scholarly journals Disinfection of Escherichia coli and Pseudomonas aeruginosa by copper in water

2016 ◽  
Vol 14 (3) ◽  
pp. 424-432 ◽  
Author(s):  
Andrew M. Armstrong ◽  
Mark D. Sobsey ◽  
Lisa M. Casanova
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Enteric Bacteria ◽  
Inactivation Kinetics ◽  
Log10 Reduction ◽  
E Coli ◽  
Piped Water ◽  
Ionic Copper ◽  
Household Water ◽  
Kinetics Of

When households lack access to continuous piped water, water storage in the home creates opportunities for contamination. Storage in copper vessels has been shown to reduce microbes, but inactivation kinetics of enteric bacteria in water by copper alone needs to be understood. This work characterized inactivation kinetics of Escherichia coli and Pseudomonas aeruginosa by dissolved ionic copper in water. Reductions of E. coli and P. aeruginosa increase with increasing dose. At 0.3 mg/L, there was a 2.5 log10 reduction of E. coli within 6 hours. At 1 and 3 mg/L, the detection limit was reached between 3 and 6 hours; maximum reduction measured was 8.5 log10. For P. aeruginosa, at 6 hours there was 1 log10 reduction at 0.3 mg/L, 3.0 log10 at 1 mg/L, and 3.6 log10 at 3 mg/L. There was no significant decline in copper concentration. Copper inactivates bacteria under controlled conditions at doses between 0.3 and 1 mg/L. E. coli was inactivated more rapidly than P. aeruginosa. Copper at 1 mg/L can achieve 99.9% inactivation of P. aeruginosa and 99.9999997% inactivation of E. coli over 6 hours, making it a candidate treatment for stored household water.

Inactivation of Escherichia coli by Ultrasound Combined with Nisin

2018 ◽  
Vol 81 (6) ◽  
pp. 993-1000 ◽  
Author(s):  
ZUWEN WANG ◽  
XIUFANG BI ◽  
RUI XIANG ◽  
LIYI CHEN ◽  
XIAOPING FENG ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Synergistic Effect ◽  
Linear Models ◽  
Treatment Time ◽  
Nutrient Broth ◽  
Inactivation Kinetics ◽  
Growth Phases ◽  
E Coli ◽  
Kinetics Of ◽  
Inactivation Effect

ABSTRACT The aim of this study was to investigate the inactivation of nonpathogenic Escherichia coli in nutrient broth and milk through the use of either ultrasound (US) alone or US combined with nisin (US + nisin) treatments. The E. coli cells were treated at 0 to 55°C, 242.04 to 968.16 W/cm2 for 0 to 15 min. The results showed that the inactivation of E. coli by US and US + nisin increased when the temperature, US power density, and treatment time were increased. The inactivation kinetics of E. coli in nutrient broth by US and US + nisin both conformed to linear models. The largest reductions of 2.89 and 2.93 log cycles by US and US + nisin, respectively, were achieved at 968.16 W/cm2 and at 25°C for 15 min. The suspension media of the E. coli cells influenced the inactivation effect of US, while the growth phases of E. coli cells did not affect their resistance to US. Under all experiment conditions of this study, the differences between US and US + nisin in their respective inactivation effects on E. coli were not obvious. The results suggested that nisin had either no effect at all or a weak synergistic effect with US and that the E. coli cells were inactivated mainly by US, thus indicating that the inactivation of E. coli by US is an “all or nothing” event.

