The importance of the microbiota in the development of colorectal cancer (CRC) is increasingly evident, but identifying specific microbial features that influence CRC... (Review)
Review
The importance of the microbiota in the development of colorectal cancer (CRC) is increasingly evident, but identifying specific microbial features that influence CRC initiation and progression remains a central task for investigators. Studies determining the microbial mechanisms that directly contribute to CRC development or progression are revealing bacterial factors such as toxins that contribute to colorectal carcinogenesis. However, even when investigators have identified bacteria that express toxins, questions remain about the host determinants of a toxin's cancer-potentiating effects. For other cancer-correlating bacteria that lack toxins, the challenge is to define cancer-relevant virulence factors. Herein, we evaluate three CRC-correlating bacteria, colibactin-producing Escherichia coli, enterotoxigenic Bacteroides fragilis, and Fusobacterium nucleatum, for their virulence features relevant to CRC. We also consider the beneficial bioactivity of gut microbes by highlighting a microbial metabolite that may enhance CRC antitumor immunity. In doing so, we aim to elucidate unique and shared mechanisms underlying the microbiota's contributions to CRC and to accelerate investigation from target validation to CRC therapeutic discovery.
Topics: Animals; Bacteria; Carcinogenesis; Colorectal Neoplasms; Gastrointestinal Microbiome; Humans
PubMed: 35166235
DOI: 10.1172/JCI155101 -
FEMS Microbiology Reviews Nov 2014The presence of an abnormal amount of single-stranded DNA in the bacterial cell constitutes a genotoxic alarm signal that induces the SOS response, a broad regulatory... (Review)
Review
The presence of an abnormal amount of single-stranded DNA in the bacterial cell constitutes a genotoxic alarm signal that induces the SOS response, a broad regulatory network found in most bacterial species to address DNA damage. The aim of this review was to point out that beyond being a repair process, SOS induction leads to a very strong but transient response to genotoxic stress, during which bacteria can rearrange and mutate their genome, induce several phenotypic changes through differential regulation of genes, and sometimes acquire characteristics that potentiate bacterial survival and adaptation to changing environments. We review here the causes and consequences of SOS induction, but also how this response can be modulated under various circumstances and how it is connected to the network of other important stress responses. In the first section, we review articles describing the induction of the SOS response at the molecular level. The second section discusses consequences of this induction in terms of DNA repair, changes in the genome and gene expression, and sharing of genomic information, with their effects on the bacteria's life and evolution. The third section is about the fine tuning of this response to fit with the bacteria's 'needs'. Finally, we discuss recent findings linking the SOS response to other stress responses. Under these perspectives, SOS can be perceived as a powerful bacterial strategy against aggressions.
Topics: Bacteria; DNA Repair; Gene Expression Regulation, Bacterial; SOS Response, Genetics; Stress, Physiological
PubMed: 24923554
DOI: 10.1111/1574-6976.12077 -
PloS One 2021Microorganisms in oral cavity are called oral microbiota, while microbiome consists of total genome content of microorganisms in a host. Interaction between host and... (Clinical Trial)
Clinical Trial
BACKGROUND
Microorganisms in oral cavity are called oral microbiota, while microbiome consists of total genome content of microorganisms in a host. Interaction between host and microorganisms is important in nervous system development and nervous diseases such as Autism, Alzheimer, Parkinson and Multiple Sclerosis (MS). Bacterial infections, as an environmental factor in MS pathogenesis play role in T helper 17(Th17) increase and it enhancing the production of pro-inflammatory cytokines such as Interlukin-21(IL-21), IL-17 and IL -22. Oral microbiota consists diverse populations of cultivable and uncultivable bacterial species. Denaturing gradient gel electrophoresis (DGGE) is an acceptable method for identification of uncultivable bacteria. In this study, we compared the bacterial population diversity in the oral cavity between MS and healthy people.
METHODS
From October to March 2019, samples were taken at Kermanshah University of Medical Sciences' MS patients center. A total of 30 samples were taken from MS patients and another 30 samples were taken from healthy people. Phenotypic tests were used to identify bacteria after pure cultures were obtained. DNA was extracted from 1 mL of saliva, and PCR products produced with primers were electrophoresed on polyacrylamide gels.
