Bacteriocins: Recent advances in application as an antimicrobial alternative

2021 ◽  
Vol 22 ◽  
Author(s):  
Hadis Fathizadeh ◽  
Farzaneh Pakdel ◽  
Mahmood Saffari ◽  
Davoud Davoud Esmaeili ◽  
Mansooreh Momen-Heravi ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
General Information ◽  
Producer Strain ◽  
Adequate Knowledge ◽  
Antimicrobial Studies ◽  
Functional Mechanisms ◽  
Further Development ◽  
Number Of Bacteria

: Due to the emergence and development of antibiotic resistance in the treatment of bacterial infections, efforts to discover new antimicrobial agents have increased. One of these antimicrobial agents is a compound produced by a large number of bacteria called bacteriocin. Bacteriocins are small ribosomal polypeptides that can exert their antibacterial effects against bacteria close to their producer strain or even non-closely strains. Adequate knowledge of the structure and functional mechanisms of bacteriocins and their spectrum of activity, as well as knowledge of the mechanisms of possible resistance to these compounds will lead to further development of their use as an alternative to antibiotics. Furthermore, most bacteria that live in the gastrointestinal tract (GIT) have the ability to produce bacteriocins, which spread throughout the GIT. Despite antimicrobial studies in vitro, our knowledge of bacteriocins in the GIT and the migration of these bacteriocins from the epithelial barrier is low. Hence, in this study, we reviewed general information about bacteriocins, such as classification, mechanism of action and resistance, emphasizing their presence, stability, and spectrum of activity in the GIT.

Synthesis, In Vitro and In Silico Studies of Indolequinone Derivatives against Clinically Relevant Bacterial Pathogens

2020 ◽  
Vol 20 (3) ◽  
pp. 192-208 ◽  
Author(s):  
Talita Odriane Custodio Leite ◽  
Juliana Silva Novais ◽  
Beatriz Lima Cosenza de Carvalho ◽  
Vitor Francisco Ferreira ◽  
Leonardo Alves Miceli ◽  
...  
Keyword(s):  
In Silico ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Mass Spectrometry Analysis ◽  
World Health ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Dione Derivative ◽  
In Silico Studies

Background: According to the World Health Organization, antimicrobial resistance is one of the most important public health threats of the 21st century. Therefore, there is an urgent need for the development of antimicrobial agents with new mechanism of action, especially those capable of evading known resistance mechanisms. Objective: We described the synthesis, in vitro antimicrobial evaluation, and in silico analysis of a series of 1H-indole-4,7-dione derivatives. Methods: The new series of 1H-indole-4,7-diones was prepared with good yield by using a copper(II)- mediated reaction between bromoquinone and β-enamino ketones bearing alkyl or phenyl groups attached to the nitrogen atom. The antimicrobial potential of indole derivatives was assessed. Molecular docking studies were also performed using AutoDock 4.2 for Windows. Characterization of all compounds was confirmed by one- and two-dimensional NMR techniques 1H and 13C NMR spectra [1H, 13C – APT, 1H x 1H – COSY, HSQC and HMBC], IR and mass spectrometry analysis. Results: Several indolequinone compounds showed effective antimicrobial profile against Grampositive (MIC = 16 µg.mL-1) and Gram-negative bacteria (MIC = 8 µg.mL-1) similar to antimicrobials current on the market. The 3-acetyl-1-(2,5-dimethylphenyl)-1H-indole-4,7-dione derivative exhibited an important effect against different biofilm stages formed by a serious hospital life-threatening resistant strain of Methicillin-Resistant Staphylococcus aureus (MRSA). A hemocompatibility profile analysis based on in vitro hemolysis assays revealed the low toxicity effects of this new series. Indeed, in silico studies showed a good pharmacokinetics and toxicological profiles for all indolequinone derivatives, reinforcing their feasibility to display a promising oral bioavailability. An elucidation of the promising indolequinone derivatives binding mode was achieved, showing interactions with important sites to biological activity of S. aureus DNA gyrase. These results highlighted 3-acetyl-1-(2-hydroxyethyl)-1Hindole- 4,7-dione derivative as broad-spectrum antimicrobial prototype to be further explored for treating bacterial infections. Conclusion: The highly substituted indolequinones were obtained in moderate to good yields. The pharmacological study indicated that these compounds should be exploited in the search for a leading substance in a project aimed at obtaining new antimicrobials effective against Gram-negative bacteria.

