Comparative characteristic of antimicrobial resistance in geriatric hospital: a retrospective cohort study

To examine antimicrobial resistance of commonly isolated pathogens in elderly hospitalized patients.

Data regarding all clinically significant isolates from blood and urine cultures of patients admitted to a multilevel geriatric hospital during March 2015 to April 2016 were collected. Antimicrobial susceptibility testing was performed according to Clinical and Laboratory Standard Institute guidelines.

Escherichia coli, Proteus mirabilis, and Klebsiella pneumoniae were the most common isolates, with proportions of extended spectrum beta-lactamase positivity of 60, 40, and 61% respectively. Adjusted logistic regression models indicated that resistance of Escherichia coli to ceftriaxone [odds ratio (OR) 2.8, 95% confidence interval (CI) 1.5-5.1], ceftazidime (OR 2.8, 95% CI 1.5-5.1), ciprofloxacin (OR 2.2, 95% CI 1.2-4.0), amoxicillin/clavulanic acid (OR 2.3, 95% CI 1.2-4.3), and trimethoprim/sulfamethoxazole (OR 2.4, 95% CI 1.4-4.3) was significantly higher in skilled nursing wards than in acute geriatric wards. Resistance of Proteus mirabilis to ceftriaxone (OR 3.1, 95% CI 1.5-6.4) and Klebsiella pneumoniae to ciprofloxacin (OR 3.2, 95% CI 1.3-7.9) was significantly higher in skilled nursing wards than in acute wards.

Antimicrobial resistance was found to be high in a multilevel geriatric hospital, especially in skilled nursing wards. These findings call for rethinking of the empirical antimicrobial therapy and of the efforts for prevention of nosocomial infection.