Abstract
Aim: To describe the epidemiology of Staphylococcus aureus (S. aureus) and Streptococcal pyogenes (S. pyogenes) skin infections in Auckland, New Zealand.
Method: A population-based retrospective analysis of skin swab culture results (2010-2020), collected in primary care, was conducted to determine incidence rates and rate ratios (RR) with 95% confidence intervals (CI), using 2013 New Zealand Census data as the denominator.
Results: Over one-quarter of Auckland's population were tested for suspected skin infections over the 11-year observation period, at 31.4 persons per 1,000 person-years. S. aureus affected all demographics. S. pyogenes infection rates were higher for children under 10 years of age (RR 3.1, 95% CI 3.1-3.2; compared with ≥10-year-olds), Māori and Pacific peoples (RR 4.7, 95% CI 4.6-4.8; compared with European/Other) and individuals in the most socio-economically deprived areas (RR 2.1, 95% CI 1.9-2.3; compared with least deprived areas). Individuals who were S. aureus-positive were twice (2.1, 95% CI 1.9-2.3) as likely to test S. pyogenes-positive, relative to those testing negative for S. aureus or positive for another skin pathogen.
Conclusion: Children, Māori, Pacific peoples and people in lower socio-economic areas are more likely to have a skin infection test positive for S. pyogenes. S. aureus infection is a risk factor for co-infection with S. pyogenes.