scholarly journals Antibiotics, Acid and Heat Tolerance of Honey adapted Escherichia coli, Salmonella Typhi and Klebsiella pneumoniae

Foods ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 311 ◽  
Author(s):  
Rabia Ayub ◽  
Muhammad Umer ◽  
Abid Aslam Maan ◽  
Bilal Rasool ◽  
Muhammad Kashif Iqbal Khan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Pathogenic Bacteria ◽  
Salmonella Typhi ◽  
Low Ph ◽  
Cross Resistance ◽  
Ziziphus Mauritiana ◽  
Continuous Exposure ◽  
E Coli ◽  
The Impact

The medicinal importance of honey has been known for many decades due to its antimicrobial properties against life-threatening bacteria. However, previous studies revealed that microorganisms are able to develop adaptations after continuous exposure to antimicrobial compounds. The present study was conducted to explore the impact of subinhibitory concentrations of branded honey (Marhaba) and unbranded honey (extracted from Ziziphus mauritiana plant) locally available in Pakistan on Escherichia coli ATCC 10536, Salmonella Typhi and Klebsiella pneumoniae by investigating the development of self- or cross-resistance to antibiotics (gentamicin, kanamycin and imipenem). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of autoclaved honeys were determined. The bacterial cells of E. coli ATCC 10536, S. Typhi and K. pneumoniae were subjected to honey adaptation by exposing to ¼ × MIC (4 passages) and ½ × MIC (4 passages) of both honeys. Moreover, tolerance to low pH and high temperature was also studied in adapted and unadapted cells. The decreasing trend in growth pattern (OD600nm) of E. coli ATCC 10536, S. Typhi and K. pneumoniae was observed with increases in the concentration of honeys (6.25–50% v/v) respectively. Our results showed that continuous exposure of both honeys did not lead to the development of any self- or cross-resistance in tested bacteria. However, percent survival to low pH was found to be significantly higher in adapted cells as compared to unadapted cells. The results indicate that both branded honey (Marhaba) and unbranded honey (extracted from Ziziphus mauritiana plant) were effective in controlling the growth of tested pathogenic bacteria. However, the emergence of tolerance to adverse conditions (pH 2.5, temperature 60 °C) deserves further investigation before proposing honey as a better antibacterial agent in food fabrication/processing, where low pH and high temperatures are usually implemented.

scholarly journals Clinical and Economic Impact of Third-Generation Cephalosporin-Resistant Infection or Colonization Caused by Escherichia coli and Klebsiella pneumoniae: A Multicenter Study in China

2020 ◽  
Vol 17 (24) ◽  
pp. 9285
Author(s):  
Xuemei Zhen ◽  
Cecilia Stålsby Lundborg ◽  
Xueshan Sun ◽  
Xiaoqian Hu ◽  
Hengjin Dong
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Hospital Mortality ◽  
Multicenter Study ◽  
Generation Cephalosporin ◽  
Total Hospital Cost ◽  
Third Generation ◽  
E Coli ◽  
Significant Difference ◽  
The Impact

Quantifying economic and clinical outcomes for interventions could help to reduce third-generation cephalosporin resistance and Escherichia coli or Klebsiella pneumoniae. We aimed to compare the differences in clinical and economic burden between third-generation cephalosporin-resistant E. coli (3GCREC) and third-generation cephalosporin-susceptible E. coli (3GCSEC) cases, and between third-generation cephalosporin-resistant K. pneumoniae (3GCRKP) and third-generation cephalosporin-susceptible K. pneumoniae (3GCSKP) cases. A retrospective and multicenter study was conducted. We collected data from electronic medical records for patients who had clinical samples positive for E. coli or K. pneumoniae isolates during 2013 and 2015. Propensity score matching (PSM) was conducted to minimize the impact of potential confounding variables, including age, sex, insurance, number of diagnoses, Charlson comorbidity index, admission to intensive care unit, surgery, and comorbidities. We also repeated the PSM including length of stay (LOS) before culture. The main indicators included economic costs, LOS and hospital mortality. The proportions of 3GCREC and 3GCRKP in the sampled hospitals were 44.3% and 32.5%, respectively. In the two PSM methods, 1804 pairs and 1521 pairs were generated, and 1815 pairs and 1617 pairs were obtained, respectively. Compared with susceptible cases, those with 3GCREC and 3GCRKP were associated with significantly increased total hospital cost and excess LOS. Inpatients with 3GCRKP were significantly associated with higher hospital mortality compared with 3GCSKP cases, however, there was no significant difference between 3GCREC and 3GCSEC cases. Cost reduction and outcome improvement could be achieved through a preventative approach in terms of both antimicrobial stewardship and preventing the transmission of organisms.

