جستجوی مقالات مرتبط با کلیدواژه "minimal inhibitory concentration" در نشریات گروه "پزشکی"

The aim of this study was to investigate the antimicrobial properties of silver nanoparticles synthesized using Lycium ruthenicum extract. In this experimental study, Escherichia coli (ATCC25922), Pseudomonas aeruginosa (ATCC27853), Klebsiella pneumoniae (ATCC9997), Staphylococcus aureus (ATCC25923) and Enterococcus faecalis (ATCC29212) were studied. Aqueous extract of L. ruthenicum was prepared. silver nanoparticles were prepared in combination with L. ruthenicumextract. The MIC of silver nanoparticles was investigated alone and in combination with the L. ruthenicumplant using the broth microdilution method for Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus and Enterococcus faecalis.: This study showed that the nanoparticle synthesized with the aqueous extract of the Lycium ruthenicum plant had a significant inhibitory effect on E. coli, P. aeruginosa, and S. aureus compared to the aqueous extract alone (P < 0.05). Also, the highest inhibitory activity of L. ruthenicum extract was for K.pneumoniae and E. faecalis with MIC 2.5 mg / ml. On the other hand, biosynthesized silver nanoparticles against E. coli with MIC 1.25 mg / ml showed the highest inhibitory activity. In general, silver nanoparticles synthesized with L. ruthenicum extract had significant antibacterial effects on the studied bacteria, in comparison with silver nanoparticles by chemical method as well as the plant L. ruthenicum alone. The results of the present study showed that silver nanoparticles synthesized with L. ruthenicumextract have significant antibacterial effects, which can be used as a suitable treatment option for antibiotics due to the side effects of antibiotics after further studies on animal models.

Nanosilver particles have the potential to serve as bactericidal agent because of the antimicrobial influences of silver ion. This in vitro study aimed to evaluate the antimicrobial and antibiofilm properties of nanosilver against two dental plaque microorganisms, namely Streptococcus mutans (Sm) and Aggregatibacter actinomycetemcomitans (Aa).

Initially, growth inhibition zone test was performed in brain heart infusion agar medium using Cup-plate method. Subsequently, microdilution method was utilized to determine the Minimal Inhibitory Concentrations (MIC) and Minimal Bactericidal Concentrations (MBC). Furthermore, the kinetics of bacterial death was assessed by the Time-Kill Test in different time points (i.e., 30, 60, and 120 sec, as well as 5 min). In addition, the effect of these microorganisms was investigated on the formation of the bacterial biofilms using the tissue Culture Plate Method (TCP).

The results of the t-test indicated that chlorhexidine (120 μg/ml) and nanosilver (200 μg/ml) had the same antimicrobial effect on S m, whereas chlorhexidine was more effective against Aa (P<0.0001). The MIC and MBC of silver nanoparticles were 3.90 and 3.90 μg/ml for Sm and 6.5 and 13.01 μg/ml for Aa. The kinetics of bacterial death evaluation demonstrated that in both tested bacteria, the antimicrobial agents were able to reduce microorganism populations regarding 6 algorithmic cycles significantly after 30 sec of the contact with the antibacterial agent. The t-test statistical analysis showed no significant difference between nanosilver and chlorhexidine groups regarding the biofilm decreasing percentage for Sm and Aa (P>0.05).

Nanosilver had rapid and significant antibacterial effects against dental plaque microorganisms. It is also very effective in inhibiting biofilm formation in two bacterial species in in vitro condition.

Aims: Bacillus amyloliquefaciens lipopeptide are made of amino acids and fatty acid chain, and have many antifungal activities against several important pathogenic yeasts. The present research was carried out with the aim of extraction and evaluation of antifungal effect of lipopeptide compounds produced by Esfahan native Bacillus amyloliquefaciens M13RW01 against Candida albicans, Candida glabrata, Candida krusei, Candida parapsilosis, and Candida tropicalis.
In this experimental study, Bacillus amyloliquefaciens M13RW01 was cultured in modified Peptone-Glucose-Yeast extract medium (PGY) for 72 hours. Then, the lipopeptide compounds produced in the medium by precipitation with HCl 6M were extracted and dissolved in methanol (50% water; 50% methanol). The antifungal activity of lipopeptide compounds against 5 species of Candida was investigated by well diffusion method, Minimum Inhibitory Concentration (MIC), and Minimum Fungal Concentration (MFC). Also, germ tube production by Candida albicans in tube containing lipopeptide was investigated.
Findings: The Bacillus amyloliquefaciens M13RW01 lipopeptide metabolites inhibited germ tube production in all C. albicans yeasts, but no inhibitory or fatal effect was observed on other species of Candida. Inhibition zone was not observed around the wells; in all dilutions, Candida yeasts grew. Therefore, minimal inhibitory concentration and minimal fungicidal concentration were not determined.
The lipopeptide metabolites produced by Bacillus amyloliquefaciens M13RW01 have no inhibitory or fungal effects on the studied species of Candida, but inhibit the germ tubes production by Candida albicans yeast.

