scholarly journals A3, a Scorpion Venom Derived Peptide Analogue with Potent Antimicrobial and Antibiofilm Activity against Clinical Isolates of Multi-Drug Resistant Gram Positive Bacteria

2018 ◽  
Author(s):  
Ammar Almaaytah ◽  
Ahmad Farajallah ◽  
Ahmad Abualhaijaa ◽  
Qosay Al-balas
Keyword(s):  
Host Defense ◽  
Mammalian Cells ◽  
Scorpion Venom ◽  
Clinical Isolates ◽  
Drug Resistant ◽  
Gram Positive ◽  
Peptide Analogue ◽  
Gram Positive Bacteria ◽  
Conventional Antibiotics

Current research in the field of antimicrobials is focused on the development of novel antibiotics and antimicrobial agents to counteract the huge dilemma that the human population is mainly facing in regards to the rise of bacterial resistance and biofilm infections. Host Defense peptides (HDPs) are a promising group of molecules for antimicrobial development as they share unique characteristics suitable for antimicrobial activity including their broad spectrum of activity and potency against bacteria. AamAP1 is a novel HDP that was identified through molecular cloning from the venom of the North African scorpion Androctonus amoeruxi. In vitro antimicrobial assays revealed that the peptide displays moderate activity against different strains of Gram-positive and Gram-negative bacteria. Additionally, the peptide proved to be highly hemolytic and displaying significantly high toxicity against mammalian cells. In our study, a novel synthetic peptide analogue named A3 was designed from the naturally occurring scorpion venom host defense peptide. The design strategy depended on modifying the amino acid sequence of the parent peptide in order to increase its net positive charge, percentage helicity and optimize other physico-chemical parameters involved theoretically in HDPs activity. Accordingly, A3 was evaluated for its in vitro antimicrobial and anti-biofilm activity individually and in combination with four different types of conventional antibiotics against clinical isolates of multi-drug resistant (MDR) Gram-positive bacteria. A3 was also evaluated for its cytotoxicity against mammalian cells. A3 displayed potent and selective in vitro antimicrobial activities against a wide range of MDR Gram-positive bacteria. Our results also showed that combining A3 with conventional antibiotics displayed a synergistic mode of action which resulted in decreasing the MIC value for A3 peptide as low as 0.125 µM. These effective concentrations were associated with negligible toxicities on mammalian cells. In conclusion, A3 exhibits enhanced activity and selectivity when compared with the parent natural scorpion venom peptide. The combination of A3 with conventional antibiotics may be pursued as a potential novel treatment strategy against MDR and biofilm forming bacteria.

scholarly journals In Vitro Activity of Eravacycline against Gram-Positive Bacteria Isolated in Clinical Laboratories Worldwide from 2013 to 2017

2019 ◽  
Vol 64 (3) ◽  
Author(s):  
Ian Morrissey ◽  
Stephen Hawser ◽  
Sibylle H. Lob ◽  
James A. Karlowsky ◽  
Matteo Bassetti ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Clinical Isolates ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Microdilution Method ◽  
Clinical Laboratories ◽  
Broth Microdilution Method ◽  
Doubling Dilution

