scholarly journals The spectrum of antibacterial activity of human defensins and cathelicidin against gram-positive and gram-negative bacterial strains isolated from hospitalized patients

2020 ◽  
Author(s):  
Albert Bolatchiev
Keyword(s):  
Antibacterial Activity ◽  
Synergistic Effect ◽  
Hospitalized Patients ◽  
New Drugs ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Conventional Antibiotics ◽  
Human Defensins

AbstractBackgroundTo date, there is a spread of resistance of microorganisms to antibiotics. To solve this problem, the search and development of new drugs with antibacterial activity is necessary. Antimicrobial peptides (AMPs) have pronounced antibacterial activity and may be promising candidates for the role of new drugs. Besides, AMPs can be used to overcome conventional antibiotics resistance due to the possible synergistic effect. In this work, the combined effect of some AMPs (human defensins, HNP-1, hBD-1, hBD-3 and cathelicidin, LL-37) with conventional antibiotics (vancomycin and imipenem) against gram-positive (Enterococcus faecalis; Staphylococcus aureus, methicillin-sensitive, MSSA, and methicillin-resistant, MRSA) and gram-negative (Escherichia coli; Klebsiella pneumoniae; Pseudomonas aeruginosa) bacterial strains was investigated.MethodsBacterial strains were isolated from hospitalized patients of the intensive care unit. Commercially available AMPs (HNP-1, hBD-1, hBD-3, LL-37 by Cloud-Clone Corp., USA) and antibiotics, vancomycin (Sandoz, Slovenia) and imipenem (Merck Sharp and Dohme, USA) were used. Antibiotic resistance phenotypes of isolated bacterial strains were carried out using the disk diffusion method. The standard checkerboard assays were used to study minimum inhibitory concentrations (MIC) of antimicrobials. The combined microbicidal effect of two substances (AMP+conventional antibiotic) was assessed by the fractional inhibitory concentration index (FICI). If FICI ≤ 0,5, then it was considered that two substances showed synergism of action; if 0.5 < FICI < 4 – no interaction; if FICI > 4 – antagonism.ResultsAll studied AMPs had antibacterial activity against the studied strains. hBD-3 showed the lowest MICs compared to other AMPs. MIC of hBD-3 against S. aureus (MSSA and MRSA), E. coli, K. pneumoniae was the same – 0.5 mg/L, and against P. aeruginosa it was 2 mg/L. The combinations HNP-1+vancomycin (against E. faecalis) and hBD-3+imipenem (against E. coli, K. pneumoniae, P. aeruginosa) according to FICI values have shown the synergistic effect. The results of this study can be used to develop novel antibiotics based on AMPs. Also, in some cases, AMPs can help to overcome resistance to conventional antibiotics.

scholarly journals Antibacterial Potential of Aloe weloensis (Aloeacea) Leaf Latex against Gram-Positive and Gram-Negative Bacteria Strains

2019 ◽  
Vol 2019 ◽  
pp. 1-4
Author(s):  
Yohannes Kelifa Emiru ◽  
Ebrahim Abdela Siraj ◽  
Tekleab Teka Teklehaimanot ◽  
Gedefaw Getnet Amare
Keyword(s):  
Antibacterial Activity ◽  
Bacterial Infections ◽  
Inhibition Zone ◽  
Antibacterial Activities ◽  
Maximum Activity ◽  
New Drugs ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative

Objective. To evaluate the antibacterial effects of the leaf latex of Aloe weloensis against infectious bacterial strains. Methods. The leaf latex of A. weloensis at different concentrations (400, 500, and 600 mg/ml) was evaluated for antibacterial activities using the disc diffusion method against some Gram-negative species such as Escherichia coli (ATCC 14700) and Pseudomonas aeruginosa (ATCC 35619) and Gram-positive such as Staphylococcus aureus (ATCC 50080) and Enterococcus fecalis (ATCC 4623). Results. The tested concentrations of the latex ranging between 400 and 600 mg·mL−1 showed significant antibacterial activity against bacterial strain. The highest dose (600 mg/ml) of A. weloensis leaf latex revealed the maximum activity (25.93 ± 0.066 inhibition zone) followed by the dose 500 mg/ml against S. aureus. The lowest antibacterial activity was observed by the concentration 400 mg/ml (5.03 ± 0.03) against E. coli. Conclusion. The results of the present investigation suggest that the leaf latex of A. weloensis can be used as potential leads to discover new drugs to control some bacterial infections.

scholarly journals Design, Synthesis, and Antibacterial Screening of Some Novel Heteroaryl-Based Ciprofloxacin Derivatives as DNA Gyrase and Topoisomerase IV Inhibitors

