scholarly journals The Effects of Different Solvents on the Growth-inhibitory Activity of Rhazya stricta Extract Against Antibiotic-resistant Escherichia coli

2021 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Bahman Fazeli-Nasab ◽  
Mehrangiz Ghafari ◽  
Sima Saravani
Keyword(s):  
Escherichia Coli ◽  
Ethyl Acetate ◽  
Standard Procedure ◽  
Antimicrobial Properties ◽  
New Drugs ◽  
Economic Losses ◽  
Dilution Method ◽  
Inhibitory Zone ◽  
E Coli ◽  
Drug Resistant Strains

Background: Escherichia coli (Gram-negative bacilli) inflicts large economic losses on the poultry industry and is one of the most important causes of poultry diseases. The indiscriminate use of antibiotics has contributed to today’s increasing prevalence of drug-resistant strains, which their emergence appears to exceed the discovery of new drugs. Therefore, several attempts have been dedicated to find new compounds as effective alternatives to antibiotics. Medicinal plants constitute a rich source for various antimicrobial compounds. Objectives: The aim of this study was to evaluate the antibiotic resistance trend of the E. coli strains isolated from Quail feces samples and to investigate the antimicrobial effects of Eshvarak extract against these strains. Methods: Eshvarak plant was collected from Saravan (Sistan and Baluchestan province, Iran) and identified in the botany laboratory of Zabol University. Escherichia coli samples were isolated from poultry feces. Various solvents (methanol (100%), ethanol (100%), water (100%), hydro-alcohol (70%), and ethyl-acetate (100%)) were used to prepare Eshvarak extract. Inhibitory zone diameter was determined in an agar-based medium using a standard procedure. The MIC and MBC of prepared extracts were determined by the micro-dilution method. Results: The lowest MIC values were obtained for the methanolic (12.5 ppm), ethanolic (12.5 ppm), aqueous (12.5 ppm), hydroalcoholic (25 ppm), and ethyl-acetate (12.5 ppm) Eshvarak extracts. The highest inhibitory zone diameters against E. coli were recorded at the 100-ppm concentration of the methanolic (8 mm), ethanolic (7 mm), aqueous (8 mm), hydroalcoholic (10 mm), and ethyl-acetate (5 mm) Eshvarak extracts. Conclusions: Eshvarak extract, particularly in the hydroalcoholic solvent, inhibited the growth of E. coli. However, the antimicrobial properties of plant extracts seem to be independent of the extraction method or the type of solvent.

scholarly journals Phytochemical Investigation and Antimicrobial Activity of Hexane, Ethyl Acetate and Methanol Fractions from Stem Bark of Icacina Trichantha Oliv. (Icacinaceae)

2020 ◽  
Vol 7 (1) ◽  
pp. 7-12
Author(s):  
Ojah Emmanuel Onah ◽  
Kachi Jolly Babangida
Keyword(s):  
Ethyl Acetate ◽  
Methanol Extract ◽  
Antimicrobial Properties ◽  
Ethyl Acetate Fraction ◽  
Hexane Fraction ◽  
Diffusion Method ◽  
Economic Losses ◽  
Phytochemical Screening ◽  
E Coli ◽  
Micro Organisms