ABSTRACT Eravacycline is a novel, fully synthetic fluorocycline antibiotic being developed for the treatment of serious infections, including those caused by resistant Gram-positive pathogens. Here, we evaluated the in vitro activities of eravacycline and comparator antimicrobial agents against a recent global collection of frequently encountered clinical isolates of Gram-positive bacteria. The CLSI broth microdilution method was used to determine in vitro MIC data for isolates of Enterococcus spp. (n = 2,807), Staphylococcus spp. (n = 4,331), and Streptococcus spp. (n = 3,373) isolated primarily from respiratory, intra-abdominal, urinary, and skin specimens by clinical laboratories in 37 countries on three continents from 2013 to 2017. Susceptibilities were interpreted using both CLSI and EUCAST breakpoints. There were no substantive differences (a >1-doubling-dilution increase or decrease) in eravacycline MIC90 values for different species/organism groups over time or by region. Eravacycline showed MIC50 and MIC90 results of 0.06 and 0.12 μg/ml, respectively, when tested against Staphylococcus aureus, regardless of methicillin susceptibility. The MIC90 values of eravacycline for Staphylococcus epidermidis and Staphylococcus haemolyticus were equal (0.5 μg/ml). The eravacycline MIC90s for Enterococcus faecalis and Enterococcus faecium were 0.06 μg/ml and were within 1 doubling dilution regardless of the vancomycin susceptibility profile. Eravacycline exhibited MIC90 results of ≤0.06 μg/ml when tested against Streptococcus pneumoniae and beta-hemolytic and viridans group streptococcal isolates. In this surveillance study, eravacycline demonstrated potent in vitro activity against frequently isolated clinical isolates of Gram-positive bacteria (Enterococcus, Staphylococcus, and Streptococcus spp.), including isolates collected over a 5-year period (2013 to 2017), underscoring its potential benefit in the treatment of infections caused by common Gram-positive pathogens.

In vitro activity of quinupristin/dalfopristin against clinical isolates of common gram-positive bacteria in Taiwan

1999 ◽  
Vol 33 (4) ◽  
pp. 299-303 ◽  
Author(s):  
Shan-Chwen Chang ◽  
Chi-Tai Fang ◽  
Po-Ren Hsueh ◽  
Kwen-Tay Luh ◽  
Wei-Chuan Hsieh
Keyword(s):  
Vitro Activity ◽  
Clinical Isolates ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Positive Bacteria

scholarly journals In Vitro Activities of Ertapenem (MK-0826) against Clinical Bacterial Isolates from 11 North American Medical Centers

2001 ◽  
Vol 45 (6) ◽  
pp. 1915-1918 ◽  
Author(s):  
Peter C. Fuchs ◽  
Arthur L. Barry ◽  
Steven D. Brown
Keyword(s):  
American Medical ◽  
North American ◽  
Half Life ◽  
Clinical Isolates ◽  
Bacterial Isolates ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Medical Centers ◽  
Amoxicillin Clavulanate

ABSTRACT This study compared the in vitro activities of the new long-half-life carbapenem ertapenem (also known as MK-0826 and L-749,345) with those of imipenem, amoxicillin-clavulanate, and ciprofloxacin against 5,558 recent clinical isolates from 11 North American medical centers. We confirmed the greater activity of ertapenem than of imipenem against the Enterobacteriaceae and the greater activity of imipenem against pseudomonads and gram-positive bacteria.

scholarly journals Antimicrobial activity of crude henna extract against Gram-positive bacteria

2021 ◽  
Vol 5 (3) ◽  
Keyword(s):  
Antimicrobial Activity ◽  
Crude Extract ◽  
Antibacterial Properties ◽  
Diffusion Method ◽  
Drug Resistant ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Bacterial Agent ◽  
Henna Extract

Objectives: This study aimed to examine the effect of ethanolic extract of local Basra henna leaves on Gram-positive bacteria species. Also, to assess the antibacterial properties of henna crude extract in vitro and compare them with antibiotics. Methods: In this study, Lawsonia inermis (henna) leaves were extracted with ethanol using the solvent extraction technique. The pathogens were isolated from wound samples obtained from hospitalized patients in two different hospitals in Duhok city. The culture of thirty isolates had been recognized by routine methods. Different concentrations of ethanol crude extract were acquired and bio-assayed in vitro to inhibit the growth of five human pathogenic Gram-positive bacteria. Agar well diffusion assay was used for achieving henna antibiotic activity. Moreover, an antibiotics susceptibility test was done by the disk diffusion method using the Muller-Hinton agar medium. Results: The growth of all tested bacteria was suppressed to various degrees by increasing the concentration of the extract. The data has revealed that Staphylococcus aureus was more sensitive than other examined isolates, where the diameter zone of inhibition was ranging from 16-27, 14-25, and 8-18 mm for Staphylococcus epidermidis, Lactobacillus spp. and Streptococcus pneumonia respectively. The antimicrobial activity of henna extract indicates that it is suitable for being used as significant certain medications. Consequently, henna is active to serve as an anti-bacterial agent against multi-drug resistant Gram-positive bacteria. Conclusion: The antimicrobial activity of henna extract indicates that it is suitable for being used as significant certain medications. Consequently, henna is active to serve as an anti-bacterial agent against multi-drug resistant Gram-positive bacteria.

