Vol.72 No.3 May 2024
An attempt to evaluate the appropriate use of antimicrobials using the antibiotic heterogeneity index (AHI) in a small hospital
1)Department of Pharmacy, Kochi Prefectural Aki General Hospital
2)Department of Clinical Infectious Diseases, Kochi Medical School, Kochi University
Abstract
Infections caused by antibiotic-resistant organisms have become a global problem, and at present, antimicrobial stewardship (AS) activity is being promoted as one of the measures against antimicrobial resistance (AMR). Measurement of the antibiotic heterogeneity index (AHI) has been reported as being useful for evaluating AS activities against AMR, but the effect of using AHI on the antibiogram of the target strains in small hospitals remains unclear. Studies are needed to measure the effects of AS activities aimed at suppressing resistant bacteria in small hospitals, as no indicators have been established yet. Since 2017, we have set an AHI･AUD (antimicrobial use density) target of 0.85 or higher for four classes (penicillins, cephalosporins, carbapenems, and fluoroquinolones) of antipseudomonal agents (tazobactam/piperacillin, ceftazidime, cefepime, meropenem, and levofloxacin), calculated from the %AUD every 6 months from the first half of FY2015 to the second half of FY2021, and restricted the use of each of these classes of antimicrobials according to its %AUD value. Moreover, the in-hospital antibiogram for Pseudomonas aeruginosa was calculated for each semi-annual period from the first half of FY2016 to the second half of FY2021, and the use of antimicrobials with a susceptibility rate of 85% or less was restricted until the next antibiogram was determined. Based on the results, we examined the relationship between antimicrobial use and the in-hospital antibiograms. Consequently, the mean AHI･AUD value increased significantly from 0.63 before the above AS activity was introduced to 0.77 after the AS activity was introduced (p=0.046). In addition, the mean AHI values for the four classes of antipseudomonal agents with a susceptibility rate of 81% or higher were as follows: AHI・AUD, 0.78; AHI・DOT (days of therapy), 0.80. Therefore, evaluation of the AS activity using AHI could improve the bias in the use of antipseudomonal agents with improved drug susceptibility, thereby suppressing the emergence of drug-resistant bacteria.
Key word
antibiotic heterogeneity index, antimicrobial use density, days of therapy, antimicrobial stewardship, Pseudomonas aeruginosa
Received
December 11, 2023
Accepted
March 11, 2024
Jpn. J. Chemother. 72 (3): 331-342, 2024
