What an Escherichia coli Mutant Can Teach Us About the Antibacterial Effect of Chlorophyllin

Due to the increasing development of antibiotic resistances in recent years, scientists search intensely for new methods to control bacteria. Photodynamic treatment with porphyrins such as chlorophyll derivatives is one of the most promising methods to handle bacterial infestation, but their use is dependent on illumination and they seem to be more effective against Gram-positive bacteria than against Gram-negatives. In this study, we tested chlorophyllin against three bacterial model strains, the Gram-positive Bacillus subtilis 168, the Gram-negative Escherichia coli DH5α and E. coli strain NR698 which has a deficient outer membrane, simulating a Gram-negative “without” its outer membrane. Illuminated with a standardized light intensity of 12 mW/cm2, B. subtilis showed high sensitivity already at low chlorophyllin concentrations (≤105 cfu/mL: ≤0.1 mg/L, 106–108 cfu/mL: 0.5 mg/L), whereas E. coli DH5α was less sensitive (≤105 cfu/mL: 2.5 mg/L, 106 cfu/mL: 5 mg/L, 107–108 cfu/mL: ineffective at ≤25 mg/L chlorophyllin). E. coli NR698 was almost as sensitive as B. subtilis against chlorophyllin, pointing out that the outer membrane plays a significant role in protection against photodynamic chlorophyllin impacts. Interestingly, E. coli NR698 and B. subtilis can also be inactivated by chlorophyllin in darkness, indicating a second, light-independent mode of action. Thus, chlorophyllin seems to be more than a photosensitizer, and a promising substance for the control of bacteria, which deserves further investigation.

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Synthesis of Chalcones and Nucleosides Incorporating [1, 3, 4]Oxadiazolenone Core and Evaluation of their Antifungal and Antibacterial Activities

Current Bioactive Compounds ◽

10.2174/1573407214666180911130110 ◽

2020 ◽

Vol 15 (6) ◽

pp. 665-679

Author(s):

Alok K. Srivastava ◽

Lokesh K. Pandey

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Antibacterial Activity ◽

Bacillus Subtilis ◽

Antifungal Activity ◽

Aspergillus Niger ◽

Gram Negative ◽

E Coli ◽

Gram Positive Bacteria ◽

Good Antibacterial Activity

Background: [1, 3, 4]oxadiazolenone core containing chalcones and nucleosides were synthesized by Claisen-Schmidt condensation of a variety of benzaldehyde derivatives, obtained from oxidation of substituted 5-(3/6 substituted-4-Methylphenyl)-1, 3, 4-oxadiazole-2(3H)-one and various substituted acetophenone. The resultant chalcones were coupled with penta-O-acetylglucopyranose followed by deacetylation to get [1, 3, 4] oxadiazolenone core containing chalcones and nucleosides. Various analytical techniques viz IR, NMR, LC-MS and elemental analysis were used to confirm the structure of the synthesised compounds.The compounds were targeted against Bacillus subtilis, Staphylococcus aureus and Escherichia coli for antibacterial activity and Aspergillus flavus, Aspergillus niger and Fusarium oxysporum for antifungal activity. Methods: A mixture of Acid hydrazides (3.0 mmol) and N, Nʹ- carbonyl diimidazole (3.3 mmol) in 15 mL of dioxane was refluxed to afford substituted [1, 3, 4]-oxadiazole-2(3H)-one. The resulted [1, 3, 4]- oxadiazole-2(3H)-one (1.42 mmol) was oxidized with Chromyl chloride (1.5 mL) in 20 mL of carbon tetra chloride and condensed with acetophenones (1.42 mmol) to get chalcones 4. The equimolar ratio of obtained chalcones 4 and β -D-1,2,3,4,6- penta-O-acetylglucopyranose in presence of iodine was refluxed to get nucleosides 5. The [1, 3, 4] oxadiazolenone core containing chalcones 4 and nucleosides 5 were tested to determined minimum inhibitory concentration (MIC) value with the experimental procedure of Benson using disc-diffusion method. All compounds were tested at concentration of 5 mg/mL, 2.5 mg/mL, 1.25 mg/mL, 0.62 mg/mL, 0.31 mg/mL and 0.15 mg/mL for antifungal activity against three strains of pathogenic fungi Aspergillus flavus (A. flavus), Aspergillus niger (A. niger) and Fusarium oxysporum (F. oxysporum) and for antibacterial activity against Gram-negative bacterium: Escherichia coli (E. coli), and two Gram-positive bacteria: Staphylococcus aureus (S. aureus) and Bacillus subtilis(B. subtilis). Result: The chalcones 4 and nucleosides 5 were screened for antibacterial activity against E. coli, S. aureus and B. subtilis whereas antifungal activity against A. flavus, A. niger and F. oxysporum. Compounds 4a-t showed good antibacterial activity whereas compounds 5a-t containing glucose moiety showed better activity against fungi. The glucose moiety of compounds 5 helps to enter into the cell wall of fungi and control the cell growth. Conclusion: Chalcones 4 and nucleosides 5 incorporating [1, 3, 4] oxadiazolenone core were synthesized and characterized by various spectral techniques and elemental analysis. These compounds were evaluated for their antifungal activity against three fungi; viz. A. flavus, A. niger and F. oxysporum. In addition to this, synthesized compounds were evaluated for their antibacterial activity against gram negative bacteria E. Coli and gram positive bacteria S. aureus, B. subtilis. Compounds 4a-t showed good antibacterial activity whereas 5a-t showed better activity against fungi.