Background: Micro-organisms are responsible for the transmission of a large number of diseases. It is hard to comprehend the amount of diseases, deaths and economic losses caused by micro-organisms alone. Plants are good sources of eco-friendly and readily available antimicrobial agents. Purpose: The aim of this study was to evaluate the chemical constituents and antimicrobial characteristics of three fractions from ethnomedicinal Icacina trichantha. Oliv. (Icacinaceae).Methods: Methanol extract from Icacina trichantha. Oliv was obtained by maceration and fractionated successively using hexane, and ethyl acetate. The antimicrobial properties of Icacina trichantha. Oliv was assessed using agar cup diffusion method on MRSA, P. aeruginosa, S. typhi, C. krusei, S. dysenteriae, S. pyrogenes, E. coli, K. pneumoniae, C. albicans, and C. tropicalis. Phytochemical screening on fractions was also evaluated using standard methods.Results: Phytochemical screening on fractions revealed the presence of saponins, alkaloids, steroids, tannins, and glycosides. Agar diffusion assay on fractions showed growth inhibitory effect on all the organisms except P. aeruginosa, S. typhi, and C. tropicalis. The MIC revealed that n-hexane fraction was active against MRSA, S. pyrogenes, E. coli, K. pneumonia, C. albicans and C. krusei at 10 mg/mL while S. dysenteriae was active at 5 mg/mL. The ethyl acetate fraction was active against all the organisms at a concentration of 5 mg/mL except P.aeruginosa, S.typhi and C.tropicalis. Methanol fraction showed activity of 5 mg/mL against MRSA, S. pyrogenes, E. coli, S. dysenteriae, C. albicans and C. krusei except for K. pneumoniae with activity at 10 mg/mL. Minimum bactericidal concentration/fungicidal concentration MBC/MFC evaluated on the n-hexane fraction revealed that MRSA, S. pyrogenes, E. coli, K. pneumoniae, S. dysenteriae, C. albicans, and C. krusei were activeat 20 mg/mL, while the ethyl acetate fraction had MBC/MFC of 10 mg/mL against all the organisms except P. aeruginosa, S. typhi, C. tropicalis. Methanol extract had MBC/MFC of 10 mg/mL against MSRA, E.coli and S. dysenteriae whereas S. pyrogenes, K. pneumoniae, C. albicans and C. krusei had MBC/MFC at 20 mg/mL.Conclusion: Icacina trichantha. Oliv. contain constituents with concentration dependent antimicrobial properties based on type of organism. The plant could be useful in the prevention and treatment of multi-resistant disease causing microorganisms.

scholarly journals Susceptibility of virulent and resistant Escherichia coli strains to non-polar and polar compounds identified in Microplumeria anomala

2020 ◽  
Vol 13 (7) ◽  
pp. 1376-1387
Author(s):  
Livia Roberta Piedade Camargo ◽  
Vania Maria de Carvalho ◽  
Ingrit Elida Collantes Díaz ◽  
Mateus Luís Barradas Paciencia ◽  
Sergio Alexandre Frana ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Natural Products ◽  
Protocatechuic Acid ◽  
Polar Compounds ◽  
New Drugs ◽  
Economic Losses ◽  
Isolation And Identification ◽  
E Coli ◽  
Nuclear Magnetic Resonance Spectrometry ◽  
Human Infections

Background and Aim: Escherichia coli is one of the main pathogens responsible for veterinary and human infections, and it is associated with significant economic losses in the livestock, as it causes severe diseases to humans, particularly in children. For that reason, there is a need for introducing new drugs to treat E. coli diseases. The Brazilian species richness is a source of potential new antibacterial natural products. The study aimed at the biological and chemical investigation of the organic extract obtained from the stem of Microplumeria anomala (Apocynaceae), EB127, as it was identified as a potential source of new antibacterial compounds to be used in Veterinary. Materials and Methods: The antibacterial activity was evaluated by disk diffusion and microdilution assays; chromatography, nuclear magnetic resonance spectrometry, and mass spectrometry were used in the isolation and identification of compounds. Results: EB127 showed activity against E. coli ATCC25922, and against three E. coli strains that were isolated from frigarte's cloaca, named 31/1A, 35A, and 51A. Lupeol, 3-acetyl-11-oxo-β-amyrin, 3-acetyl-11-oxo-α-amyrin, sitosterol, stigmasterol, 3β,7α-dihydroxy-cholest-5-ene, 3β-hydroxy-cholest-5-en-7-one, and 3β-hydroxy-cholest-5,22-dien-7-one were identified in fraction Hex/CHCl3, while loganin, loganic acid, methylanomaline, and anomaline were all identified in EB127 and protocatechuic acid hexoside, ferulic acid, secoxyloganin, feruloylquinic acid, vanillic acid hexoside, protocatechuic acid-4-O-β-hexoside, and rosmarinic acid were tentatively identified in fraction 10%ACN/H2O. E. coli 51A (virulent/non-resistant) showed sensitivity to the antibacterial action of fraction Hex/CHCl3 which contains alkaloids, triterpenes, and steroids, while E. coli 35A (resistant/non-virulent) were more susceptible to 10%ACN/H2O, which contains iridoids as loganin and loganic acid, and glycosylated and non-glycosylated caffeic acids. Conclusion: Fraction 10%ACN/H2O is of interest in pursuing new drugs to treat resistant E. coli, in veterinary. All compounds were isolated from the plant for the first time and have shown potential as new antibacterial natural products from Amazon plants to be used in veterinary and human diseases.

