scholarly journals Antibacterial activity and time kill kinetics of Amlodipine, Thioridazine and Promethazine against pathogenic clinical bacterial isolates

2021 ◽  
Vol 22 (3) ◽  
pp. 397-406
Author(s):  
O.J. Akinjogunla ◽  
A.N. Umo ◽  
M.F. Alozie ◽  
G.O. Oshosanya ◽  
G.I. Saturday
Keyword(s):  
Antibacterial Activities ◽  
Post Inoculation ◽  
Disc Diffusion ◽  
Bacterial Isolates ◽  
E Coli ◽  
Cell Counts ◽  
Antibiotic Drugs ◽  
Time Kill ◽  
Kinetics Of

Background: The emergence of multi-drug resistant bacterial strains worldwide has necessitated the scientific search for novel, potent, and affordable antimicrobial agents including medicinal plants and non-antibiotic drugs for therapy of infectious diseases. The objective of this study is to assess in vitro antibacterial activities and time kill kinetics of some non-antibiotic drugs against pathogenic clinical bacterial isolates.Methodology: In vitro antibacterial activities including minimum inhibitory concentration (MIC), minimum bactericidal concentration  (MBC) and time kill kinetics of Amlodipine (AML), Thioridazine (THI) and Promethazine (PRO) against Staphylococcus aureus, coagulase negative staphylococci (CoNS), Streptococcus spp, Escherichia coli, Enterobacter spp, Klebsiella pneumoniae and Pseudomonas aeruginosa clinical isolates were determined using disc diffusion, broth microdilution and plate count techniques.Results: The mean growth inhibition zones by the disc diffusion assay of AML, THI and PRO against the isolates were ≤15.1±1.0 mm with MIC and MBC values ranging from 12.5 to 50μg/ml and 25 to 100μg/ml respectively. The time-kill assay revealed bactericidal effect of AML, THI and PRO on Gram positive bacteria evidenced by mean log reductions in viable bacterial cell counts ranging from 0.13 Log10 to 2.41 Log10 CFU/ml for S. aureus, 0.88 Log10 to 2.08 Log10 CFU/ml for Streptococcus spp, and 0.26 Log10 to 2.34 Log10 CFU/ml for CoNS after ≤30hrs post inoculation at 1xMIC. The range of log reduction in viable cell counts of Gram-negative bacteria exposed to AML, THI and PRO were E. coli (0.11 to 3.23 Log10 CFU/ml), P. aeruginosa (0.52 to 2.56 Log10 CFU/ml), K. pneumoniae (0.85 to 3.0 Log10 CFU/ml) and  Enterobacter spp (0.38 to 2.08 Log10 CFU/ml) after ≤30 hrs post inoculation at 1x MIC.Conclusion: These findings demonstrate in vitro antibacterial efficacies and time kill kinetics of AML, THI and PRO against pathogenic clinical bacterial isolates, which indicate that these non-antibiotic drugs may be useful therapeutic alternatives in the bid to reduce the burden of infectious diseases associated with antibiotic resistant pathogens. Keywords: Amlodipine, Thioridazine, Promethazine, Time-Kill, Kinetics, MIC, MBC, bacteria   French title: Activité antibactérienne et cinétique de destruction du temps de l'amlodipine, de la thioridazine et de la prométhazine contre les isolats bactériens cliniques pathogènes Contexte: L'émergence de souches bactériennes multirésistantes dans le monde a rendu nécessaire la recherche scientifique d'agents antimicrobiens nouveaux, puissants et abordables, notamment des plantes médicinales et des médicaments non antibiotiques pour le traitement des maladies infectieuses. L'objectif de cette étude est d'évaluer les activités antibactériennes in vitro et la cinétique de destruction temporelle de certains médicaments non antibiotiques contre les isolats bactériens cliniques pathogènes. Méthodologie: activités antibactériennes in vitro, y compris la concentration minimale inhibitrice (CMI), la concentration bactéricide minimale (MBC) et la cinétique de destruction du temps de l'amlodipine (AML), de la thioridazine (THI) et de la prométhazine (PRO) contre Staphylococcus aureus, les staphylocoques à coagulase négative (CoNS), Streptococcus spp, Escherichia coli, Enterobacter spp, Klebsiella pneumoniae et Pseudomonas aeruginosa ont été déterminés en utilisant des techniques de diffusion sur disque, de microdilution en bouillon et de numération sur plaque. Résultats: Les zones moyennes d'inhibition de la croissance par le test de diffusion de disque d'AML, THI et PRO contre les isolats étaient ≤15,1±1,0mm avec des valeurs MIC et MBC allant de 12,5 à 50μg/ml et de 25 à 100μg/ml respectivement. Le dosage temporel a révélé un effet bactéricide de la LMA, du THI et du PRO sur les bactéries Gram positives, mis en évidence par des réductions logarithmiques moyennes du nombre de cellules bactériennes viables allant de 0,13 Log10 à 2,41 Log10 CFU/ml pour S. aureus, 0,88 Log10 à 2,08 Log10 CFU/ml pour Streptococcus spp et 0,26 Log10 à 2,34 Log10 CFU/ml pour CoNS après ≤ 30 heures après l'inoculation à 1 x MIC. La plage de réduction logarithmique du nombre de cellules viables de bactéries à Gram négatif exposées à la LMA, au THI et au PRO était E. coli (0,11 à 3,23 Log10 CFU/ml), P. aeruginosa (0,52 à 2,56 Log10 CFU/ml), K. pneumoniae (0,85 à 3,0 Log10 CFU/ml) et Enterobacter spp (0,38 à 2,08 Log10 CFU/ml) après ≤ 30 heures après l'inoculation à 1 x MIC. Conclusion: Ces résultats démontrent une efficacité antibactérienne in vitro et une cinétique de destruction du temps des LMA, THI et PRO contre les isolats bactériens cliniques pathogènes, ce qui indique que ces médicaments non antibiotiques peuvent être des alternatives thérapeutiques utiles dans le but de réduire le fardeau des maladies infectieuses associées aux antibiotiques pathogènes résistants. Mots-clés: Amlodipine, Thioridazine, Prométhazine, Time-Kill, Cinétique, MIC, MBC, bactéries  

