scholarly journals Statistical comparison of the antibacterial activities of broad-spectrum penicillins against gram-negative bacilli.

1983 ◽  
Vol 24 (2) ◽  
pp. 156-162 ◽  
Author(s):  
R J Fass
2021 ◽  
Author(s):  
Byungji Kim ◽  
Qinglin Yang ◽  
Leslie W. Chan ◽  
Sangeeta N. Bhatia ◽  
Erkki Ruoslahti ◽  
...  

RNAi-mediated immunotherapy provided by fusogenic porous silicon nanoparticles demonstrates superior therapeutic efficacy against both Gram-positive and Gram-negative bacterial infections compared with first-line antibiotics.


ACS Omega ◽  
2021 ◽  
Author(s):  
Faizan Abul Qais ◽  
Mohammad Shavez Khan ◽  
Iqbal Ahmad ◽  
Fohad Mabood Husain ◽  
Rais Ahmad Khan ◽  
...  

2006 ◽  
Vol 50 (6) ◽  
pp. 2261-2264 ◽  
Author(s):  
Hee-Soo Park ◽  
Hyun-Joo Kim ◽  
Min-Jung Seol ◽  
Dong-Rack Choi ◽  
Eung-Chil Choi ◽  
...  

ABSTRACT DW-224a showed the most potent in vitro activity among the quinolone compounds tested against clinical isolates of gram-positive bacteria. Against gram-negative bacteria, DW-224a was slightly less active than the other fluoroquinolones. The in vivo activities of DW-224a against gram-positive bacteria were more potent than those of other quinolones.


β-Lactam antibiotics resistant to β-lactamase degradation can be produced by many chemical modifications, but often at the expense of antibacterial activity. Substitution onto several positions in the molecule produces different and often selective resistance; for instance, heavily sterically hindered acyl groups give staphylococcal P-lactamase resistance to penicillins, and resistance to some enzymes from Gram-negative pathogens to both penicillins and cephalosporins. 6-α- or 7-α-substituents respectively confer a broad spectrum of resistance (e.g. cefoxitin), but changes at positions 2 or 3 have only a minor influence on enzyme susceptibility. Changes in the ring condensed with the β-lactam, such as changing ceph-3-em to ceph-2-em may greatly enhance stability. Small improvements can occur when the nuclear sulphur atom is oxidized, but a much better effect is obtained when it is replaced by another atom such as oxygen, as in clavulanic acid. This compound appears to have broad spectrum resistance which is actually due to susceptibility and subsequent product inhibition.


2013 ◽  
Vol 829 ◽  
pp. 294-298 ◽  
Author(s):  
Mehrdad Rashidzadeh

High purity Cadmium (Cd) metal was used as raw material and placed in a microwave susceptor. an evaporation/oxidation process occurs under exposure to microwave in less than 2 minutes. Then, Evaporated cadmium reacted with oxygen and cadmium oxide was collected on the inner surface of a glassy container that was placed a few centimeters above the susceptor. Morphological and structural information of As-synthesized CdO nanopowder, were investigated via SEM and X-ray diffraction (XRD) spectroscopy. The antibacterial activities of different concentration of the CdO nanoparticles were tested by treating Escherichia coli (Gram negative) cultures with CdO nanoparticles. The Study indicates that cadmium oxide nanoparticles show effective antibacterial activity toward the gram-negative bacterium E. coli. Electrochemical properties of as-synthesized powder were investigated via linear and two vertex cyclic voltammetery in the presence of ethanol, a pair of Oxidation/reduction peaks were achieved.


2014 ◽  
Vol 58 (8) ◽  
pp. 4911-4914 ◽  
Author(s):  
Gerald A. Denys ◽  
Chris M. Pillar ◽  
Daniel F. Sahm ◽  
Peter O'Hanley ◽  
Jackson T. Stephens

ABSTRACTThis study summarizes the topical E-101 solution susceptibility testing results for 760 Gram-positive and Gram-negative target pathogens collected from 75 U.S. sites between 2008 and 2012 and 103 ESKAPE pathogens. E-101 solution maintained potent activity against all bacterial species studied for each year tested, with MICs ranging from <0.008 to 0.25 μg porcine myeloperoxidase (pMPO)/ml. These results confirm that E-101 solution retains its potent broad-spectrum activity against U.S. clinical isolates and organisms with challenging resistance phenotypes.