scholarly journals Assessment of Antimicrobial Activities and Toxicological Effects of Green and Red Cultivars of Roselle- Hibiscus sabdariffa L

2020 ◽  
pp. 11-22
Author(s):  
Serifat Olatundun Salami ◽  
Anthony Jide Afolayan
Keyword(s):  
Brine Shrimp ◽  
Antimicrobial Properties ◽  
Antimicrobial Activities ◽  
Artemia Salina ◽  
New Drugs ◽  
Dilution Method ◽  
Toxicological Effects ◽  
Resistant Strains ◽  
Antibacterial And Antifungal ◽  
Drug Resistant Strains

Aims: The use of synthetic antibiotics has been the major way of curing diseases; however, over-use of antibiotics has led to emergence of multi-drug-resistant strains of several groups of microorganisms. This study aimed at examining roselle extracts for antimicrobial properties with a view to providing the best alternative to the injudicious use of synthetic antibiotics and also examines the toxicological effects of roselle extracts. Methodology: Ethanolic and aqueous extracts of roselle leaves and calyces were evaluated for antimicrobial activity based on minimum inhibitory concentration (MIC50) using Broth dilution method. The toxicological effects based on LC50 were also evaluated using Brine shrimp- Artemia salina. Simple percentage was used to determine the mortality rate of the nauplii while the minimum inhibitory concentrations of the extracts were determined using MINITAB 17 statistical package (P<0.05). Data were expressed as mean ± standard deviation of three replicates. Results: Roselle calyces, pre-flowering green and flowering red exhibited excellent inhibition to bacteria. Calyces had better antimicrobial activities and higher toxicological effects than the leaves. Green roselle at pre-flowering stage and red flowering were good for antimicrobial screening. Conclusion: Roselle extracts possessed excellent antibacterial and antifungal properties. These can be explored to develop new drugs, which can suppress the resistant strains. All the plant extracts were greater than 1000 mg/mL, which indicates that they were non-toxic to brine shrimp larvae.

scholarly journals Essential Oils from Indigenous Iranian Plants: A Natural Weapon vs. Multidrug-Resistant Escherichia coli

2022 ◽  
Vol 10 (1) ◽  
pp. 109
Author(s):  
Mohammadreza Pajohi Alamoti ◽  
Behnaz Bazargani-Gilani ◽  
Razzagh Mahmoudi ◽  
Anna Reale ◽  
Babak Pakbin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Essential Oil ◽  
Essential Oils ◽  
Antimicrobial Properties ◽  
Multidrug Resistant ◽  
Zataria Multiflora ◽  
Cuminum Cyminum ◽  
Plant Essential Oils ◽  
E Coli ◽  
Mentha Longifolia

Aim of this study was to investigate the antimicrobial properties of herbal plant essential oils (EOs) from selected Iranian plant species such as Ferulago angulata, Zataria multiflora, Cuminum cyminum, and Mentha longifolia against antibiotic-resistant Escherichia coli (E. coli) strains. For this purpose, the Escherichia coli strains, isolated from raw cow’s milk and local dairy products (yogurt, cream, whey, cheese, and confectionery products) collected from different areas of Hamedan province, Iran, were investigated for their resistance to antibiotics (i.e., streptomycin, tetracycline, gentamicin, chloramphenicol, ciprofloxacin, and cefixime). Thus, the E. coli strains were tested for their susceptibility to the above-mentioned essential oils. Regarding antibiotics, the E. coli strains were highly sensitive to ciprofloxacin. In relation to essential oils, the most effective antibacterial activity was observed with Zataria multiflora; also, the bacteria were semi-sensitive to Cuminum cyminum and Mentha longifolia essential oils. All strains were resistant to Ferulago angulata essential oil. According to the results, the essential oil of Zataria multiflora can be considered as a practical and alternative antibacterial strategy to inhibit the growth of multidrug-resistant E. coli of dairy origin.