2021 ◽  
Vol 14 (5) ◽  
pp. 399
Author(s):  
Lamya H. Al-Wahaibi ◽  
Amer A. Amer ◽  
Adel A. Marzouk ◽  
Hesham A.M. Gomaa ◽  
Bahaa G. M. Youssif ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Dna Gyrase ◽  
Bacterial Strains ◽  
Topoisomerase Iv ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Antibacterial Screening ◽  
Ic50 Values

A novel series of ciprofloxacin hybrids comprising various heterocycle derivatives has been synthesized and structurally elucidated using 1H NMR, 13C NMR, and elementary analyses. Using ciprofloxacin as a reference, compounds 1–21 were screened in vitro against Gram-positive bacterial strains such as Staphylococcus aureus and Bacillus subtilis and Gram-negative strains such as Escherichia coli and Pseudomonas aeruginosa. As a result, many of the compounds examined had antibacterial activity equivalent to ciprofloxacin against test bacteria. Compounds 2–6, oxadiazole derivatives, were found to have antibacterial activity that was 88 to 120% that of ciprofloxacin against Gram-positive and Gram-negative bacteria. The findings showed that none of the compounds tested had antifungal activity against Aspergillus flavus, but did have poor activity against Candida albicans, ranging from 23% to 33% of fluconazole, with compound 3 being the most active (33% of fluconazole). The most potent compounds, 3, 4, 5, and 6, displayed an IC50 of 86, 42, 92, and 180 nM against E. coli DNA gyrase, respectively (novobiocin, IC50 = 170 nM). Compounds 4, 5, and 6 showed IC50 values (1.47, 6.80, and 8.92 µM, respectively) against E. coli topo IV in comparison to novobiocin (IC50 = 11 µM).

scholarly journals Antibacterial Activity of Floral Petals of Some Angiosperms

2019 ◽  
pp. 1-5 ◽  
Author(s):  
L. Rajanna ◽  
N. Santhosh Kumar ◽  
N. S. Suresha ◽  
S. Lavanya
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Inhibition Zone ◽  
Bacterial Strains ◽  
Inhibitory Zone ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Antibacterial Assay

The in vitro antibacterial assay was carried out against both Gram positive (B. cerus and S. aureus) and Gram negative (E. coli and K. pneumoniae) bacteria. Floral petals of 20 different species of plants were collected and tested for antibacterial activity. The result showed that the petals were active against both Gram positive and Gram negative. Out of 20 floral petals tested, 19 floral petals exhibited antibacterial activity against selected bacterial strains. The minimal inhibitory zone of floral petal discs against human pathogenic bacteria varies from 2 – 6 mm. Rosa carolina and Ruellia tuberosa showed significance inhibition zone for all the bacterial strains while Lantana camara does not show inhibition zone for any of these pathogenic bacteria.

SYNTHESIS AND EVALUATION OF ANTIBACTERIAL, ANTHELMINTIC ACTIVITIES OF SUBSTITUTED BENZIMIDAZOLE DERIVATIVES

INDIAN DRUGS ◽  
2017 ◽  
Vol 54 (06) ◽  
pp. 69-76
Author(s):  
D Sharma ◽  
◽  
G. K Sharma ◽  
D. Pathak ◽  
M. C. Sharma
Keyword(s):  
Antibacterial Activity ◽  
Anthelmintic Activity ◽  
Benzimidazole Derivatives ◽  
The Novel ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Alkyl Aryl ◽  
Gram Negative ◽  
E Coli

The study was undertaken to synthesize and evaluate antibacterial, anthelmintic activities of N’ (substituted benzylidene)-2-(2-alkyl/aryl-1H-benzo[d] imidazole-1yl) acetohydrazide derivatives. All the novel benzimidazole derivatives were screened for anthelmintic activity against Pherituma posthuma species of earthworms and antibacterial activity against following bacterial strains: S. aureus, B.subtilis (Gram positive) and E. coli and P.aeruginosa (Gram negative). The antibacterial data suggest that compounds having nitro and hydroxyl substitution were more potent and the anthelmintic data suggest that compounds having chloro were most active.

scholarly journals New Polymeric Films with Antibacterial Activity Obtained by UV-induced Copolymerization of Acryloyloxyalkyltriethylammonium Salts with 2-Hydroxyethyl Methacrylate

2019 ◽  
Vol 20 (11) ◽  
pp. 2696 ◽  
Author(s):  
Francesco Galiano ◽  
Raffaella Mancuso ◽  
Maria Grazia Guzzo ◽  
Fabrizio Lucente ◽  
Ephraim Gukelberger ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Alkyl Chain ◽  
Polymeric Films ◽  
Significant Activity ◽  
Hydroxyethyl Methacrylate ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Dependent Activity