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Pyelonephritis in Pediatric Uropathic Patients: Differences from Community-Acquired Ones and Therapeutic Protocol Considerations. A 10-Year Single-Center Retrospective Study

Children ◽

10.3390/children8060436 ◽

2021 ◽

Vol 8 (6) ◽

pp. 436

Author(s):

Giovanni Parente ◽

Tommaso Gargano ◽

Stefania Pavia ◽

Chiara Cordola ◽

Marzia Vastano ◽

...

Keyword(s):

Escherichia Coli ◽

Retrospective Study ◽

Success Rate ◽

Pediatric Population ◽

Gram Negative Bacteria ◽

Gram Positive ◽

Gram Negative ◽

Gram Positive Bacteria ◽

Significant Difference ◽

Klebsiella Spp

Pyelonephritis (PN) represents an important cause of morbidity in the pediatric population, especially in uropathic patients. The aim of the study is to demonstrate differences between PNs of uropathic patients and PNs acquired in community in terms of uropathogens involved and antibiotic sensitivity; moreover, to identify a proper empiric therapeutic strategy. A retrospective study was conducted on antibiograms on urine cultures from PNs in vesicoureteral reflux (VUR) patients admitted to pediatric surgery department and from PNs in not VUR patients admitted to Pediatric Emergency Unit between 2010 and 2020. We recorded 58 PNs in 33 patients affected by VUR and 112 PNs in the not VUR group. The mean age of not VUR patients at the PN episode was 1.3 ± 2.6 years (range: 20 days of life–3 years), and almost all the urine cultures, 111 (99.1%), isolated Gram-negative bacteria and rarely, 1 (0.9%), Gram-positive bacteria. The Gram-negative uropathogens isolated were Escherichia coli (97%), Proteus mirabilis (2%), and Klebsiella spp. (1%). The only Gram-positive bacteria isolated was an Enterococcus faecalis. As regards the antibiograms, 96% of not VUR PNs responded to beta-lactams, 99% to aminoglycosides, and 80% to sulfonamides. For the VUR group, mean age was 3.0 years ± 3.0 years (range: 9 days of life–11 years) and mean number of episodes per patient was 2.0 ± 1.0 (range: 1–5); 83% of PNs were by Gram-negatives bacteria vs. 17% by Gram-positive: the most important Gram-negative bacteria were Pseudomonas aeruginosa (44%), Escherichia coli (27%), and Klebsiella spp. (12%), while Enterococcus spp. determined 90% of Gram-positive UTIs. Regimen ampicillin/ceftazidime (success rate: 72.0%) was compared to ampicillin/amikacin (success rate of 83.0%): no statistically significant difference was found (p = 0.09). The pathogens of PNs in uropathic patients are different from those of community-acquired PNs, and clinicians should be aware of their peculiar antibiotic susceptibility. An empiric therapy based on the association ampicillin + ceftazidime is therefore suggested.

