ETHANOL SUPPLEMENTATION AS A NEW APPROACH TO REGULATE GROWTH AND HYDROGEN PRODUCTION OF $ \textit{ESCHERICHIA COLI} $ UPON GLYCEROL FERMENTATION

2020 ◽  
Vol 54 (2 (252)) ◽  
pp. 138-146
Author(s):  
A.A. Poladyan
Keyword(s):  
Escherichia Coli ◽  
Redox Potential ◽  
Bacterial Growth ◽  
H2 Production ◽  
Glycerol Fermentation ◽  
Medium Ph ◽  
New Approach ◽  
E Coli ◽  
Peptone Medium ◽  
By Products

Molecular hydrogen (H2) and ethanol are the main by-products of glycerol fermentation by Escherichia coli. In this study, the growth of E. coli BW25113 was investigated with the addition of small amounts (0.05 to 2 %) of ethanol alone and in a combination with glycerol The bacterial growth, the kinetic of the redox potential, and the H2 production in peptone medium, pH 7.5, were investigated upon various amounts of ethanol supplementation. In the presence of any amount of ethanol, but upon the absence of other sources of carbon, no H2 production was observed. Whereas ethanol (0.3 to 1 %) with a combination of glycerol stimulated both bacterial growth and H2 production, pH 7.5. A correlation was observed between the redox potential and stimulated by ethanol bacterial growth. The obtained results can be applied to regulate fermentation processes in biotechnology.

Effect of Tannins on the In Vitro Growth of Escherichia coli O157:H7 and In Vivo Growth of Generic Escherichia coli Excreted from Steers

2007 ◽  
Vol 70 (3) ◽  
pp. 543-550 ◽  
Author(s):  
BYENG R. MIN ◽  
WILLIAM E. PINCHAK ◽  
ROBIN C. ANDERSON ◽  
TODD R. CALLAWAY
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Bacterial Growth ◽  
Escherichia Coli O157 ◽  
Tannin Extract ◽  
Bacterial Growth Rate ◽  
Linear Effect ◽  
E Coli

The effect of commercially available chestnut and mimosa tannins in vitro (experiment 1) or in vivo (experiment 2) on the growth or recovery of Escherichia coli O157:H7 or generic fecal E. coli was evaluated. In experiment 1, the mean growth rate of E. coli O157:H7, determined via the measurement of optical density at 600 nm during anaerobic culture in tryptic soy broth at 37°C, was reduced (P < 0.05) with as little as 400 μg of either tannin extract per ml of culture fluid. The addition of 200, 400, 600, 800, and 1,200 μg of tannins per ml significantly (P < 0.01) reduced the specific bacterial growth rate when compared with the nontannin control. The specific growth rate decreased with increasing dose levels up to 800 μg of tannins per ml. Bacterial growth inhibition effects in chestnut tannins were less pronounced than in mimosa tannins. Chestnut tannin extract addition ranged from 0 to 1,200 μg/ml, and a linear effect (P < 0.05) was observed in cultures incubated for 6 h against the recovery of viable cells, determined via the plating of each strain onto MacConkey agar, of E. coli O157:H7 strains 933 and 86-24, but not against strain 6058. Similar tests with mimosa tannin extract showed a linear effect (P < 0.05) against the recovery of E. coli O157:H7 strain 933 only. The bactericidal effect observed in cultures incubated for 24 h with the tannin preparations was similar, although it was less than that observed from cultures incubated for 6 h. When chestnut tannins (15 g of tannins per day) were infused intraruminally to steers fed a Bermuda grass hay diet in experiment 2, fecal E. coli shedding was lower on days 3 (P < 0.03), 12 (P = 0.08), and 15 (P < 0.001) when compared with animals that were fed a similar diet without tannin supplementation. It was concluded that dietary levels and sources of tannins potentially reduce the shedding of E. coli from the gastrointestinal tract.

scholarly journals Phenotypic Detection of Plasmid-Mediated Colistin Resistance in Enterobacteriaceae

