(ASPOT35) Geographical visualization of Antibiotic use and Escherichia coli Antibiotic resistance Patterns in the greater Sydney community from 2016 to 2018

Background: Antibiotic use has been identified as one of the key modifiable risk factors for antibiotic resistance development. Escherichia coli is a commensal of the human microbiome. It is known for its dynamic resistance, with many one health (i.e., animal, environment, human) factors influencing the resistance of this bacteria. Research shows that antibiotic use and resistance vary between countries and over time. Little is known about the differences within one region.

Objectives: The aim of this research is to explore the potential of geospatial analysis in the pharmaco-epidemiology of antibiotic use and antibiotic resistance in the Illawarra-Shoalhaven region.

Methods: For this study, we used two separate datasets to ecologically explore the geospatial differences between antibiotic use and resistance for five antibiotics (amoxicillin, amoxicillin-clavulanate, cephalexin, norfloxacin, and trimethoprim). We used resistance data from urine E. coli isolates from a community-based laboratory and antibiotics data from a cohort of older adults that were linked to the Australian Pharmaceutical Benefits Scheme (reimbursement) records to assess community-based dispensing. The total number of antibiotics reimbursed per amount of people and the proportion of resistance isolates were mapped per antibiotic, area, and year.

Results: Over the three years, amoxicillin (63.4%) and cefalexin (61.9%) were most frequently dispensed in one region, followed by amoxicillin with clavulanate (23.7%), trimethoprim (11.6%) and norfloxacin (5.8%). Resistance of E. coli isolates was highest for amoxicillin (61.1%), followed by trimethoprim (37.8%), amoxicillin-clavulanate (17.7%), cefalexin (14.0%) and norfloxacin (14.0%). There was considerable variation across the region, for both antibiotic use and resistance that fluctuated between areas, over time, and per antibiotic type.

Conclusions: Geospatial analysis helps to visualize the temporal and geographical changes of Escherichia coli AMR. This research showed variation between areal antibiotic use and resistance implying that antibiotic use in humans is not the only important factor in mitigating AMR. Linked individual data on antibiotic use and resistance is needed to confirm these findings to enable comprehensive surveillance in the local community in one region.