Attachment Strength to Pork Skin and Resistance to Quaternary Ammonium Salt and Heat of Escherichia coli Isolates Recovered from a Pork Slaughter Line

2005 ◽  
Vol 68 (11) ◽  
pp. 2447-2450 ◽  
Author(s):  
AZADEH NAMVAR ◽  
KEITH WARRINER
Keyword(s):  
Escherichia Coli ◽  
Ammonium Salt ◽  
Quaternary Ammonium ◽  
Quaternary Ammonium Salt ◽  
Enteric Bacteria ◽  
Salt Resistance ◽  
Inactivation Kinetics ◽  
Genetic Lineage ◽  
E Coli ◽  
Attachment Strength

The aim of this study was to determine whether the attachment strength to pork skin, quaternary ammonium salt resistance, and thermal inactivation kinetics (at 65°C) of a range of Escherichia coli isolates could be correlated with their temporal stability (persistence) within a pork slaughter line. The genetic lineage of the E. coli isolates was determined using entero-bacterial repetitive intergenic consensus–PCR. The genotypes were divided into transient and endemic populations based on the number of times they were recovered within and across sampling visits made to a pork slaughterhouse. No significant variation in the D-value at 65°C (0.27 to 0.51 min) was observed among the genotypes tested. However, differences in D-values were found for 100 ppm quaternary ammonium salt (3.0 to 6.0 min). All of the E. coli genotypes attached strongly to pork skin, and a high proportion of cells were irreversibly bound (39 to 42% of the initial inoculum). However, variation among genotypes was found with respect to loose attachment (21 to 33% of inoculated cells). No correlation between persistence of E. coli genotypes within the slaughter line and attachment strength or quaternary ammonium salt resistance was found. Variation in either physiological attribute could not be predicted based on genetic lineage. Additional or alternative factors may contribute to the ability of E. coli populations to become endemic within pork processing facilities. More studies should be conducted to elucidate the underlying factors that promote the formation of endemic populations of E. coli and other enteric bacteria (e.g., Salmonella) within slaughter lines.

Viability of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in Yellow Fat Spreads as Affected by Storage Temperature

2003 ◽  
Vol 66 (4) ◽  
pp. 549-558 ◽  
Author(s):  
SARAH L. HOLLIDAY ◽  
LARRY R. BEUCHAT
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Storage Temperature ◽  
Salt Content ◽  
Inactivation Kinetics ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Inhibition Of Growth ◽  
Time Required ◽  
Kinetics Of

A study was conducted to characterize the survival and inactivation kinetics of a five-serotype mixture of Salmonella (6.23 to 6.55 log10 CFU per 3.5-ml or 4-g sample), a five-strain mixture of Escherichia coli O157:H7 (5.36 to 6.14 log10 CFU per 3.5-ml or 4-g sample), and a six-strain mixture of Listeria monocytogenes (5.91 to 6.18 log10 CFU per 3.5-ml or 4-g sample) inoculated into seven yellow fat spreads (one margarine, one butter-margarine blend, and five dairy and nondairy spreads and toppings) after formulation and processing and stored at 4.4, 10, and 21°C for up to 94 days. Neither Salmonella nor E. coli O157:H7 grew in any of the test products. The time required for the elimination of each pathogen depended on the product and the storage temperature. Death was more rapid at 21°C than at 4.4 or 10°C. Depending on the product, the time required for the elimination of viable cells at 21°C ranged from 5 to 7 days to >94 days for Salmonella, from 3 to 5 days to 28 to 42 days for E. coli O157:H7, and from 10 to 14 days to >94 days for L. monocytogenes. Death was most rapid in a water-continuous spray product (pH 3.66, 4.12% salt) and least rapid in a butter-margarine blend (pH 6.66, 1.88% salt). E. coli O157:H7 died more rapidly than did Salmonella or L. monocytogenes regardless of storage temperature. Salmonella survived longer in high-fat (≥61%) products than in products with lower fat contents. The inhibition of growth is attributed to factors such as acidic pH, salt content, the presence of preservatives, emulsion characteristics, and nutrient deprivation. L. monocytogenes did not grow in six of the test products, but its population increased between 42 and 63 days in a butter-margarine blend stored at 10°C and between 3 and 7 days when the blend was stored at 21°C. On the basis of the experimental parameters examined in this study, traditional margarine and spreads not containing butter are not “potentially hazardous foods” in that they do not support the growth of Salmonella, E. coli O157:H7, or L. monocytogenes.

scholarly journals Faecal Indicator Bacteria and Pseudomonas aeruginosa in Marine Coastal Waters: Is there a Relationship?

