High burden of extended-spectrum β-lactamase-positive Escherichia coli in geriatric patients.

Few studies have described how an expanding elderly population influences the burden of antimicrobial resistance in micro-organisms. This study aimed to investigate trends in age-stratified extended-spectrum β-lactamase (ESBL)-positive Escherichia coli metrics in relation to an ageing population. The antimicrobial resistance database of E. coli from a healthcare region in Hong Kong from 2003 to 2012 was retrospectively reviewed. Future trends in age-stratified ESBL metrics were predicted up to 2022. Susceptibility results of clinical E. coli isolates from patients aged 0-74 years (n = 17 853) and aged ≥75 years (n = 17 047) were analysed. For the period 2003-2012, 23.7 % of the hospital admissions were of patients aged ≥75 years. However, approximately half of the annual ESBL-positive E. coli isolates were recovered from patients aged ≥75 years, being 55.0 % (233/424) in 2003 and 56.0 % (639/1142) in 2012. During this period of time, the annual prevalence and cumulative incidence of ESBL-positive E. coli in patients aged ≥75 years were significantly higher than in patients aged 0-74 years. From 2012-2022, it is predicted that ESBL-positive E. coli prevalence among patients aged 0-74 years and ≥75 years would increase from 25.4 % to 50.2 % and from 30.8 % to 70.0 %, respectively. In 2022, the predicted ESBL-positive E. coli cumulative incidence would be 63.7 per 10 000 admissions and 178.7 per 10 000 admissions among patients aged 0-74 years and ≥75 years, respectively. In conclusion, a rapidly expanding elderly population would substantially add to the burden of ESBL.