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Journal of Applied Microbiology Sep 2017Escherichia coli is classified as a rod-shaped, Gram-negative bacterium in the family Enterobacteriaceae. The bacterium mainly inhabits the lower intestinal tract of... (Review)
Review
Escherichia coli is classified as a rod-shaped, Gram-negative bacterium in the family Enterobacteriaceae. The bacterium mainly inhabits the lower intestinal tract of warm-blooded animals, including humans, and is often discharged into the environment through faeces or wastewater effluent. The presence of E. coli in environmental waters has long been considered as an indicator of recent faecal pollution. However, numerous recent studies have reported that some specific strains of E. coli can survive for long periods of time, and potentially reproduce, in extraintestinal environments. This indicates that E. coli can be integrated into indigenous microbial communities in the environment. This naturalization phenomenon calls into question the reliability of E. coli as a faecal indicator bacterium (FIB). Recently, many studies reported that E. coli populations in the environment are affected by ambient environmental conditions affecting their long-term survival. Large-scale studies of population genetics revealed the diversity and complexity of E. coli strains in various environments, which are affected by multiple environmental factors. This review examines the current knowledge on the ecology of E. coli strains in various environments with regard to its role as a FIB and as a naturalized member of indigenous microbial communities. Special emphasis is given on the growth of pathogenic E. coli in the environment, and the population genetics of environmental members of the genus Escherichia. The impact of environmental E. coli on water quality and public health is also discussed.
Topics: Animals; Escherichia coli; Escherichia coli Infections; Feces; Fresh Water; Humans; Public Health; Water Pollution
PubMed: 28383815
DOI: 10.1111/jam.13468 -
Molecular Microbiology Jun 2006Pathogenic Escherichia coli cause over 160 million cases of dysentery and one million deaths per year, whereas non-pathogenic E. coli constitute part of the normal...
Pathogenic Escherichia coli cause over 160 million cases of dysentery and one million deaths per year, whereas non-pathogenic E. coli constitute part of the normal intestinal flora of healthy mammals and birds. The evolutionary pathways underlying this dichotomy in bacterial lifestyle were investigated by multilocus sequence typing of a global collection of isolates. Specific pathogen types [enterohaemorrhagic E. coli, enteropathogenic E. coli, enteroinvasive E. coli, K1 and Shigella] have arisen independently and repeatedly in several lineages, whereas other lineages contain only few pathogens. Rates of evolution have accelerated in pathogenic lineages, culminating in highly virulent organisms whose genomic contents are altered frequently by increased rates of homologous recombination; thus, the evolution of virulence is linked to bacterial sex. This long-term pattern of evolution was observed in genes distributed throughout the genome, and thereby is the likely result of episodic selection for strains that can escape the host immune response.
Topics: Alleles; Biological Evolution; Escherichia coli; Genes, Bacterial; Humans; Mutation; Phylogeny; Recombination, Genetic
PubMed: 16689791
DOI: 10.1111/j.1365-2958.2006.05172.x -
Transboundary and Emerging Diseases May 2018Escherichia coli comprises a highly diverse group of Gram-negative bacteria and is a common member of the intestinal microflora of humans and animals. Generally, such... (Review)
Review
Escherichia coli comprises a highly diverse group of Gram-negative bacteria and is a common member of the intestinal microflora of humans and animals. Generally, such colonization is asymptomatic; however, some E. coli strains have evolved to become pathogenic and thus cause clinical disease in susceptible hosts. One pathotype, the Shiga toxigenic E. coli (STEC) comprising strains expressing a Shiga-like toxin is an important foodborne pathogen. A subset of STEC are the enterohaemorrhagic E. coli (EHEC), which can cause serious human disease, including haemolytic uraemic syndrome (HUS). The diagnosis of EHEC infections and the surveillance of STEC in the food chain and the environment require accurate, cost-effective and timely tests. In this review, we describe and evaluate tests now in routine use, as well as upcoming test technologies for pathogen detection, including loop-mediated isothermal amplification (LAMP) and whole-genome sequencing (WGS). We have considered the need for improved diagnostic tools in current strategies for the control and prevention of these pathogens in humans, the food chain and the environment. We conclude that although significant progress has been made, STEC still remains an important zoonotic issue worldwide. Substantial reductions in the public health burden due to this infection will require a multipronged approach, including ongoing surveillance with high-resolution diagnostic techniques currently being developed and integrated into the routine investigations of public health laboratories. However, additional research requirements may be needed before such high-resolution diagnostic tools can be used to enable the development of appropriate interventions, such as vaccines and decontamination strategies.
