scholarly journals Inhibition of MurA Enzyme from Escherichia coli and Staphylococcus aureus by Diterpenes from Lepechinia meyenii and Their Synthetic Analogs

Antibiotics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1535
Author(s):  
Macarena Funes Chabán ◽  
Martina Hrast ◽  
Rok Frlan ◽  
Dafni G. Graikioti ◽  
Constantinos M. Athanassopoulos ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pathogenic Bacteria ◽  
Plant Origin ◽  
Synthetic Analogs ◽  
E Coli ◽  
Ic50 Values ◽  
Resistant Strains ◽  
Hydroxy Groups ◽  
And Staphylococcus Aureus

Enzymes MurA and MurF, involved in bacterial cell wall synthesis, have been validated as targets for the discovery of novel antibiotics. A panel of plant-origin antibacterial diterpenes and synthetic analogs derived therefrom were investigated for their inhibitory properties on these enzymes from Escherichia coli and Staphylococcus aureus. Six compounds were proven to be effective for inhibiting MurA from both bacteria, with IC50 values ranging from 1.1 to 25.1 µM. To further mechanistically investigate the nature of binding and to explain the activity, these compounds were docked into the active site of MurA from E. coli. The aromatic ring of the active compounds showed a T-shaped π–π interaction with the phenyl ring of Phe328, and at least one hydrogen bond was formed between the hydroxy groups and Arg120 and/or Arg91. The results disclosed here establish new chemical scaffolds for the development of novel entities targeting MurA as potential antibiotics to combat the threat of pathogenic bacteria, particularly resistant strains.

Microbiological Quality of Hot Meals Served by Airlines

1998 ◽  
Vol 61 (8) ◽  
pp. 1052-1056 ◽  
Author(s):  
MAIJA HATAKKA
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Clostridium Perfringens ◽  
Pathogenic Bacteria ◽  
Microbiological Quality ◽  
Geometric Means ◽  
E Coli ◽  
The World ◽  
And Staphylococcus Aureus

The microbiological quality of 1,012 hot meals served on aircraft was studied in 1991 to 1994. The material included dishes prepared in 33 countries all over the world. The geometric means of aerobic colony counts and Escherichia coli were significantly lower in breakfasts (P < 0.05) than in main dishes. Pathogenic bacteria were found in 30 samples (3.0%), Bacillus cereus being the most common pathogen. The frequencies of B. cereus and Staphylococcus aureus did not differ between breakfasts and main dishes. Many of the samples exceeded the minimum acceptable microbiological standards recommended by the Association of European Airlines (AEA) for E. coli, S. aureus, B. cereus, Clostridium perfringens, and Salmonella; i.e., 8.2%, 0.6%, 0.7%, 0.7% and 0.3%, respectively. There were considerable differences in aerobic colony counts and E. coli counts between countries where the food was prepared.

scholarly journals Evaluation of antibacterial and antioxidant activities of three types of benzoin resin

2018 ◽  
Vol 9 (4) ◽  
pp. 408-411
Author(s):  
Zineb Hacini ◽  
Fatima Khedja ◽  
Ibrahim Habib ◽  
Zaouia Kendour ◽  
Zineb Debba
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antioxidant Activity ◽  
Essential Oils ◽  
Pathogenic Bacteria ◽  
Antioxidant Activities ◽  
Ic50 Values ◽  
Therapeutic Properties ◽  
Resin Extract ◽  
And Staphylococcus Aureus

The benzoin resin is used extensively in traditional medicine for its many reported therapeutic properties. The essential oils of three different types of benzoin resin were extracted using the traditional method in this study. The yield of essential oils of the white, red and gray types of resin was 1.01, 0.92 and 0.54%, respectively. The obtained extracts were tested against two types of pathogenic bacteria, Staphylococcus aureus and Escherichia coli. The tests showed that essential oil of gray type resin is effective against both Escherichia coli (14 mm) and Staphylococcus aureus (11 mm). The antioxidant activity has been also evaluated to compare the efficiency of different type of resin with DPPH· assay. In the DPPH· system, the antioxidant activity of the red resin extract (0.01 μg/mL) was superior to that of the white (27.32 μg/mL) and gray (42.90 μg/mL) extracts, with IC50 values, respectively.