Evaluation of Binding and Abrasion Properties of Grey Mangrove (Avicennia marina) Leaf Extract Against Escherichia coli K12 DNA

2021 ◽  
Vol 19 ◽  
Author(s):  
Praveen Tudu ◽  
Shouvik Mahanty ◽  
Sushmitha Sriramulu ◽  
Punarbasu Chaudhuri ◽  
Surajit Pathak
Keyword(s):  
Escherichia Coli ◽  
Comet Assay ◽  
Ethyl Acetate ◽  
Ames Test ◽  
Leaf Extract ◽  
Antimicrobial Properties ◽  
Avicennia Marina ◽  
Drug Candidate ◽  
Escherichia Coli K12 ◽  
Grey Mangrove

Background: Mangroves are globally known for their ecological importance and are found to be extensively used in traditional medicine. Avicennia marina, commonly known as grey mangroves exhibit strong antimicrobial properties and are also considered being a promising drug candidate in neutralizing pathogens. Objective: In our present study, the leaf extract from Avicennia marina was isolated using organic solvents of ascensive polarity to evaluate binding and abrasive properties in Escherichia coli K12 DNA. Methods: Samples of the pulverized leaves were used for sequential extraction using ethyl acetate, chloroform and acetone. The minimum inhibitory concentration of isolates from ethyl acetate, chloroform and acetone were quantified to be 0.125gL-1, 0.0625gL-1 and 0.125gL-1, respectively. These values were further utilized to calculate the binding constant between Escherichia coli DNA and isolates. In addition, mutagenicity of the isolates was assessed using Ames test in which the Escherichia coli K12 (strain AB1157) bacteria was cultured in minimal glucose media supplemented with isolates for assessing their DNA modifying ability. Further, DNA abrasion potential was assessed for all the isolates using Comet assay. Results: Results of Ames test showed that the isolates have DNA modifying ability, whereas the Comet assay demonstrated that isolates do not exhibit DNA degrading potential. Conclusion: In conclusion, the mechanism by which the isolates degrade the bacterial cell must be contrary to its DNA degrading potential. Experiments paved the way for further quantification and examination using bioinformatics tools to find the best drug candidate and to run clinical trials

BaeR participates in cephalosporins susceptibility by regulating the expression level of outer membrane proteins in Escherichia coli

2020 ◽  
Author(s):  
Shuaiyang Wang ◽  
Chunbo You ◽  
Fareed Qumar Memon ◽  
Geyin Zhang ◽  
Yawei Sun ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
Efflux Pump ◽  
Outer Membrane Proteins ◽  
Expression Level ◽  
Antibiotics Resistance ◽  
Dilution Method ◽  
Expression Levels ◽  
E Coli

Abstract The two-component system BaeSR participates in antibiotics resistance of Escherichia coli. To know whether the outer membrane proteins involve in the antibiotics resistance mediated by BaeSR, deletion of acrB was constructed and the recombined plasmid p-baeR was introduced into E. coli K12 and K12△acrB. Minimum inhibitory concentrations (MICs) of antibacterial agents were determined by 2-fold broth micro-dilution method. Gene expressions related with major outer membrane proteins and multidrug efflux pump-related genes were determined by real-time quantitative reverse transcription polymerase chain reaction. The results revealed that the MICs of K12ΔacrB to the tested drugs except for gentamycin and amikacin decreased 2- to 16.75-folds compared with those of K12. When BaeR was overexpressed, the MICs of K12ΔacrB/p-baeR to ceftiofur and cefotaxime increased 2.5- and 2-fold, respectively, compared with their corresponding that of K12△acrB. At the same time, the expression levels of ompC, ompF, ompW, ompA and ompX showed significant reduction in K12ΔacrB/p-baeR as compared with K12△acrB. Moreover, the expression levels of ompR, marA, rob and tolC also significantly ‘decreased’ in K12ΔacrB/p-baeR. These findings indicated that BaeR overproduction can decrease cephalosporins susceptibility in acrB-free E. coli by decreasing the expression level of outer membrane proteins.