Topics: Animals; Communicable Disease Control; Enterohemorrhagic Escherichia coli; Escherichia coli Infections; Humans; Shiga-Toxigenic Escherichia coli; Zoonoses
PubMed: 29369531
DOI: 10.1111/tbed.12789 -
Cell Sep 2015
Topics: Education, Graduate; Escherichia coli; Genetics, Microbial; History, 20th Century; Microbial Viability; New York
PubMed: 26359976
DOI: 10.1016/j.cell.2015.08.048 -
Cellular Microbiology Nov 2013Enteropathogenic and enterohaemorrhagic Escherichia coli use a novel infection strategy to colonize the gut epithelium, involving translocation of their own receptor,... (Review)
Review
Enteropathogenic and enterohaemorrhagic Escherichia coli use a novel infection strategy to colonize the gut epithelium, involving translocation of their own receptor, Tir, via a type III secretion system and subsequent formation of attaching and effecting (A/E) lesions. Following integration into the host cell plasma membrane of cultured cells, and clustering by the outer membrane adhesin intimin, Tir triggers multiple actin polymerization pathways involving host and bacterial adaptor proteins that converge on the host Arp2/3 actin nucleator. Although initially thought to be involved in A/E lesion formation, recent data have shown that the known Tir-induced actin polymerization pathways are dispensable for this activity, but can play other major roles in colonization efficiency, in vivo fitness and systemic disease. In this review we summarize the roadmap leading from the discovery of Tir, through the different actin polymerization pathways it triggers, to our current understanding of their physiological functions.
Topics: Bacterial Adhesion; Enterohemorrhagic Escherichia coli; Enteropathogenic Escherichia coli; Epithelial Cells; Host-Pathogen Interactions
PubMed: 23927593
DOI: 10.1111/cmi.12179 -
Journal of Applied Microbiology Aug 2014The aim of this study was to characterize Escherichia fergusonii and Escherichia albertii isolated from water.
AIMS
The aim of this study was to characterize Escherichia fergusonii and Escherichia albertii isolated from water.
METHODS AND RESULTS
The characterization of E. fergusonii and E. albertii isolated from water was determined using an Escherichia coli-specific uidA PCR, a tuf PCR, and with phylogenetic analysis using three housekeeping genes (adk, gyrB, and recA) from the E. coli MLST scheme, selected for their ability to discriminate among all Escherichia species. Among the 527 isolates tested, 25 (4·7%) were uidA PCR negative and tuf PCR positive. Phylogenetic analysis using adk, gyrB and recA genes showed that 6, 18 and 1 of these 25 non-E. coli Escherichia spp. isolates grouped with reference strains of E. fergusonii, E. albertii, and E. coli, respectively. Finally, the 25 non-E. coli Escherichia spp. strains isolated were investigated for the presence of pathogenic factors, comprising intimin (eae gene), cytolethal distending toxin (cdtB gene) and shiga toxin (stx gene). With the PCR primers used, the presence of eae and stx genes was not detected. However, cdtB genes types I/IV were detected for 3 (16·7%) E. albertii strains, whereas 15 of 18 (83·3%) possessed the cdtB gene types II/III/V.
CONCLUSIONS
These results showed that MLST scheme allows a more accurate identification of non-E. coli species than phenotypic tests. We also showed that E. fergusonii and E. albertii represent, respectively, 0·8 and 2·5% of all Escherichia species isolated and the pathogenic cdtB genes were present in 83·3% of these strains.
SIGNIFICANCE AND IMPACT OF THE STUDY
The data presented in this study provided an efficient way to correctly identify non-E. coli species contributing to our understanding of the risks associated with Escherichia species in water consumed by humans and animals. Furthermore, the results give an insight about the natural habitats of these species.