scholarly journals Synthesis and Antimicrobial Properties of Highly Cross-Linked pH-Sensitive Hydrogels through Gamma Radiation

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2223
Author(s):  
Moises Bustamante-Torres ◽  
Victor H. Pino-Ramos ◽  
David Romero-Fierro ◽  
Sandra P. Hidalgo-Bonilla ◽  
Héctor Magaña ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Film Formation ◽  
Antimicrobial Properties ◽  
Ph Sensitive ◽  
Scanning Calorimetry ◽  
Polymeric Systems ◽  
E Coli ◽  
High Prevalence

The design of new polymeric systems for antimicrobial drug release focused on medical/surgical procedures is of great interest in the biomedical area due to the high prevalence of bacterial infections in patients with wounds or burns. For this reason, in this work, we present a new design of pH-sensitive hydrogels copolymerized by a graft polymerization method (gamma rays), intended for localized prophylactic release of ciprofloxacin and silver nanoparticles (AgNPs) for potential topical bacterial infections. The synthesized hydrogels were copolymerized from acrylic acid (AAc) and agar. Cross-linked hydrogel film formation depended on monomer concentrations and the degree of radiation used (Cobalt-60). The obtained hydrogel films were characterized by attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and mechanical testing. The swelling of the hydrogels was evidenced by the influence of their pH-sensitiveness. The hydrogel was loaded with antimicrobial agents (AgNPs or ciprofloxacin), and their related activity was evaluated. Finally, the antimicrobial activity of biocidal-loaded hydrogel was tested against Escherichia coli (E. coli) and methicillin-resistant Staphylococcus aureus (MRSA) on in vitro conditions.

scholarly journals Comparative In Vitro Activities of AC98-6446, a Novel Semisynthetic Glycopeptide Derivative of the Natural Product Mannopeptimycin α, and Other Antimicrobial Agents against Gram-Positive Clinical Isolates

2004 ◽  
Vol 48 (3) ◽  
pp. 739-746 ◽  
Author(s):  
Peter J. Petersen ◽  
T. Z. Wang ◽  
Russell G. Dushin ◽  
Patricia A. Bradford
Keyword(s):  
Natural Product ◽  
Bactericidal Activity ◽  
Antimicrobial Agents ◽  
Marked Decrease ◽  
Gram Positive ◽  
Novel Structure ◽  
Resistant Strains ◽  
Vancomycin Resistant ◽  
Further Development

ABSTRACT AC98-6446 is a novel semisynthetic cyclic glycopeptide antibiotic related to the natural product mannopeptimycin α (AC98-1). In the present study the activity of AC98-6446 was evaluated against a variety of recent clinical gram-positive pathogens including multiply resistant strains. AC98-6446 demonstrated similar potent activities against methicillin-susceptible and methicillin-resistant staphylococci and glycopeptide-intermediate staphylococcal isolates (MICs at which 90% of isolates are inhibited [MIC90s], 0.03 to 0.06 μg/ml). AC98-6446 also demonstrated good activities against both vancomycin-resistant and -susceptible strains of enterococci (MIC90s, 0.12 and 0.25 μg/ml, respectively) as well as against streptococcal strains (MIC90s, ≤ 0.008 to 0.03 μg/ml). AC98-6446 demonstrated bactericidal activity in terms of the reduction in the viable counts (>3 log10 CFU/ml) of staphylococcal and streptococcal isolates and a marked decrease in the viable counts of most enterococcal strains (from 0.2 to 2.5 log10 CFU/ml). Unlike vancomycin, which demonstrates time-dependent killing, AC98-6446 demonstrated concentration-dependent killing. The potent activity, novel structure, and bactericidal activity demonstrated by AC98-6446 make it an attractive candidate for further development.

scholarly journals Isolation and Characterization of Novel Phages Targeting Pathogenic Klebsiella pneumoniae

2021 ◽  
Vol 11 ◽  
Author(s):  
Na Li ◽  
Yigang Zeng ◽  
Rong Bao ◽  
Tongyu Zhu ◽  
Demeng Tan ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
S1 Nuclease ◽  
Isolation And Characterization ◽  
Comprehensive Knowledge ◽  
Future Challenges ◽  
Lactamase Gene

