Seasonal variation in the infection rate with certain Gram-negative organisms has been previously described, but few studies have been published regarding Escherichia coli. The aim of this study was ...to investigate the incidence rate of E. coli bloodstream infection (BSI) and the association with temperature in different seasons in the Yizrael Valley. Positive blood cultures sent to the microbiology laboratory of Ha'Emek Medical Centre over a period of 8 years (January 2001 to December 2008) were included. The mean monthly temperature in the Yizrael Valley in the same period was compared with the monthly E. coli BSI rate. We divided the year into three periods: winter (December to February: mean temperature <15°C), transitional (March, April and November: mean temperature 15–19°C) and summer (May to October: mean temperature ≥20°C). In addition, we correlated the mean monthly antibiotic use in the same period measured as total defined daily doses for the whole regional population with E. coli BSI. During the study period, 2810 BSIs were recorded (35% E. coli). In 67.4% of the cases of E. coli bacteraemia, the source was urinary tract infection. The crude incidence of E. coli BSI was 4.1/1000 admissions. There was no difference in the number of cultures/month (mean: 29 ± 6). However, E. coli BSI was 19% and 21% more frequent in summer than in the transitional and winter seasons, respectively (p 0.01). The antibiotic consumption was significantly higher in the winter period. We found significantly higher rates of E. coli BSI in the summer period. Host, bacterial and ecological factors, together with high consumption of antibiotics during the winter season, could partially explain these findings.
Natural products are widely employed in our daily lives as food additives, pharmaceuticals, nutraceuticals, and cosmetic ingredients, among others. However, their supply has often been limited ...because of low-yield extraction from natural resources such as plants. To overcome this problem, metabolically engineered Escherichia coli has emerged as a cell factory for natural product biosynthesis because of many advantages including the availability of well-established tools and strategies for metabolic engineering and high cell density culture, in addition to its high growth rate. We review state-of-the-art metabolic engineering strategies for enhanced production of natural products in E. coli, together with representative examples. Future challenges and prospects of natural product biosynthesis by engineered E. coli are also discussed.
E. coli has emerged as a prominent host for natural product biosynthesis.Improved enzymes with higher activity, altered substrate specificity, and product selectivity can be obtained by structure-based or computer simulation-based protein engineering.Balancing the expression levels of genes or pathway modules is effective in increasing the metabolic flux towards target compounds.System-wide analysis of metabolic networks, omics analysis, adaptive laboratory evolution, and biosensor-based screening can further increase the production of target compounds.Systems metabolic engineering allows the development of engineered E. coli strains that are capable of more efficiently producing diverse natural products.
Diarrheal diseases are one of the major causes of mortality among children under five years old and intestinal pathogenic
(InPEC) plays a role as one of the large causative groups of these infections ...worldwide. InPECs contribute significantly to the burden of intestinal diseases, which are a critical issue in low- and middle-income countries (Asia, Africa and Latin America). Intestinal pathotypes such as enteropathogenic
(EPEC) and enterotoxigenic
(ETEC) are mainly endemic in developing countries, while ETEC strains are the major cause of diarrhea in travelers to these countries. On the other hand, enterohemorrhagic
(EHEC) are the cause of large outbreaks around the world, mainly affecting developed countries and responsible for not only diarrheal disease but also severe clinical complications like hemorrhagic colitis and hemolytic uremic syndrome (HUS). Overall, the emergence of antibiotic resistant strains, the annual cost increase in the health care system, the high incidence of traveler diarrhea and the increased number of HUS episodes have raised the need for effective preventive treatments. Although the use of antibiotics is still important in treating such infections, non-antibiotic strategies are either a crucial option to limit the increase in antibiotic resistant strains or absolutely necessary for diseases such as those caused by EHEC infections, for which antibiotic therapies are not recommended. Among non-antibiotic therapies, vaccine development is a strategy of choice but, to date, there is no effective licensed vaccine against InPEC infections. For several years, there has been a sustained effort to identify efficacious vaccine candidates able to reduce the burden of diarrheal disease. The aim of this review is to summarize recent milestones and insights in vaccine development against InPECs.
