Almost everyone in the developed world will receive several courses of antibiotic during their lifetime. It is therefore not surprising that most clinicians and dentists will prescribe these drugs on a regular basis throughout their professional career. Indeed, several antibiotics figure among the most frequent of all prescribed drugs.
Antibiotics are not only life-saving with regard to severe infections, such as pneumonia, meningitis, and endocarditis, but are also responsible for controlling much of the morbidity associated with non-life-threatening infectious disease; illness is abbreviated, return to normal activities is hastened and there is often economic benefit to the individual, as well as society, by reducing the number of working days lost. In addition, infectious complications of many commonly conducted surgical procedures are now preventable by the use of peri-operative antibiotic prophylaxis. These benefits are well known to healthcare professionals and to the public who no longer fear infection in the way earlier generations did. The very success of antimicrobial chemotherapy has led to a perception that such agents are generally safe and that industry will continue to generate new agents to ensure the effective control of most infectious problems.
Antibiotics have largely been derived from natural sources, mainly from environmental bacteria and fungi. Their use in clinical medicine has been one of the major successes of the past century. The term ‘antibiotic’ was coined by Selman A Waksman, who recognized that these ‘naturally derived substances were antagonistic to the growth of other micro-organisms in high dilution.’ Over the years, other agents have been developed by chemical synthesis and more recently, as a result of genomic research. The term ‘antimicrobial agents’ captures all such compounds which in turn have been subdivided into antiviral, antibacterial, antifungal, antiparasitic (anthelminthic and antiprotozoal) agents according to the target pathogen. However, this purist approach is often ignored in practice and the term antibiotic is somewhat loosely applied to all these agents. The reader will find all such terms in use in this book.
Antibiotics are unique among therapeutic agents in that they target invading micro-organisms rather than any pathological process arising from host cells or tissues. Furthermore, unlike other classes of drug, micro-organisms have the inherent or acquired ability to evade or inactivate antimicrobial activity of these drugs. Such resistance presents a major threat to sustaining effective treatment of infectious disease.
Indeed, controlling antibiotic resistance is one of the greatest challenges facing healthcare professionals and the public and is likely to remain so. While new drugs, vaccines and better diagnostic methods are still a requirement, the fundamental issue is to ensure that existing agents are used effectively. This can only be achieved by ensuring that doctors, dentists, and, increasingly, other healthcare professionals who use these agents in the care of their patients, pursue good prescribing practice.
Good prescribing practice is the product of sound education, with particular emphasis on the acquisition of appropriate knowledge, skills, and professional behaviour. Good science informs good practice and since the knowledge base for prescribing practice is continuously expanding, the need for life-long learning is self-evident.
Patient safety remains paramount in medicine. Since antibiotics are often used in the management of mild to moderate community infections and the prophylaxis of infections this is of particular importance. The safety of antibiotics is monitored closely during drug development, at licensing and in clinical use. Since no drug is free from side effects, it is essential that the balance of risks and benefits of prescribing is appreciated and constantly considered by the prescribing practitioner. With more than 100 antimicrobial compounds currently available in the UK, this remains a particular challenge.
Setting forth the principles of rational antimicrobial chemotherapy is the whole purpose of this book. We sincerely hope that this 5th edition of Antimicrobial Chemotherapy will continue to furnish students and all healthcare professionals throughout the world with the necessary framework for understanding what antimicrobial agents will and will not do, and provide a firm basis for their informed use in the treatment and control of infection.