Pathogens ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 13 ◽  
Author(s):  
Adriana P. Januário ◽  
Clélia N. Afonso ◽  
Susana Mendes ◽  
Maria J. Rodrigues
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Coastal Waters ◽  
Enteric Bacteria ◽  
Most Probable Number ◽  
Coastal Current ◽  
Strong Positive Correlation ◽  
Probable Number ◽  
E Coli ◽  
Intestinal Enterococci

To estimate the quality of coastal waters, European Union Directive 2006/7/EC provides guidelines to assess levels of faecal bacteria, including Escherichia coli and intestinal enterococci. These microbiological criteria are based on studies that determine the risk of bathers having diseases caused by enteric bacteria, not necessarily measuring the potential danger associated with the presence of nonenteric pathogens. The association between the presence of faecal contaminant indicators and nonenteric pathogenic microorganisms has not been well defined yet. The purpose of this study is to establish a relationship between Pseudomonas aeruginosa and microbiological indicators of faecal contamination. Presence of microbiological contamination in the coastal waters near the sewage treatment plant (STP) of Peniche (Portugal) was confirmed (P. aeruginosa 135.8 Colony Forming Unit/100 mL, Escherichia coli 1100.1 Most Probable Number/100 mL, intestinal enterococci 2685.9 MPN/100 mL) with much lower levels in the areas located south of the STP, along the main water coastal current (beach 1: 0.7 CFU/100 mL, 16.5 MPN/100 mL, 100.5 MPN/100 mL; beach 2: 0.3 CFU/100 mL, 74.0 MPN/100 mL, 145.9 MPN/100 mL, respectively). Analysis of Pearson’s correlation revealed a strong positive correlation between E. coli and P. aeruginosa, suggesting E. coli as an indicator of P. aeruginosa presence.

scholarly journals Indole Production Promotes Escherichia coli Mixed-Culture Growth with Pseudomonas aeruginosa by Inhibiting Quorum Signaling

2011 ◽  
Vol 78 (2) ◽  
pp. 411-419 ◽  
Author(s):  
Weihua Chu ◽  
Tesfalem R. Zere ◽  
Mary M. Weber ◽  
Thomas K. Wood ◽  
Marvin Whiteley ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Mixed Culture ◽  
Receptor Gene ◽  
Enteric Bacteria ◽  
Wild Type ◽  
Content Type ◽  
E Coli ◽  
Culture Growth ◽  
Indole Production

ABSTRACTIndole production byEscherichia coli, discovered in the early 20th century, has been used as a diagnostic marker for distinguishingE. colifrom other enteric bacteria. By using transcriptional profiling and competition studies with defined mutants, we show that cyclic AMP (cAMP)-regulated indole formation is a major factor that enablesE. coligrowth in mixed biofilm and planktonic populations withPseudomonas aeruginosa. Mutants deficient in cAMP production (cyaA) or the cAMP receptor gene (crp), as well as indole production (tnaA), were not competitive in coculture withP. aeruginosabut could be restored to wild-type competitiveness by supplementation with a physiologically relevant indole concentration.E. colisdiAmutants, which lacked the receptor for both indole andN-acyl-homoserine lactones (AHLs), showed no change in competitive fitness, suggesting that indole acted directly onP. aeruginosa. AnE. colitnaAmutant strain regained wild-type competiveness if grown withP. aeruginosaAHL synthase (rhlIandrhlI lasI) mutants. In contrast to the wild type,P. aeruginosaAHL synthase mutants were unable to degrade indole. Indole produced during mixed-culture growth inhibited pyocyanin production and other AHL-regulated virulence factors inP. aeruginosa. Mixed-culture growth withP. aeruginosastimulated indole formation inE. colicpdA, which is unable to regulate cAMP levels, suggesting the potential for mixed-culture gene activation via cAMP. These findings illustrate how indole, an early described feature ofE. colicentral metabolism, can play a significant role in mixed-culture survival by inhibiting quorum-regulated competition factors inP. aeruginosa.