scholarly journals In vitro antibacterial activities of crude extracts of nine plants on multidrug resistance bacterial isolates of wound infections

2021 ◽  
Vol 22 (7) ◽  
Author(s):  
Muhammad Evy Prastiyanto ◽  
NI MADE BUNGA ANGGELIA DEWI ◽  
TUSY DIAH PRATININGTIAS ◽  
NI MADE RAI PRATIWI ◽  
ANGGIS WINDAYANI ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Allium Sativum ◽  
Antibacterial Activities ◽  
Bitter Melon ◽  
Syzygium Cumini ◽  
Wound Infections ◽  
Bacterial Isolates ◽  
E Coli ◽  
Inhibition Zones

Abstract. Prastiyanto ME, Dewi NMBA, Pratiningtias TD, Pratiwi NMR, Windayani A, Wahyunengsih E, Astuti, Amir E, Wardoyo FA. 2021. In vitro antibacterial activities of crude extracts of nine plants on multidrug resistance bacterial isolates of wound infections. Biodiversitas 22: 2641-2647. Wound infections caused by bacteria is a become serious health problems, multidrug resistance bacteria (MDR) have increased this problem more severely, and therefore, antibacterial agents from natural biological sources are necessary to overcome these problems. This study examined the antibacterial activities of nine plants, i.e. garlic (Allium sativum), Solo garlic (Allium sativum), Java plum leaf (Syzygium cumini), Java plum fruit (Syzygium cumini), lime (Citrus aurantifolia), Kaffir lime (Citrus hystrix), Siamese weed (Chromolaena odorata), mangosteen (Garcinia mangostana) and bitter melon (Momordica charantia), against MDR bacteria isolated from wounds. The antibacterial activities were evaluated using agar well diffusion assay to determine the inhibition zones, and microdilution method to determine the value of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The best antibacterial activities were calculated as the most extensive inhibition zones with the smallest MIC and MBC values. Ethanol extracts from five plants (garlic, Solo garlic, Java plum (leaf), Kaffir lime and bitter melon) showed antibacterial activities against three MDR bacteria isolated from wounds. The bitter melon extract had the largest zones, 19.3 mm (methicillin-resistant Staphylococcus aureus [MRSA]), 10.6 mm (ESBL-producing Escherichia coli), and 13 mm (carbapenemase-resistant Pseudomonas aeruginosa [CRPA]) with the smallest MIC and MBC values against MRSA (3.12 and 25 mg/mL), ESBL- producing E. coli (12.25 and 50 mg/mL), and CRPA (6.25 and 25 mg/mL). This concludes that bitter melon has the potential to be developed as an antibacterial agent, particularly against MRSA strains, ESBL-producing E. coli, and CRPA that cause wound infections. Further in vivo research and the discovery of modes of action are needed to explain the antibacterial effects.

