scholarly journals The Biology of Colicin M and Its Orthologs

Antibiotics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1109
Author(s):  
Dimitri Chérier ◽  
Delphine Patin ◽  
Didier Blanot ◽  
Thierry Touzé ◽  
Hélène Barreteau
Keyword(s):  
Pathogenic Bacteria ◽  
Current Knowledge ◽  
Antibacterial Properties ◽  
Multidrug Resistant ◽  
Public Health Issue ◽  
Sequence Alignments ◽  
Food Preservatives ◽  
E Coli ◽  
Lipid Ii ◽  
Colicin M

The misuse of antibiotics during the last decades led to the emergence of multidrug resistant pathogenic bacteria. This phenomenon constitutes a major public health issue. Consequently, the discovery of new antibacterials in the short term is crucial. Colicins, due to their antibacterial properties, thus constitute good candidates. These toxin proteins, produced by E. coli to kill enteric relative competitors, exhibit cytotoxicity through ionophoric activity or essential macromolecule degradation. Among the 25 colicin types known to date, colicin M (ColM) is the only one colicin interfering with peptidoglycan biosynthesis. Accordingly, ColM develops its lethal activity in E. coli periplasm by hydrolyzing the last peptidoglycan precursor, lipid II, into two dead-end products, thereby leading to cell lysis. Since the discovery of its unusual mode of action, several ColM orthologs have also been identified based on sequence alignments; all of the characterized ColM-like proteins display the same enzymatic activity of lipid II degradation and narrow antibacterial spectra. This publication aims at being an exhaustive review of the current knowledge on this new family of antibacterial enzymes as well as on their potential use as food preservatives or therapeutic agents.

scholarly journals The Biology of Colicin M and Its Orthologs

2021 ◽  
Author(s):  
Dimitri Chérier ◽  
Delphine Patin ◽  
Didier Blanot ◽  
Thierry Touzé ◽  
Hélène Barreteau
Keyword(s):  
Pathogenic Bacteria ◽  
Antibacterial Properties ◽  
Multidrug Resistant ◽  
Public Health Issue ◽  
Sequence Alignments ◽  
Food Preservatives ◽  
E Coli ◽  
Peptidoglycan Biosynthesis ◽  
Lipid Ii ◽  
Colicin M

The misuse of antibiotics during the last decades led to the emergence of multidrug resistant pathogenic bacteria. This phenomenon constitutes a major public health issue. Consequently, the discovery of new antibacterials in the short term is crucial. Colicins, due to their antibacterial properties, thus constitute good candidates. These toxin proteins, produced by E. coli to kill enteric relative competitors, exhibit cytotoxicity through ionophoric activity or essential macromolecule degradation. Among the 25-colicin types known to date, colicin M (ColM) is the only one colicin interfering with peptidoglycan biosynthesis. Accordingly, ColM develops its lethal activity in E. coli periplasm by hydrolyzing the last peptidoglycan precursor, lipid II, into two dead-end products, thereby leading to cell lysis. Since the discovery of its unusual mode of action, several ColM orthologs have also been identified based on sequence alignments; all of the characterized ColM-like proteins display the same enzymatic activity of lipid II degradation and narrow antibacterial spectra. This publication aims at being an exhaustive review about what is currently known on this new family of antibacterial enzymes as well as on their potential use of food preservatives or therapeutic agents.

Mechanistic and structural diversity between cytochrome bd isoforms of Escherichia coli

2021 ◽  
Vol 118 (50) ◽  
pp. e2114013118
Author(s):  
Tamara N. Grund ◽  
Melanie Radloff ◽  
Di Wu ◽  
Hojjat G. Goojani ◽  
Luca F. Witte ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pathogenic Bacteria ◽  
Reduction Rate ◽  
Structural Diversity ◽  
Multidrug Resistant ◽  
E Coli ◽  
Structural And Functional Properties ◽  
Oxygen Reductase ◽  
General Architecture ◽  
Structural Insights