Efficacy of Chemical Treatments in Eliminating Salmonella and Escherichia coli O157:H7 on Scarified and Polished Alfalfa Seeds

2001 ◽  
Vol 64 (10) ◽  
pp. 1489-1495 ◽  
Author(s):  
SARAH L. HOLLIDAY ◽  
ALAN J. SCOUTEN ◽  
LARRY R. BEUCHAT
Keyword(s):  
Escherichia Coli ◽  
Chemical Treatment ◽  
Organic Material ◽  
Pathogenic Bacteria ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Mechanical Abrasion ◽  
Chemical Treatments ◽  
The Impact ◽  
Alfalfa Seeds

Alfalfa seeds are sometimes subjected to a scarification treatment to enhance water uptake, which results in more rapid and uniform germination during sprout production. It has been hypothesized that this mechanical abrasion treatment diminishes the efficacy of chemical treatments used to kill or remove pathogenic bacteria from seeds. A study was done to compare the effectiveness of chlorine (20,000 ppm), H2O2 (8%), Ca(OH)2 (1%), Ca(OH)2 (1%) plus Tween 80 (1%), and Ca(OH)2 (1%) plus Span 20 (1%) treatments in killing Salmonella and Escherichia coli O157:H7 inoculated onto control, scarified, and polished alfalfa seeds obtained from two suppliers. The influence of the presence of organic material in the inoculum carrier on the efficacy of sanitizers was investigated. Overall, treatment with 1% Ca(OH)2 was the most effective in reducing populations of the pathogens. Reduction in populations of pathogens on seeds obtained from supplier 1 indicate that chemical treatments are less efficacious in eliminating the pathogens on scarified seeds compared to control seeds. However, the effectiveness of chemical treatment in removing Salmonella and E. coli O157:H7 from seeds obtained from supplier 2 was not markedly affected by scarification or polishing. The presence of organic material in the inoculum carrier did not have a marked influence on the efficacy of chemicals in reducing populations of test pathogens. Additional lots of control, scarified, and polished alfalfa seeds of additional varieties need to be tested before conclusions can be drawn concerning the impact of mechanical abrasion on the efficacy of chemical treatment in removing or killing Salmonella and E. coli O157:H7.

scholarly journals Antibacterial Activity of Liverworts of Dumortiera hirsute (Sw.) Nees Ethyl Acetate Extract Against Pathogenic Bacteria

2021 ◽  
Vol 9 (2) ◽  
pp. 75
Author(s):  
Luthfiah Luthfiah ◽  
Dwi Setyati ◽  
Sattya Arimurti
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Ethyl Acetate ◽  
Pathogenic Bacteria ◽  
Ethyl Acetate Extract ◽  
Antibacterial Properties ◽  
Salmonella Typhi ◽  
Diffusion Method ◽  
E Coli ◽  
Agar Well Diffusion Method

Dumortiera hirsuta is one of the liverworts that can be used as a medicinal to prevent infection by pathogenic bacteria. The content of secondary metabolites of D. hirsuta has potential as antibacterial properties includes flavonoids, alkaloids and steroids. This research is to analyze the antibacterial activity of moss D. hirsuta against pathogenic bacteria that will be beneficial to humans. Liverworts of D. hirsuta were extracted using ethyl acetate solvent and tested against three types of pathogenic bacteria using the agar well-diffusion method. The results of this study indicated that the ethyl acetate extract of D. hirsuta at 100% concentration could inhibit the growth of Escherichia coli, Staphylococcus aureus, and Salmonella typhi bacteria. The range of antibacterial activity categories of the ethyl acetate extract of D. hirsuta to E. coli, S. aureus, and S. typhi between weak to moderate.