Comparison of the Effects of Silver in Nanostructured and Ultrahigh Diluted Form on Growth and Volatile Compounds Produced by Escherichia coli and Staphylococcus aureus

2020 ◽  
Vol 10 (3) ◽  
pp. 316-329
Author(s):  
Fateme Mirzajani ◽  
Amin Hamidi
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Life Cycles ◽  
Gas Chromatography Mass Spectrometry ◽  
Untreated Sample ◽  
E Coli ◽  
Volatile Metabolites ◽  
Octyl Acetate ◽  
Volatile Organic ◽  
And Staphylococcus Aureus

Introduction: In this project, the growth and volatile metabolites profiles of Escherichia coli (E. coli ) and Staphylococcus aureus were monitored under the influence of silver base chemical, nanoparticle and ultra-highly diluted compounds. Materials & Methods: The treatments were done for 12000 life cycles using silver nanoparticles (AgNPs) as well as ultra-highly diluted Argentum nitricum (Arg-n). Volatile organic metabolites analysis was performed using gas chromatography mass spectrometry (GC-MS). The results indicated that AgNPs treatment made the bacteria resistant and adapted to growth in the nanoparticle condition. The use of ultra-highly diluted Arg-n initially increased growth but it decreased later. Also, with the continuous usage of these materials, no more bacterial growth was observed. Results: The most important compounds produced by E. coli are Acetophenone, Octyl acetate, Styrene, 1,8-cineole, 4-t-butyl-2-(1-methyl-2-nitroethyl)cyclohexane, hexadecane and 2-Undecanol. The main compounds derived from S. aureus are Acetophenone,1,8-cineole, Benzaldehyde, 2-Hexan-1-ol, Tridecanol, Dimethyl Octenal and tetradecane. Acetophenone and 1,8-cineole were common and produced by both organisms. Conclusion: Based on the origin of the produced volatiles, main volatiles percentage of untreated sample is hydrocarbon (>50%), while bacteria treatments convert the ratio in to aldehydes, ketones and alcohols in the case of AgNPs, (>80%) and aldehydes, ketones and terpenes in the case of Arg-n (>70%).

scholarly journals Antimicrobial Efficacy and Spectrum of Phosphorous-Fluorine Co-Doped TiO2 Nanoparticles on the Foodborne Pathogenic Bacteria Campylobacter jejuni, Salmonella Typhimurium, Enterohaemorrhagic E. coli, Yersinia enterocolitica, Shewanella putrefaciens, Listeria monocytogenes and Staphylococcus aureus

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1786
Author(s):  
György Schneider ◽  
Bettina Schweitzer ◽  
Anita Steinbach ◽  
Botond Zsombor Pertics ◽  
Alysia Cox ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Campylobacter Jejuni ◽  
Food Industry ◽  
Pathogenic Bacteria ◽  
Antibacterial Activities ◽  
Tio2 Nps ◽  
E Coli ◽  
Foodborne Pathogenic Bacteria ◽  
And Staphylococcus Aureus ◽  
Co Doped

Contamination of meats and meat products with foodborne pathogenic bacteria raises serious safety issues in the food industry. The antibacterial activities of phosphorous-fluorine co-doped TiO2 nanoparticles (PF-TiO2) were investigated against seven foodborne pathogenic bacteria: Campylobacter jejuni, Salmonella Typhimurium, Enterohaemorrhagic E. coli, Yersinia enterocolitica, Shewanella putrefaciens, Listeria monocytogenes and Staphylococcus aureus. PF-TiO2 NPs were synthesized hydrothermally at 250 °C for 1, 3, 6 or 12 h, and then tested at three different concentrations (500 μg/mL, 100 μg/mL, 20 μg/mL) for the inactivation of foodborne bacteria under UVA irradiation, daylight exposure or dark conditions. The antibacterial efficacies were compared after 30 min of exposure to light. Distinct differences in the antibacterial activities of the PF-TiO2 NPs, and the susceptibilities of tested foodborne pathogenic bacterium species were found. PF-TiO2/3 h and PF-TiO2/6 h showed the highest antibacterial activity by decreasing the living bacterial cell number from ~106 by ~5 log (L. monocytogenes), ~4 log (EHEC), ~3 log (Y. enterolcolitca, S. putrefaciens) and ~2.5 log (S. aureus), along with complete eradication of C. jejuni and S. Typhimurium. Efficacy of PF-TiO2/1 h and PF-TiO2/12 h NPs was lower, typically causing a ~2–4 log decrease in colony forming units depending on the tested bacterium while the effect of PF-TiO2/0 h was comparable to P25 TiO2, a commercial TiO2 with high photocatalytic activity. Our results show that PF-co-doping of TiO2 NPs enhanced the antibacterial action against foodborne pathogenic bacteria and are potential candidates for use in the food industry as active surface components, potentially contributing to the production of meats that are safe for consumption.

