bekanamycin and Staphylococcal-Infections

The Staphylococcus aureus can switch to a transient genotype-invariant dormancy, known as a persister, to survive treatment with high doses of antibiotics. This transient persister is an important reason underlying its resistance. There is an urgent need to find new antibacterial agents capable of eradicating methicillin-resistant S. aureus (MRSA) persisters. In this study, 37 new derivatives of cajaninstilbene acid (CSA) were designed and synthesized, and their biological activity against MRSA persisters was evaluated. Most of the newly synthesized derivatives exhibit more potent antimicrobial properties against S. aureus and MRSA than CSA itself, and 23 of the 37 derivatives show a tendency to eradicate MRSA persisters. A representative compound (A6) was demonstrated to target bacterial cell membranes. It eradicated the adherent biofilm of MRSA in a concentration dependent manner, and showed a synergistic antibacterial effect with piperacilin. In a model mouse abscess caused by MRSA persisters, A6 effectively reduced the bacterial load in vivo. These results indicate that A6 is a potential candidate for treatment of MRSA persister infections.

Topics: Animals; Anti-Bacterial Agents; Biofilms; Cell Survival; Cell Wall; Disease Models, Animal; Methicillin-Resistant Staphylococcus aureus; Mice; Microbial Sensitivity Tests; RAW 264.7 Cells; Salicylates; Skin Diseases; Staphylococcal Infections; Staphylococcus aureus; Stilbenes; Structure-Activity Relationship

Possible synergistic effects of the combination of EDTA-tromethamine (EDTA-Tris) and three antimicrobial agents (cephaloridine, kanendomycin and enrofloxacin) against resistant Gram-positive and Gram-negative bacteria are reported. Bacteria were isolated from eight cases of chronic otitis externa, five cases of chronic dermatitis and four cases of recurrent cystitis in dogs which had previously been treated with one of the three antibiotics without success. Animals exposed to EDTA-tromethamine plus the antibiotic recovered completely within 10 days, and were controlled clinically and bacteriologically for 180 days. Local irrigation with EDTA-tromethamine solution was well tolerated and no side effects were recorded.

Topics: Animals; Anti-Bacterial Agents; Anti-Infective Agents; Buffers; Cephaloridine; Cephalosporins; Cystitis; Dermatitis; Dog Diseases; Dogs; Drug Synergism; Edetic Acid; Enrofloxacin; Escherichia coli Infections; Female; Fluoroquinolones; Kanamycin; Male; Otitis; Proteus Infections; Proteus mirabilis; Pseudomonas Infections; Quinolones; Staphylococcal Infections; Time Factors; Tromethamine