scholarly journals Synthesis and Assessment of Antibacterial Activities of Ruthenium(III) Mixed Ligand Complexes Containing 1,10-Phenanthroline and Guanide

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Atakilt Abebe ◽  
Tizazu Hailemariam
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activities ◽  
Drug Resistant ◽  
E Coli ◽  
Antibiotic Drugs ◽  
Wide Range ◽  
In Vivo Cytotoxicity ◽  
Better Than

In this work, two complexes of ruthenium(III) ([Ru(phen)2Cl2]Cl·2H2O and [Ru(phen)2(G)Cl]2Cl·H2O) were synthesized from 1,10-phenanthroline alone as well as from both 1,10-phenanthroline and guanide. The synthesis was checked using halide test, conductance measurement, and spectroscopic (ICP-OES, FTIR, and UV/Vis) analysis. Their in vitro antibacterial activities were also investigated on two Gram-positive (Staphylococcus aureus (S. aureus) and methicillin resistant Staphylococcus aureus (MRSA)) and two Gram-negative (Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae)) bacteria. These complexes showed wide-range better activities than the commercially available controls (Chloramphenicol and Ciprofloxacin) against even the most drug resistant K. pneumoniae. [Ru(phen)2(G)Cl]2Cl·H2O inhibited S. aureus, MRSA, E. coli, and K. pneumoniae by 17.5%, 27.4%, 16%, and 52%, respectively, better than Chloramphenicol. It also inhibited these pathogens by 5.9%, 5.1%, 2.3%, and 17.2%, respectively, better than Ciprofloxacin. Similarly, [Ru(Phen)2(Cl)2]Cl·2H2O inhibited these pathogens by 11%, 8.7%, 0.1%, and 31.2%, respectively, better than Chloramphenicol. Therefore, after in vivo cytotoxicity investigations, these compounds can be considered as potential antibiotic drugs.

scholarly journals In Vitro Activities of Aminomethyl-Substituted Analogs of Novel Tetrahydrofuranyl Carbapenems

1999 ◽  
Vol 43 (3) ◽  
pp. 454-459 ◽  
Author(s):  
William J. Weiss ◽  
Peter J. Petersen ◽  
Nilda V. Jacobus ◽  
Yang-I Lin ◽  
Panayota Bitha ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
The Other ◽  
Significant Activity ◽  
Postantibiotic Effect ◽  
E Coli ◽  
Medical Centers ◽  
The Family ◽  
Kill Curve ◽  
Time Kill

