[New antibiotics for the therapy of respiratory tract infections].

The need for new antibiotics is ongoing in view of manifold resistance developments. The resistance of Streptococcus pneumoniae against macrolides and penicillins in the USA already amounts to more than 30 %. The approval of new antibiotics, particularly those with a new mode of action, has been decreasing over the past years which is anticipated to result in a lack of resourceful therapy options in the future. Some new substances with good in vitro activity against S. pneumoniae have turned out to raise safety issues as shown for a number of quinolones. Likewise daptomycin, a lipopeptide with a new mechanism of action, did not show satisfying results due to its inactivation by surfactant. Established quinolones are levofloxacin and moxifloxacin, the latter being available as i. v. formulation since 2002. For ketolides, telithromycin (oral) and for azalides azithromycin (since 2005 as i. v. formulation) are available for antimicrobial therapy. Linezolid is the only approved oxazolidinone. Tigecycline, a tetracycline derivate, will be approved in 2006 in Germany. The latest approval regarding carbapenems was ertapenem in 2003, while doripenem, a new antibiotic from this group, is still under clinical development.