scholarly journals Reclaiming the Efficacy of β-Lactam–β-Lactamase Inhibitor Combinations: Avibactam Restores the Susceptibility of CMY-2-Producing Escherichia coli to Ceftazidime

2014 ◽  
Vol 58 (8) ◽  
pp. 4290-4297 ◽  
Author(s):  
Krisztina M. Papp-Wallace ◽  
Marisa L. Winkler ◽  
Julian A. Gatta ◽  
Magdalena A. Taracila ◽  
Sujatha Chilakala ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rate Constant ◽  
Clinical Isolates ◽  
Inactivation Kinetics ◽  
Content Type ◽  
E Coli ◽  
Cephalosporin Resistance ◽  
Molecular Modeling Studies ◽  
Kinetics Of ◽  
Lactamase Inhibitor

ABSTRACTCMY-2 is a plasmid-encoded Ambler class C cephalosporinase that is widely disseminated inEnterobacteriaceaeand is responsible for expanded-spectrum cephalosporin resistance. As a result of resistance to both ceftazidime and β-lactamase inhibitors in strains carryingblaCMY, novel β-lactam–β-lactamase inhibitor combinations are sought to combat this significant threat to β-lactam therapy. Avibactam is a bridged diazabicyclo [3.2.1]octanone non-β-lactam β-lactamase inhibitor in clinical development that reversibly inactivates serine β-lactamases. To define the spectrum of activity of ceftazidime-avibactam, we tested the susceptibilities ofEscherichia coliclinical isolates that carryblaCMY-2orblaCMY-69and investigated the inactivation kinetics of CMY-2. Our analysis showed that CMY-2-containing clinical isolates ofE. coliwere highly susceptible to ceftazidime-avibactam (MIC90, ≤0.5 mg/liter); in comparison, ceftazidime had a MIC90of >128 mg/liter. More importantly, avibactam was an extremely potent inhibitor of CMY-2 β-lactamase, as demonstrated by a second-order onset of acylation rate constant (k2/K) of (4.9 ± 0.5) × 104M−1s−1and the off-rate constant (koff) of (3.7 ± 0.4) ×10−4s−1. Analysis of the reaction of avibactam with CMY-2 using mass spectrometry to capture reaction intermediates revealed that the CMY-2–avibactam acyl-enzyme complex was stable for as long as 24 h. Molecular modeling studies raise the hypothesis that a series of successive hydrogen-bonding interactions occur as avibactam proceeds through the reaction coordinate with CMY-2 (e.g., T316, G317, S318, T319, S343, N346, and R349). Our findings support the microbiological and biochemical efficacy of ceftazidime-avibactam againstE. colicontaining plasmid-borne CMY-2 and CMY-69.

scholarly journals Inactivation of particle-associated Escherichia coli with chlorine dioxide

2016 ◽  
Vol 17 (1) ◽  
pp. 151-160 ◽  
Author(s):  
Tao Lin ◽  
Bingwei Hou ◽  
Zhe Wang ◽  
Wei Chen
Keyword(s):  
Escherichia Coli ◽  
Chlorine Dioxide ◽  
Inactivation Rate ◽  
Inactivation Kinetics ◽  
Strong Temperature Dependence ◽  
E Coli ◽  
Inactivation Rate Constant ◽  
Effects Of Ph ◽  
Inactivation Efficiency ◽  
Kinetics Of

In this paper, the inactivation of both free Escherichia coli (FE) and particle-associated E. coli (PAE) with chlorine dioxide (ClO2) were investigated using granular activated carbon effluent water samples. The inactivation rate of FE was higher than that of PAE and the reactivation ratio of PAE was higher than that of FE, indicating the threat of particle-associated bacteria. Response surface methodology (RSM) was applied to determine the factors influencing the disinfection efficiency of ClO2 in inactivating PAE. The experimental results indicated that particle concentration was a principal factor influencing the PAE inactivation efficiency, presenting a negative correlation, while exposure time and ClO2 dosage revealed a positive correlation. The inactivation kinetics of PAE using ClO2 was also investigated and the results demonstrated that PAE inactivation with ClO2 fitted the Chick–Watson kinetic model. The inactivation rate constants of PAE were found to follow the Arrhenius expression with an activation energy of 107.5 kJ/mol, indicating a relatively strong temperature dependence. However, there are minor effects of pH and initial ClO2 dosage on PAE inactivation rate constant.

