Centralised surveys to validate routine data offer a practical approach

Antibiotic resistance is increasing and significant public health problems are feared. Actions to mitigate the problem include development of new antimicrobials, better infection control, and greater conservation of existing agents. One pressing problem is the paucity of data to measure the impact of resistance on public health or the effect of interventions to prevent its emergence and spread. Moreover, other factors besides clinical prescribing may drive resistance — failure of infection control; institutionalisation of care for the very young and elderly; changing population age structures; agricultural use of antibiotics; and the spread of strains that are effective colonists and which, coincidentally, are resistant.1 Better surveillance of resistance is needed to understand this interplay as well as to advise on empirical therapy. 2 3 Once relations between use and resistance have been established surveillance data then can serve as “information for action” for initiatives to decrease unnecessary prescribing and prolong the usefulness of existing antibiotics.

Establishing such surveillance presents several problems. 2 3 It is easiest to count resistance rates of bacteria received at laboratories, but these organisms form a biased sample because (a) laboratory requesting varies greatly among clinicians; (b) some diseases (such as chronic obstructive airways disease) are more likely to generate laboratory specimens than others (such as pneumonia); (c) some age groups, particularly the elderly, are more likely to have specimens taken than others; and (d) primary care specimens are usually sent only from patients who have failed to respond to empirical treatment or who have comorbidities. Ideally resistance should have a clinical denominator (number of infected patients) not a laboratory one (number of isolates), but this is not easy except in uncommon diseases such …