Incidence and prevalence of antimicrobial resistance in outpatients with cancer: a multicentre, retrospective, cohort study

This retrospective cohort study aimed to compare the frequency of antimicrobial resistance (AMR) bacterial pathogens in outpatients with and without cancer. Data were collected from 198 outpatient healthcare settings in the USA. The study found that AMR proportions and IRRs for most key pathogens were up to three-times higher in isolates from outpatients with cancer than those without cancer. This highlights the need for enhanced surveillance, infection prevention, and timely diagnostic stewardship to improve antibiotic prescribing in this population. The study found that Pseudomonas aeruginosa, Enterobacterales, fluoroquinolone, carbapenem, multidrug-resistant pathogens, and extended-spectrum β-lactamase producers were more susceptible to AMR in patients with cancer than those without cancer. The rates and corresponding IRRs of AMR pathogens per 1000 isolates were also higher in patients with cancer compared with patients without cancer.