The use of drugs to treat diseases led to the emergence of resistant strains of bacteria. Bacterial resistance to antibiotics is the most common problems in medical science. In this study, the antibacterial effect of ethanolic extract of Alcea digitata L., Satureja bachtiarica L. and Ferulago Angulata L on four pathogenic bacteria, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and Streptococcus agalactiae was investigated. In this experimental study, the extracts have been prepared from Alcea digitata L., Satureja bachtiarica L. and Ferulago Angulata L. Their antibacterial activity at different concentrations (800, 400, 200, 100 mg/ml) was determined by disk-diffusion agar method and the dilution method. The antibiotics tetracycline and gentamicin as a positive control and DMSO was used as negative control and the MIC and MBC were determined. Based on the results of this study, three plant extracts dose-dependently increased the bacteria inhibition zone especially in the gram-positive bacteria compared to the gram- negative bacteria (p<0.05). Extract of Ferulago Angulata L has maximum antibacterial activity on the growth of bacteria S. aureus (25±0.57) (p<0.05). According to the results of this study, three extracts had growth inhibitory effect on all four bacteria. Extract of Ferulago Angulata L. had greater antibacterial activity than the others and the Staphylococcus aureus was the most sensitive strain to the extracts.

In this study the major components of essential oil of Coriandrum sativum، Achillea millefolium and Anethum graveolens were studied and the antibacterial effects of these 3 plants on four pathogens including Escherichia coli، Bacillus cereus، Bacillus licheniformis and Pseudomonas aeruginosa were evaluated in vitro and Minimal Inhibitory Concentration (MIC) were determined. In this experimental study the essential oil of the plants by distillation with water and clevenger was extracted. The constituents of these plants essential oil analysis by gas chromatography (GC) and gas chromatograph linked to mass spectrometry (GC/MS) were identified and the percentage of their componants was determined. For determining the MIC for each essential oil on four pathogens Micro Dilution was used. Results indicated that in essential oil of Achillea millefolium، α-Pinene، in Coriandrum sativum D-varvone and in Anethum graveolens، Linalool were the essential compounds. Generally it was found that for inhibiting Escherichia coli and Bacillus licheniformis growth، Anethum graveolens essential oil with 312. 5 ppm and for inhibiting Bacillus cereus and Pseudomonas aeruginosa growth، respectively Coriandrum sativum and Achillea millefolium essence with 1250 ppm and 312. 5 ppm concentration was effective. All three extracts of Coriandrum sativum، Achilleh millefolium، Anethum graveolens، had superlative effect on pathogens and may be beneficil in the treatment of infectious diseases.

Microorganisms resistant to both antibiotics and metals have been isolated from nosocomial and urinary tract infection. Most heavy metal-resistant hospital infections including Klebsiella pneumoniae (K. pneumoniae) harbor plasmids with different molecular sizes. The aim of this study was the molecular detection of simultaneous occurrence of antibiotic and heavy metal resistance in Klebsiella isolated from urinary tract infection (UTI). Overall, 144 K. pneumonia strains were isolated from UTI samples in the laboratories of hospitals and clinics. Primary selection of β-lactam-resistant strains was conducted using combined disk and double-disk (DD) synergy methods according to the guidelines of Clinical and Laboratory Standards Institute (CLSI). Polymerase chain reaction (PCR) was also performed to detect TEM-1 and SHV-1 genes in resistant strains. Minimal inhibitory concentrations (MICs) of the heavy metals were determined for Hg2+, Cu2+, Pb2+, and Cd2+. Among the 61.81% antibiotic-resistant strains, 42.69% were β-lactamase producers. After performing PCR, from 38 positive extended spectrum beta lactamase (ESBL) strains, 28.94% of Klebsiella strains harbored SHV gene and 34.21% harbored TEM gene. The highest resistance was to Hg2+ (35 mg/L), Cu2+ (650 mg/L), Pb2+ (350 mg/L), and Cd2+ (200 mg/L). A significant difference was observed between antibiotic-resistant and heavy metals-resistant strains (P = 0.012(. Plasmid-carrying isolates that showed resistant to heavy metals were highly resistant to antibiotics. The results showed that it is possible for the plasmids which carry genes for resistance to antibiotics and heavy metals to be exchanged by bacterial strains.