Aims: National responses to antimicrobial resistance (AMR) require an understanding of the factors driving its development and spread. Research to date has primarily focused on determining individual-level risk factors for AMR-associated infections. However, additional insights may be gained by investigating exposures associated with AMR variation at the population level.
Methods: We used an ecological study design to describe the association between the incidence rate of methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum β-lactamase producing Escherichia coli (ESBL-E. coli) infection and population-level variables among 18 geographically distinct populations, defined by district health boards, in Aotearoa New Zealand. Associations were described using Spearman's correlational analysis.
Results: Positive correlations were found between the incidence of both MRSA and ESBL-E. coli infection and household crowding and community antimicrobial use. Positive correlations were also observed between MRSA and socioeconomic deprivation; age <5 years; Māori ethnicity; and Pacific ethnicity. For ESBL-E. coli, positive correlations were also observed with Asian ethnicity; Pacific ethnicity; and overseas-born new arrivals. European ethnicity was negatively correlated with both MRSA and ESBL-E. coli infection.
Conclusions: These findings provide insight into the potential contribution of population-level exposures to MRSA and ESBL-E. coli infection in New Zealand. Exposures such as household crowding, community antimicrobial use and socioeconomic deprivation, are in principle modifiable and may present potentially novel opportunities to reduce the burden of AMR.