Cohort Profile: The Australian Generating evidence on antimicrobial resistance in the aged care environment (GRACE) study; alignment with national population characteristics

Purpose The emergence of antibiotic-resistant bacteria represents a considerable threat to human health, particularly for vulnerable populations such as those living in residential aged care. However, antimicrobial resistance (AMR) carriage and modes of transmission remain incompletely understood. The Generating evidence on antimicrobial Resistance in the Aged Care Environment (GRACE) study was established to determine principal risk factors of AMR carriage and transmission in residential aged care facilities (RACF). Participants Between March 2019 and March 2020, 279 participants were recruited from five South Australian RACFs. The median age was 88.6 years, the median period in residence was 681 days, and 71.7% were female. A dementia diagnosis was recorded in 54.5% and more than two thirds had moderate to severe cognitive impairment (68.8%). Sixty-one percent had received at least one course of antibiotics in the 12 months prior to enrolment. Findings to date To investigate the representation of the GRACE cohort to Australians in residential aged care, its characteristics were compared to a subset of the historical cohort of the Registry of Senior Australians (ROSA). This included 142,923 individuals who were permanent residents of RACFs on June 30th, 2017. GRACE and ROSA cohorts were similar in age, sex, and duration of residential care, prevalence of health conditions, and recorded dementia diagnoses. Differences were observed in care requirements and antibiotic exposure (both higher for GRACE participants). GRACE participants had fewer hospital visits compared to the ROSA cohort, and a smaller proportion were prescribed psycholeptic medications. Future plans Participant and built environment metagenomes will be used to determine microbiome and resistome characteristics. Individual and facility risk exposures will be aligned with metagenomic data to identify principal determinants for AMR carriage. Ultimately, this analysis will inform measures aimed at reducing the emergence and spread of antibiotic resistant pathogens in this high-risk population. Strengths and limitations of this study ### Competing Interest Statement CW is a board member of the aged care organisation Helping Hand. ### Funding Statement This research was supported by an Australian Medical Research Future Fund (MRFF) grant from the Australian Department of Health (GNT1152268). The Australian Department of Health reviewed the study proposal, but did not play a role in study design, data collection, analysis, interpretation, or manuscript writing. LC is supported by an Australian Government Research Training Program Scholarship (no applicable award number). MI is supported by The Hospital Research Foundation Mid-Career Fellowship (MCF-27-2019) and National Health and Medical Research Council (NHMRC) Investigator Grant (APP119378). GR is supported by a Matthew Flinders Research Fellowship (no applicable award number) and a National Health and Medical Research Council Senior Research Fellowship (GNT1155179). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics approval for the GRACE study was obtained from the Southern Adelaide Clinical Human Research Ethics Committee (HREC/18/SAC/244). Participants provided written informed consent themselves or where third-party consent was required, a legal guardian or family member with power of attorney provided consent on their behalf. ROSA has been reviewed and approved by the following Human Research Ethics Committees (HREC): University of South Australia HREC (Ref: 200487; October 2017), Australian Institute of Health and Welfare (AIHW Ref: EO2018/1/418; February 2018), the SA Department for Health & Wellbeing HREC (Ref: HREC/18/SAH/90; November 2018), the NSW Population and Health Services Research Ethics Committee (Ref: 2019/ETH12028; September 2019) and the Aboriginal Health Research Ethics Committee (AHREC Ref 04-20-895; September 2020). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes The GRACE study data are available upon reasonable request. GRACE study data described in this article are available to all interested researchers through collaboration. Please contact GR (geraint.rogers@sahmri.com). Metagenomic sequencing data will be made available via a public registry once completed. Due to data custodian restrictions related to the sharing of linked data in ROSA, these data cannot be made publicly available to other researchers. * GRACE : Generating evidence on antimicrobial Resistance in the Aged Care Environment ROSA : Registry Of Senior Australians RACF : Residential Aged Care Facility AMR : Antimicrobial Resistance MDRO : Multi-Drug Resistant Organism PBS : Pharmaceutical Benefits Scheme MBS : Medicare Benefits Schedule DHS : Department of Human Services ACFI : Aged Care Funding Instrument PAS-CIS : Psychogeriatric Assessment Scales – Cognitive Impairment Scale GP : General Practitioner