is emerging even against these newest antibiotics, the older ones are all plagued with problems of resistance, in some cases already very serious, in some only just emerging. The most problematic pathogens with respect to resistance include among the gram-positive organisms MRSA/E (methicillin resistant- Staphylococcus aureus epidermidis, often multiresistant against all b-lactams, macrolides, quino-lones, and, especially worryingly, increasingly also against vancomycin), VRE (vancomycin-resistant enterococci), and DRSP [drug (i.e., penicillin and macro-lide)-resistant Streptococcus pneumoniae]. An additional problem is posed by Mycobacterium tuberculosis, which is showing an increasing trend towards multiresistant variants. Among gram-negative organisms, Pseudomonas aeruginosa - which owing to its extremely effective permeation barrier and efflux systems is naturally resistant against many available antibiotics - and the growing number of Entero-bacteriaceae microbes with extended spectrum b-lactamases pose the greatest problems. For more details on current resistance issues, the reader is referred to some excellent recent reviews [4-6].

Measures such as improved infection control and hygiene procedures, together with more prudent use of antibiotics are certainly of great importance in dealing with these issues and should help to preserve the usefulness of antibiotics already on the market for longer. However, it should be clear from what has been said that, eventually, novel antibiotic classes free from cross-resistance against those currently on the market need to be discovered and developed to prevent us from a public health disaster. The question then arises: Where will the new antibiotics come from, and what are the chances of discovering, developing, and introducing them into clinical practice?

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