2019 ◽  
Vol 58 (3) ◽  
Author(s):  
Edgar Gonzales Escalante ◽  
Katherine Yauri Condor ◽  
Jose A. Di Conza ◽  
Gabriel O. Gutkind
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Serratia Marcescens ◽  
Bacterial Growth ◽  
Screening Test ◽  
Colistin Resistance ◽  
Content Type ◽  
E Coli

ABSTRACT The aim of this work was to evaluate an easy-to-perform assay based upon inhibition of mobile colistin resistance (MCR) activity by EDTA. We included 92 nonrelated isolates of Enterobacteriaceae (74 Escherichia coli, 17 Klebsiella pneumoniae, and 1 Serratia marcescens). Our proposed method is based on a modification of the colistin agar-spot screening test (CAST), a plate containing 3 μg/ml colistin, by adding an extra plate of colistin agar-spot supplemented with EDTA (eCAST). Bacterial growth was evaluated after 24 h of incubation at 35°C. All the colistin-resistant isolates showed development on the CAST plates. Colistin-resistant K. pneumoniae without mcr-1 and S. marcescens also grew on the eCAST plates. In contrast, colistin-resistant MCR-producing E. coli was not able to grow in eCAST plates. The combined CAST/eCAST test could provide a simple and easy-to-perform method to differentiate MCR-producing Enterobacteriaceae from those in which colistin resistance is mediated by chromosomal mechanisms.

Reduction of Listeria monocytogenes and Escherichia coli O157:H7 Numbers on Vacuum-Packaged Fresh Beef Treated with Nisin or Nisin Combined with EDTA†

1999 ◽  
Vol 62 (10) ◽  
pp. 1123-1127 ◽  
Author(s):  
SHANSHAN ZHANG ◽  
AZLIN MUSTAPHA
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Bacterial Growth ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Key Factor ◽  
Vacuum Package ◽  
And Storage

Nisin or nisin combined with EDTA was used to treat fresh beef. Beef cubes (2.5 by 2.5 by 2.5 cm) that were inoculated with approximately 7 log CFU/ml of Listeria monocytogenes Scott A or Escherichia coli O157:H7 505 B were dipped in the following solutions: (i) H2O, (ii) HCl, (iii) nisin, (iv) EDTA, or (v) nisin combined with EDTA, respectively, for 10 min each, with an exception of one set of control beef samples without treatment. Beef samples were then drip-dried for 15 min, vacuum packaged, and stored at 4°C for up to 30 days. The pH on beef after different treatments was not a key factor in preventing bacterial growth. Treatment with nisin or with nisin combined with EDTA reduced the population of L. monocytogenes by 2.01 and 0.99 log CFU/cm2 as compared to the control, respectively, under the conditions of vacuum package and storage at 4°C for up to 30 days. However, the effect of nisin and nisin combined with EDTA against E. coli O157:H7 505 B was marginal at 1.02 log CFU/cm2 and 0.8 log CFU/cm2 reductions, respectively.

scholarly journals Restriction of bacterial growth by inhibition of polyamine biosynthesis by using monofluoromethylornithine, difluoromethylarginine and dicyclohexylammonium sulphate

1982 ◽  
Vol 208 (2) ◽  
pp. 435-441 ◽  
Author(s):  
A J Bitonti ◽  
P P McCann ◽  
A Sjoerdsma
Keyword(s):  
Escherichia Coli ◽  
Ornithine Decarboxylase ◽  
Bacterial Growth ◽  
Active Site ◽  
Bacterial Infections ◽  
Polyamine Biosynthesis ◽  
E Coli ◽  
Subsequent Investigation ◽  
Generation Times ◽  
Viable Approach