The treatment of infectious diseases caused by multidrug-resistant pathogens is a major clinical challenge of the 21st century. The membrane-embedded respiratory cytochrome bd-type oxygen reductase is a critical survival factor utilized by pathogenic bacteria during infection, proliferation and the transition from acute to chronic states. Escherichia coli encodes for two cytochrome bd isoforms that are both involved in respiration under oxygen limited conditions. Mechanistic and structural differences between cydABX (Ecbd-I) and appCBX (Ecbd-II) operon encoded cytochrome bd variants have remained elusive in the past. Here, we demonstrate that cytochrome bd-II catalyzes oxidation of benzoquinols while possessing additional specificity for naphthoquinones. Our data show that although menaquinol-1 (MK1) is not able to directly transfer electrons onto cytochrome bd-II from E. coli, it has a stimulatory effect on its oxygen reduction rate in the presence of ubiquinol-1. We further determined cryo-EM structures of cytochrome bd-II to high resolution of 2.1 Å. Our structural insights confirm that the general architecture and substrate accessible pathways are conserved between the two bd oxidase isoforms, but two notable differences are apparent upon inspection: (i) Ecbd-II does not contain a CydH-like subunit, thereby exposing heme b595 to the membrane environment and (ii) the AppB subunit harbors a structural demethylmenaquinone-8 molecule instead of ubiquinone-8 as found in CydB of Ecbd-I. Our work completes the structural landscape of terminal respiratory oxygen reductases of E. coli and suggests that structural and functional properties of the respective oxidases are linked to quinol-pool dependent metabolic adaptations in E. coli.

scholarly journals Broad and efficient control of major foodborne pathogenic strains ofEscherichia coliby mixtures of plant-produced colicins

2015 ◽  
Vol 112 (40) ◽  
pp. E5454-E5460 ◽  
Author(s):  
Steve Schulz ◽  
Anett Stephan ◽  
Simone Hahn ◽  
Luisa Bortesi ◽  
Franziska Jarczowski ◽  
...  
Keyword(s):  
United States ◽  
Pathogenic Bacteria ◽  
Thermal Inactivation ◽  
Bacterial Load ◽  
The United States ◽  
Broth Culture ◽  
Animal Products ◽  
E Coli ◽  
Colicin M ◽  
Very High

EnterohemorrhagicEscherichia coli(EHEC) is one of the leading causes of bacterial enteric infections worldwide, causing ∼100,000 illnesses, 3,000 hospitalizations, and 90 deaths annually in the United States alone. These illnesses have been linked to consumption of contaminated animal products and vegetables. Currently, other than thermal inactivation, there are no effective methods to eliminate pathogenic bacteria in food. Colicins are nonantibiotic antimicrobial proteins, produced byE. colistrains that kill or inhibit the growth of otherE. colistrains. Several colicins are highly effective against key EHEC strains. Here we demonstrate very high levels of colicin expression (up to 3 g/kg of fresh biomass) in tobacco and edible plants (spinach and leafy beets) at costs that will allow commercialization. Among the colicins examined, plant-expressed colicin M had the broadest antimicrobial activity against EHEC and complemented the potency of other colicins. A mixture of colicin M and colicin E7 showed very high activity against all major EHEC strains, as defined by the US Department of Agriculture/Food and Drug Administration. Treatments with low (less than 10 mg colicins per L) concentrations reduced the pathogenic bacterial load in broth culture by 2 to over 6 logs depending on the strain. In experiments using meats spiked withE. coliO157:H7, colicins efficiently reduced the population of the pathogen by at least 2 logs. Plant-produced colicins could be effectively used for the broad control of pathogenicE. coliin both plant- and animal-based food products and, in the United States, colicins could be approved using the generally recognized as safe (GRAS) regulatory approval pathway.

Characterization of Antibiotic Resistance in Escherichia coli Isolated from Shrimps and Their Environment

2014 ◽  
Vol 77 (8) ◽  
pp. 1394-1401 ◽  
Author(s):  
KANJANA CHANGKAEW ◽  
FUANGFA UTRARACHKIJ ◽  
KANOKRAT SIRIPANICHGON ◽  
CHIE NAKAJIMA ◽  
ORASA SUTHIENKUL ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pathogenic Bacteria ◽  
Multidrug Resistant ◽  
Drug Resistant ◽  
E Coli ◽  
Class 1 Integrons ◽  
Class 1 ◽  
Resistance Rates ◽  
Drug Resistant Strains ◽  
Shrimp Farms

Antimicrobial resistance in bacteria associated with food and water is a global concern. To survey the risk, 312 Escherichia coli isolates from shrimp farms and markets in Thailand were examined for susceptibility to 10 antimicrobials. The results showed that 17.6% of isolates (55 of 312) were resistant to at least one of the tested drugs, and high resistance rates were observed to tetracycline (14.4%; 45 of 312), ampicillin (8.0%; 25 of 312), and trimethroprim (6.7%; 21 of 312); 29.1% (16 of 55) were multidrug resistant. PCR assay of the tet(A), tet(B), tet(C), tet(D), tet(E), and tet(G) genes detected one or more of these genes in 47 of the 55 resistant isolates. Among these genes, tet(A) (69.1%; 38 of 55) was the most common followed by tet(B) (56.4%; 31 of 55) and tet(C) (3.6%; 2 of 55). The resistant isolates were further investigated for class 1 integrons. Of the 55 resistant isolates, 16 carried class 1 integrons and 7 carried gene cassettes encoding trimethoprim resistance (dfrA12 or dfrA17) and aminoglycosides resistance (aadA2 or aadA5). Two class 1 integrons, In54 (dfrA17-aadA5) and In27 (dfrA12-orfF-aadA2), were found in four and three isolates, respectively. These results indicate a risk of drug-resistant E. coli contamination in shrimp farms and selling places. The occurrence of multidrug-resistant E. coli carrying tet genes and class 1 integrons indicates an urgent need to monitor the emergence of drug-resistant E. coli to control the dissemination of drug-resistant strains and the further spread of resistance genes to other pathogenic bacteria.