ABSTRACT CL 188,624, CL 190,294, and CL 191,121 are novel aminomethyl tetrahydrofuranyl (THF)-1β-methylcarbapenems. The in vitro antibacterial activities of these THF carbapenems were evaluated and compared with those of biapenem, imipenem, and meropenem against 554 recent clinical isolates obtained from geographically distinct medical centers across North America. The antibacterial activities of the THF carbapenems were equivalent to that of biapenem, and the THF carbapenems were slightly more active than imipenem and less active than meropenem against most of the members of the family Enterobacteriaceae but lacked significant activity against Pseudomonasisolates. In general, CL 191,121 was two- to fourfold more active than CL 188,624 and CL 190,294 against the staphylococcal and enterococcal isolates tested. CL 191,121 was twofold less active than imipenem against methicillin-susceptible staphylococci and was as activity as imipenem against Enterococcus faecalis isolates. Biapenem and meropenem were two- and fourfold less active than CL 191,121, respectively, against the methicillin-susceptible staphylococci andE. faecalis. All the carbapenems displayed equivalent good activities against the streptococci. Biapenem was slightly more active than the other carbapenems againstBacteroides fragilis isolates. Time-kill curve studies demonstrated that the THF carbapenems were bactericidal in 6 h against Escherichia coli andStaphylococcus aureus isolates. The postantibiotic effect exerted by CL 191,121 was comparable to or slightly longer than that of imipenem against isolates of S. aureus, E. coli, and Klebsiella pneumoniae.

scholarly journals Restoring colistin sensitivity in colistin-resistant E. coli: Combinatorial use of MarR inhibitor with efflux pump inhibitor

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Niranjana Sri Sundaramoorthy ◽  
Pavithira Suresh ◽  
Subramaniapillai Selva Ganesan ◽  
ArunKumar GaneshPrasad ◽  
Saisubramanian Nagarajan
Keyword(s):  
Muscle Tissue ◽  
Efflux Pump ◽  
Efflux Pump Inhibitor ◽  
E Coli ◽  
Log Reduction ◽  
Cell Counts ◽  
Highly Effective ◽  
Time Kill

AbstractAntibiotics like colistin are the last resort to deal with infections by carbapenem-resistant Enterobacteriaceae (CREB). Resistance to colistin severely restricts therapeutic options. To tackle this dire situation, urgent measures to restore colistin sensitivity are needed. In this study, whole-genome sequencing of colistin-resistant E. coli strain was performed and the genome analysis revealed that the strain belonged to the sequence type ST405. Multiple mutations were observed in genes implicated in colistin resistance, especially those related to the L-Ara-4-N pathway but mgrB was unmutated and mcr1-9 genes were missing. MarR inhibitor salicylate was used to re-sensitize this strain to colistin, which increased the negative charge on the cell surface especially in colistin resistant E. coli (U3790 strain) and thereby facilitated a decrease in colistin MIC by 8 fold. It is indeed well known that MarR inhibition by salicylate triggers the expression of AcrAB efflux pumps through MarA. So, in order to fully restore colistin sensitivity, a potent efflux pump inhibitor (BC1), identified earlier by this group was employed. The combination of colistin with both salicylate and BC1 caused a remarkable 6 log reduction in cell counts of U3790 in time-kill assay. Infection of muscle tissue of zebrafish with U3790 followed by various treatments showed that the combination of colistin + salicylate + BC1 was highly effective in reducing bioburden in infected muscle tissue by 4 log fold. Thus, our study shows that a combination of MarR inhibitor to enhance colistin binding and efflux pump inhibitor to reduce colistin extrusion was highly effective in restoring colistin sensitivity in colistin-resistant clinical isolate of E. coli in vitro and in vivo.

scholarly journals Flavone-Rich Fractions and Extracts from Oroxylum indicum and Their Antibacterial Activities against Clinically Isolated Zoonotic Bacteria and Free Radical Scavenging Effects

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1773
Author(s):  
Patchima Sithisarn ◽  
Piyanuch Rojsanga ◽  
Pongtip Sithisarn
Keyword(s):  
Antibacterial Activities ◽  
Inhibitory Effect ◽  
Total Flavonoid ◽  
Total Phenolic ◽  
Antibacterial Effects ◽  
E Coli ◽  
Young Fruit ◽  
Oroxylum Indicum ◽  
Zoonotic Bacteria

