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 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.

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.

Escherichia coli O157:H7 Cells Exposed to Lettuce Leaf Lysate in Refrigerated Conditions Exhibit Differential Expression of Selected Virulence and Adhesion-Related Genes with Altered Mammalian Cell Adherence

2016 ◽  
Vol 79 (7) ◽  
pp. 1259-1265 ◽  
Author(s):  
NICOLE M. KENNEDY ◽  
NABANITA MUKHERJEE ◽  
PRATIK BANERJEE
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Mammalian Cells ◽  
Pathogenic Bacteria ◽  
Cold Shock ◽  
Cold Shock Protein ◽  
Toxin Gene ◽  
Adhesion Assay ◽  
Escherichia Coli O157 ◽  
The Impact

ABSTRACT Contamination by and persistence of pathogenic bacteria in ready-to-eat produce have emerged as significant food safety and public health concerns. Viable produceborne pathogens cope with several stresses (e.g., temperature fluctuations and low-temperature storage) during production and storage of the commodities. In this study, we investigated the impact of transient cold shock on Escherichia coli O157:H7 (EcO157) cells in a produce matrix (romaine lettuce leaf lysate). EcO157 cells were exposed to 25°C for 1 h, 4°C for 1 h, and 4°C for 10 min in lettuce lysate. The expression of selected genes coding for virulence, stress response, and heat and cold shock proteins was quantified by real-time quantitative reverse transcription PCR assay. Treated EcO157 cells adhered to MAC-T mammalian cells were enumerated by in vitro bioassay. Expression of the Shiga toxin 1 gene (stx1a) was upregulated significantly (P < 0.05) upon cold shock treatments, but virulence genes related to EcO157 attachment (eaeA, lpfA, and hcpA) were down-regulated. Two key members of the cold shock regulon, cold shock protein (cspA) and gyrA, were significantly induced (P < 0.05) at the refrigeration temperature (4°C). Significant upregulation of an SOS response gene, recA, was also observed. E. coli heat shock regulon member grpE was induced, but a universal stress protein (uspA) was down-regulated at the refrigeration temperatures in lettuce lysate. The adhesion assay revealed a temperature-dependent reduction in the attachment of cold-shocked EcO157 cells. The results of the current study indicate a reduction in the attachment of cold-shocked EcO157 to epithelial cells and higher levels of Shiga toxin gene expression at the molecular level.

Colonization resistance against potentially pathogenic bacteria in hexaflora-associated gnotobiotic mice

1978 ◽  
Vol 24 (2) ◽  
pp. 79-83 ◽  
Author(s):  
Kunwar K. Srivastava
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Pathogenic Bacteria ◽  
Enterobacter Aerogenes ◽  
Lactobacillus Brevis ◽  
Colonization Resistance ◽  
Post Challenge ◽  
E Coli ◽  
Gnotobiotic Mice ◽  
Akr Mice

A study of colonization resistance against potentially pathogenic bacteria (Escherichia coli and Pseudomonas aeruginosa) was conducted in hexaflora-associated gnotobiotic mice. Groups of germfree AKR mice were swabbed with five bacterial and a single gastrointestinal yeast species: Streptococcus faecalis, Lactobacillus brevis, Staphylococcus epidermidis, Enterobacter aerogenes, Bacteroides fragilis var. vulgatus, and Torulopsis sp. All species became established in the gut in 8 weeks. Later these associated mice were divided and challenged by four graded doses of E. coli or P. aeruginosa. The presence of challenge organism was monitored specifically in the freshly voided fecal specimens of the challenged mice. Escherichia coli colonized the gut of each mouse at each level up to 60 days post challenge. Pseudomonas aeruginosa was completely eliminated from each mouse at each dose level after 30 days post challenge. Evidence suggests that all six species were sufficient to prevent the colonization of P. aeruginosa and not of E. coli in the gut of the gnotobiotic mice.