Klebsiella pneumoniae is a dominant cause of community-acquired and nosocomial infections, specifically among immunocompromised individuals. The increasing occurrence of multidrug-resistant (MDR) isolates has significantly impacted the effectiveness of antimicrobial agents. As antibiotic resistance is becoming increasingly prevalent worldwide, the use of bacteriophages to treat pathogenic bacterial infections has recently gained attention. Elucidating the details of phage-bacteria interactions will provide insights into phage biology and the better development of phage therapy. In this study, a total of 22 K. pneumoniae isolates were assessed for their genetic and phenotypic relatedness by multi-locus sequence typing (MLST), endonuclease S1 nuclease pulsed-field gel electrophoresis (S1-PFGE), and in vitro antibiotic susceptibility testing. In addition, the beta-lactamase gene (blaKPC) was characterized to determine the spread and outbreak of K. pneumoniae carbapenemase (KPC)-producing enterobacterial pathogens. Using these ST11 carbapenem-resistant K. pneumoniae isolates, three phages (NL_ZS_1, NL_ZS_2, and NL_ZS_3) from the family of Podoviridae were isolated and characterized to evaluate the application of lytic phages against the MDR K. pneumoniae isolates. In vitro inhibition assays with three phages and K. pneumoniae strain ZS15 demonstrated the strong lytic potential of the phages, however, followed by the rapid growth of phage-resistant and phage-sensitive mutants, suggesting several anti-phage mechanisms had developed in the host populations. Together, this data adds more comprehensive knowledge to known phage biology and further emphasizes their complexity and future challenges to overcome prior to using phages for controlling this important MDR bacterium.

scholarly journals A Pyrrhic Victory: The PMN Response to Ocular Bacterial Infections

2019 ◽  
Vol 7 (11) ◽  
pp. 537 ◽  
Author(s):  
Erin T. Livingston ◽  
Md Huzzatul Mursalin ◽  
Michelle C. Callegan
Keyword(s):  
Bacterial Infections ◽  
Bacterial Pathogen ◽  
General Information ◽  
Ocular Disease ◽  
Ocular Infection ◽  
The Face ◽  
Novel Therapeutic Strategies ◽  
Pathogen Clearance ◽  
Pyrrhic Victory

Some tissues of the eye are susceptible to damage due to their exposure to the outside environment and inability to regenerate. Immune privilege, although beneficial to the eye in terms of homeostasis and protection, can be harmful when breached or when an aberrant response occurs in the face of challenge. In this review, we highlight the role of the PMN (polymorphonuclear leukocyte) in different bacterial ocular infections that invade the immune privileged eye at the anterior and posterior segments: keratitis, conjunctivitis, uveitis, and endophthalmitis. Interestingly, the PMN response from the host seems to be necessary for pathogen clearance in ocular disease, but the inflammatory response can also be detrimental to vision retention. This “Pyrrhic Victory” scenario is explored in each type of ocular infection, with details on PMN recruitment and response at the site of ocular infection. In addition, we emphasize the differences in PMN responses between each ocular disease and its most common corresponding bacterial pathogen. The in vitro and animal models used to identify PMN responses, such as recruitment, phagocytosis, degranulation, and NETosis, are also outlined in each ocular infection. This detailed study of the ocular acute immune response to infection could provide novel therapeutic strategies for blinding diseases, provide more general information on ocular PMN responses, and reveal areas of bacterial ocular infection research that lack PMN response studies.

Antimicrobial activity, total phenolic content and flavonoid concentrations of Teucrium species

2012 ◽  
Vol 7 (4) ◽  
pp. 664-671 ◽  
Author(s):  
Milan Stanković ◽  
Olgica Stefanović ◽  
Ljiljana Čomić ◽  
Marina Topuzović ◽  
Ivana Radojević ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Total Phenolic Content ◽  
Antimicrobial Agents ◽  
Phenolic Content ◽  
Fungal Species ◽  
Total Phenolic ◽  
Total Phenols ◽  
Further Development ◽  
Ethyl Acetate Extracts