Topics: Animals; Escherichia; Escherichia coli; Genes, Bacterial; Humans; Phylogeny; Polymerase Chain Reaction; Water Microbiology
PubMed: 24849008
DOI: 10.1111/jam.12551 -
Molecular Microbiology Jun 2011The human pathogens enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC) share a unique mechanism of colonization that results from the concerted... (Review)
Review
The human pathogens enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC) share a unique mechanism of colonization that results from the concerted action of effector proteins translocated into the host cell by a type III secretion system (T3SS). EPEC and EHEC not only induce characteristic attaching and effacing (A/E) lesions, but also subvert multiple host cell signalling pathways during infection. Our understanding of the mechanisms by which A/E pathogens hijack host cell signalling has advanced dramatically in recent months with the identification of novel activities for many effectors. In addition to further characterization of established effectors (Tir, EspH and Map), new effectors have emerged as important mediators of virulence through activities such as mimicry of Rho guanine nucleotide exchange factors (Map and EspM), inhibition of apoptosis (NleH and NleD), interference with inflammatory signalling pathways (NleB, NleC, NleE and NleH) and phagocytosis (EspF, EspH and EspJ). The findings have highlighted the multifunctional nature of the effectors and their ability to participate in redundant, synergistic or antagonistic relationships, acting in a co-ordinated spatial and temporal manner on different host organelles and cellular pathways during infection.
Topics: Animals; Enterohemorrhagic Escherichia coli; Enteropathogenic Escherichia coli; Escherichia coli Infections; Escherichia coli Proteins; Humans; Signal Transduction
PubMed: 21488979
DOI: 10.1111/j.1365-2958.2011.07661.x -
Microbiology (Reading, England) Dec 2013Micro-organisms react to a rapid temperature downshift by triggering a physiological response to ensure survival in unfavourable conditions. Adaptation includes changes... (Review)
Review
Micro-organisms react to a rapid temperature downshift by triggering a physiological response to ensure survival in unfavourable conditions. Adaptation includes changes in membrane composition and in the translation and transcription machineries. The cold shock response leads to a growth block and overall repression of translation; however, there is the induction of a set of specific proteins that help to tune cell metabolism and readjust it to the new conditions. For a mesophile like E. coli, the adaptation process takes about 4 h. Although the bacterial cold shock response was discovered over two decades ago we are still far from understanding this process. In this review, we aim to describe current knowledge, focusing on the functions of RNA-interacting proteins and RNases involved in cold shock adaptation.
Topics: Adaptation, Physiological; Cold Temperature; Escherichia coli; Stress, Physiological; Time Factors
PubMed: 24068238
DOI: 10.1099/mic.0.052209-0 -
Applied and Environmental Microbiology Mar 2015Aldehydes are a class of chemicals with many industrial uses. Several aldehydes are responsible for flavors and fragrances present in plants, but aldehydes are not known... (Review)
Review
Aldehydes are a class of chemicals with many industrial uses. Several aldehydes are responsible for flavors and fragrances present in plants, but aldehydes are not known to accumulate in most natural microorganisms. In many cases, microbial production of aldehydes presents an attractive alternative to extraction from plants or chemical synthesis. During the past 2 decades, a variety of aldehyde biosynthetic enzymes have undergone detailed characterization. Although metabolic pathways that result in alcohol synthesis via aldehyde intermediates were long known, only recent investigations in model microbes such as Escherichia coli have succeeded in minimizing the rapid endogenous conversion of aldehydes into their corresponding alcohols. Such efforts have provided a foundation for microbial aldehyde synthesis and broader utilization of aldehydes as intermediates for other synthetically challenging biochemical classes. However, aldehyde toxicity imposes a practical limit on achievable aldehyde titers and remains an issue of academic and commercial interest. In this minireview, we summarize published efforts of microbial engineering for aldehyde synthesis, with an emphasis on de novo synthesis, engineered aldehyde accumulation in E. coli, and the challenge of aldehyde toxicity.
Topics: Aldehydes; Escherichia coli; Metabolic Engineering; Microbial Viability
PubMed: 25576610
DOI: 10.1128/AEM.03319-14 -
Nature Communications Feb 2018Self-assembly is a promising route for micro- and nano-fabrication with potential to revolutionise many areas of technology, including personalised medicine. Here we...
Self-assembly is a promising route for micro- and nano-fabrication with potential to revolutionise many areas of technology, including personalised medicine. Here we demonstrate that external control of the swimming speed of microswimmers can be used to self assemble reconfigurable designer structures in situ. We implement such 'smart templated active self assembly' in a fluid environment by using spatially patterned light fields to control photon-powered strains of motile Escherichia coli bacteria. The physics and biology governing the sharpness and formation speed of patterns is investigated using a bespoke strain designed to respond quickly to changes in light intensity. Our protocol provides a distinct paradigm for self-assembly of structures on the 10 μm to mm scale.
Topics: Escherichia coli; Kinetics; Light
PubMed: 29472614
DOI: 10.1038/s41467-018-03161-8