Optimizing a production strategy for a nonspecific nuclease from Yersinia enterocolitica subsp. palearctica in genetically engineered Escherichia coli

2019 ◽  
Vol 366 (24) ◽  
Author(s):  
Yan Ge ◽  
Senlin Guo ◽  
Tao Liu ◽  
Chen Zhao ◽  
Duanhua Li ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Yersinia Enterocolitica ◽  
Inclusion Bodies ◽  
Genetically Engineered ◽  
Biological Research ◽  
Dilution Method ◽  
E Coli ◽  
Protein Renaturation ◽  
Engineered Escherichia Coli ◽  
Pharmaceutical Production

ABSTRACT A nuclease from Yersinia enterocolitica subsp. palearctica (Nucyep) is a newly found thermostable nonspecific nuclease. The heat-resisting ability of this nuclease would be extremely useful in biological research or pharmaceutical production. However, the application of this nuclease is limited because of its poor yield. This research aimed to improve Nucyep productivity by producing a novel genetically engineered Escherichia coli and optimizing the production procedures. After 4 h of induction by lactose, the new genetically engineered E. coli can express a substantial amount of Nucyep in the form of inclusion bodies. The yield was approximately 0.3 g of inclusion bodies in 1 g of bacterial pellets. The inclusion bodies were extracted by sonication and solubilized in an 8 M urea buffer. Protein renaturation was successfully achieved by dilution method. Pure enzyme was obtained after subjecting the protein solution to anion exchange. The Nucyep showed its nonspecific and heat resistant properties as previously reported (Boissinot et  al. 2016). Through a quantification method, its activity was determined to be 1.3 × 10 6 Kunitz units (K.U.)/mg. These results can serve as a reference for increasing Nucyep production.

scholarly journals Plasmid mediated colistin resistant mcr-1 and co-existence of OXA-48 among Escherichia coli from clinical and poultry isolates: first report from Nepal

Gut Pathogens ◽  
2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Bijaya Muktan ◽  
Upendra Thapa Shrestha ◽  
Binod Dhungel ◽  
Bagish Chandra Mishra ◽  
Nabaraj Shrestha ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Resistance Gene ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Colistin Resistance ◽  
Clinical Specimens ◽  
E Coli ◽  
Resistant Genes ◽  
Rectal Swabs

Abstract Background Plasmid-mediated resistance to the last-resort drugs: carbapenems and colistin is an emerging public health threat. The studies on the prevalence and co-expression of resistant genes among livestock and human pathogens are rare in Nepal. This is the first study in Nepal exploring the prevalence and co-existence of colistin resistance gene, mcr-1 along with carbapenemase resistance gene, OXA-48 in Escherichia coli isolated from poultry and clinical specimens. Methods A total of 240 rectal swabs from chickens of five different poultry farms of Kathmandu valley and 705 mid-stream urine samples from human subjects attending Kantipur Hospital, Kathmandu were collected between August, 2018 and March, 2019. Rectal swabs and urine specimens were cultured. E. coli isolated from the specimens were screened for antimicrobial susceptibility testing (AST) using disk diffusion method’. Minimum inhibitory concentration (MIC) of colistin was determined by agar dilution method using 0.5 µg/ml to 32 µg/ml. The E. coli isolates were first screened for mcr-1 followed by screening for OXA-48 genes using conventional Polymerase chain reaction (PCR). Results Of the total samples analyzed, E. coli was isolated from 31.7% (76/240) of poultry and 7.9% (56/705) of clinical specimens. In AST, 80% (61/76) of E. coli from poultry and 79% (44/56) from clinical specimens were MDR. The phenotypic prevalence of colistin resistance in poultry specimens were 31.6% (24/76) and clinical specimens were 21.4% (12/56). In PCR assay, 27.6% (21/76) of poultry and 19.6% (11/56) of clinical isolates had colistin resistant mcr-1 gene. MICs value of E. coli isolates ranged from 4 to 32 (µg/ml) in both clinical and poultry isolates. Prevalence of co-existing carbapenem resistance gene, OXA-48, among colistin resistant mcr-1 positive isolates was 38% (8/21) in poultry specimens and 18.2% (2/11) in clinical specimens. Conclusions The high prevalence of colistin and carbapenem resistant genes, and their co-existence in plasmid DNA of E. coli isolates in this study suggests the possible spread to other animal, human and environmental pathogens. Molecular methods in addition to the conventional diagnostics in laboratories can help in early diagnosis, effective management and control of their potential transmission.

