Chapter 12. Antibacterial Agents

Abstract

Publisher Summary The recent studies in antibacterial agents highlight the advances including improved gram-positive, anaerobe, chlamydia activity, and in some cases improved pharmacokinetics in comparison with ciprofloxacin. Major areas of antibiotic research also include the quinolones, β-lactams, glycopeptides, and a variety of other compounds that are active against methicillin resistant S. aureus (MRSA). The bacteriology, clinical utility and experience, and pharmacokinetics of the newer quinolones are studied. The mechanism of resistance to quinolones is still undergoing active investigation. A recent review suggests that resistance is because of mutations affecting deoxyribonucleic acid (DNA) gyrase and/or drug permeability. A combination of decreased permeability and DNA susceptibility is seen in experimental endocarditis with Pseudomonas aeruginosa and in experimental peritonitis with Enterobacter cloacae. Decreased permeability is seen as the mechanism of resistance in E. coli mutants, while changes in DNA gyrase are cited in studies on E. coli and Serratia marcescens. Widespread resistance among MRSA has been found in some regions. Research has focused on the structures having stability to lactarnase enzymes and improved pharmacological properties BRL 44154 is the preferred compound in a series of alkoxyimino penicillins synthesized because of its activity e. MRSA, stability to staphylococcal β-lactarnase, and ease of synthesis. As for research in glycopeptides, a distinction is proposed that would distinguish the glycodalbaheptides that have only sugars attached to the peptide core (vancomycins, ristocetins, avoparcins) and lipoglycodalbaheptides that have a fatty acid chain attached to the core (teicoplanins, kibdelins, parvodicins).