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Multi-Drug Resistant Escherichia Coli In Diarrhoeagenic Foals: Pulsotyping, Phylotyping, Serotyping, Antibiotic Resistance And Virulence Profiling, C.A. Kennedy, Ciara Walsh, M. Karczmarczyk, S. O'Brien, N. Akasheh, M. Quirke, S. Farrell-Ward, T. Buckley, U. Fogherty, K. Kavanagh, C.T. Parker, T. Sweeney, S. Fanning

Articles

Extraintestinal pathogenic E. coli (ExPEC) possess the ability to cause extraintestinal infections such as urinary tract infections, neonatal meningitis and sepsis. While information is readily available describing pathogenic E. coli populations in food-producing animals, studies in companion/sports animals such as horses are limited. In addition, many antimicrobial agents used in the treatment of equine infections are also utilised in human medicine, potentially contributing to the spread of antibiotic resistance determinants among pathogenic strains. The aim of this study was to phenotypically and genotypically characterise the multidrug resistance and virulence associated with 83 equine E. coli isolates recovered from foals with …

Assessing Stress Responses To Atmospheric Cold Plasma Exposure Using Escherichia Coli Knock Out Mutants, Lu Han, Daniela Boehm, Sonal Patil, Patrick Cullen, Paula Bourke

Articles

Aim: This study investigated the effect of Atmospheric cold plasma (ACP) exposure induced stress on microbial inactivation patterns and the regulation of genes involved in the microbial stress response in conjunction with key processing parameters of exposure time and post treatment storage time.

Methods and Results: Cell suspensions of Escherichia coli BW 25113 and its isogenic knock-out mutants in rpoS, soxR, soxS, oxyR and dnaK genes were treated with high voltage ACP in a sealed package for 1, 3 and 5 min followed by 0, 1 and 24 h post-treatment storage. ROS densities and colony formation were …

Bacterial Inactivation By High Voltage Atmospheric Cold Plasma: Influence Of Process Parameters And Effects On Cell Leakage And Dna, Lu Han, Sonal Patil, Kevin M. Keener, Patrick Cullen, Paula Bourke

Articles

Aims: This study investigated a range of atmospheric cold plasma (ACP) process parameters for bacterial inactivation with further investigation of selected parameters on cell membrane integrity and DNA damage. The effects of high voltage levels, mode of exposure, gas mixture and treatment time against Escherichia coli and Listeria monocytogenes were examined.

Methods and Results: 10⁸ CFU ml^-1 E. coli ATCC 25922, E. coli NCTC 12900 and L. monocytogenes NCTC11994 were ACP treated in 10ml phosphate buffered saline (PBS). Working gas mixtures used were; Air (gas mix 1), 90% N₂+10% O₂ (gas mix 2) and 65% …

Atmospheric Cold Plasma Inactivation Of Escherichia Coli In Liquid Media Inside A Sealed Package, Dana Ziuzina, Sonal Patil, Paula Bourke, Kevin Keener, Patrick Cullen

Articles

Abstract Aims: The main objective of this study was to determine the inactivation efficacy of dielectric barrier discharge atmospheric cold plasma (DBD-ACP) generated inside a sealed package for Escherichia coli ATCC 25922. Methods and Results: A plasma discharge was generated between two circular aluminium electrodes at 40 kV. E. coli suspensions (10^7 CFU/ml) in either maximum recovery diluent (MRD) or phosphate buffered saline (PBS) were treated in a 96-well microtitre plate inside a sealed package. The effects of treatment time, post-treatment storage time, either direct or indirect samples exposure to the plasma discharge and suspension media were studied. Regardless of …

Assessing The Microbial Oxidative Stress Of Ozone: Significant Role Of The Oxidative Stress Proteins In The Survival Of E. Coli In Ozone Treatment, Sonal Patil, Vasilis Valdramidis, A. Katratzas, Patrick Cullen, Paula Bourke

Articles

Aims: To investigate the effect of the oxidative stress of ozone on microbial inactivation, cell membrane integrity, membrane permeability and morphology changes of Escherichia coli during ozone treatment.