scholarly journals Inactivation of Nitrosomonas europaea and pathogenic Escherichia coli by chlorine and monochloramine

2008 ◽  
Vol 6 (3) ◽  
pp. 315-322 ◽  
Author(s):  
Christian Chauret ◽  
Curtis Smith ◽  
Hélène Baribeau
Keyword(s):  
Escherichia Coli ◽  
Distribution System ◽  
Distribution Systems ◽  
Pure Water ◽  
Nitrosomonas Europaea ◽  
Inactivation Kinetics ◽  
Soil Material ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
Kinetics Of

The purpose of this study was to measure the chlorine and monochloramine inactivation kinetics of Nitrosomonas europaea at 21°C in the presence and absence of particles. The inactivation kinetics rates were compared with those obtained with Escherichia coli O157:H7. The results show that, in pure water, the use of free chlorine produced 4 log10 of N. europaea inactivation at a CT value of 0.8 mg.min l−1, whereas monochloramine yielded 4 log10 of inactivation at CT values of approximately 9.9–16.4 mg.min l−1. With E. coli, chlorine produced approximately 4 log10 of inactivation at a CT of 0.13 mg.min l−1, whereas monochloramine resulted in 4 log10 of inactivation at a CT of approximately 9.2 mg.min l−1. These results suggest that N. europaea is more resistant to monochloramine and chlorine than E. coli. Corrosion debris, soil material and wastewater had no statistically significant (p < 0.05) impact on the inactivation of N. europaea by either chlorine or monochloramine. It seems likely that the CT values present in distribution systems would be sufficient to control suspended cells of these two organisms, especially under conditions of breakpoint chlorination, which could be used to control nitrification. Adequate disinfection should prevent the growth of these organisms in a distribution system.

Антимікробна резистентність провідних збудників інфекцій сечових шляхів у Києві (Україна)

2017 ◽  
Vol 1 (2) ◽  
pp. 48-60
Author(s):  
A.G. Salmanov ◽  
A.V. Rudenko
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
Staphylococcus Epidermidis ◽  
Klebsiella Oxytoca ◽  
Enterobacter Aerogenes ◽  
Enterobacter Cloacae ◽  
Proteus Vulgaris ◽  
Providencia Rettgeri ◽  
E Coli