Oroxylum indicum extracts from the seeds collected from Lampang and Pattani provinces in Thailand, and young fruits and flowers exhibited in vitro display antioxidant and antibacterial activities against clinically isolated zoonotic bacteria including Staphylococcus intermedius, Streptococcus suis, Pseudomonas aeruginosa, β-hemolytic Escherichia coli and Staphylococcus aureus. The orange crystals and yellow precipitates were obtained from the preparation processes of the seed extracts. The orange-red crystals from the seeds collected from Lampang province exhibited strong in vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging effects (EC50 value = 25.99 ± 3.30 μg/mL) and antibacterial effects on S. intermedius and β-hemolytic E. coli while the yellow precipitate from the same source exhibited only antioxidant activity. Quantitative analysis of phytochemicals in O. indicum samples by spectrophotometric and HPLC techniques showed that they contained different amounts of total phenolic, total flavonoid and three major flavones; baicalin, baicalein and chrysin contents. Young fruit extract, which contained low amounts of flavone contents, still promoted antibacterial effects against the tested bacteria with IC50 values lower than 1 mg/mL and MIC values between 4 to 10 mg/mL in S. intermedius, S. aureus and S suis while higher IC50 and MIC values against P. aeruginosa and β-hemolytic E. coli were found. From scanning electron microscopy, the extract of the young fruit of O. indicum promoted morphological changes in the bacterial cells by disrupting the bacterial cell walls, inducing leakage of the cellular content, and generating the abnormal accumulation of cells. The mechanism of action of the extract for this antibacterial effect may be the disruption of the cell membrane and abnormal cell aggregations. Regression analysis of the results suggests the correlation between total phenolic and total flavonoid contents and antioxidant and antibacterial effects. Baicalin was found to have a high correlation with an inhibitory effect against β-hemolytic E. coli while three unidentified peaks, which could be flavones, showed high correlations with an inhibitory effect against S. intermedius, S. suis, P. aeruginosa and S. aureus.

scholarly journals Tantalum doped SiO2-CaO-P2O5 based bioactive glasses: Investigation of in vitro bioactivity and antibacterial activities

2020 ◽  
Vol 6 (1) ◽  
pp. 10-22
Author(s):  
Zakaria Tabia ◽  
Sihame Akhtach ◽  
Khalil El Mabrouk ◽  
Meriame Bricha ◽  
Khalid Nouneh ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
Silica Matrix ◽  
Morphological Properties ◽  
Metallic Ions ◽  
X Ray Diffraction ◽  
Bioactive Glasses ◽  
E Coli ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Electron Scanning Microscopy

AbstractMultifunctionality can be achieved for bioactive glasses by endowing them with multiple other properties along with bioactivity. One way to address this topic is by doping these glasses with therapeutic metallic ions. In this work, we put under investigation a series of bioactive glasses doped with tantalum. We aim to study the effect of tantalum, on the structure, bioactivity and antibacterial property of a ternary bioactive glass composition based on SiO2-CaO-P2O5. Fourier Transformed Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) and Electron Scanning Microscopy (SEM) were used to assess the structural and morphological properties of these glasses and monitor their changes after in vitro acellular bioactivity test. Antibacterial activity was tested against gram positive and negative bacteria. Characterization results confirmed the presence of calcium carbonate crystallites along with the amorphous silica matrix. The assessment of bioactivity in SBF indicated that all compositions showed a fast bioactive response after only six hours of immersion period. However, analytical characterization revealed that tantalum introduced a slight latency in hydroxyapatite deposition at higher concentrations (0.8-1 %mol). Antibacterial test showed that tantalum ions had an inhibition effect on the growth of E. coli and S. aureus. This effect was more pronounced in compositions where mol% of tantalum is superior to 0.4%. These results proved that tantalum could be used, in intermediate proportions, as a promising multifunctional dopant element in bioactive glasses for bone regeneration applications.

scholarly journals Antibacterial Inhibitory Effects of Punica Granatum Gel on Cariogenic Bacteria: An in vitro Study

2017 ◽  
Vol 10 (2) ◽  
pp. 152-157 ◽  
Author(s):  
Grazielle Millo ◽  
Apa Juntavee ◽  
Ariya Ratanathongkam ◽  
Natsajee Nualkaew ◽  
Peerapattana, Jomjai ◽  
...  
Keyword(s):  
High Performance ◽  
In Vitro Study ◽  
Punica Granatum ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
Inhibitory Effects ◽  
Cariogenic Bacteria ◽  
Zones Of Inhibition ◽  
Time Kill