scholarly journals A Large, Refractory Nosocomial Outbreak of Klebsiella pneumoniae Carbapenemase-Producing Escherichia coli Demonstrates Carbapenemase Gene Outbreaks Involving Sink Sites Require Novel Approaches to Infection Control

2018 ◽  
Vol 62 (12) ◽  
Author(s):  
V. Decraene ◽  
H. T. T. Phan ◽  
R. George ◽  
D. H. Wyllie ◽  
O. Akinremi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Control Measures ◽  
Effective Control ◽  
Infection Prevention And Control ◽  
Content Type ◽  
E Coli ◽  
Incidence Trends ◽  
Carbapenemase Gene ◽  
The Impact

ABSTRACT Carbapenem-resistant Enterobacteriaceae (CRE) represent a health threat, but effective control interventions remain unclear. Hospital wastewater sites are increasingly being highlighted as important potential reservoirs. We investigated a large Klebsiella pneumoniae carbapenemase (KPC)-producing Escherichia coli outbreak and wider CRE incidence trends in the Central Manchester University Hospital NHS Foundation Trust (CMFT) (United Kingdom) over 8 years, to determine the impact of infection prevention and control measures. Bacteriology and patient administration data (2009 to 2017) were linked, and a subset of CMFT or regional hospital KPC-producing E. coli isolates (n = 268) were sequenced. Control interventions followed international guidelines and included cohorting, rectal screening (n = 184,539 screens), environmental sampling, enhanced cleaning, and ward closure and plumbing replacement. Segmented regression of time trends for CRE detections was used to evaluate the impact of interventions on CRE incidence. Genomic analysis (n = 268 isolates) identified the spread of a KPC-producing E. coli outbreak clone (strain A, sequence type 216 [ST216]; n = 125) among patients and in the environment, particularly on 2 cardiac wards (wards 3 and 4), despite control measures. ST216 strain A had caused an antecedent outbreak and shared its KPC plasmids with other E. coli lineages and Enterobacteriaceae species. CRE acquisition incidence declined after closure of wards 3 and 4 and plumbing replacement, suggesting an environmental contribution. However, ward 3/ward 4 wastewater sites were rapidly recolonized with CRE and patient CRE acquisitions recurred, albeit at lower rates. Patient relocation and plumbing replacement were associated with control of a clonal KPC-producing E. coli outbreak; however, environmental contamination with CRE and patient CRE acquisitions recurred rapidly following this intervention. The large numbers of cases and the persistence of blaKPC in E. coli, including pathogenic lineages, are of concern.

scholarly journals Polymorphic Variation in Susceptibility and Metabolism of Triclosan-Resistant Mutants of Escherichia coli and Klebsiella pneumoniae Clinical Strains Obtained after Exposure to Biocides and Antibiotics

2015 ◽  
Vol 59 (6) ◽  
pp. 3413-3423 ◽  
Author(s):  
Tânia Curiao ◽  
Emmanuela Marchi ◽  
Carlo Viti ◽  
Marco R. Oggioni ◽  
Fernando Baquero ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Antimicrobial Susceptibility ◽  
Cross Resistance ◽  
Fitness Costs ◽  
Content Type ◽  
Relative Growth Rates ◽  
Global Regulators ◽  
E Coli ◽  
Reverse Transcription Pcr

ABSTRACTExposure to biocides may result in cross-resistance to other antimicrobials. Changes in biocide and antibiotic susceptibilities, metabolism, and fitness costs were studied here in biocide-selectedEscherichia coliandKlebsiella pneumoniaemutants.E. coliandK. pneumoniaemutants with various degrees of triclosan susceptibility were obtained after exposure to triclosan (TRI), benzalkonium chloride (BKC), chlorhexidine (CHX) or sodium hypochlorite (SHC), and ampicillin or ciprofloxacin. Alterations in antimicrobial susceptibility and metabolism in mutants were tested using Phenotype MicroArrays. The expression of AcrAB pump and global regulators (SoxR, MarA, and RamA) was measured by quantitative reverse transcription-PCR (qRT-PCR), and the central part of thefabIgene was sequenced. The fitness costs of resistance were assessed by a comparison of relative growth rates. Triclosan-resistant (TRIr) and triclosan-hypersusceptible (TRIhs) mutants ofE. coliandK. pneumoniaewere obtained after selection with biocides and/or antibiotics.E. coliTRIrmutants, including those with mutations in thefabIgene or in the expression ofacrB,acrF, andmarA, exhibited changes in susceptibility to TRI, CHX, and antibiotics. TRIrmutants for which the TRI MIC was high presented improved metabolism of carboxylic acids, amino acids, and carbohydrates. In TRIrmutants, resistance to one antimicrobial provoked hypersusceptibility to another one(s). TRIrmutants had fitness costs, particularlymarA-overexpressing (E. coli) orramA-overexpressing (K. pneumoniae) mutants. TRI, BKC, and CIP exposure frequently yielded TRIrmutants exhibiting alterations in AraC-like global regulators (MarA, SoxR, and RamA), AcrAB-TolC, and/or FabI, and influencing antimicrobial susceptibility, fitness, and metabolism. These various phenotypes suggest a trade-off of different selective processes shaping the evolution toward antibiotic/biocide resistance and influencing other adaptive traits.