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Construction of Leaderless-Bacteriocin-Producing Bacteriophage Targeting E. coli and Neighboring Gram-Positive Pathogens

Microbiology Spectrum ◽

10.1128/spectrum.00141-21 ◽

2021 ◽

Author(s):

Yoshimitsu Masuda ◽

Shun Kawabata ◽

Tatsuya Uedoi ◽

Ken-ichi Honjoh ◽

Takahisa Miyamoto

Keyword(s):

Antimicrobial Agents ◽

Host Strain ◽

Phage Resistance ◽

Gram Positive ◽

Gram Negative ◽

E Coli ◽

Gram Positive Bacteria ◽

T7 Phage

We demonstrated that we could combine LLB and phage to construct promising novel antimicrobial agents, LLB-phage. The first LLB-phage, lnqQ -T7 phage, can control the growth of both the Gram-negative host strain and neighboring Gram-positive bacteria while preventing the emergence of phage resistance in the host strain.

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A Peptidomimetic Antibiotic Targets Outer Membrane Proteins and Disrupts Selectively the Outer Membrane in Escherichia coli

Journal of Biological Chemistry ◽

10.1074/jbc.m115.691725 ◽

2015 ◽

Vol 291 (4) ◽

pp. 1921-1932 ◽

Cited By ~ 47

Author(s):

Matthias Urfer ◽

Jasmina Bogdanovic ◽

Fabio Lo Monte ◽

Kerstin Moehle ◽

Katja Zerbe ◽

...

Keyword(s):

Escherichia Coli ◽

Outer Membrane ◽

Outer Membrane Proteins ◽

Permeability Barrier ◽

Gram Negative ◽

Fluorescence Studies ◽

E Coli ◽

Interaction Sites ◽

External Stresses ◽

Antibiotic Discovery

Increasing antibacterial resistance presents a major challenge in antibiotic discovery. One attractive target in Gram-negative bacteria is the unique asymmetric outer membrane (OM), which acts as a permeability barrier that protects the cell from external stresses, such as the presence of antibiotics. We describe a novel β-hairpin macrocyclic peptide JB-95 with potent antimicrobial activity against Escherichia coli. This peptide exhibits no cellular lytic activity, but electron microscopy and fluorescence studies reveal an ability to selectively disrupt the OM but not the inner membrane of E. coli. The selective targeting of the OM probably occurs through interactions of JB-95 with selected β-barrel OM proteins, including BamA and LptD as shown by photolabeling experiments. Membrane proteomic studies reveal rapid depletion of many β-barrel OM proteins from JB-95-treated E. coli, consistent with induction of a membrane stress response and/or direct inhibition of the Bam folding machine. The results suggest that lethal disruption of the OM by JB-95 occurs through a novel mechanism of action at key interaction sites within clusters of β-barrel proteins in the OM. These findings open new avenues for developing antibiotics that specifically target β-barrel proteins and the integrity of the Gram-negative OM.

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Water-dispersible glycosylated poly(2,5′-thienylene)porphyrin-based nanoparticles for antibacterial photodynamic therapy

Photochemical & Photobiological Sciences ◽

10.1039/c8pp00470f ◽

2019 ◽

Vol 18 (5) ◽

pp. 1147-1155 ◽

Cited By ~ 5

Author(s):

Rehan Khan ◽

Melis Özkan ◽

Aisan Khaligh ◽

Dönüs Tuncel

Keyword(s):

Antibacterial Activity ◽

Photodynamic Therapy ◽

Singlet Oxygen ◽

Gram Negative Bacteria ◽

Gram Positive ◽

Gram Negative ◽

E Coli ◽

Water Dispersible ◽

Gram Positive Bacteria ◽

High Yields

Water-dispersible glycosylated poly(2,5′-thienylene)porphyrin-based nanoparticles have the ability to generate singlet oxygen in high yields and exhibit light-triggered antibacterial activity against Gram negative bacteria, E. coli as well as Gram positive bacteria, B. subtilis.