AbstractIn vitro antimicrobial activity of 21 crude extracts obtained from seven taxa of the genus Teucrium (T. chamaedrys, T. montanum, T. arduini, T. polium, T. scordium subsp. scordium, T. scordium subsp. scordioides and T. botrys) was tested against bacterial and fungal species. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using a microdilution analysis method. Total phenolic content and flavonoid concentrations were measured spectrophotometrically. Total phenols were determined using Folin-Ciocalteu reagent and their amounts ranged from 28.49 up to 159.84 mg CA/g of extract (chlorogenic acid equivalent). The amounts of flavonoids ranged from 38.17 up to 190.45 mg RU/g of extract (rutin equivalent).The plant extracts showed greater potential of antibacterial than antifungal activity. A relationship was found between total phenolics and biological activity. The highest level of total phenols was measured in the methanol extracts, which demonstrated higher antimicrobial activity than acetone and ethyl acetate extracts. Staphylococcus aureus ATCC 25923 appeared to be the most sensitive organism. Our results indicate that Teucrium spp extracts are rich sources of phenolic compounds and are promising candidates for further development as natural antimicrobial agents.

scholarly journals Staphylococcus aureus biofilm and the role of bacteriophages in its eradication

2018 ◽  
Vol 72 ◽  
pp. 101-107
Author(s):  
Natalia Łubowska ◽  
Lidia Piechowicz
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Methicillin Resistance ◽  
Therapeutic Option ◽  
Resistant Bacteria ◽  
Prosthetic Heart Valves ◽  
Biofilm Structure ◽  
Implanted Devices

The ability to form biofilm is an important virulence factor of many microorganisms. Infections involving biofilms account for approx. 65% of all human infections. Biofilms may develop on intravascular catheters or implanted devices such as prosthetic heart valves. Implanted devices are covered by biofilm and become reservoirs of microorganisms which can be a cause of persistent infections (endocarditis, deep tissue abscesses, septic arthritis, and osteomyelitis). Treatment of infections caused by biofilm-growing cells is linked to a high risk of failure due to an extreme resistance to antimicrobial agents and increased capacity to evade the immune responses. A large number of biofilm-associated infections involve Staphylococcus aureus. Treatment of staphylococcal infections is a great challenge for clinicians because of the presence of various mechanisms of resistance to antibiotics in S. aureus, for example methicillin resistance and biofilm production. Therapeutic difficulties related with antibiotic-resistant bacteria and limitations in research on new antimicrobials were the reasons that nearly 100 years after discovery, bacteriophages caught the attention of scientists around the world as a new therapeutic option for bacterial infections. Numerous in vitro studies on S. aureus strains showed that phages can both prevent biofilm formation and contribute to the elimination of bacteria from the mature biofilm structure. The major role in biofilm eradication play depolymerases produced by some phages which facilitate their penetration into the inner layers of biofilm by disturbing the biofilm structure. This leads to the conclusion that bacteriophages treatment might become a new strategy in the prevention and eradication of infectious bacterial biofilms, including these formed by S. aureus.

scholarly journals Inhibitory Effects of Lipopeptides and Glycolipids on C. albicans–Staphylococcus spp. Dual-Species Biofilms

2021 ◽  
Vol 11 ◽  
Author(s):  
Chiara Ceresa ◽  
Maurizio Rinaldi ◽  
Francesco Tessarolo ◽  
Devid Maniglio ◽  
Emanuele Fedeli ◽  
...  
Keyword(s):  
Metabolic Activity ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Soluble Form ◽  
Total Biomass ◽  
Chronic Infections ◽  
Host Immune Responses ◽  
Microbial Biofilms ◽  
Staphylococcus Spp

Microbial biofilms strongly resist host immune responses and antimicrobial treatments and are frequently responsible for chronic infections in peri-implant tissues. Biosurfactants (BSs) have recently gained prominence as a new generation of anti-adhesive and antimicrobial agents with great biocompatibility and were recently suggested for coating implantable materials in order to improve their anti-biofilm properties. In this study, the anti-biofilm activity of lipopeptide AC7BS, rhamnolipid R89BS, and sophorolipid SL18 was evaluated against clinically relevant fungal/bacterial dual-species biofilms (Candida albicans, Staphylococcus aureus, Staphylococcus epidermidis) through quantitative and qualitative in vitro tests. C. albicans–S. aureus and C. albicans–S. epidermidis cultures were able to produce a dense biofilm on the surface of the polystyrene plates and on medical-grade silicone discs. All tested BSs demonstrated an effective inhibitory activity against dual-species biofilms formation in terms of total biomass, cell metabolic activity, microstructural architecture, and cell viability, up to 72 h on both these surfaces. In co-incubation conditions, in which BSs were tested in soluble form, rhamnolipid R89BS (0.05 mg/ml) was the most effective among the tested BSs against the formation of both dual-species biofilms, reducing on average 94 and 95% of biofilm biomass and metabolic activity at 72 h of incubation, respectively. Similarly, rhamnolipid R89BS silicone surface coating proved to be the most effective in inhibiting the formation of both dual-species biofilms, with average reductions of 93 and 90%, respectively. Scanning electron microscopy observations showed areas of treated surfaces that were free of microbial cells or in which thinner and less structured biofilms were present, compared to controls. The obtained results endorse the idea that coating of implant surfaces with BSs may be a promising strategy for the prevention of C. albicans–Staphylococcus spp. colonization on medical devices, and can potentially contribute to the reduction of the high economic efforts undertaken by healthcare systems for the treatment of these complex fungal–bacterial infections.

