Resistance to antimicrobial agents as a public health problem: importance of the use of antibiotics in animals

A generalized sense of alarm regarding the problem of resistance of certain microorganisms to antibiotics is arising simultaneously in a number of places in the world [l-6]. This is an increasingly prominent problem that suggests that we are at the gate of an uncertain future in which the conditions that existed before 1940, in the pre-antibiotic era, may recur. It is not unthinkable that certain bacteria that were once sensitive to several commonly used antibiotics may become insensitive to any currently available antibiotics. In the words of Alexander Tomasz, ‘The specter of a pathogen resistant to all antimicrobial agents is closer to science fact than science fiction’ (1994 Annu. Meet. American Association for the Advancement of Science, San Francisco, California) [7]. As if this were not enough reason for concern, it is unlikely that new drugs will soon be developed whose antimicrobial activity is notably better and that will substantially improve our antibiotic armamentarium. Resistant pathogens are increasing in prevalence, for example: multidrug-resistant Acinetobacter baumannii whose resistance includes the carbapenems and whose only and original susceptibility is restricted to sulbactam and polymyxin B [8]; methicillin-resistant Staphylococcus aureus, which is threatening to become vancomycin resistant as well (teicoplanin-resistant strains have emerged during therapy [9]): vancomycin-resistant beta-lactamase-producing Enterococcus spp., to name only a few examples of microbial resistance that have been observed in hospital-acquired pathogens. In the non-hospital environment the situation is no better. Although microbial resistance