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Inactivation of Escherichia coli and Staphyloccocus aureus in Litchi Juice by Dimethyl Dicarbonate (DMDC) Combined With Nisin

Journal of Food Research ◽

10.5539/jfr.v3n3p1 ◽

2014 ◽

Vol 3 (3) ◽

pp. 1 ◽

Cited By ~ 4

Author(s):

Yuanshan Yu ◽

Yujuan Xu ◽

Jijun Wu ◽

Gengsheng Xiao ◽

Jing Wen ◽

...

Keyword(s):

Escherichia Coli ◽

Synergistic Effect ◽

Ph Value ◽

Inactivation Rate ◽

Gram Positive ◽

Gram Negative ◽

E Coli ◽

Complete Inactivation ◽

Staphyloccocus Aureus ◽

Addition Level

Inactivation of Gram-negative Escherichia coli and Gram-positive Staphyloccocus aureus in litchi juice by DMDC combined with nisin was individually investigated. A 1.66 log cycles reduction of E. coli and 2.03 log cycles reduction of S. aureus in litchi juice (pH 4.5) added without nisin was achieved as exposed to 150 mg/l DMDC at 30 °C for 1 h, and the inactivation rate of E. coli and S. aureus during initial 1 h was far greater than during the remaining 5 h. As exposed to 150 mg/l DMDC at 30 °C for 1 h, the inactivation of E. coli and S. aureus in the litchi juice showed a trend toward increase with increasing of nisin addition level in the range from 0 to 200 IU/ml. Moreover, DMDC and nisin exhibited a synergistic effect on the inactivation of E. coli and S. aureus in litchi juice, and the inactivation of E. coli and S. aureus in the litchi juice also depends on the temperature of litchi juice, pH value of litchi juice and DMDC concentration when treated with DMDC and nisin. In addition, E. coli showed higher resistance to nisin as comparing with S. aureus. After E. coli and S. aureus in the litchi juice of pH 4.0 were individually treated with 150 mg/l DMDC combined with 200 IU/ml nisin at 30 °C for 1 h, a complete inactivation of S. aureus (6.59 log cycles) was achieved, but only 3.52 log cycles reduction of E. coli was observed.

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Survival of some non-starter bacteria in naturally ripened and enzyme-accelerated Cheddar cheese

Journal of Dairy Research ◽

10.1017/s0022029900033380 ◽

1988 ◽

Vol 55 (4) ◽

pp. 597-602 ◽

Cited By ~ 5

Author(s):

Lydia Bautista ◽

Rohan G. Kroll

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Enterococcus Faecalis ◽

Enzyme System ◽

Cheddar Cheese ◽

Gram Negative Bacteria ◽

Gram Positive ◽

Gram Negative ◽

Ripening Period ◽

Gram Positive Bacteria

SummaryEffects of the addition of a proteinase (Neutrase 1–5S) and a peptidase (aminopeptidase DP-102) as agents for accelerating the ripening of Cheddar cheese on the survival of some non-starter bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coliand aSalmonellasp.) were studied throughout a 4-month ripening period. The enzymes were found to have no significant effect on the survival of the Gram-positive bacteria but some significant effects were observed, at some stages of the ripening period, with the Gram-negative bacteria in that lower levels were recovered from cheeses treated with the enzyme system.

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Synthesis and Antibacterial Activity of Chalcones and Pyrimidine-2-ones

E-Journal of Chemistry ◽

10.1155/2005/134830 ◽

2005 ◽

Vol 2 (2) ◽

pp. 109-112

Author(s):

A. K. Parekh ◽

K. K. Desai

Keyword(s):

Antibacterial Activity ◽

Spectral Data ◽

Elemental Analysis ◽

Aromatic Aldehydes ◽

Gram Negative Bacteria ◽

Gram Positive ◽

Gram Negative ◽

E Coli ◽

Gram Positive Bacteria ◽

H Nmr

Some new chalcones have been prepared by Claisen-schmidt condensation of ketone and different aromatic aldehydes. These chalcones on condensation with urea in presence of acid gave Pyrimidine-2-ones. The synthesized compounds have been characterized by elemental analysis, IR and1H NMR spectral data. They have been screened for their antibacterial activity against Gram positive bacteria B. subtillis & S. aureus and Gram negative bacteria E. coli & S. typhi.