scholarly journals Bacteriocins, Antimicrobial Peptides from Bacterial Origin: Overview of Their Biology and Their Impact against Multidrug-Resistant Bacteria

2020 ◽  
Vol 8 (5) ◽  
pp. 639 ◽  
Author(s):  
Alexis Simons ◽  
Kamel Alhanout ◽  
Raphaël E. Duval
Keyword(s):  
Antimicrobial Resistance ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Multidrug Resistant Bacteria ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Further Development

Currently, the emergence and ongoing dissemination of antimicrobial resistance among bacteria are critical health and economic issue, leading to increased rates of morbidity and mortality related to bacterial infections. Research and development for new antimicrobial agents is currently needed to overcome this problem. Among the different approaches studied, bacteriocins seem to be a promising possibility. These molecules are peptides naturally synthesized by ribosomes, produced by both Gram-positive bacteria (GPB) and Gram-negative bacteria (GNB), which will allow these bacteriocin producers to survive in highly competitive polymicrobial environment. Bacteriocins exhibit antimicrobial activity with variable spectrum depending on the peptide, which may target several bacteria. Already used in some areas such as agro-food, bacteriocins may be considered as interesting candidates for further development as antimicrobial agents used in health contexts, particularly considering the issue of antimicrobial resistance. The aim of this review is to present an updated global report on the biology of bacteriocins produced by GPB and GNB, as well as their antibacterial activity against relevant bacterial pathogens, and especially against multidrug-resistant bacteria.

Synthesis, Antimicrobial Evaluation and In silico Studies of Novel 2,4- disubstituted-1,3-thiazole Derivatives

2018 ◽  
Vol 16 (2) ◽  
pp. 160-173 ◽  
Author(s):  
Mir Mohammad Masood ◽  
Mohammad Irfan ◽  
Shadab Alam ◽  
Phool Hasan ◽  
Aarfa Queen ◽  
...  
Keyword(s):  
In Silico ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Docking Studies ◽  
Bacterial Strains ◽  
Thiazole Derivatives ◽  
Standard Drug ◽  
Hek 293 ◽  
In Silico Studies

Background: 2,4-disubstituted-1,3-thiazole derivatives (2a–j), (3a–f) and (4a–f) were synthesized, characterized and screened for their potential as antimicrobial agents. In the preliminary screening against a panel of bacterial strains, nine compounds showed moderate to potent antibacterial activity (IC50 = 13.7-90.8 μg/ml). </P><P> Methods: In the antifungal screening, compound (4c) displayed potent antifungal activity (IC50 = 26.5 &#181;g/ml) against Candida tropicalis comparable to the standard drug, fluconazole (IC50 = 10.5 &#181;g/ml). Based on in vitro antimicrobial results, compounds 2f, 4c and 4e were selected for further pharmacological investigations. Hemolytic activity using human red blood cells (hRBCs) and cytotoxicity by MTT assay on human embryonic kidney (HEK-293) cells revealed non-toxic nature of the selected compounds (2f, 4c and 4e). To ascertain their possible mode of action, docking studies with the lead inhibitors (2f, 4c and 4e) were performed using crystal structure coordinates of bacterial methionine aminopeptidases (MetAPs), an enzyme involved in bacterial protein synthesis and maturation. Results: The results of in vitro and in silico studies provide a rationale for selected compounds (2f, 4c and 4e) to be carried forward for further structural modifications and structure-activity relationship (SAR) studies against these bacterial infections. Conclusion: The study suggested binding with one or more key amino acid residues in the active site of Streptococcus pneumoniae MetAP (SpMetAP) and Escherichia coli MetAP (EcMetAP). In silico physicochemical properties using QikProp confirmed their drug likeliness.

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