In vitro activity of daptomycin against clinical isolates of Gram-positive bacteria

2005 ◽  
Vol 11 (4) ◽  
pp. 207-209 ◽  
Author(s):  
Kerryl E. Piper ◽  
James M. Steckelberg ◽  
Robin Patel ◽  
Robin Patel
Keyword(s):  
Vitro Activity ◽  
Clinical Isolates ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Positive Bacteria

scholarly journals In vitro activity of CP-99,219, a new fluoroquinolone, against clinical isolates of gram-positive bacteria.

1993 ◽  
Vol 37 (2) ◽  
pp. 366-370 ◽  
Author(s):  
G M Eliopoulos ◽  
K Klimm ◽  
C T Eliopoulos ◽  
M J Ferraro ◽  
R C Moellering
Keyword(s):  
Vitro Activity ◽  
Clinical Isolates ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Positive Bacteria

scholarly journals In Vitro Activities of the Glycylcycline GAR-936 against Gram-Positive Bacteria

2000 ◽  
Vol 44 (8) ◽  
pp. 2225-2229 ◽  
Author(s):  
Helen W. Boucher ◽  
Christine B. Wennersten ◽  
George M. Eliopoulos
Keyword(s):  
Clinical Isolates ◽  
Gram Positive ◽  
Gram Positive Bacteria

ABSTRACT The in vitro activities of GAR-936, the 9-t-butylglycylamido derivative of minocycline, were compared with those of doxycycline, minocycline, and tetracycline against 527 gram-positive clinical isolates. GAR-936 inhibited all strains, including those resistant to other tetracyclines, at concentrations of ≤2 μg/ml, except two strains of JK diphtheroids for which the MIC was 4 μg/ml.

scholarly journals Size Attenuated Copper Doped Zirconia Nanoparticles Enhances in Vitro Antimicrobial Properties

2021 ◽  
Author(s):  
Nishakavya S ◽  
Agnishwar Girigoswami ◽  
Deepa R ◽  
Divya A ◽  
Ajith S ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Biomedical Applications ◽  
Antimicrobial Properties ◽  
Gram Positive ◽  
Antimicrobial Drugs ◽  
Xtt Assay ◽  
Gram Positive Bacteria ◽  
Positively Charged ◽  
Zirconia Nanoparticles

Abstract Biofilm formation hinders the activity of antimicrobial drugs at the site of infections and any agent that can act on both Gram- positive and Gram- bacteria by inhibiting the bacterial growth and rupture the biofilm is needed for the management of infection. In the present study, we have synthesized ZrO2 NPs and copper doped zirconia nanoparticles (Cu-ZrO2 NPs) and characterized them using dynamic light scattering, X-ray diffractometry and scanning electron microscopy (SEM). The size of the Cu-ZrO2 NPs drastically reduced compared to ZrO2 NPs and the antimicrobial activity was studied against Gram- positive bacteria (Lactobacillus sp.) and Gram- negative bacteria (Pseudomonas aeruginosa), respectively. The synthesized Cu-ZrO2 NPs showed superior inhibitory action against Lactobacillus sp. compared to ZrO2 NPs, due to the negatively charged cell wall of Lactobacillus sp. which could attract readily the positively charged Cu-ZrO2 NPs, thereby inhibiting its activity. The biocompatibility was tested using XTT assay in FL cells and the results demonstrated that Cu-ZrO2 NPs were non- toxic to mammalian cells. Hence, it could be proposed that the synthesized Cu-ZrO2 NPs possess possible biomedical applications and can be used as antibacterial agents without causing toxicity in mammalian cells.

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