Bacterial growth was measurably slowed by a combination of drugs which inhibit polyamine-biosynthetic enzymes. Addition of DL-alpha-monofluoromethylornithine, which was shown to inactivate irreversibly ornithine decarboxylase extracted from Escherichia coli (Ki = 0.36 mM) and Pseudomonas aeruginosa (Ki = 0.30 mM), DL-alpha-difluoromethylarginine and dicyclohexylammonium sulphate to cultures of E. coli or P. aeruginosa resulted in a 40 and 70% increase in generation times (decreased growth rates) respectively, which was completely reversed by the addition of 0.1 mM-putrescine plus 0.1 mM-spermidine to the medium. Decreased intracellular polyamine concentrations correlated with increased generation times; putrescine concentration was decreased by 70% in E. coli and 80% in P. aeruginosa, while spermidine concentration was decreased by 50% in E. coli and 95% in P. aeruginosa. Subsequent investigation of the inactivation of the ornithine decarboxylase by monofluoromethylornithine indicated that it was active-site directed, as the normal substrate ornithine slowed the rate of inhibition. Specific interference with polyamine biosynthesis may be a viable approach to control of some bacterial infections.

scholarly journals UJI AKTIVITAS ANTIBAKTERI EKSTRAK DAN FRAKSI SPONS Leucetta chagosensis DARI PERAIRAN PULAU MANTEHAGE SULAWESI UTARA TERHADAP PERTUMBUHAN BAKTERI Staphylococcus aureus DAN Escherichia coli

PHARMACON ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 834
Author(s):  
Eunike Pelealu ◽  
Defny S. Wewengkang ◽  
Surya Sumantri Abdullah
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Bacterial Growth ◽  
Pathogenic Bacteria ◽  
Inhibition Zone ◽  
Disk Diffusion ◽  
E Coli ◽  
Activity Test ◽  
Escherichia Coli Bacteria ◽  
Metabolite Content

ABSTRACTSponges are one of the biota components that make up coral reefs which are quite widely distributed. The metabolite content in the sponge can ward off and inhibit the pathogenic bacteria that interfere with it. This study aims to determine the activity of inhibiting bacterial growth from the extract and fraction of Leucetta chagosensis sponge against the growth of Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. The samples were extracted using the maceration method with 95% ethanol solvent and then fractionated using 3 solvents with different polarity levels, namely methanol, n-hexane and chloroform. Activity test using the disk diffusion agar method of Kirby and Bauer. Only the MeOH fraction was able to inhibit the growth of E. coli bacteria with an average inhibition zone of 6.88 mm. Whereas for S.aureus bacteria extracts and all fractions showed activity to inhibit bacterial growth with an average inhibition zone of EtOH (6.61 mm), CHCI3 (6.68 mm), n-hexane (7.83 mm) and MeOH (8.00 mm), respectively. All activities that are shown are categorized as weak (weak).Keywords: Antibacterial, Leucetta chagosensis, Staphylococcus aureus, Escherichia coli ABSTRAKSpons merupakan salah satu komponen biota penyusun terumbu karang yang penyebarannya cukup luas. Kandungan metabolit yang ada di dalam spons dapat menangkal dan menghambat bakteri patogen pengganggunya.  Penelitian ini bertujuan untuk melihat aktivitas menghambat pertumbuhan bakteri dari ekstrak dan fraksi spons Leucetta chagosensis. terhadap pertumbuhan bakteri Gram positif Staphylococcus aureus dan Gram negatif Escherichia coli. Sampel di ekstraksi menggunakan metode maserasi dengan pelarut etanol 95% lalu di fraksinasi dengan menggunakan 3 pelarut dengan tingkat kepolaran yang berbeda yaitu metanol, n-heksan dan kloroform. Uji aktivitas menggunakan metode disk diffusion agar Kirby dan Bauer.  Hanya fraksi MeOH yang mampu menghambat pertumbuhan bakteri E.coli dengan zona hambat rata-rata 6,88 mm. Sedangkan terhadap bakteri S.aureus ekstrak dan semua fraksi menunjukan aktifitas menghambat pertumbuhan bakteri dengan rata-rata zona hambat masing-masing EtOH (6,61 mm), CHCl3 (6,68 mm), n-Heksan (7,83 mm), dan MeOH (8,00 mm). Semua aktivitas yang ditunjukan dikategorikan lemah (weak).Kata kunci : Antibakteri, Leucetta chagosensis, Staphylococcus aureus,  Escherichia coli

scholarly journals Aerobic and Anaerobic Microbiology of Surgical-Site Infection Following Spinal Fusion