scholarly journals An N-Halamine/Graphene Oxide-Functionalized Electrospun Polymer Membrane That Inactivates Bacteria on Contact and by Releasing Active Chlorine

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2784
Author(s):  
Shi Lan ◽  
Jinghua Zhang ◽  
Jie Li ◽  
Yanan Guo ◽  
Xianliang Sheng ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Antibacterial Properties ◽  
Polymer Membrane ◽  
Water Disinfection ◽  
Fibrous Membrane ◽  
Active Chlorine ◽  
Public Health Issue ◽  
Emerging Pathogens ◽  
Electrospinning Technique ◽  
E Coli

The emergence of antibiotic-resistant “superbugs” in recent decades has led to widespread illness and death and is a major ongoing public health issue. Since traditional antimicrobials and antibiotics are in many cases showing limited or no effectiveness in fighting some emerging pathogens, there is an urgent need to develop and explore novel antibacterial agents that are both powerful and reliable. Combining two or more antibiotics or antimicrobials has become a hot topic in antibacterial research. In this contribution, we report on using a simple electrospinning technique to create an N-halamine/graphene oxide-modified polymer membrane with excellent antibacterial activity. With the assistance of advanced techniques, the as-obtained membrane was characterized in terms of its chemical composition, morphology, size, and the presence of active chlorine. Its antibacterial properties were tested with Escherichia coli (E. coli) as the model bacteria, using the colony-counting method. Interestingly, the final N-halamine/graphene oxide-based antibacterial fibrous membrane inactivated E. coli both on contact and by releasing active chlorine. We believe that the synergistic antimicrobial action of our as-fabricated fibrous membrane should have great potential for utilization in water disinfection, air purification, medical and healthcare products, textile products, and other antibacterial-associated fields.

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 Bacterial Contamination of Healthcare worker’s Mobile Phones; a Case Study at Two Referral Hospitals in Uganda

2021 ◽  
Author(s):  
Tusabe Fred
Keyword(s):  
Mobile Phone ◽  
Mobile Phones ◽  
Healthcare Workers ◽  
Pathogenic Bacteria ◽  
Bacterial Contamination ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
E Coli ◽  
Referral Hospitals

Abstract Background Hospital and Community-acquired infections are escalating and pose significant public health unhealthiness worldwide. The advancements of telemedicine and automation of healthcare records are supported by cellphones, laptops and wearable devices. This study focused on the incidence of healthcare workers’ mobile phones becoming contaminated with pathogenic bacteria and their possible roles as vehicles of transmission of antimicrobial-resistant bacteria.Method: A case study at two referral hospitals in Uganda between May and October 2020. Self-administered questionnaires were administered to participants after informed consent. Mobile phones of the participants in different departments of the hospitals were swabbed and samples were collected and transported to the microbiology laboratory for bacterial culture and antimicrobial susceptibility tests. Results: The point prevalence of Healthcare workers’ mobile phone bacterial contamination with one or more species was 93%. Organisms isolated were E. coli 5.6% (1), Micrococcus spp 11.1% (2), Coagulase-negative staphylococci, CoNS, 61.1% (11) and Bacillus spp 22.2% (4). About 45% of the organisms were multidrug-resistant. Resistance was major to penicillin, cotrimoxazole, ciprofloxacin and Gentamycin respectively. The isolated E. coli was resistant to all antibiotics used in the study. Only 15% (2) of the participants disinfected their phones at least once a week and 8% cleaned their hands after using a mobile phone.Conclusion: Healthcare Workers’ mobile phones can act as fomites for the transmission of multidrug-resistant micro-organisms. This study provides strong evidence for developing and strengthening disinfection protocols for mobile phones and does not underscore the importance of hand hygiene in the middle of a patient encounter especially when the HCW grabs a phone but doesn't re-clean their hands before patient contact.