scholarly journals Electroceutical disinfection strategies impair the motility of pathogenic Pseudomonas aeruginosa and Escherichia coli

2016 ◽  
Author(s):  
Kristina Doxsee ◽  
Ryan Berthelot ◽  
Suresh Neethirajan
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Acetic Acid ◽  
Mammalian Cells ◽  
Pathogenic Bacteria ◽  
Electrical Potential ◽  
Microfluidic Platform ◽  
E Coli ◽  
Therapeutic Benefits ◽  
The Impact

Electrotaxis or galvanotaxis refers to the migration pattern of cells induced in response to electrical potential. Although it has been extensively studied in mammalian cells, electrotaxis has not been explored in detail in bacterial cells; information regarding the impact of current on pathogenic bacteria is severely lacking. Therefore, we designed a series of single and multi-cue experiments to assess the impact of varying currents on bacterial motility dynamics in pathogenic multi-drug resistant (MDR) strains of Pseudomonas aeruginosa and Escherichia coli using a microfluidic platform. Motility plays key roles in bacterial migration and the colonization of surfaces during the formation of biofilms, which are inherently recalcitrant to removal and resistant to traditional disinfection strategies (e.g. antibiotics). Use of the microfluidic platform allows for exposure to current, which can be supplied at a range that is biocidal to bacteria, yet physiologically safe in humans (single cue). This system also allows for multi-cue experiments where acetic acid, a relatively safe compound with anti-fouling/antimicrobial properties, can be combined with current to enhance disinfection. These strategies may offer substantial therapeutic benefits, specifically for the treatment of biofilm infections, such as those found in the wound environment. Furthermore, microfluidic systems have been successfully used to model the unique microfluidic dynamics present in the wound environment, suggesting that these investigations could be extended to more complex biological systems. Our results showed that the application of current in combination with acetic acid has profound inhibitory effects on MDR strains of P. aeruginosa and E. coli, even with brief applications. Specifically, E. coli motility dynamics and cell survival were significantly impaired starting at a concentration of 125 μA DC and 0.31% acetic acid, while P. aeruginosa was impaired at 70 μA and 0.31% acetic acid. As these strains are relevant wound pathogens, it is likely that this strategy would be effective against similar strains in vivo and could represent a new approach to hasten wound healing.

scholarly journals The Burden of Antimicrobial Resistance among Urinary Tract Isolates of Escherichia coli in the United States in 2017

2019 ◽  
Author(s):  
Ian A Critchley ◽  
Nicole Cotroneo ◽  
Michael J Pucci ◽  
Rodrigo Mendes
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Hospital Setting ◽  
Clonal Expansion ◽  
The United States ◽  
Cross Resistance ◽  
E Coli ◽  
Oral Agents ◽  
Tract Infections ◽  
The Impact