Prevalence of antibiotic-resistant Escherichia coli isolated from urban and agricultural streams in Canterbury, New Zealand

2019 ◽  
Vol 366 (8) ◽  
Author(s):  
Sophie Van Hamelsveld ◽  
Muyiwa E Adewale ◽  
Brigitta Kurenbach ◽  
William Godsoe ◽  
Jon S Harding ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
New Zealand ◽  
Pathogenic Bacteria ◽  
Freshwater Ecosystems ◽  
Urban Setting ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Mesophilic Bacteria ◽  
Resistant Strains ◽  
Population Counts

Abstract Baseline studies are needed to identify environmental reservoirs of non-pathogenic but associating microbiota or pathogenic bacteria that are resistant to antibiotics and to inform safe use of freshwater ecosystems in urban and agricultural settings. Mesophilic bacteria and Escherichia coli were quantified and isolated from water and sediments of two rivers, one in an urban and one in an agricultural area near Christchurch, New Zealand. Resistance of E. coli to one or more of nine different antibiotics was determined. Additionally, selected strains were tested for conjugative transfer of resistances. Despite having similar concentrations of mesophilic bacteria and E. coli, the rivers differed in numbers of antibiotic-resistant E. coli isolates. Fully antibiotic-susceptible and -resistant strains coexist in the two freshwater ecosystems. This study was the first phase of antibiotic resistance profiling in an urban setting and an intensifying dairy agroecosystem. Antibiotic-resistant E. coli may pose different ingestion and contact risks than do susceptible E. coli. This difference cannot be seen in population counts alone. This is an important finding for human health assessments of freshwater systems, particularly where recreational uses occur downstream.

Food Poisoning Potential of Artificially Contaminated Vacuum Packaged Sliced Ham in Sandwiches1

1981 ◽  
Vol 44 (6) ◽  
pp. 430-434 ◽  
Author(s):  
JAMES E. STEELE ◽  
MICHAEL E. STILES
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Storage Temperature ◽  
Food Poisoning ◽  
Microbial Competition ◽  
Growth And Survival ◽  
E Coli ◽  
Enteropathogenic Bacteria ◽  
Test Conditions ◽  
And Staphylococcus Aureus

Ham sandwiches inoculated with a mixture of five enteropathogenic bacteria, Bacillus cereus, Clostridium perfringens. Escherichia coli, Salmonella typhimurium and Staphylococcus aureus, were held at 30, 21 and 4 C for up to 24 h. Food poisoning potential was judged by the growth and survival of the inoculated pathogens. Major differences were observed between new and old (30 days of storage at 4 C) ham samples. On new ham, all enteropathogens were able to grow except C. perfringens, whereas on old ham, with high microbial competition. the pathogens survived but did not grow. Severe storage temperature abuse was necessary to develop a food poisoning potential in new ham samples. The safety of old ham was attributed to the competitive microflora that grew in the ham during storage at 4 C for 30 days. Infective pathogens, E. coli and S. typhimurium, either survived or increased in numbers under all test conditions. The safety of vacuum packaged sliced ham for use in sandwiches, in its present market form, was indicated by these studies.

