A three-point time series study of antibiotic usage on an intensive care unit, following an antibiotic stewardship programme, after an outbreak of multi-resistant Acinetobacter baumannii

Abstract

Antibiotic use in intensive care units (ICUs) can promote antimicrobial resistance. Outbreaks of multi-resistant bacteria significantly affect patient outcomes and delivery of care. Antibiotic stewardship programmes (ASPs), combining root-cause analyses and multi-faceted prevention strategies, are necessary, often at significant cost and time. Which elements of such strategies have the largest impact on antibiotic usage following an outbreak is unclear. The aim of this study was to investigate how antibiotic usage in a university hospital ICU changed with a non-protocolised ASP following a disruptive outbreak of multi-resistant Acinetobacter baumannii (MRAB). This was a three time-period observational cohort study. The primary endpoint was the change in overall antibiotic usage (daily defined dose, DDD, antibiotic-days, antibiotic-courses) for consecutive ICU patients staying >48 h, over three 6-month study time periods pre-MRAB (2008, n = 84) and post-MRAB (2010, n = 88; 2012, n = 122). Secondary endpoints were changes in antibiotic usage and patient demographics, in predefined admission categories (Medical Emergency, ME; Surgical Elective, SEL; and Surgical Emergency, SE). The mean age (54.6 ± 17.7, 58.1 ± 17.9, 62.8 ± 19.1 years*) and severity of illness (APACHE 14.8 ± 8.0, 16.7 ± 6.8, 18.3 ± 6.1*) increased, particularly medical admissions. There was a sustained reduction in DDD antibiotic usage [1895.1 (2008), 1224.2 (2010), 1236.6 (2012) per 1000 patient-days] but no overall change in antibiotic-days or antibiotic-courses. Antibiotic usage (antibiotic-days) fell significantly in surgical emergency admissions [20.2 ± 32.1, 4.6 ± 7.4*, 5.9 ± 7.3]. There was a sustained drop in beta-lactam, quinolone, glycopeptide and macrolide usage. Following an MRAB outbreak, and subsequent operational changes including enhanced ASPs (non-protocolised), there was a sustained overall fall in antibiotic usage in spite of an increase in disease severity over 5 years.

Evaluating the long-term impact of an antimicrobial stewardship programme in a Central London mixed medical and surgical intensive care unit

“…That said, we could not ethically conduct a randomized controlled trial of ASP versus standard care, when the presumed health improvement benefits of consultant microbiologist-directed ASP were necessary following the highly disruptive outbreak of MRAb. 8 Cluster randomized controlled trials could feasibly assess the value of an ASP by introducing it sequentially across multiple ICUs and differing cohort periods, so long as the case mix and practices across hospitals are similar. 17 The study may have been subject to selection bias as admissions shorter than 2 days were excluded, because APACHE II score was not calculated for these patients.…”

“…Data collected during ASP implementation were reviewed with an addition of a fourth cohort (2017) since our previous publication. 8 Fewer data were collected in the previous three cohorts as these were collected before patient records were electronically retrievable.…”

“…In a retrospective cohort study on patients in the ICU at three cohort periods; before, 1 and 3 years after ASP implementation, there was a sustained drop in antimicrobial usage. 8 In the context of an observed increased severity of illness of patients, decreased antimicrobial burden was favourable. Carbapenem usage, however, had increased, while there was an increasing trend in overall DDD 3 years after ASP introduction.…”

“…Carbapenem usage, however, had increased, while there was an increasing trend in overall DDD 3 years after ASP introduction. 8 …”

Acinetobacter baumannii resistente aos carbapenêmicos em Minas Gerais: epidemiologia hospitalar, multirresistência e disseminação de clones de alto risco

“…Dessa forma, é possível comparar a frequência de microrganismos e seus fenótipos de resistência. Estudos envolvendo a DDD do uso de antimicrobianos mostraram que o consumo médio de carbapenêmicos é 224.2 DDD/1000 pacientes-dia na Inglaterra (SINGH et al, 2015), 250,0 DDD/1000 pacientes-dia na China (GUO et al, 2019) e 389,3 DDD/1000 pacientes-dia no Brasil (ROSSI et al, 2016).…”