New polymeric films with antibacterial activity have been prepared, by simple UV-induced copolymerization of readily available ω-(acryloyloxy)-N,N,N-triethylalcan-1-aminium bromides (or acryloyloxyalkyltriethylammonium bromides, AATEABs) with commercially available 2-hydroxyethyl methacrylate (HEMA), at different relative amounts. In particular, the antibacterial activity of polymeric films derived from 11-(acryloyloxy)-N,N,N-triethylundecan-1-aminium bromide (or acryloyloxyundecyltriethylammonium bromide, AUTEAB; bearing a C-11 alkyl chain linker between the acrylate polymerization function and the quaternary ammonium moiety) and 12-(acryloyloxy)-N,N,N-triethyldodecan-1-aminium bromide (or acryloyloxydodecyltriethylammonium bromide, ADTEB, bearing a C-12 alkyl chain linker) has been assessed against Gram-negative Escherichia Coli and Gram-positive Staphylococcus aureus cells. The results obtained have shown a clear concentration-dependent activity against both bacterial strains, the films obtained from homopolymerization of pure AUTEAB and ADTEAB being the most effective. Moreover, ADTEAB-based films showed a higher antibacterial activity with respect to the AUTEAB-based ones. Interestingly, however, both types of films presented a significant activity not only toward Gram-positive S. aureus, but also toward Gram-negative E. Coli cells.

Imidazole Derivatives and their Antibacterial Activity – a Mini-Review

2020 ◽  
Vol 20 ◽  
Author(s):  
Andrei Șerban Gâz ◽  
Francisc Andrei Boda ◽  
Rahela Roxana Pop
Keyword(s):  
Antibacterial Activity ◽  
Relevant Literature ◽  
New Drugs ◽  
Public Health Issue ◽  
Bacterial Strains ◽  
Pharmacokinetics And Pharmacodynamics ◽  
Gram Positive ◽  
Gram Negative ◽  
Imidazole Derivatives ◽  
Chemical Structures

Background:: The development of drug resistance by bacterial strains is a public health issue, being the main cause for the decrease in effectiveness of numerous antibiotics. In this context, it is essential to find new drugs with better antibacterial activity. Objective:: The authors proposed to cover relevant literature, published following the review article written by Rani et al., illustrating chemical structures and antibacterial activity of some imidazole derivatives. Method:: Approximately 100 scientific articles, presenting more than 150 compounds have been reviewed. The most relevant data have been extracted and systematically arranged in figures and tables. Results:: The reviewed studies used a broad number of bacterial strains, however Staphylococcus aureus as Gram-positive, and Escherichia coli as Gram-negative bacterial strains were most frequently used to assess the activity of these compounds. Conclusion:: Some of the compounds showed promising results against both Gram-positive and Gram-negative bacterial strains, thus further analysis should be performed in terms of toxicity, pharmacokinetics and pharmacodynamics. Additional screening of these imidazole derivatives could lead to useful compounds with potential broad-spectrum antibacterial activity against resistant pathogens.

scholarly journals Rosuvastatin as forthcoming antibiotic or as adjuvant additive agent: In vitro novel antibacterial study

2018 ◽  
Vol 10 (03) ◽  
pp. 271-275 ◽  
Author(s):  
Hayder M. Al-Kuraishy ◽  
Ali I. Al-Gareeb ◽  
Ali K. Al-Buhadily
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Inhibitory Concentration ◽  
Cholesterol Biosynthesis ◽  
Lipid Lowering ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli

ABSTRACT INTRODUCTION: Rosuvastatin is a lipid-lowering agent that inhibits 3-hydroxy-3-methylglutaryl coenzyme A reductase leading to a reduction of cholesterol biosynthesis. Many studies have shown an association between statins use and the reduction of sepsis. The aim of the present study was to evaluate the in vitro combined antibacterial activity of rosuvastatin and cefixime. MATERIALS AND METHODS: Five pathogenic bacteria isolates (Gram positive and Gram negative) were used for testing the antibacterial activity of rosuvastatin alone and in combination with cefixime. Results: Rosuvastatin mainly inhibited Klebsiella pneumoniae and Escherichia coli where it caused zones of inhibition of (17.9 ± 0.6 mm) and (16.9 ± 0.3 mm), respectively; however, it moderately inhibited the growth of Staphylococcus epidermidis (12.9 ± 0.2 mm) and Staphylococcus aureus (12.76 ± 0.2) and produced less inhibition for Pseudomonas aeruginosa growth where it led to a zone of inhibition equal to (9.1 ± 0.5 mm). Minimal inhibitory concentration (μg/mL) of rosuvastatin was high compared to cefixime. Fractional inhibitory concentration (FIC) of rosuvastatin was low for E. coli and K. pneumoniae compared to the other types of bacterial strains. Rosuvastatin exhibited additive effects with cefixime against E. coli and K. pneumoniae. ΣFIC index was 0.536 and 0.734 for E. coli and K. pneumoniae, respectively. Conclusions: Rosuvastatin has a significant antibacterial activity against both Gram-negative and Gram-positive bacteria with a potential additive effect when used in combination with cefixime.