AbstractUrinary tract infections (UTIs) caused by Escherichia coli have been historically managed with oral antibiotics including the cephalosporins, fluoroquinolones and trimethoprim-sulfamethoxazole. The use of these agents is being compromised by the increase in extended spectrum β-lactamase (ESBL)-producing organisms, mostly caused by the emergence and clonal expansion of E. coli multilocus sequence typing (ST) 131. In addition, ESBL isolates show co-resistance to many of oral agents. Management of UTIs caused by ESBL and fluoroquinolone-resistant organisms is becoming increasingly challenging to treat outside of the hospital setting with clinicians having to resort to intravenous agents. The aim of this study was to assess the prevalence of ESBL phenotypes and genotypes among UTI isolates of E. coli collected in the US during 2017 as well as the impact of co-resistance to oral agents such as the fluoroquinolones and trimethoprim-sulfamethoxazole. The national prevalence of ESBL phenotypes of E. coli was 15.7% and was geographically distributed across all nine Census regions. Levofloxacin and trimethoprim-sulfamethoxazole-resistance rates were ≥ 24% among all isolates and this co-resistance phenotype was considerably higher among isolates showing an ESBL phenotype (≥ 59.2%) and carrying blaCTX-M-15 (≥ 69.5%). The agents with the highest potency against UTI isolates of E. coli, including ESBL isolates showing cross-resistance across oral agents, were the intravenous carbapenems. The results of this study indicate that new oral options with the spectrum and potency similar to the intravenous carbapenems would address a significant unmet need for the treatment of UTIs in an era of emergence and clonal expansion of ESBL isolates resistant to several classes of antimicrobial agents, including oral options.

scholarly journals In-Vitro Evaluation of Antimicrobial Activities of Escherichia coli, Klebsiella pneumoniae, Salmonella typhi, Neisseria gonorrhoeae, and Candida albicans Nosodes

Homeopathy ◽  
2021 ◽  
Author(s):  
Renuka Munshi ◽  
Gitanjali Talele ◽  
Rajesh Shah
Keyword(s):  
Escherichia Coli ◽  
Candida Albicans ◽  
Klebsiella Pneumoniae ◽  
Neisseria Gonorrhoeae ◽  
Salmonella Typhi ◽  
Antimicrobial Activities ◽  
Positive Control ◽  
E Coli ◽  
Inhibition Of Growth

Abstract Background This study presents the results of the minimum inhibitory concentration (MIC) assay of a series of nosodes: namely Escherichia coli, Klebsiella pneumoniae, Salmonella typhi, Neisseria gonorrhoeae, and Candida albicans. Each was tested against its corresponding infection as well as cross infections. Methods In-vitro efficacy of polyvalent nosodes was tested using the MIC assay technique. The nosodes, namely C. albicans polyvalent nosode (35c, 100c), N. gonorrhoeae (35c), K. pneumoniae (35c, 100c), E. coli polyvalent nosode (35c, 100c) and Salmonella typhi polyvalent nosode (30c, 100c), were tested along with positive and negative controls. Nosodes were studied in different potencies and at 1:1 dilution. Results C. albicans polyvalent nosode 35c, 100c, N. gonorrhoeae 35c, and positive control amphotericin B showed inhibition of the growth of C. albicans species. K. pneumoniae 35c, E. coli polyvalent nosode 100c, and meropenem (positive control) showed inhibition of the growth of K. pneumoniae; this effect was not seen with ceftriaxone, ofloxacin and amoxicillin antibiotics. E. coli polyvalent nosode 30c in 10% alcohol (direct and dilution 1:1) and the positive controls ciprofloxacin, ofloxacin, and amoxicillin showed inhibition of the growth of E. coli. The S. typhi polyvalent nosode 30c in 10% alcohol showed inhibition of growth of S. typhi. Conclusion This study reveals that the tested nosodes exhibited antibacterial potential against the corresponding micro-organisms and against other selected organisms studied using this assay.

scholarly journals Evaluación antibacteriana y perfil cromatográfico (CG-EM) de fracciones de hojas y tallo de Calotropis procera (Linn).

2018 ◽  
Vol 2 (2) ◽  
pp. 19-25
Author(s):  
Asoso Oluwakemi-Sola ◽  
Oladunmoye Muftau-Kolawole ◽  
Ogundare Ayodele Oluyemisi
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Salmonella Typhi ◽  
Shigella Dysenteriae ◽  
Calotropis Procera ◽  
E Coli