scholarly journals Using a Chemical Genetic Screen to Enhance Our Understanding of the Antimicrobial Properties of Gallium against Escherichia coli

Genes ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 34 ◽  
Author(s):  
Natalie Gugala ◽  
Kate Chatfield-Reed ◽  
Raymond J. Turner ◽  
Gordon Chua
Keyword(s):  
Escherichia Coli ◽  
Cell Envelope ◽  
Antimicrobial Properties ◽  
Iron Sulfur Cluster ◽  
Nucleotide Biosynthesis ◽  
E Coli ◽  
Chemical Genetic ◽  
Iron Sulfur ◽  
Insight Into ◽  
Mutant Collection

The diagnostic and therapeutic agent gallium offers multiple clinical and commercial uses including the treatment of cancer and the localization of tumors, among others. Further, this metal has been proven to be an effective antimicrobial agent against a number of microbes. Despite the latter, the fundamental mechanisms of gallium action have yet to be fully identified and understood. To further the development of this antimicrobial, it is imperative that we understand the mechanisms by which gallium interacts with cells. As a result, we screened the Escherichia coli Keio mutant collection as a means of identifying the genes that are implicated in prolonged gallium toxicity or resistance and mapped their biological processes to their respective cellular system. We discovered that the deletion of genes functioning in response to oxidative stress, DNA or iron–sulfur cluster repair, and nucleotide biosynthesis were sensitive to gallium, while Ga resistance comprised of genes involved in iron/siderophore import, amino acid biosynthesis and cell envelope maintenance. Altogether, our explanations of these findings offer further insight into the mechanisms of gallium toxicity and resistance in E. coli.

scholarly journals Genomic Avenue to Avian Colisepticemia

mBio ◽  
2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Sagi Huja ◽  
Yaara Oren ◽  
Eva Trost ◽  
Elzbieta Brzuszkiewicz ◽  
Dvora Biran ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genetic Analysis ◽  
Virulence Factors ◽  
Iron Uptake ◽  
Secretion System ◽  
Economic Losses ◽  
Content Type ◽  
E Coli ◽  
Type 3 Secretion System ◽  
Type 3

ABSTRACTHere we present an extensive genomic and genetic analysis of Escherichia coli strains of serotype O78 that represent the major cause of avian colisepticemia, an invasive infection caused by avian pathogenicEscherichia coli(APEC) strains. It is associated with high mortality and morbidity, resulting in significant economic consequences for the poultry industry. To understand the genetic basis of the virulence of avian septicemic E. coli, we sequenced the entire genome of a clinical isolate of serotype O78—O78:H19 ST88 isolate 789 (O78-9)—and compared it with three publicly available APEC O78 sequences and one complete genome of APEC serotype O1 strain. Although there was a large variability in genome content between the APEC strains, several genes were conserved, which are potentially critical for colisepticemia. Some of these genes are present in multiple copies per genome or code for gene products with overlapping function, signifying their importance. A systematic deletion of each of these virulence-related genes identified three systems that are conserved in all septicemic strains examined and are critical for serum survival, a prerequisite for septicemia. These are the plasmid-encoded protein, the defective ETT2 (E. colitype 3 secretion system 2) type 3 secretion system ETT2sepsis, and iron uptake systems. Strain O78-9 is the only APEC O78 strain that also carried the regulon coding for yersiniabactin, the iron binding system of theYersiniahigh-pathogenicity island. Interestingly, this system is the only one that cannot be complemented by other iron uptake systems under iron limitation and in serum.IMPORTANCEAvian colisepticemia is a severe systemic disease of birds causing high morbidity and mortality and resulting in severe economic losses. The bacteria associated with avian colisepticemia are highly antibiotic resistant, making antibiotic treatment ineffective, and there is no effective vaccine due to the multitude of serotypes involved. To understand the disease and work out strategies to combat it, we performed an extensive genomic and genetic analysis of Escherichia coli strains of serotype O78, the major cause of the disease. We identified several potential virulence factors, conserved in all the colisepticemic strains examined, and determined their contribution to growth in serum, an absolute requirement for septicemia. These findings raise the possibility that specific vaccines or drugs can be developed against these critical virulence factors to help combat this economically important disease.

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