ABSTRACT Aim This study evaluated the in vitro antibacterial effects of the formulated Punica granatum (PG) gel against Streptococcus mutans, Streptococcus sanguinis, and Lactobacillus casei. Materials and methods The PG extract was dissolved in water at 500 mg/mL. High performance liquid chromatography (HPLC) was used for identification and quantification of chemical marker punicalagin. Minimum bactericidal concentration (MBC) and time-kill assay (TKA) were investigated. Antibacterial activities of the formulated PG gel, 2% chlorhexidine (CHX) gel and blank gel were tested by measuring the zones of inhibition through agar well diffusion method. Results The HPLC results showed presence of punicalagin at 2023.58 ± 25.29 μg/mL in the aqueous PG extract and at 0.234% (w/w) in the formulated PG gel. The MBC for S. mutans, S. Sanguinis, and L. casei were 250, 125, and 500 mg/mL respectively. The TKA of 500 mg/mL aqueous PG extract showed total inhibition of S. mutans, S. Sanguinis, and L. casei at 6, 1, and 24 hours contact time respectively. Agar well diffusion revealed that for S. mutans, CHX gel > PG gel > blank gel; for S. sanguinis, CHX gel = PG gel > blank gel; for L. casei, CHX gel > PG gel = blank gel. Comparison of the PG gel potency showed that S. sanguinis = S. mutans > L. casei. Conclusion The PG gel equivalent to 0.234% punicalagin (w/w) inhibited S. mutans and S. sanguinis but not L. casei within 24 hours incubation period and has the potential to be used for caries prevention. How to cite this article Millo G, Juntavee A, Ratanathongkam A, Nualkaew N, Peerapattana J, Chatchiwiwattana S. Antibacterial Inhibitory Effects of Punica Granatum Gel on Cariogenic Bacteria: An in vitro Study. Int J Clin Pediatr Dent 2017;10(2):152-157.

scholarly journals Kinetics of Targeted Phage Rescue in a Mouse Model of SystemicEscherichia coliK1

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
György Schneider ◽  
Nikolett Szentes ◽  
Marianna Horváth ◽  
Ágnes Dorn ◽  
Alysia Cox ◽  
...  
Keyword(s):  
Capsular Polysaccharide ◽  
Protective Efficacy ◽  
Lytic Bacteriophage ◽  
E Coli ◽  
Causative Agents ◽  
High Level ◽  
Systemic Infections ◽  
Kinetics Of

Escherichia (E.) coliK1 strains remain common causative agents of neonatal sepsis and meningitis. We have isolated a lytic bacteriophage (ΦIK1) againstE. colistrain IHE3034 and tested its specificityin vitro, as well as distribution and protective efficacyin vivo. The phage was shown to be specific to the K1 capsular polysaccharide. In the lethal murine model, a high level of protection was afforded by the phage with strict kinetics. A single dose of 1 x 108phage particles administered 10 and 60 minutes following the bacterial challenge elicited 100 % and 95 % survival, respectively. No mice could be rescued if phage administration occurred 3 hours postinfection. Tissue distribution surveys in the surviving mice revealed that the spleen was the primary organ in which accumulation of active ΦIK1 phages could be detected two weeks after phage administration. These results suggest that bacteriophages have potential as therapeutic agents in the control of systemic infections.

scholarly journals In vitro Insecticidal and Time-Kill Profile of Ethyl Acetate Extract of Marine Streptomyces sp. Isolated from Sundarbans, Bangladesh

2015 ◽  
Vol 17 (2) ◽  
pp. 151-156 ◽  
Author(s):  
Md Anwarul Haque ◽  
Ashish Kumar Sarker ◽  
Mohammad Sayful Islam ◽  
Md Ajijur Rahman ◽  
Md Akter Uzzaman Chouduri ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Mangrove Forest ◽  
Bacterial Strains ◽  
Streptomyces Species ◽  
Streptomyces Sp ◽  
Cell Counts ◽  
Wide Range ◽  
Marine Streptomyces ◽  
Time Kill

