APH 1999, 57, 243-250:

Surveillance of antibiotic resistance: which strategies for which objectives ?

M. Struelens

Keywords: antibiotic resistance, surveillance systems, antibiotic policy, infection control, multicenter studies, harmonisation of laboratory methods, epidemiological typing

Surveillance of antibiotic resistance can be performed at different levels, from a local programme to an international programme, and serve a number of different objectives. A first objective is to monitor the probability of pathogens causing a particular infectious syndrome to be resistant  to empirical therapy and to guide recommendations for changing empirical therapeutic schemes. This entails community-specific or hospital-specific monitoring of resistance frequency to commonly used antibiotics from clinically significant, representative samples of bacteria, usually on a yearly basis. A second objective of local surveillance can be to detect the emergence of new patterns of resistance and epidemic spread of resistant clones of a particular pathogen. A third, and related objective, is to monitor the effect of interventions, such as infection control or antibiotic policy, to prevent or curb antibiotic resistance emergence and spread. For the latter two objectives, more comprehensive samples including colonising isolates, should be included in the surveillance data and special detection methods may be required. Epidemiologic typing is necessary to delineate clonal spread.  Multicentre surveillance at national and international levels can provide early warning of emerging resistance and monitoring of secular trends by region or by country. However, because laboratories use different methods and interpretative definition of resistance vary by country, passive reporting and comparison of routinely produced test results is biased. Cross-validation with centralised surveys and proficiency testing can improve the reliability of numerator data. New, active surveillance methods must be defined and applied in a co-ordinated manner to monitor more accurately the disease burden and dynamics of antibiotic resistance. This includes revision of sampling procedures and selection of denominator based indicators designed to meet specific public health objectives.