Methods and Results: E. coli BW 25113 and its isogenic mutants in soxR, soxS, oxyR, rpoS, dnaK genes were treated with ozone at a concentration of 6 µg mL^-1 for a period up to 4 min. A significant effect of ozone exposure on microbial inactivation was observed. After ozonation, minor effects on the cell membrane integrity and permeability were observed. Scanning Electron Microscopy (SEM) analysis showed slightly altered cell …

Inactivation Of Escherichia Coli By Ozone Treatment Of Apple Juice At Different Ph Levels, Sonal Patil, Vasilis Valdramidis, Patrick Cullen, Jesus Maria Frias, Paula Bourke

Articles

This research investigated the efficacy of gaseous ozone for the inactivation of Escherichia coli ATCC 25922 and NCTC 12900 strains in orange juice. Orange juice inoculated with E. coli (10⁶ CFU mL^-1) as a challenge microorganism was treated with ozone at 75-78µg mL^-1 for different time periods (0-18 min). The efficacy of ozone for inactivation of both strains of E. coli was evaluated as a function of different juice types: model orange juice, fresh unfiltered juice, juice without pulp, and juice filtered through 500mm or 1mm sieves. Fast inactivation rates for total reduction of E. coli …

Inactivation Of Escherichia Coli In Orange Juice Using Ozone, Sonal Patil, Paula Bourke, Jesus Maria Frias, Brijesh Tiwari, Patrick Cullen

Articles

This research investigated the efficacy of gaseous ozone for the inactivation of Escherichia coli ATCC 25922 and NCTC 12900 strains in orange juice. Orange juice inoculated with E. coli (10⁶ CFU mL^-1) as a challenge microorganism was treated with ozone at 75-78µg mL^-1 for different time periods (0-18 min). The efficacy of ozone for inactivation of both strains of E. coli was evaluated as a function of different juice types: model orange juice, fresh unfiltered juice, juice without pulp, and juice filtered through 500mm or 1mm sieves. Fast inactivation rates for total reduction of E. coli …

Synthesis And Antimicrobial Evaluation Of Carbohydrate And Polyhydroxylated Non-Carbohydrate Fatty Acid Ester And Ether Derivatives, Aoife Smith, Patricia Nobmann, Gary Henehan, Paula Bourke, Julie Dunne

Articles

A series of fatty acid ester and ether derivatives have been chemically synthesised based on carbohydrate and non-carbohydrate polyhydroxylated scaffolds. The synthesised compounds, along with their corresponding fatty acid monoglyceride antimicrobials, were evaluated for antimicrobial activity against Staphylococcus aureus and Escherichia coli. Of the derivatives synthesised several of the carbohydrate based compounds have antimicrobial efficacy comparable with commercially available antimicrobials. The results suggest that the nature of the carbohydrate core plays a role in the efficacy of carbohydrate fatty acid derivatives as antimicrobials.

Antimicrobial Resistance In Irish Isolates Of Verocytotoxigenic Escherichia Coli (E. Coli)-Vtec., Ciara Walsh, Geraldine Duffy, R. O'Mahoney, I. S. Blair, D. A. Mcdowell

Articles

This study compared the antimicrobial resistance profiles of Escherichia coli O157:H7 isolates (n = 257) recovered from bovine hides, minced beef and human clinical samples in Ireland, to those profiles of a range of Irish non-O157 E. coli (O111 and O26) isolates (n=31) from a variety of clinical and veterinary sources. Four multi-drug resistant (MDR) E. coli O157:H7 food isolates were identified, with resistance to 10 (1 isolate), 6 (1 isolate) and 4 (2 isolates) antimicrobial agents respectively. Two of these isolates (resistant to 7 and 4 antimicrobial classes) were characterised further by molecular methods and found to contain class …