To investigate the genetic features and biological costs of the plasmid pTW4 harboring tet(M) in an isolate of Escherichia coli ST162 from a duck. The complete nucleotide sequence of plasmid pTW4 was ...determined. The characteristics of plasmid pTW4 in E. coli were investigated by stability and direct competition assays. pTW4 is an IncHI2-type plasmid that contained the resistant genes tet(M), floR, strAB, sul2, rmtB, and blaCMY-2. Tet(M) is located in the composite transposon Tn6539 within the multidrug resistant (MDR) region on this plasmid. Furthermore, the resistance gene rmtB and blaCMY−2 were found outside the MDR region. The plasmid pTW4 remained stable in the host strain E. coli J53 after passage under an antibiotic-free environment for 7 days. However, the strain E. coli J53/pTW4 showed a fitness disadvantage of 6% per ten generations in the process of growth competition with E. coli J53. In conclusion, the plasmid pTW4, a mobile MDR vehicle, may promote the dissemination of tet(M), floR, rmtB, strAB, sul2, and blaCMY-2 among bacteria and then, but it appears to confer growth disadvantage to the host.
Abstract Detection of diarrheagenic Escherichia coli (DEC) typically depends on identification of virulence genes from stool cultures, not on stool itself. We developed a multiplex polymerase chain ...reaction (PCR) assay that detects key DEC virulence genes ( stx1 , stx2 , eae , bfpA , ipaH , LT , STh , aaiC , aatA ). The assay involved a multiplex PCR reaction followed by detection of amplicon(s) using Luminex beads. The assay was evaluated on over 100 colony and broth specimens. We then evaluated the assay using DNA extracted from stool, colony pools, and Gram-negative broths, using stool spiked with known quantities of DEC. Performance of the assay on stool DNA was most quantitative, while stool broth DNA offered the lowest limit of detection. The assay was prospectively evaluated on clinical specimens in Tanzania. Stool DNA yielded higher sensitivity than colony pools compared with broth DNA as the standard. We propose using this assay to screen for DEC directly in stool or stool broths.
Summary
Escherichia coli biofilm consists of a bacterial colony embedded in a matrix of extracellular polymeric substances (EPS) which protects the microbes from adverse environmental conditions and ...results in infection. Besides being the major causative agent for recurrent urinary tract infections, E. coli biofilm is also responsible for indwelling medical device‐related infectivity. The cell‐to‐cell communication within the biofilm occurs due to quorum sensors that can modulate the key biochemical players enabling the bacteria to proliferate and intensify the resultant infections. The diversity in structural components of biofilm gets compounded due to the development of antibiotic resistance, hampering its eradication. Conventionally used antimicrobial agents have a restricted range of cellular targets and limited efficacy on biofilms. This emphasizes the need to explore the alternate therapeuticals like anti‐adhesion compounds, phytochemicals, nanomaterials for effective drug delivery to restrict the growth of biofilm. The current review focuses on various aspects of E. coli biofilm development and the possible therapeutic approaches for prevention and treatment of biofilm‐related infections.
BackgroundAntibiotic-resistance in E. coli is a global issue affecting humans especially the pediatric population. Antibiotic-resistant E. coli is a pathogen frequently pediatric population as well ...as healthy adults. MethodsThis study aimed to examine the antibiotic resistance of E. coli causing pediatric diarrhea and its drug-resistant rates, its adhering abilities to cell line in vitro, and inhibition efficiency of a few selected chemical compounds. Clinical strains were isolated from both the healthy and infected pediatric population of Mizoram. ResultsAdhesion is a significant pathogenic process during bacterial infections, which has been employed for pathotyping of DEC by comparing adhesion efficiency in both normal (CHO-k1) and cancer (HeLa) cell lines. E. coli adherent pathotypes were identified by both PCR assay and in-vitro cell adhesion assays; the study also evaluated the adhesion inhibition ability of human skimmed milk, gentamicin, and cephalexin in-vitro. Of all isolates, 20.05% of adherent DEC (EPEC, DAEC, and EIEC) and 11.39 % of non-adherent DEC (STEC and ETEC) were found to be associated with pediatric diarrhoea in Mizoram. Human skimmed milk has a high potential adhesion inhibition against EAEC (50.25/90.90 μg/mL), EPEC (53.42/259.70 μg/mL), and EIEC (59.13/30.30 μg/mL) in both cell lines in comparison with gentamicin and cephalexin. ConclusionThis study concludes that as a dietary supplement-human skimmed milk has high potential to prevent adhesion of DEC pathotypes in cells in-vitro thus in in-vivo.
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