Fate of Pathogens Inoculated onto Vacuum-Packaged Sliced Hams to Simulate Contamination During Packaging1

1979 ◽  
Vol 42 (6) ◽  
pp. 464-469 ◽  
Author(s):  
M. E. STILES ◽  
L.-K. NG
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Salmonella Typhimurium ◽  
Bacillus Cereus ◽  
Clostridium Perfringens ◽  
Subsequent Treatment ◽  
Vacuum Packaging ◽  
E Coli ◽  
Survival And Growth ◽  
And Staphylococcus Aureus

Ham and chopped ham from two manufacturers were contaminated with five enteropathogens: Bacillus cereus, Clostridium perfringens, Escherichia coli, Salmonella typhimurium and Staphylococcus aureus, at time of slicing and vacuum-packaging, to simulate contamination by manufacturer. Subsequent treatment of the samples, representing sound and undesirable retail handling and consumer use conditions, indicated marked differences in the fate of the pathogens between these products and within product type between the two manufacturers. Greatest differences were observed between the chopped ham products. All pathogens, except C. perfringens, grew actively in fresh ham and chopped ham with abusive holding at 30 and 21 C. After storage at 4 or 10 C for 30 days, B. cereus and C. perfringens were no longer detected, even after subsequent holding at 30 or 21 C for 24 h. E. coli survival and growth was variable, S. typhimurium survived well and grew under some conditions and S. aureus was generally inhibited at high levels of competition.

Sensitivity analysis of Escherichia coli and Staphylococcus aureus of mixed salad vegetables during washing step at packing house

2020 ◽  
Author(s):  
Sukhuntha Osiriphun ◽  
Phichaya Poonlarp ◽  
Danai Boonyakiat ◽  
Patcharin Raviyan
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Sensitivity Analysis ◽  
Assessment Model ◽  
Health Food ◽  
E Coli ◽  
Global Trend ◽  
Washing Process ◽  
Fresh Cut ◽  
And Staphylococcus Aureus

Fresh cut vegetables are a source of minerals, vitamins, and phytonutrients that are convenient foods for consumers which are following the global trend of inclination toward health food. In terms of food safety, contamination of vegetables with microorganisms can occur at multiple points along the supply chain. This study was conducted to investigate the risk factors of Escherichia coli and Staphylococcus aureus which contaminate freshly cut vegetables during production (receiving, washing, centrifuging, and packing areas) by using a statistical method for sensitivity analysis and an exposure assessment model complying with the @RiskTM software program. At washing step, the numbers of S. aureus found in the vegetables and water were 0.79 ±1.76 Log cfu/g and 0.68±1.52 Log cfu, respectively. For the equipment, the hand, and the table swabbing samples, the numbers of S. aureus were 0.48±1.07 Log cfu/25 cm2, 1.81±1.69 Log cfu/25 cm2 , and 0.54±1.21 Log cfu/25 cm2 , respectively. An amount of E. coli of 0.48±1.07 Log cfu/25 cm2 was found in the table swabbing samples at the packing area. E.coli and S. aureus were not found in any of the mixed fresh-cut salad samples; therefore, the product samples could be considered safe for consumers. The result of the sensitivity analysis showed that the temperature and pH of water samples were the important factors in the washing process. The suggested interventions included monitoring and maintaining the water temperature at 5°C; also, maintaining the pH of water between 6.5 and 7.5 could help to reduce pathogen contamination of freshly cut vegetables.

Study on Propolis Quality from China and Uruguay

2000 ◽  
Vol 55 (9-10) ◽  
pp. 778-784 ◽  
Author(s):  
Josep Serra Bonvehí ◽  
Francesc Ventura Coll
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Bacillus Subtilis ◽  
Biological Activities ◽  
The State ◽  
Active Components ◽  
E Coli ◽  
Geographic Origins ◽  
Potential Activity ◽  
And Staphylococcus Aureus