The marine soil and sediment samples were collected from different locations of mangrove forest Sundarbans, Bangladesh the largest tidal halophytic mangrove forest in the world. A total of twenty nine Actinomycete strains (AIAH-1 to AIAH-29) were isolated by serial dilution method using isolation media. Among twenty nine strains, AIAH-10 was selected for further study due to its potent antibacterial activity against a wide range of pathogenic bacterial strains. On the basis of morphological, cultural and biochemical studies, the strain AIAH-10 was assigned to Streptomyces sp. The present study was designed to investigate the in vitro insecticidal and time-kill profile of ethyl acetate extracts of marine Streptomyces sp. A dose dependent mortality was observed against the larvae of Sitophilus oryzae. The larval mortality was recorded as 100% in the concentration of 80 mg/ml and higher concentrations, LC50 was found as 11.48 mg/ml. The minimum inhibitory concentration was recorded as 8 to 32 mg/ml against six different pathogenic bacterial strains. Average Log10 reductions in viable cell counts for the extracts ranged from 1.91 Log10 and 2.86 Log10 cfu/mL after 3 h interaction and 2.10 Log10 and 2.93 Log10 after 6 h interaction at MIC, 2 × MIC, 3 × MIC and 4 × MIC concentrations. This investigation reveals that the Streptomyces species isolated from Sundarbans, Bangladesh may be interesting source for the isolation of potent bioactive compounds. DOI: http://dx.doi.org/10.3329/bpj.v17i2.22332 Bangladesh Pharmaceutical Journal 17(2): 151-156, 2014

scholarly journals Investigating In Vitro Antibacterial Activities of Medicinal Plants Having Folkloric Repute in Ethiopian Traditional Medicine

2019 ◽  
Vol 24 ◽  
pp. 2515690X1988627 ◽  
Author(s):  
Mekonnen Sisay ◽  
Negussie Bussa ◽  
Tigist Gashaw ◽  
Getnet Mengistu
Keyword(s):  
Antibacterial Activity ◽  
Medicinal Plants ◽  
Antimicrobial Agents ◽  
Bacterial Isolates ◽  
Zone Of Inhibition ◽  
Traditional Use ◽  
Gram Negative ◽  
E Coli ◽  
Slow Development

Medicinal plants are targeted in the search for new antimicrobial agents. Nowadays, there is an alarmingly increasing antimicrobial resistance to available agents with a very slow development of new antimicrobials. It is, therefore, necessary to extensively search for new agents based on the traditional use of herbal medicines as potential source. The antibacterial activity of 80% methanol extracts of the leaves of Verbena officinalis (Vo-80ME), Myrtus communis (Mc-80ME), and Melilotus elegans (Me-80ME) was tested against 6 bacterial isolates using agar well diffusion technique. In each extract, 3 concentrations of 10, 20, and 40 mg/well were tested for each bacterium. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also determined. Vo-80ME and Mc-80ME exhibited promising antibacterial activity against Staphylococcus aureus with the highest zone of inhibition being 18.67 and 26.16 mm, respectively at concentration of 40 mg/well. Regarding gram-negative bacteria, Vo-80ME exhibited an appreciable activity against Escherichia coli and Salmonella typhi. Mc-80ME displayed remarkable activity against all isolates including Pseudomonas aeruginosa with the maximum zone of inhibition being 22.83 mm. Me-80ME exhibited better antibacterial activity against E coli, but its secondary metabolites had little or no activity against other gram-negative isolates. The MIC values of Vo-80ME ranged from 0.16 to 4.00 mg/mL. The lowest MIC was observed in Mc-80ME, with the value being 0.032 mg/mL. Mc-80ME had bactericidal activity against all tested bacterial isolates. Mc-80ME showed remarkable zone of inhibitions in all tested bacterial isolates. Besides, Vo-80ME showed good antibacterial activity against S aureus, E coli, and S typhi. Conversely, Me-80ME has shown good activity against E coli only. Generally, M communis L and V officinalis have good MIC and MBC results.

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