1999 ◽  
Vol 37 (3) ◽  
pp. 841-843 ◽  
Author(s):  
Itzhak Brook ◽  
Edith H. Frazier
Keyword(s):  
Escherichia Coli ◽  
Spinal Fusion ◽  
Bacterial Growth ◽  
Anaerobic Bacteria ◽  
Surgical Site Infections ◽  
Aerobic Bacteria ◽  
Site Infection ◽  
E Coli ◽  
Naval Hospital ◽  
Aerobic And Anaerobic

The aerobic and anaerobic microbiology of surgical-site infections (SSI) following spinal fusion was retrospectively studied. This was done by reviewing the clinical and microbiological records at the Naval Hospital in Bethesda, Md., from 1980 to 1992. Aspirates of pus from 25 infection sites showed bacterial growth. Aerobic bacteria only were recovered from 9 (36%) specimens, anaerobic bacteria only were recovered from 4 (16%), and mixed aerobic and anaerobic bacteria were recovered from 12 (48%). Sixty isolates were recovered: 38 aerobes (1.5 isolates per specimen) and 22 anaerobes (0.9 isolate per specimen). The predominant aerobes were Escherichia coli(n = 8) and Proteus sp. (n = 7). The predominant anaerobes wereBacteroides fragilis group (n = 9) andPeptostreptococcus sp. (n = 6) isolates. An increase in recovery of E. coli and B. fragilis was noted in patients with bowel or bladder incontinence. This study highlights the polymicrobial nature of SSI and the importance of anaerobic bacteria in SSI following spinal fusion.

scholarly journals Environmental Growth Conditions Influence the Ability of Escherichia coli K1 To Invade Brain Microvascular Endothelial Cells and Confer Serum Resistance

1998 ◽  
Vol 66 (12) ◽  
pp. 5692-5697 ◽  
Author(s):  
Julie L. Badger ◽  
Kwang Sik Kim
Keyword(s):  
Escherichia Coli ◽  
Endothelial Cells ◽  
Blood Brain Barrier ◽  
Bacterial Growth ◽  
Growth Conditions ◽  
Brain Barrier ◽  
Microvascular Endothelial Cells ◽  
Serum Resistance ◽  
Brain Microvascular Endothelial Cells ◽  
E Coli

ABSTRACT A major limitation to advances in prevention and therapy of neonatal meningitis is our incomplete understanding of the pathogenesis of this disease. In an effort to understand the pathogenesis of meningitis due to Escherichia coli K1, we examined whether environmental growth conditions similar to those that the bacteria might be exposed to in the blood could influence the ability ofE. coli K1 to invade brain microvascular endothelial cells (BMEC) in vitro and to cross the blood-brain barrier in vivo. We found that the following bacterial growth conditions enhanced E. coli K1 invasion of BMEC 3- to 10-fold: microaerophilic growth, media buffered at pH 6.5, and media supplemented with 50% newborn bovine serum (NBS), magnesium, or iron. Growth conditions that significantly repressed invasion (i.e., 2- to 250-fold) included iron chelation, a pH of 8.5, and high osmolarity. More importantly, E. coli K1 traversal of the blood-brain barrier was significantly greater for the growth condition enhancing BMEC invasion (50% NBS) than for the condition repressing invasion (osmolarity) in newborn rats with experimental hematogenous meningitis. Of interest, bacterial growth conditions that enhanced or repressed invasion also elicited similar serum resistance phenotype patterns. This is the first demonstration that bacterial ability to enter the central nervous system can be affected by environmental growth conditions.

scholarly journals Construction of Direct Z-Scheme Photocatalyst by Mg1.2Ti1.8O5 and g-C3N4 Nanosheets toward Photocatalytic H2 Production and Disinfection