La medicina tradicional, también conocida como medicina ancestral o popular, comprende sistemas de conocimientos que se desarrollaron a lo largo de generaciones dentro de varias sociedades antes de la era de la medicina moderna. La cromatografía en columna fue utilizada para recolectar fracciones  crudas; se utilizaron disolventes como éter de petróleo, cloroformo y metanol. Las actividades antibacterianas de las fracciones crudas de Calotropis procera (hojas y tallo) se evaluaron en este estudio, utilizando algunos microorganismos seleccionados como Escherichia coli, Shigella dysenteriae ATCC 24162, Salmonella typhi y Klebsiella pneumoniae ATCC 34089; para tal fin, la planta fue extraída usando  acetona y metanol acuoso. El método de difusión en disco de papel fue usado después de que la zona de inhibición alrededor de los discos fue estimada. Los resultados mostraron que en las hojas de la planta, E. coli con la fracción acuoso-metanol y K. pneumoniae ATCC 34089 con la fracción del éter de petróleo-acetona, tuvieron el rendimiento más alto de 30mm respectivamente;  mientras que en el  tallo, K. pneumoniae ATCC 34089 con la fracción del metanol-metanol tuvo el rendimiento más alto de 25mm. La elucidación estructural de los compuestos bioactivos en los extractos fue evaluada usando CG-EM, identificándose compuestos químicos como fenol, palmitato metílico, ácido ftálico, ácido 9-octadecenoico y otros compuestos conocidos como antimicrobianos valiosos, con actividades biológicas y propiedades antioxidantes. Las hojas y el tallo han presentado buenos compuestos químicos, que pueden ser responsables del efecto antimicrobiano observado.

Radiosensitization of Escherichia coli and Salmonella Typhi in Ground Beef

2004 ◽  
Vol 67 (6) ◽  
pp. 1157-1162 ◽  
Author(s):  
F. CHIASSON ◽  
J. BORSA ◽  
B. OUATTARA ◽  
M. LACROIX
Keyword(s):  
Escherichia Coli ◽  
Ascorbic Acid ◽  
Pathogenic Bacteria ◽  
Ground Beef ◽  
Relative Sensitivity ◽  
Salmonella Typhi ◽  
Modified Atmosphere ◽  
Tetrasodium Pyrophosphate ◽  
E Coli

The radiosensitization of two pathogenic bacteria, Escherichia coli and Salmonella Typhi, was evaluated in the presence of thyme and its principal essential oil constituents (carvacrol and thymol) in ground beef. Ground beef was inoculated with E. coli or Salmonella Typhi (105 CFU/g), and each compound was added separately at various concentrations (0 to 3.5%, wt/wt). The antimicrobial potential of carvacrol, thymol, and thyme was evaluated in unirradiated meat by determining the MIC in percentage (wt/wt) after 24 h of storage at 4 ± 1°C. Results showed a MIC of 0.88 ± 0.12%, 1.14 ± 0.05%, and 2.33 ± 0.32% for E. coli in the presence of carvacrol, thymol, and thyme, respectively. MICs of 1.15 ± 0.02%, 1.60 ± 0.01%, and 2.75 ± 0.17% were observed for Salmonella Typhi in the presence of the same compounds, respectively. The best antimicrobial compound (i.e., carvacrol) was selected and added to the sterilized ground beef along with ascorbic acid (0.5%, wt/wt) and tetrasodium pyrophosphate (0.1%, wt/wt). Meat samples (10 g) were packed in air and then irradiated in a 60Co irradiator at doses of 0 to 0.7 kGy for the determination of E. coli radiation D10 and 0 to 2.25 kGy for the determination of Salmonella Typhi radiation D10. Addition of carvacrol increased the relative sensitivity of both bacteria 2.2 times. The radiation D10 was reduced from 0.126 ± 0.0039 to 0.057 ± 0.0015 kGy for E. coli and from 0.519 ± 0.0308 to 0.235 ± 0.0158 kGy for Salmonella Typhi. The addition of tetrasodium pyrophosphate did not affect significantly (P > 0.05) the radiosensitization of either bacterium. However, the presence of ascorbic acid in the media reduced significantly (P ≤ 0.05) the radiosensitivity of both bacteria. An additive effect of carvacrol addition and packaging under modified atmosphere conditions (60% O2–30% CO2–10% N2) was also observed on bacterial radiosensitization at 4°C. Compared with the control packed under air, modified atmosphere packaging conditions in the presence of carvacrol and tetrasodium pyrophosphate improved the relative sensitivity of E. coli by 2.7 times and Salmonella Typhi by 9.9 times.

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