The in vitro activity of HR756, a new semisynthetic cephalosporin, was compared with the activities of cephalothin, cefoxitin, and cefamandole against 1,535 isolates of gram-positive and gram-negative bacteria. HR756 was less active than cephalothin and cefamandole and twofold more active than cefoxitin against Staphylococcus. All four of the antibiotics were inactive against the enterococcus g...

The ability of cecropin A to permeabilize and depolarize the membranes of Escherichia coli ML-35p bacteria has been compared to its bactericidal activity in an extension of earlier studies performed on synthetic lipid vesicle membranes (L. Silvestro, K. Gupta, J. H. Weiser, and P. H. Axelsen, Biochemistry 36:11452-11460, 1997). Our results indicate that differences in the concentration dependen...

The activity of cefoperazone, a new broad-spectrum cephalosporin, was tested in vitro against 670 clinical isolates of gram-negative bacilli and gram-positive cocci. With the exception of Enterobacter spp., it inhibited the majority of all organisms tested at a concentration of 6.25 microgram/ml. Of particular interest is its good activity against Pseudomonas aeruginosa isolates which are usual...

Investigation of the alcoholic extract of chamomile against growth and production of catalase, Dnase and haemolysin of Staphylococcus aureus (ATCC29213) were the aims of this study In this study, German chamomile was prepared from Tehran agricultural researches center. Extraction was performed by ethanol 85 (Maceration method) then solvent is removed by vacuum distillation system (concentrated ...

A series of nine substituted 2-hydroxy-N-[1-oxo-1-(phenylamino)alkan-2-yl]benzamides was assessed as prospective bactericidal agents against three clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and S. aureus ATCC 29213 as the reference and quality control strain. The minimum bactericidal concentration was determined by subculturing aliquots from MIC determination onto s...

was prevented completely by DW-224a at concentrations of 1·, 2· and 4· MIC by 24 h, although regrowth occurred in the presence of ciprofloxacin at 1· MIC concentration. DW-224a also showed a dose-dependent bactericidal activity against all test organisms up to 4· the MIC. The MBCs of DW-224a in Mueller–Hinton broth (MHB) were identical to 1·MIC or at most twice the MIC for all strains tested. B...

A new method of assessing the bactericidal activity of quinolones and other antibacterial agents, known as the bactericidal index or BI, is introduced and discussed. The BI represents total bacterial kill over a drug concentration range limited to levels achievable in vivo. This method allows the bactericidal activity of drugs to be readily compared. Calculation of BI produces a single value pe...

Observe the synergistic effect and dose-effect relationship of Trimethoprim (TMP) on bactericidal activity with Flos Lonicerae in vitro. Microamount chessboard dilution method was conducted to determine the minimal inhibitory concentration (MIC) of Trimethoprim, Flos Lonicerae, as well as the combination of Trimethoprim and Flos Lonicerae separately against Staphylococcus aureus, Escherichia co...

The effects of nalidixic acid and four fluoroquinolones on DNA, RNA, and protein synthesis in the presence and absence of 20 mg of chloramphenicol per liter were examined by comparing the killing kinetics, MIC, morphological response, and maximum concentration to induce recA in Escherichia coli. All agents demonstrated paradoxical killing kinetics, in that above an optimum concentration the rat...

ABSTRACT: Mastitis causes significant economic losses to the dairy cattle industry. The present study aimed evaluate antibacterial properties of 39 heterocyclic derivatives (1,3-thiazoles and 4-thiazolidinones) against clinical mastitis isolates from cows. Milk samples were collected cows with bacterial species identified by PCR. Antibacterial activity was assessed using broth microdilution met...