Toxin–antitoxin Systems as Regulators of Bacterial Fitness and Virulence

Fleming, Brittany A.; Mulvey, Matthew

doi:10.1002/9781119004813.ch39

Cited by 3 publications

(2 citation statements)

References 95 publications

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“…S. pneumoniae infections may adopt a biofilm way of growth, thus protecting the bacterial community from antibiotic treatments, turning many of pneumococcal infections into chronic ones [ 54 ]. In addition, some of the type II TAs found in E. coli participate in persistence and in biofilm formation [ 55 , 56 , 57 , 58 ], and this later feature is one of the few clearly confirmed TA functions [ 59 ]. Thus, we decided to test whether deletion of the two pneumococcal operons showed their participation in biofilm formation.…”

Section: Resultsmentioning

confidence: 99%

The Streptococcus pneumoniae yefM-yoeB and relBE Toxin-Antitoxin Operons Participate in Oxidative Stress and Biofilm Formation

Chan¹,

Domenech

Moreno-Córdoba

et al. 2018

Toxins

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Type II (proteic) toxin-antitoxin systems (TAs) are widely distributed among bacteria and archaea. They are generally organized as operons integrated by two genes, the first encoding the antitoxin that binds to its cognate toxin to generate a harmless protein–protein complex. Under stress conditions, the unstable antitoxin is degraded by host proteases, releasing the toxin to achieve its toxic effect. In the Gram-positive pathogen Streptococcus pneumoniae we have characterized four TAs: pezAT, relBE, yefM-yoeB, and phD-doc, although the latter is missing in strain R6. We have assessed the role of the two yefM-yoeB and relBE systems encoded by S. pneumoniae R6 by construction of isogenic strains lacking one or two of the operons, and by complementation assays. We have analyzed the phenotypes of the wild type and mutants in terms of cell growth, response to environmental stress, and ability to generate biofilms. Compared to the wild-type, the mutants exhibited lower resistance to oxidative stress. Further, strains deleted in yefM-yoeB and the double mutant lacking yefM-yoeB and relBE exhibited a significant reduction in their ability for biofilm formation. Complementation assays showed that defective phenotypes were restored to wild type levels. We conclude that these two loci may play a relevant role in these aspects of the S. pneumoniae lifestyle and contribute to the bacterial colonization of new niches.

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Section: Resultsmentioning

confidence: 99%

The Streptococcus pneumoniae yefM-yoeB and relBE Toxin-Antitoxin Operons Participate in Oxidative Stress and Biofilm Formation

Chan¹,

Domenech

Moreno-Córdoba

et al. 2018

Toxins

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“…Stressful conditions can result in degradation of the antitoxins and subsequent toxin activation. This, in turn, can cause bacteria to form quiescent, antibiotic-tolerant persister cells (117). Of the dozens of TA systems that have been identified, only a subset is encoded by strains of UPEC (118, 119).…”

Section: Regulation Of Intracellular Bacterial Growth and Persistencementioning

confidence: 99%

Invasion of Host Cells and Tissues by Uropathogenic Bacteria

2016

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Within the mammalian urinary tract uropathogenic bacteria face many challenges, including the shearing flow of urine, numerous antibacterial molecules, the bactericidal effects of phagocytes, and a scarcity of nutrients. These problems may be circumvented in part by the ability of uropathogenic Escherichia coli (UPEC) and several other uropathogens to invade the epithelial cells that line the urinary tract. By entering host cells, uropathogens can gain access to additional nutrients and protection from both host defenses and antibiotic treatments. Translocation through host cells can facilitate bacterial dissemination within the urinary tract, while the establishment of stable intracellular bacterial populations may create reservoirs for relapsing and chronic urinary tract infections (UTIs). Here we review the mechanisms and consequences of host cell invasion by uropathogenic bacteria, with consideration of the defenses that are brought to bear against facultative intracellular pathogens within the urinary tract. The relevance of host cell invasion to the pathogenesis of UTIs in human patients is also assessed, along with some of the emerging treatment options that build upon our growing understanding of the infectious life cycle of UPEC and other uropathogenic bacteria.

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Virulence and transcriptome profile of multidrug-resistant Escherichia coli from chicken

Hussain

Zahid

Seleem

et al. 2017

Sci Rep

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Numerous studies have examined the prevalence of pathogenic Escherichia coli in poultry and poultry products; however, limited data are available regarding their resistance- and virulence-associated gene expression profiles. This study was designed to examine the resistance and virulence of poultry E. coli strains in vitro and in vivo via antibiotic susceptibility, biofilm formation and adhesion, and invasion and intracellular survivability assays in Caco-2 and Raw 264.7 cell lines as well as the determination of the median lethal dose in two-day old chickens. A clinical pathogenic multidrug-resistant isolate, E. coli 381, isolated from broilers, was found to be highly virulent in cell culture and 1000-fold more virulent in a chicken model than other strains; accordingly, the isolate was subsequently selected for transcriptome analysis. The comparative gene expression profile of MDR E. coli 381 and the reference human strain E. coli ATCC 25922 was completed with Illumina HiSeq. 2500 transcriptome analysis. Differential gene expression analysis indicates that there are multiple pathways involved in the resistance and virulence of this highly virulent strain. The results garnered from this study provide critical information about the highly virulent MDR E. coli strain of poultry origin and warrant further investigation due to its significant threat to public health.

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Toxin–antitoxin Systems as Regulators of Bacterial Fitness and Virulence

Cited by 3 publications

References 95 publications

The Streptococcus pneumoniae yefM-yoeB and relBE Toxin-Antitoxin Operons Participate in Oxidative Stress and Biofilm Formation

The Streptococcus pneumoniae yefM-yoeB and relBE Toxin-Antitoxin Operons Participate in Oxidative Stress and Biofilm Formation

Invasion of Host Cells and Tissues by Uropathogenic Bacteria

Virulence and transcriptome profile of multidrug-resistant Escherichia coli from chicken

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