ceragenin-csa-13 and Hemolysis

Ceragenin CSA-13, a cationic steroid, is here reported to show a concentration-dependent bactericidal/bacteriolytic activity against pathogenic streptococci, including multidrug-resistant Streptococcus pneumoniae. The autolysis promoted by CSA-13 in pneumococcal cultures appears to be due to the triggering of the major S. pneumoniae autolysin LytA, an N-acetylmuramoyl-L-alanine amidase. CSA-13 also disintegrated pneumococcal biofilms in a very efficient manner, although at concentrations slightly higher than those required for bactericidal activity on planktonic bacteria. CSA-13 has little hemolytic activity which should allow testing its antibacterial efficacy in animal models.

Topics: Animals; Anti-Bacterial Agents; Biofilms; Erythrocytes; Hemolysis; Humans; Microbial Sensitivity Tests; Microbial Viability; Plankton; Sheep, Domestic; Steroids; Streptococcus pneumoniae

Ceragenin CSA-13 is a synthetic mimic of cationic antibacterial peptides, with facial amphiphilic morphology reproduced using a cholic acid scaffold. Previous data have shown that this molecule displays broad-spectrum antibacterial activity, which decreases in the presence of blood plasma. However, at higher concentrations, CSA-13 can cause lysis of erythrocytes. This study was designed to assess in vitro antibacterial and haemolytic activity of CSA-13 in the presence of pluronic F-127.. CSA-13 bactericidal activity against clinical strains of bacteria associated with topical infections and in an experimental setting relevant to their pathophysiological environment, such as various epithelial tissue fluids and the airway sputum of patients suffering from cystic fibrosis (CF), was evaluated using minimum inhibitory and minimum bactericidal concentration (MIC/MBC) measurements and bacterial killing assays. We found that in the presence of pluronic F-127, CSA-13 antibacterial activity was only slightly decreased, but CSA-13 haemolytic activity was significantly inhibited. CSA-13 exhibits bacterial killing activity against clinical isolates of Staphylococcus aureus, including methicillin-resistant strains, Pseudomonas aeruginosa present in CF sputa, and biofilms formed by different Gram (+) and Gram (-) bacteria. CSA-13 bactericidal action is partially compromised in the presence of plasma, but is maintained in ascites, cerebrospinal fluid, saliva, and bronchoalveolar lavage fluid. The synergistic action of CSA-13, determined by the use of a standard checkerboard assay, reveals an increase in CSA-13 antibacterial activity in the presence of host defence molecules such as the cathelicidin LL-37 peptide, lysozyme, lactoferrin and secretory phospholipase A (sPLA).. These results suggest that CSA-13 may be useful to prevent and treat topical infection.. Combined application of CSA-13 with pluronic F-127 may be beneficial by reducing CSA-13 toxicity.

Topics: Anti-Bacterial Agents; Antimicrobial Cationic Peptides; Biofilms; Cholic Acid; Cystic Fibrosis; Hemolysis; Humans; Poloxamer; Pseudomonas aeruginosa; Pseudomonas Infections; Skin Diseases, Bacterial; Staphylococcus aureus; Steroids; Surface-Active Agents

The goal of this study was to evaluate the effects of DNA and F-actin [polyanions present in high concentration in cystic fibrosis (CF) airway fluid] on the antibacterial activities of the cationic steroid antibiotic CSA-13 and the cationic peptides LL37, WLBU2 and HB71.. Light scattering intensity was used to evaluate the aggregation of DNA and F-actin by the cationic antibacterial agents. Bacterial killing assays, atomic force microscopy, determination of MIC values and bacterial load of CF sputa were used to determine the bactericidal activity. Inhibition of nuclear factor-kappaB (NF-kappaB) translocation in human aorta endothelial cells (HAECs) was quantified as an assay of anti-inflammatory action.. CSA-13 is significantly more effective than cationic antibacterial peptides against kanamycin-resistant Pseudomonas aeruginosa and less susceptible to inactivation by DNA or F-actin. The concentration of CSA-13 sufficient to decrease the CF sputa bacteria load by approximately 90% is at least 10 times lower than that at which CSA-13 formed aggregates with DNA or F-actin. Both CSA-13 and LL37 prevent lipopolysaccharide-induced translocation of NF-kappaB in HAEC, thereby suggesting that these antibacterial molecules might prevent systemic inflammation caused by bacterial wall components.. Charge-based interactions that strongly inhibit the antibacterial activity of host cationic antibacterial peptides present in CF sputa have significantly less effect on molecules from the ceragenin family such as CSA-13 due in part to their smaller net charge and distribution of this charge over a hydrophobic scaffold. CSA molecules therefore have potential for the treatment of chronic infections and inflammation that occur in CF airways and other settings in which extracellular polyanions accumulate.

Topics: Actins; Adult; Amino Acid Sequence; Anti-Bacterial Agents; Bacteria; Cell Line; Cystic Fibrosis; Deoxyribonuclease I; DNA; Drug Resistance, Bacterial; Electrolytes; Endothelial Cells; Erythrocytes; Hemolysis; Humans; Lipopolysaccharides; Microbial Sensitivity Tests; Microscopy, Atomic Force; Peptides; Sputum; Steroids; Teichoic Acids