Therapeutic and epidemiologic recommendations to reduce the spread of type-I β-lactamase resistance

The objectives of this United States Consensus Panel meeting were to evaluate the effectiveness of current surveillance systems for the detection of bacterial resistance as well as to formulate recommendations that can assist hospitals in determining actions that should be taken when a resistance problem is detected. These recommendations may be particulary helpful in controlling the emergence and spread of type-I β-lactamase resistance. Numerous case reports of antimicrobial resistance among Enterobacter species, Pseudomonas aeruginosa, and other Gram-negative nosocomial pathogens known to provide type-I β-lactamases have appeared in the literature since the introduction of the newer 'third-generation' cephalosporins. The widespread use of these new antimicrobial agents, often selected as standard therapy for serious hospital-acquired infections, has been associated with a corresponding increase in resistance to them. The failure of hispitalwide surveillance methods to describe the scope of this problem, especially among the most critically ill patients, may have resulted in a false sense of security among some infectious disease specialists and clinicians prescribing these antimicrobials as empiric therapy. High-level resistance in individual hospital units may be masked in hospitalwide antibiograms. A variety of conclusions and recommendations were formulated based on the collective experiences of the Consensus Panel members. Microbiology laboratories must make it a high priority to identify markers that will assist in rapidly identifying resistant organisms. Cooperative efforts are needed among users of commercial and automated microbiology test instruments to standardize results and to improve quality control, thereby making the data more directly comparable between laboratories. Participation in both national and local surveillance systems should be encouraged. Optimally, monitoring programs should provide data by hospital unit, by anatomic site, by sentinel organism, and even categorized by type of patient. In this manner, the collection of clearly defined susceptibility data will facilitate the rapid identification of resistance outbreaks, an assessment of which antimicrobial agents have been most commonly associated with the emergence of resistance, and an appropriate response to the problem. Furthermore, the panel suggests that it is imperative to study the dynamics of the spread of infection in order to determine whether the organisms originate in the patient's own flora or have been acquired from an exogenous source. The widespread and indiscriminate use of certain drugs associated with the emergence of type-I β-lactamase resistance should be discouraged. These are some of the new strategies that should be investigated: (a) restrict antibiotics that can select or have selected for resistant organisms, (b) rotate the use of certain antimicrobial agents within an institution to preempt the emergence/selection of resistance, and (c) utilize alternative therapies (combinations and so forth) when appropriate so as to minimize but not totally limit the emergence of resistance. In addition, clinicians should be altered to the scope of this problem because it has been associated with increased morbidity and mortality.