Community-acquired bacteraemia and antibiotic resistance. Trends during a 17-year period in a Danish county.

INTRODUCTION

The aim was to ascertain the prevalence of antibiotic resistance among blood isolates from patients with community-acquired bacteraemia and to relate it to antibiotic consumption.

METHODOLOGY

Cases of community-acquired bacteraemia were identified in a regional bacteraemia register in the County of Northern Jutland. The study included 3974 episodes in 3805 patients during a 17-year period. Total regional consumption of antibiotics was expressed in Defined Daily Doses (DDD).

RESULTS

The prevalence of antibiotic resistance was stable with few exceptions. The most notable time trend was noted for Escherichia coli for which the prevalence of resistance to ampicillin increased from 17% (95% confidence limits (CL) 12-23%) to 28% (95% CL 23-33%); for other Enterobacteriaceae the increase was from 73% (95% CL 61-83%) to 86% (95% CL 77-92%). The prevalence of resistance to aminoglycosides, fluoroquinolones and third-generation cephalosporins remained low among all isolates of Enterobacteriaceae. Regional antibiotic consumption ranged from 10.2 to 13.6 DDD/1000 inhabitants/day. Consumption of penicillins with Gram-negative spectrum reached a maximum of 4.6 DDD/1000 inhabitants/day in 1993 and decreased towards the end of the study period. The prevalence of ampicillin-resistant E. coli was positively correlated with consumption of penicillins with Gram-negative spectrum; the correlation was stronger when adjustment was made for co-selection by tetracyclines and sulphonamides.

CONCLUSION

Therapeutic options for community-acquired bacteraemia have not yet become seriously limited by prevalence of acquired antibiotic resistance. Still we found some evidence that consumption of penicillins with Gram-negative spectrum, sulphonamides and tetracyclines promotes antibiotic resistance among Enterobacteriaceae.