RESULTS
The genera Staphylococcus, Actinomyces, Fusobacterium, Bacteroides, Porphyromonas, Prevotella, Veillonella, Propionibacterium and uncultivable bacteria with accession number MW880919-25, JQ477416.1, KF074888.1 and several other un-culturable strains were significantly more abundant in the MS group while Lactobacillus and Peptostreptococcus were more prevalent in the normal healthy group according to logistic regression method.
CONCLUSION
Oral micro-organisms may alleviate or exacerbate inflammatory condition which impact MS disease pathogenesis. It may be assumed that controlling oral infections may result in reduction of MS disease progression.
Topics: Adult; Bacteria; Female; Humans; Mouth; Multiple Sclerosis
PubMed: 34847159
DOI: 10.1371/journal.pone.0260384 -
Microbiology Spectrum Mar 2019is usually regarded as a bacterial pathogen due to its ability to cause multiple types of invasive infections. Nevertheless, colonizes about 30% of the human... (Review)
Review
is usually regarded as a bacterial pathogen due to its ability to cause multiple types of invasive infections. Nevertheless, colonizes about 30% of the human population asymptomatically in the nares, either transiently or persistently, and can therefore be regarded a human commensal as well, although carriage increases the risk of infection. Whereas many facets of the infection processes have been studied intensively, little is known about the commensal lifestyle of . Recent studies highlight the major role of the composition of the highly variable nasal microbiota in promoting or inhibiting colonization. Competition for limited nutrients, trace elements, and epithelial attachment sites, different susceptibilities to host defense molecules and the production of antimicrobial molecules by bacterial competitors may determine whether nasal bacteria outcompete each other. This chapter summarizes our knowledge about mechanisms that are used by for efficient nasal colonization and strategies used by other nasal bacteria to interfere with its colonization. An improved understanding of naturally evolved mechanisms might enable us to develop new strategies for pathogen eradication.
Topics: Bacteria; Bacterial Physiological Phenomena; Humans; Microbiota; Nasal Cavity; Staphylococcal Infections; Staphylococcus aureus
PubMed: 31004422
DOI: 10.1128/microbiolspec.GPP3-0029-2018 -
Aging Aug 2021
Topics: Animals; Bacteria; Bone and Bones; DNA Damage; Gastrointestinal Microbiome; Humans; Intestines; Radiation, Ionizing; Radiotherapy
PubMed: 34406126
DOI: 10.18632/aging.203446 -
Cellular Microbiology May 2021
Topics: Animals; Bacteria; Bacterial Infections; Host-Pathogen Interactions; Humans; Immune Evasion; Virulence
PubMed: 33369087
DOI: 10.1111/cmi.13300 -
International Journal of Molecular... Nov 2019Breast cancer is the second most common cause of cancer-related mortality among women around the world. Conventional treatments in the fight against breast cancer, such... (Review)
Review
Breast cancer is the second most common cause of cancer-related mortality among women around the world. Conventional treatments in the fight against breast cancer, such as chemotherapy, are being challenged regarding their effectiveness. Thus, strategies for the treatment of breast cancer need to be continuously refined to achieve a better patient outcome. We know that a number of bacteria are pathogenic and some are even associated with tumor development, however, recent studies have demonstrated interesting results suggesting some bacteria may have potential for cancer therapy. Therefore, the therapeutic role of bacteria has aroused attention in medical and pharmaceutical studies. Furthermore, genetic engineering has been used in bacterial therapy and may led to greater efficacy with few side effects. Some genetically modified non-pathogenic bacterial species are more successful due to their selectivity for cancer cells but with low toxicity for normal cells. Some live, attenuated, or genetically modified bacterias are capable to multiply in tumors and inhibit their growth. This article aims to review the role of bacteria and their products including bacterial peptides, bacteriocins, and toxins for the treatment of breast cancer.
Topics: Animals; Bacteria; Bacteriocins; Breast Neoplasms; Colicins; Humans; Nisin; Peptides, Cyclic
PubMed: 31771178
DOI: 10.3390/ijms20235880