Microbiological and Sensory Tests of Beef Treated with Acetic and Formic Acids1,2

1986 ◽  
Vol 49 (3) ◽  
pp. 207-210 ◽  
Author(s):  
M. F. BELL ◽  
R. T. MARSHALL ◽  
M. E. ANDERSON
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Acetic Acid ◽  
Formic Acid ◽  
Distilled Water ◽  
E Coli ◽  
Viable Cells ◽  
Adductor Muscles ◽  
Rate Of Increase ◽  
Sensory Tests

One-centimeter cubes of the semimembranosus and adductor muscles of beef were inoculated with 5.2 × 106 of Salmonella typhimurium, Shigella sonnei, Yersinia enterocolitica, Escherichia coli, Pseudomonas aeruginosa or Streptococcus faecalis. Exposure of the meat by dipping in 1.2% acetic acid for 10 s reduced averge numbers recoverable of these bacteria by 65%. E. coli was the most resistant, losing 46% of its viable cells. One-half of the acetic acid was replaced with 0.046% formic acid without loss in effectiveness. The rate of increase in antimicrobial effects of the treatment declined with time. Discoloration of the meat occurred after dipping in both 1.2% acetic acid, and 0.6% acetic plus 0.046% formic acids for 10 s. In triangle tests of flavor, panelists failed to differentiate samples of baked ground beef treated (before grinding) with 0.6% acetic acid and 0.046% formic acid from controls dipped in water (P<0.05). However, the same type of test showed a significant flavor difference between meat dipped in 1.2% acetic acid or distilled water.

scholarly journals Model System To Evaluate the Effect of ampD Mutations on AmpC-Mediated β-Lactam Resistance

2006 ◽  
Vol 50 (6) ◽  
pp. 2030-2037 ◽  
Author(s):  
Amber J. Schmidtke ◽  
Nancy D. Hanson
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Structural Gene ◽  
Model System ◽  
Alternative Mechanism ◽  
Citrobacter Freundii ◽  
E Coli ◽  
K 12 ◽  
Carboxy Terminal ◽  
The Impact

ABSTRACT Mutations within the structural gene of ampD can lead to AmpC overproduction and increases in β-lactam MICs in organisms with an inducible ampC. However, identification of mutations alone cannot predict the impact that those mutations have on AmpD function. Therefore, a model system was designed to determine the effect of ampD mutations on ceftazidime MICs using an AmpD− mutant Escherichia coli strain which produced an inducible plasmid-encoded AmpC. ampD genes were amplified by PCR from strains of E. coli, Citrobacter freundii, and Pseudomonas aeruginosa. Also, carboxy-terminal truncations of C. freundii ampD genes were constructed representing deletions of 10, 21, or 25 codons. Amplified ampD products were cloned into pACYC184 containing inducible bla ACT-1-ampR. Plasmids were transformed into E. coli strains JRG582 (AmpD−) and K-12 259 (AmpD+). The strains were evaluated for a derepressed phenotype using ceftazidime MICs. Some mutated ampD genes, including the ampD gene of a derepressed C. freundii isolate, resulted in substantial decreases in ceftazidime MICs (from >256 μg/ml to 12 to 24 μg/ml) for the AmpD− strain, indicating no role for these mutations in derepressed phenotypes. However, ampD truncation products and ampD from a partially derepressed P. aeruginosa strain resulted in ceftazidime MICs of >256 μg/ml, indicating a role for these gene modifications in derepressed phenotypes. The use of this model system indicated that alternative mechanisms were involved in the derepressed phenotype observed in strains of C. freundii and P. aeruginosa. The alternative mechanism involved in the derepressed phenotype of the C. freundii isolate was downregulation of ampD transcription.

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 Targeting of Pseudomonas aeruginosa cell surface via GP12, an Escherichia coli specific bacteriophage protein

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
George M. Ongwae ◽  
Mahendra D. Chordia ◽  
Jennie L. Cawley ◽  
Brianna E. Dalesandro ◽  
Nathan J. Wittenberg ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Cell Surface ◽  
Pathogenic Bacteria ◽  
Inner Core ◽  
Tail Fiber ◽  
Bacterial Cells ◽  
Core Oligosaccharide ◽  
Gram Negative ◽  
E Coli

AbstractBacteriophages are highly abundant molecular machines that have evolved proteins to target the surface of host bacterial cells. Given the ubiquity of lipopolysaccharides (LPS) on the outer membrane of Gram-negative bacteria, we reasoned that targeting proteins from bacteriophages could be leveraged to target the surface of Gram-negative pathogens for biotechnological applications. To this end, a short tail fiber (GP12) from the T4 bacteriophage, which infects Escherichia coli (E. coli), was isolated and tested for the ability to adhere to whole bacterial cells. We found that, surprisingly, GP12 effectively bound the surface of Pseudomonas aeruginosa cells despite the established preferred host of T4 for E. coli. In efforts to elucidate why this binding pattern was observed, it was determined that the absence of the O-antigen region of LPS on E. coli improved cell surface tagging. This indicated that O-antigens play a significant role in controlling cell adhesion by T4. Probing GP12 and LPS interactions further using deletions of the enzymes involved in the biosynthetic pathway of LPS revealed the inner core oligosaccharide as a possible main target of GP12. Finally, we demonstrated the potential utility of GP12 for biomedical applications by showing that GP12-modified agarose beads resulted in the depletion of pathogenic bacteria from solution.

