This single-center retrospective study was conducted at ICMC, which is a 569-bed tertiary community acute care teaching hospital and teaching center with 34 subspecialties and a 12-bed intensive care unit, in Tokyo. , in Japan. The number of ambulance transports per year is around 10,000. This hospital has an active department of general internal medicine and its average number of inpatients is around 80 per day. This department handles cases with a variety of medical issues, including infectious diseases. The Transplant Surgery Department is also active and performs around 40 solid organ transplants per year, mainly kidney transplants. The study was approved by the Institutional Review Board of Itabashi Chuo Medical Center (#220125B). The requirement to obtain written consent from all participants was waived by the Institutional Review Board due to the observational nature of the study without any deviation from current medical practice.
The impact of our ASP on the use of antimicrobials and the incidence of nosocomial candidemia, in the hospital setting, was evaluated between two periods (pre-intervention: April 2017 to March 2018 and intervention: April 2018 to September 2020). These data were collected retrospectively from electronic records.
A multidisciplinary antimicrobial stewardship program was implemented in April 2018 (Table 1). It was composed of three doctors (pulmonology, pediatrics and nephrology; 0.1 full-time equivalent), a clinical pharmacist (1.0 full-time equivalent), a microbiology laboratory technician (0.1 full-time equivalent), a nurse in infection control (0.1 full-time equivalent) and a part-time infectious disease specialist (0.1 full-time equivalent). AST members held a one and a half hour case conference once a week. The inclusion criteria were defined as follows: patients treated with three broad-spectrum antipseudomonas agents (carbapenems, tazobactam/piperacillin and cefepime) and intravenous quinolones for more than 7 days, with positive blood cultures and not responding to treatment. Aggregate monthly hospital consumption of antimicrobials was measured in days of treatment (DOT) per 1000 patient days for broad-spectrum agents. The monthly incidence of nosocomial candidemia was measured between April 2017 and September 2020. The data used in this study were obtained from medical records. All episodes of nosocomial BSI due to candidiasis spp. were reviewed retrospectively by the members of the AST.
The total DOT per month for 1000 patient days was calculated for carbapenem (CAR) and the 3-antipseudomonals: carbapenem (meropenem), piperacillin-tazobactam and cefepime. Meropenem was assessed because its consumption accounted for more than 98% of all carbapenems during this period. Nosocomial BSI due to candidiasis spp. were diagnosed based on blood culture samples obtained 48 h from admission. Only the first episode of BSI during the study period was included, but a separate episode could be recognized if there was another episode of nosocomial BSI that occurred 30 days after the end of a treatment antifungal. The monthly incidence of candidaemia was calculated per 1000 patient days.
Interrupted time series (ITS) regression analysis was used to assess trends in monthly antimicrobial consumption and nosocomial candidemia before and after the intervention. DOTs per 1000 patient days and trends in monthly CAR DOT, 3-antipseudomonas DOT, and incidence of nosocomial candidemia detected were used8. Changes were assessed with ordinary least squares regression. Harmonic terms have been added to the models to account for seasonality. Categorical data were analyzed using chi-square test or Fisher’s exact test and non-categorical data using Student’s t-test or Wilcoxon’s rank sum test, as appropriate. One to two tails p– value