Abstract The composition, bacteriostatic and ROO• -scavenging potential activities of fifteen propolis samples from various botanic and geographic origins were determined to obtain objective information related to propolis quality. Variance analysis showed significant differences (p ≤ 0.05) in the contents of polyphenols, flavonoids and active components between fresh and aged propolis. The state of the product (fresh or aged) could be differentiate by using flavonoid pattern and biological activities. A minimum propolis concentration of 80 μg/ml was required inhibit Bacillus subtilis and Staphylococcus aureus while 800 μg/ml was required to inhibit Escherichia coli using fresh propolis. Aged propolis inhibit B. subtilis and S. aureus at concentration of 100 μg/ml and E. coli at 1000 μg/ml. A minimum flavonoids percentage of 18 g/100 g and a maximum ROO• -scavenging potential activity of 4.3 μg/ml were determined in fresh propolis. Flavonoids levels in aged propolis were approximately 20% lower than in fresh propolis. A maximum flavonoids percentage of 19.8 g/100 g and a ROO•-scavenging potential activity between 5.7 to 6.4 μg/ml in aged propolis were quantified. Another objective was to assess the use of ROO•-scavenging potential activity in propolis quality.

scholarly journals Uji Daya Hambat Ekstrak Metanol Beberapa Jenis Porifera Terhadap Bakteri Escherichia coli dan Staphylococcus aureus

Jurnal MIPA ◽  
2014 ◽  
Vol 3 (2) ◽  
pp. 129
Author(s):  
Megawati S. Saroinsong ◽  
Febby E. F. Kandou ◽  
Adelfia Papu ◽  
Marina F. O. Singkoh
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Methanol Extract ◽  
Inhibition Zone ◽  
E Coli ◽  
Activity Test ◽  
And Staphylococcus Aureus ◽  
Paper Disc ◽  
Coli Growth

Penelitian ini bertujuan untuk menguji daya hambat dari ekstrak metanol beberapa jenis porifera terhadap pertumbuhan bakteri E. coli dan S. aureus. Pengujian aktivitas antibakteri menggunakan metode Kirby-Bauer, yaitu dilakukan dengan mengukur zona hambat di sekeliling cakram kertas. Ekstrak Haliclona sp dapat menghambat pertumbuhan S. aureus pada konsentrasi ekstrak 30%, 60% dan 90% dengan hasil pengukuran diameter zona hambat 13.50 mm, 20.67 mm dan 27.33 mm; serta menghambat pertumbuhan E. coli dengan diameter zona hambat 10.08 mm, 12.83 mm dan 14.17 mm. Daya hambat ekstrak Agelas sp terhadap S. aureus menunjukkan diameter zona hambat 8.33 mm dan hanya menunjukkan pada konsentrasi ekstrak 90%, sementara daya hambat ekstrak Agelas sp pada konsentrasi 30%, 60% dan 90% terhadap E. coli menunjukkan diameter zona hambat sebesar 7.67 mm, 10.17 mm dan 14.17 mm. Daya hambat Spheciospongia sp terhadap S. aureus dan E. coli hanya terlihat pada konsentrasi ekstrak sebesar 90% dengan diameter zona hambat adalah 8.42 mm dan 8.75 mm. Berdasarkan hasil yang diperoleh, dapat disimpulkan bahwa ekstrak Haliclona sp memiliki potensi aktivitas antibakteri yang dapat digunakan sebagai bahan dasar pembuatan obat antibiotik.This research aimed to test the inhibition capabilities of methanol extract from several kinds of Porifera on Escherichia coli and Staphylococcus aureus growth. The antibacterial activity test using the Kirby-Bauer method, which delivered by measuring the inhibition zone around paper disc. The extract of Haliclona sp can inhibit the S. aureus growth at 30%, 60% and 90% of extracts concentration with the measurement of inhibition zone diameters are 13.50 mm, 20.67 mm and 27.33 mm; also inhibit the E. coli growth with inhibition zone diameters are 10.08 mm, 12.83 mm and 14.17 mm. The inhibition capability of Agelas sp extract on S. aureus shows that the inhibition zone diameters is 8.83 mm and only appear at 90% of extracts concentration, meanwhile the inhibition capability of Agelas sp extract at concentration 30%, 60% and 90% on E. coli shows diameters of inhibition zone are 7.67 mm, 10.17 mm and 14.17 mm. The inhibition capability of Spheciospongia sp on S. aureus and E. coli only occurred at 90% of extracts concentration with inhibition zone diameters 8.42 mm and 8.75 mm. Based on the results, it can be assumed that extracts of Haliclona sp has a potential antibacterial activity that can be used as a basic ingredients for antibiotic medicine.

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