Мета роботи — вивчити резистентність до антибіотиків бактеріальних збудників інфекцій сечових шляхів (ІСШ), виділених у пацієнтів урологічного стаціонару в м. Києві. Матеріали і методи. Досліджено 1612 штамів бактерій, виділених із сечі хворих з ІСШ (цистит, уретрит, пієлонефрит), госпіталізованих в урологічне відділення ДУ «Інститут урології НАМН України» у м. Києві протягом 2016 р. Серед пацієнтів переважали жінки — 1201 (74,5 %). Вік хворих становив від 17 до 74 років. Для збору даних використано медичну документацію лікарні. Мікробіологічні дослідження виконано у лабораторії мікробіології ДУ «Інститут урології НАМН України». Аналізували результати культурального дослідження зразків сечі, зібраних за наявності клінічних ознак ІСШ. Дослідження клінічного матеріалу та інтерпретацію отриманих результатів проводили загальноприйнятими методами. Вивчено чутливість уропатогенів до 31 антибіотика дискодифузійним методом відповідно до рекомендацій Інституту клінічних та лабораторних стандартів США (Clinical and Laboratory Standards Institute (CLSI)). Результати та обговорення. Аналіз мікробного спектра сечі виявив домінування серед уропатогенів штамів Escherichia coli (32,0 %), Enterococcus faecalis (19,5 %), Klebsiella pneumoniae (10,9 %), Staphylococcus epidermidis (8,9 %), S. haemolyticus (6,5 %) та Pseudomonas aeruginosa (6,4 %). Частка Enterococcus faecium, Enterobacter aerogenes і Streptococcus viridans становила відповідно 2,5, 2,2 і 1,6 %, Enterobacter cloacae, Klebsiella oxytoca, Acinetobacter baumannii, Proteus vulgaris та Providencia rettgeri — менше 1,0 %. У більшості випадків (69,7 %) мікроорганізми виділено у монокультурі, у решті випадків — у мікробних асоціа- ціях. Високу резистентність до тестованих антибіотиків виявили штами E. aerogenes (45,1 %), E. cloacae (45,7 %), E. faecium (40,9 %), E. faecalis (40,7 %), E. coli (39,9 %), P. aeruginosa (34,0 %), K. pneumoniae (28,6 %). Найбільш активними до уропатогенів були іміпенем (E. coli — 87,6 %, P. aeruginosa — 75,7 %, E. cloacae — 67,3 %, E. aerogenes — 72,6 %, K. pneumoniae — 93,2 %), меропенем (E. coli — 89,1 %, P. aeruginosa — 76,7 %, K. pneumoniae — 82,6 %), лефлоцин (E. coli — 74,5 %, ентерококи — 78,7 %, P. aeruginosa — 76,7 %, E. cloacae — 73,9 %, E. aerogenes — 80,4 %, K. pneumoniae — 83,5 %), амоксицилін/клавуланат (ентерококи — 84,6 %), фурагін (ентерококи — 82,6 %), цефоперазон (K. pneumoniae — 89,2 %, P. aeruginosa — 73,8 %), цефтріаксон (K. pneumoniae — 80,1 %). Висновки. Антибіотикорезистентність збудників ІСШ — важлива терапевтична проблема. Найбільшою активністю до уропатогенів характеризуються іміпенем, меропенем, лефлоцин, амоксицилін/ клавуланат, фурагін, цефоперазон, цефтріаксон, які можна розглядати як препарат вибору для призначення стартової терапії ІСШ. Необхідно здійснювати постійний моніторинг за резистентністю до дії антибіотиків. Політику використання антибіотиків у кожному стаціонарі слід визначати залежно від локальних даних щодо резистентності до протимікробних препаратів.

scholarly journals High-density transposon libraries utilising outward-oriented promoters identify mechanisms of action and resistance to antimicrobials

2020 ◽  
Vol 367 (22) ◽  
Author(s):  
Chris Coward ◽  
Gopujara Dharmalingham ◽  
Omar Abdulle ◽  
Tim Avis ◽  
Stephan Beisken ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Pathogenic Bacteria ◽  
Selective Advantage ◽  
Mechanisms Of Action ◽  
Over Expression ◽  
E Coli ◽  
Synthase Inhibitor ◽  
Established Technique ◽  
Bacterial Transposon

ABSTRACT The use of bacterial transposon mutant libraries in phenotypic screens is a well-established technique for determining which genes are essential or advantageous for growth in conditions of interest. Standard, inactivating, transposon libraries cannot give direct information about genes whose over-expression gives a selective advantage. We report the development of a system wherein outward-oriented promoters are included in mini-transposons, generation of transposon mutant libraries in Escherichia coli and Pseudomonas aeruginosa and their use to probe genes important for growth under selection with the antimicrobial fosfomycin, and a recently-developed leucyl-tRNA synthase inhibitor. In addition to the identification of known mechanisms of action and resistance, we identify the carbon–phosphorous lyase complex as a potential resistance liability for fosfomycin in E. coli and P. aeruginosa. The use of this technology can facilitate the development of novel mechanism-of-action antimicrobials that are urgently required to combat the increasing threat worldwide from antimicrobial-resistant pathogenic bacteria.

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