scholarly journals Antibacterial activity of Glycyrrhiza glabra roots against certain gram-positive and gram-negative bacterial strains

2013 ◽  
Vol 5 (2) ◽  
pp. 459-464 ◽  
Author(s):  
Aparajita Gupta ◽  
D. K. Maheshwari ◽  
G. Khandelwal
Keyword(s):  
Antibacterial Activity ◽  
Salmonella Typhi ◽  
Maximum Activity ◽  
Glycyrrhiza Glabra ◽  
Test Material ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Reverse Pattern

The present study aimed to evaluate the antibacterial potency of grinded crude material (root of Glycyrrhiza glabra) against some gram-positive and gram-negative bacterial strains. Two solvents (methanol and acetone) were used to extract the phytochemicals from the test material. Four different concentrations (100%, 75%, 50% and 25%) of methanolic and acetonic extract were used to investigate the inhibiting properties against Salmonella typhi, Escherichia.coli, Vibrio cholerae, Staphylococcus aureus, Bacillus cereus and Bacillus subtilis strains. Among methanol and acetone extracts, later exhibited low antibacterial activity. The 100% (w/v) concentration of both extracts showed maximum inhibition against B. subtilis followed by E. coli, S. aureus, B. cereus, S. typhi and V. Cholerae. Maximum activity in acetonic extract was obtained against B. cereus followed by S. typhi, E. coli, V. cholerae and S .aureus and minimum in B. subtilis. A reverse pattern of inhibition activity was found in both extacts (methanolic and acetonic) against B. subtilis. Maximum activity was found in methanolic extract against B. subtilis (18.6 mm) but it was only 14.3 mm against this strain in acetonic extract. The antibacterial activity of the crude samples corresponded to that of concentration. Hence there was positive correlation of antibacterial activity with the test material.

Structure-Activity Relationship and Antimicrobial Evaluation of N-Phenylpyrazole Curcumin Derivatives

2020 ◽  
Vol 16 (4) ◽  
pp. 481-488
Author(s):  
Heli Sanghvi ◽  
Satyendra Mishra
Keyword(s):  
Antibacterial Activity ◽  
Gram Negative Bacteria ◽  
Pyrazole Derivatives ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Curcumin Derivatives ◽  
Structure Activity ◽  
Electron Donating Groups ◽  
Derivatives Of

Background: Curcumin, one of the most important pharmacologically significant natural products, has gained significant consideration among scientists for decades since its multipharmacological activities. 1, 3-Dicarbonyl moiety of curcumin was found to be accountable for the rapid degradation of curcumin molecule. The aim of present work is to replace 1, 3-dicarbonyl moiety of curcumin by pyrazole and phenylpyrazole derivatives with a view to improving its stability and to investigate the role of substitution in N-phenylpyrazole curcumin on its antibacterial activity against both Gram-positive as well as Gram-negative bacteria. Methods: Pyrazole derivatives of curcumin were prepared by heating curcumin with phenyhydrazine/ substituted phenyhydrazine derivatives in AcOH. The residue was purified by silica gel column chromatography. Structures of purified compounds were confirmed by 1H NMR and Mass spectroscopy. The synthesized compounds were evaluated for their antibacterial activity by the microdilution broth susceptibility test method against gram positive (S. aureus) and gram negative (E. coli). Results: Effects of substitution in N-phenylpyrazole curcumin derivatives against S. aureus and E. coli were studied. The most active N-(3-Nitrophenylpyrazole) curcumin (12) exhibits twenty-fold more potency against S. aureus (MIC: 10μg/mL)) and N-(2-Fluoroophenylpyrazole) curcumin (5) fivefold more potency against E. coli (MIC; 50 μg/mL) than N-phenylpyrazole curcumin (4). Whereas, a remarkable decline in anti-bacterial activity against S. aureus and E. coli was observed when electron donating groups were incorporated in N-phenylpyrazole curcumin (4). Comparative studies of synthesized compounds suggest the effects of electron withdrawing and electron donating groups on unsubstituted phenylpyrazole curcumin (4). Conclusion: The structure-activity relationship (SAR) results indicated that the electron withdrawing and electron donating at N-phenylpyrazole curcumin played key roles for their bacterial inhibitory effects. The results of the antibacterial evaluation showed that the synthesized pyrazole derivatives of curcumin displayed moderate to very high activity in S. aureus. In conclusion, the series of novel curcumin derivatives were designed, synthesized and tested for their antibacterial activities against S. aureus and E. coli. Among them, N-(3-Nitrophenylpyrazole curcumin; 12) was most active against S. aureus (Gram-positive) and N-(2-Fluoroophenylpyrazole) curcumin (5) against E. coli (Gram-negative) bacteria.

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