2020 ◽  
Author(s):  
Hanh N. Lam ◽  
Tannia Lau ◽  
Adam Lentz ◽  
Jessica Sherry ◽  
Alejandro Cabrera-Cortez ◽  
...  

ABSTRACTAntibiotic resistant bacteria are an emerging global health threat. New antimicrobials are urgently needed. The injectisome type III secretion system (T3SS), required by dozens of Gram-negative bacteria for virulence but largely absent from non-pathogenic bacteria, is an attractive antimicrobial target. We previously identified synthetic cyclic peptomers, inspired by the natural product phepropeptin D, that inhibit protein secretion through the Yersinia Ysc and Pseudomonas aeruginosa Psc T3SSs, but do not inhibit bacterial growth. Here we describe identification of an isomer, 4EpDN, that is two-fold more potent (IC50 4 μM) than its parental compound. Furthermore, 4EpDN inhibited the Yersinia Ysa and the Salmonella SPI-1 T3SSs, suggesting that this cyclic peptomer has broad efficacy against evolutionarily distant injectisome T3SSs. Indeed, 4EpDN strongly inhibited intracellular growth of Chlamydia trachomatis in HeLa cells, which requires the T3SS. 4EpDN did not inhibit the unrelated Twin arginine translocation (Tat) system, nor did it impact T3SS gene transcription. Moreover, although the injectisome and flagellar T3SSs are evolutionarily and structurally related, the 4EpDN cyclic peptomer did not inhibit secretion of substrates through the Salmonella flagellar T3SS, indicating that cyclic peptomers broadly but specifically target the injestisome T3SS. 4EpDN reduced the number of T3SS basal bodies detected on the surface of Y. enterocolitica, as visualized using a fluorescent derivative of YscD, an inner membrane ring with low homology to flagellar protein FliG. Collectively, these data suggest that cyclic peptomers specifically inhibit the injectisome T3SS from a variety of Gram-negative bacteria, possibly by preventing complete T3SS assembly.IMPORTANCETraditional antibiotics target both pathogenic and commensal bacteria, resulting in a disruption of the microbiota, which in turn is tied to a number of acute and chronic diseases. The bacterial type III secretion system (T3SS) is an appendage used by many bacterial pathogens to establish infection, but is largely absent from commensal members of the microbiota. In this study, we identify a new derivative of the cyclic peptomer class of T3SS inhibitors. These compounds inhibit the T3SS of the nosocomial ESKAPE pathogen Pseudomonas aeruginosa and enteropathogenic Yersinia and Salmonella. The impact of cyclic peptomers is specific to the T3SS, as other bacterial secretory systems are unaffected. Importantly, cyclic peptomers completely block replication of Chlamydia trachomatis, the causative agent of genital, eye, and lung infections, in human cells, a process that requires the T3SS. Therefore, cyclic peptomers represent promising virulence blockers that can specifically disarm a broad spectrum of Gram-negative pathogens.


Author(s):  
Tharcitus Chilaka Onwudiwe Prince Chiazor Unekwe ◽  
Kingsley Chimsorom Chilaka Malachy Ifeanyi Obi

The problem of drug resistance to orthodox antimicrobial agents has remained a setback in the treatment of bacterial infections in the modern society. Adverse effects, coupled with scarcity and high cost of orthodox drugs have necessitated interest in the search, development and use of antibacterial agents from plant origin. Piper guineense is claimed in traditional medicine as a remedy for gram negative organism-transmitted infections. The leaves of Piper guineense plant was collected, washed, dried at room temperature and pulverized. The plant material was extracted with 80% ethanol. The ethanol-extracted residue was subjected to fractionation. Seventeen fractions were obtained, and were pooled together based on their Rf values into five pooled-fractions labeled: PF-1, PF-2, PF-3, PF-4, PF-5. Both the ethanol and fraction extracts were subjected to phytochemical analysis, preliminary antibacterial screening, minimum inhibitory and minimum bactericidal concentrations determination using both clinical isolates and type culture organisms. The yield of ethanol-extracted residue was low (21.08g) when compared to the amount of pulverized plant material (500g). Phytochemical analysis revealed the presence of flavonoids, alkaloids and terpenoids in all the extracts. The extracts produced statistically significant lower zone of inhibition (p<0.05) when compared with the standard drug (amoxicillin), it also demonstrated activity against test organisms used in the study. The findings of this study demonstrated that ethanol leaf extract of Piper guineense possess antibacterial activities, therefore justifies the traditional claim of the plant.


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