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Sijia Gu ◽  
Dan Zhang ◽  
Shirong Luo ◽  
Heng Yang
Keyword(s):  
Escherichia Coli ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
H2 Production ◽  
X Ray ◽  
E Coli ◽  
Carrier Separation ◽  
Positive Valence ◽  
Calcination Method

Exploring a novel and efficient photocatalyst is the key research goal to relieve energy and environmental issues. Herein, Z-scheme heterojunction composites were successfully fabricated by loading g-C3N4 nanosheets (CN) on the surface of Mg1.2Ti1.8O5 nanoflakes (MT) through a simple sol-gel method followed by the calcination method. The crystalline phase, morphologies, specific surface area, and optical and electrochemical performance of the samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-disperse X-ray spectroscopy (EDS), Brunauer-Emmett-Teller (BET), diffuse reflectance spectroscopy (DRS), and electrochemical measurements. Considering the suitable band structures of the components, the photocatalytic performance was evaluated by photocatalytic H2O splitting and photocatalytic inactivation of Escherichia coli (E. coli). Among the samples, MT/CN-10 (the molar percentage of melamine to as-obtained Mg-Ti gel was 10%) shows superior photocatalytic performance, which the average H2 production rate was 3.57 and 7.24 times higher than those of MT and CN alone. Additionally, the efficiency of inactivating Escherichia coli (E. coli) over MT/CN-10 was 1.95 and 2.06 times higher as compared to pure MT and CN, respectively. The enhancement of the photocatalytic performance was attributed to the advantages of the extremely negative conduction band (CB) of CN and the extremely positive valence band (VB) of MT, the enhanced light absorption, and more efficient photogenerated charge carrier separation.

Real-Time Bioluminescence Analysis of Escherichia coli O157:H7 Survival on Livestock Meats Stored Fresh, Cold, or Frozen

2018 ◽  
Vol 81 (11) ◽  
pp. 1906-1912 ◽  
Author(s):  
SEONG B. PARK ◽  
SHECOYA B. WHITE ◽  
CHRISTY S. STEADMAN ◽  
CLAY A. CAVINDER ◽  
SCOTT T. WILLARD ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Real Time ◽  
Bacterial Growth ◽  
Room Temperature ◽  
Storage Conditions ◽  
Escherichia Coli O157 ◽  
Production Environment ◽  
Real Time Monitoring ◽  
E Coli ◽  
C Storage

ABSTRACT Foodborne bacteria such as Escherichia coli O157:H7 can cause severe hemorrhagic colitis in humans following consumption of contaminated meat products. Contamination with pathogenic bacteria is frequently found in the food production environment, and adequate household storage conditions of purchased foods are vital for illness avoidance. Real-time monitoring was used to evaluate bacterial growth in ground horse, beef, and pork meats maintained under various storage conditions. Various levels of E. coli O157:H7 carrying the luxCDABE operon, which allows the cells to emit bioluminescence, were used to inoculate meat samples that were then stored at room temperature for 0.5 day, at 4°C (cold) for 7 or 9 days, or −20°C (frozen) for 9 days. Real-time bioluminescence imaging (BLI) of bacterial growth was used to assess bacterial survival or load. Ground horse meat BLI signals and E. coli levels were dose and time dependent, increasing during room temperature and −20°C storage, but stayed at low levels during 4°C storage. No bacteria survived in the lower level inoculum groups (101 and 103 CFU/g). With an inoculum of 107 CFU/g, pork meats had higher BLI signals than did their beef counterparts, displaying decreased BLI signals during 7 days storage at 4°C. Both meat types had higher BLI signals in the fat area, which was confirmed with isolated fat tissues in the beef meat. Beef lean and fat tissues contrasted with both pork fat and lean tissues, which had significantly higher BLI signals and bacterial levels. BLI appears to be a useful research tool for real-time monitoring of bacterial growth and survival in various stored livestock meats. The dependence of E. coli O157:H7 growth on meat substrate (fat or lean) and storage conditions may be used as part of an effective antibacterial approach for the production of safe ground horse, beef, and pork meats.

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