Multidrug resistant Salmonella spp. and Escherichia coli from a popular Ready-to-Eat local food (Fufu) from commercial food vendors in Ghana

2021 ◽  
Author(s):  
Courage Kosi Setsoafia Saba ◽  
Akosua Bonsu Karikar ◽  
Enoch Yeleliere ◽  
Patrick Takyi ◽  
Stephen Wilson Kpordze
Keyword(s):  
Foodborne Pathogens ◽  
Pathogenic Bacteria ◽  
Multidrug Resistant ◽  
Diffusion Method ◽  
Microbial Count ◽  
Salmonella Spp ◽  
Public Health Importance ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Susceptibility Profiles

Microbial contamination of vended foods are of public health importance due to the potential of becoming a reservoir of foodborne pathogens and resistant strains of bacteria. This study looked at the presence of pathogenic bacteria in a popular Ready-To-Eat (RTE) traditional food, Fufu in Ghana. Sixty (60) Fufu samples were obtained from various food joints categorized as Opened, Semi-closed and Closed or Restaurants. Samples were processed and analyzed using standard bacteriological methods. The susceptibility profiles of the isolates were obtained by using the Kirby-Bauer disk diffusion method with the EUCAST guidelines with the five antibiotics. Prevalence of E. coli was 85% and Salmonella species was 68%. Microbial count of isolated E. coli ranged from 0 to 3×106 cfu/ml. There were no significant differences (p>0.05) among the different modes of operations. Fufu samples from Opened, Semi-closed and Closed joints were respectively contaminated with E. coli and Salmonella species as follows: 92%, 76%; 80%, 60% and 80%, 65%. The Salmonella species showed highest resistance to erythromycin (58.5%) and E. coli species were commonly resistant to Ceftazidime (88.2%) and Ceftriaxone (94.1%). All isolates were susceptible to nitrofurantoin. Multidrug resistance was detected among 27.5% of E. coli strains and 14.6% of Salmonella species. Fufu from the different eating joints in the Tamale Metropolis were substantially contaminated with multidrug resistant pathogens. The study recommends surveillance studies of resistant pathogens in foods, increased education and training of food vendors on sanitation, food handling and safety practices in the region.

scholarly journals Antibiotic Resistance in Salmonella enterica Serovar Typhimurium Exposed to Microcin-Producing Escherichia coli

2001 ◽  
Vol 67 (8) ◽  
pp. 3763-3766 ◽  
Author(s):  
Steve A. Carlson ◽  
Timothy S. Frana ◽  
Ronald W. Griffith
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Defense Mechanism ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Multidrug Resistant ◽  
E Coli ◽  
Resistant Phenotype ◽  
Serovar Typhimurium

ABSTRACT Microcin 24 is an antimicrobial peptide secreted by uropathogenicEscherichia coli. Secretion of microcin 24 provides an antibacterial defense mechanism for E. coli. In a plasmid-based system using transformed Salmonella enterica, we found that resistance to microcin 24 could be seen in concert with a multiple-antibiotic resistance phenotype. This multidrug-resistant phenotype appeared when Salmonella was exposed to an E. coli strain expressing microcin 24. Therefore, it appears that multidrug-resistant Salmonellacan arise as a result of an insult from other pathogenic bacteria.

scholarly journals Roles of Protein Synthesis Elongation Factor EF-Tu in Heat Tolerance in Plants

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Jianming Fu ◽  
Ivana Momčilović ◽  
P. V. Vara Prasad
Keyword(s):  
Heat Tolerance ◽  
Stress Responses ◽  
Abiotic Stresses ◽  
Pathogenic Bacteria ◽  
Current Knowledge ◽  
Protein Biosynthesis ◽  
Elongation Factor ◽  
Knock Out ◽  
E Coli ◽  
Isomerase Activity

EF-Tu proteins of plastids, mitochondria, and the cytosolic counterpart EF-1α in plants, as well as EF-Tu proteins of bacteria, are highly conserved and multifunctional. The functions of EF-Tu include transporting the aminoacyl-tRNA complex to the A site of the ribosome during protein biosynthesis; chaperone activity in protecting other proteins from aggregation caused by environmental stresses, facilitating renaturation of proteins when conditions return to normal; displaying a protein disulfide isomerase activity; participating in the degradation of N-terminally blocked proteins by the proteasome; eliciting innate immunity and triggering resistance to pathogenic bacteria in plants; participating in transcription when an E. coli host is infected with phages. EF-Tu genes are upregulated by abiotic stresses in plants, and EF-Tu plays important role in stress responses. Expression of a plant EF-Tu gene confers heat tolerance in E. coli, maize knock-out EF-Tu null mutants are heat susceptible, and over-expression of an EF-Tu gene improves heat tolerance in crop plants. This review paper summarizes the current knowledge of EF-Tu proteins in stress responses in plants and progress on application of EF-Tu for developing crop varieties tolerant to abiotic stresses, such as high temperatures.

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