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Different Modes of Action of Naphthyridones in Gram-Positive and Gram-Negative Bacteria

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.50.1.385-387.2006 ◽

2006 ◽

Vol 50 (1) ◽

pp. 385-387 ◽

Cited By ~ 16

Author(s):

Ed T. Buurman ◽

Kenneth D. Johnson ◽

Roxanne K. Kelly ◽

Kathy MacCormack

Keyword(s):

Escherichia Coli ◽

Haemophilus Influenzae ◽

Mode Of Action ◽

Bacterial Pathogens ◽

Gram Negative Bacteria ◽

Gram Positive ◽

Gram Negative ◽

Gram Positive Bacteria ◽

Modes Of Action

ABSTRACT Naphthyridones that were recently described as a class of translation inhibitors in gram-positive bacteria mediate their mode of action via GyrA in Haemophilus influenzae and Escherichia coli. These are the first examples of compounds in which modes of action in different bacterial pathogens are mediated through widely different targets.

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DefiningEscherichia colias a health-promoting microbe against intestinalPseudomonas aeruginosa

10.1101/612606 ◽

2019 ◽

Author(s):

Theodoulakis Christofi ◽

Stavria Panayidou ◽

Irini Dieronitou ◽

Christina Michael ◽

Yiorgos Apidianakis

Keyword(s):

Escherichia Coli ◽

Pseudomonas Aeruginosa ◽

Lactic Acid ◽

Wound Infections ◽

Human Gut ◽

Gram Positive ◽

E Coli ◽

Gram Positive Bacteria ◽

Intestinal Pathogens ◽

Health Promoting

AbstractGut microbiota acts as a barrier against intestinal pathogens, but species-specific protection of the host from infection remains relatively unexplored. Taking a Koch’s postulates approach in reverse to define health-promoting microbes we find thatEscherichia colinaturally colonizes the gut of healthy mice, but it is depleted from the gut of antibiotic-treated mice, which become susceptible to intestinal colonization byPseudomonas aeruginosaand concomitant mortality. Reintroduction of fecal bacteria andE. coliestablishes a high titer ofE. coliin the host intestine and increases defence againstP. aeruginosacolonization and mortality. Moreover, diet is relevant in this process because high sugars or dietary fat favoursE. colifermentation to lactic acid andP. aeruginosagrowth inhibition. To the contrary, low sugars allowP. aeruginosato produce the oxidative agent pyocyanin that inhibitsE. coligrowth. Our results provide an explanation as to whyP. aeruginosadoesn’t commonly infect the human gut, despite being a formidable microbe in lung and wound infections.Author SummaryHere we interrogate the conundrum as to whyPseudomonas aeruginosais not a clinical problem in the intestine as opposed to other tissues.P. aeruginosainteracts with Neisseria, Streptococcus, Staphylococcus and Actinomyces species found in the human lung. These are predominantly gram-positive bacteria that induceP. aeruginosavirulence. Moreover, peptidoglycan, which is abundant in gram-positive bacteria, can directly trigger the virulence ofP. aeriginosa. We reasoned thatP. aeruginosamight be benign in the human gut due to the inhibitory action of benign gram-negative intestinal bacteria, such asEscherichia coli. Therefore, we dissected the antagonism betweenE. coliandP. aeruginosaand the effect of a conventional, a fat-, a carbohydrate-and a protein-based diet in intestinal dysbiosis. Our findings support the notion that an unbalanced diet or antibiotics induces gut dysbiosis by the elimination of commensalE. coli, in addition to lactic acid bacteria, imposing a gut environment conducive toP. aeruginosainfection. Moreover, commensalE. coliprovides an explanation as to whyP. aeruginosadoesn’t commonly infect the human gut, despite being a formidable microbe in lung and wound infections.

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