scholarly journals Antimicrobial Effects of Mustard Flour and Acetic Acid against Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica Serovar Typhimurium

2003 ◽  
Vol 69 (5) ◽  
pp. 2959-2963 ◽  
Author(s):  
Min-Suk Rhee ◽  
Sun-Young Lee ◽  
Richard H. Dougherty ◽  
Dong-Hyun Kang
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Listeria Monocytogenes ◽  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Bacterial Resistance ◽  
Fixed Amount ◽  
E Coli ◽  
Food Borne ◽  
Serovar Typhimurium

ABSTRACT This study was designed to investigate the individual and combined effects of mustard flour and acetic acid in the inactivation of food-borne pathogenic bacteria stored at 5 and 22°C. Samples were prepared to achieve various concentrations by the addition of acetic acid (0, 0.5, or 1%) along with mustard flour (0, 10, or 20%) and 2% sodium chloride (fixed amount). Acid-adapted three-strain mixtures of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica serovar Typhimurium strains (106 to 107 CFU/ml) were inoculated separately into prepared mustard samples stored at 5 and 22°C, and samples were assayed periodically. The order of bacterial resistance, assessed by the time required for the nominated populations to be reduced to undetectable levels against prepared mustards at 5°C, was S. enterica serovar Typhimurium (1 day) < E. coli O157:H7 (3 days) < L. monocytogenes (9 days). The food-borne pathogens tested were reduced much more rapidly at 22°C than at 5°C. There was no synergistic effect with regard to the killing of the pathogens tested with the addition of 0.5% acetic acid to the mustard flour (10 or 20%). Mustard in combination with 0.5% acetic acid had less bactericidal activity against the pathogens tested than did mustard alone. The reduction of E. coli O157:H7 and L. monocytogenes among the combined treatments on the same storage day was generally differentiated as follows: control < mustard in combination with 0.5% acetic acid < mustard alone < mustard in combination with 1% acetic acid < acetic acid alone. Our study indicates that acidic products may limit microbial growth or survival and that the addition of small amounts of acetic acid (0.5%) to mustard can retard the reduction of E. coli O157:H7 and L. monocytogenes. These antagonistic effects may be changed if mustard is used alone or in combination with >1% acetic acid.

scholarly journals Biological and Physicochemical Wastewater Treatment Processes Reduce the Prevalence of Virulent Escherichia coli

2012 ◽  
Vol 79 (3) ◽  
pp. 835-844 ◽  
Author(s):  
Dominic Frigon ◽  
Basanta Kumar Biswal ◽  
Alberto Mazza ◽  
Luke Masson ◽  
Ronald Gehr
Keyword(s):  
Escherichia Coli ◽  
Wastewater Treatment ◽  
Pathogenic Bacteria ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Freshwater Environment ◽  
Content Type ◽  
E Coli ◽  
Treatment Processes ◽  
The Impact

ABSTRACTEffluents discharged from wastewater treatment plants are possible sources of pathogenic bacteria, includingEscherichia coli, in the freshwater environment, and determining the possible selection of pathogens is important. This study evaluated the impact of activated sludge and physicochemical wastewater treatment processes on the prevalence of potentially virulentE. coli. A total of 719E. coliisolates collected from four municipal plants in Québec before and after treatment were characterized by using a customized DNA microarray to determine the impact of treatment processes on the frequency of specific pathotypes and virulence genes. The percentages of potentially pathogenicE. coliisolates in the plant influents varied between 26 and 51%, and in the effluents, the percentages were 14 to 31%, for a reduction observed at all plants ranging between 14 and 45%. Pathotypes associated with extraintestinal pathogenicE. coli(ExPEC) were the most abundant at three of the four plants and represented 24% of all isolates, while intestinal pathogenicE. colipathotypes (IPEC) represented 10% of the isolates. At the plant where ExPEC isolates were not the most abundant, a large number of isolates were classified as both ExPEC and IPEC; overall, 6% of the isolates were classified in both groups, with the majority being from the same plant. The reduction of the proportion of pathogenicE. colicould not be explained by the preferential loss of one virulence gene or one type of virulence factor; however, the quinolone resistance gene (qnrS) appears to enhance the loss of virulence genes, suggesting a mechanism involving the loss of pathogenicity islands.

Sign in / Sign up

Export Citation Format

Share Document