It was an extraordinary pleasure for me, as the secretary general, to organise, with my collaborators, this Second International Symposium on Antibiotic Resistance in the Castle of Smolenice in Czechoslovakia. We all appreciated many offers all participants must have spent to attend this Symposium and we were glad to do our best to prepare this meeting in a suitable and convenient way. We gathered in Smolenice Castle after the significant International Congress on Che motherapy in September 1973 in Athens. We had the chance of getting acquainted, on that world-wide forum, with the latest information about bacterial resistance to anti biotics. It was possible at that Congress to outline main topics of interest in the field of bacterial resistance to antibiotics which then have been placed on the programme of the subsequent Smolenice Symposium. Undoubtedly, enzymatic mechanisms by which bacteria can inactivate older and newer antibacterial drugs and which can be transmitted and spread among bacterial strains, have both medical as well as theoretical priority. Dealing specially with Pseudomonas aeruginosa is highly urgent at present from the clinical, hygienical and genetical point of view. We have realised that antibiotics have ceased to be "magic bullets" which hit the microorganisms without discrimination. Today we urgently consider the question what should be done in the area of "antibiotic policy" to preserve the effectiveness of antibiotics for the future.

Antibiotics are one of the greatest benefits science ever gave to mankind and one of the few things that cannot be misused against the man. Thus, the starting point of all our efforts is highly humanistic, and is expressed by cordial athmosphere in which we all work and communicate on a wide international basis. All our efforts are aimed to preserve the antibiotics as effective tools in medical treat ment, and thus we must deal with antibiotic resistance. Owing to it many antibiotics are slowly retreating from the first line of the battle between the man and pathogens. But new drugs are coming and we must check them very carefully to assure their efficiency as long as possible. In this process of inactivation of antibiotics, infectious resistance factors are today on the scene not only of clinicians, epidemiologists or hygienists, but equally, if not more, of geneticists and molecular-biologists. This is why we all were together in Smolenice to exchange our ideas and experience.

Proceedings from the International Symposium on Antibiotic Resistance 1979, the fourth volume in the series of material edited from the Smolenice symposium, is a continuation in the tradition of communicating new scientific results on a currently important and interesting problem. It concerns not only human and veterinary medicine and practice, but also such important fields of contemporary biology as molecular biology and genetics. Indeed, in both these disciplines, we have recently noted a strong and dynamic de velopment of scientific knowledge directed toward such outgrowths of the study of plasmids as gene manipulations, transposons, and transposition, as well as the evolution of plasmids in general. Because of a very real global development of resistance to the newest antibiotics, and the active participation of experts from medical science and practice, it was reasonable to separate the medical part of the program from the theoretical one. Consequently, priorities of the fourth symposium were transposons and the transposition of resistance of to antibiotics, with their serious impact on epidemiology, the resistance of Pseudomonas aeruginosa, that is becoming a prominent nosocomial pathogen, the ecology and epidemiology ofR plasmids, and, last though not least, the computer-assisted surveillance of resistance to antibiotics."