Impact of ethnicity and socio-economic status on Staphylococcus aureus bacteremia incidence and mortality: a heavy burden in Indigenous Australians

Abstract

BackgroundInvestigations of the impact of ethnicity and socio-economic status on incidence and outcomes of Staphylococcus aureus bacteraemia are limited.MethodsWe prospectively identified all S. aureus bacteraemia episodes in the Australian New Zealand Cooperative on Outcomes in Staphylococcal Sepsis cohort study between 2007 and 2010. We calculated population level incidence rates using regional postcodes and stratified the analysis by ethnicity, age and socio-economic status indexes.ResultsThere were 7539 episodes of S. aureus bacteraemia with an annual incidence of 11·2 episodes per 100,000 population. The age-adjusted incidence in the Indigenous population was 62·5 per 100,000 population with an age standardized incidence rate ratio of 5·9 compared to the non-Indigenous population and an incidence rate ratio of 29.2 for community-associated methicillin-resistant S. aureus (MRSA). Populations in the lowest socio-economic status quintile had an increased S. aureus bacteraemia incidence compared to higher quintiles. However, there was a disparity between Indigenous and non-Indigenous populations across all socio-economic status quintiles. The lower 30-day mortality for Indigenous patients (7%) compared to non-Indigenous patients (17%) was explained by differences in age.ConclusionsIndigenous Australians suffer from a higher rate of S. aureus bacteraemia than non-Indigenous Australians, particularly for community-associated MRSA. Ethnicity and socio-economic status had little impact on subsequent mortality, with other host factors contributing more significantly.

The clinical and molecular epidemiology of Staphylococcus aureus infections in Fiji

“…The age distribution is also similar to that in Indigenous Australian populations with a peak incidence in the 45–65 age group. This is in stark contrast to that seen in developed countries, including the non-Indigenous population of Australia, where incidence increases with age [32,33]. Although we cannot infer a causative link, there is likely to be an association between high rates of skin and soft tissue infections and the high incidence of SAB in both Fiji and Indigenous Australian populations.…”

Staphylococcus aureus Infections: Epidemiology, Pathophysiology, Clinical Manifestations, and Management

“…Similarly, Maori and Pacific Island people have significantly higher rates of incidence of SAB than do those of European ethnicity in New Zealand (33,34). Differences in markers of the socioeconomic status of indigenous compared to nonindigenous populations do not fully explain the disparity between these groups (31). The contribution of host genetic susceptibility to these ethnic differences has not yet been investigated.…”

“…In the United States, the incidence of invasive MRSA in the black population (66.5 per 100,000 person-years) is over twice that in the white population (27.7 per 100,000 person-years) (14,18). In Australia, the incidence of SAB in the indigenous population is 5.8 to 20 times that of nonindigenous Australians (30)(31)(32). Similarly, Maori and Pacific Island people have significantly higher rates of incidence of SAB than do those of European ethnicity in New Zealand (33,34).…”

“…In several recent studies involving consecutive patients with either SAB (MSSA and MRSA) (12,31,32,(56)(57)(58)(59)(60) or only MRSA bacteremia (61)(62)(63)(64)(65)(66), common primary clinical foci or sources of infection are vascular catheter-related infections, SSTIs, pleuropulmonary infections, osteoarticular infections, and IE (Table 2). These common primary clinical foci represent a subset of the common general clinical manifestations of S. aureus infections.…”

Socio-economic profile of patients with community-acquired skin and soft tissue infections in Delhi

“…Our findings could be explained by differences in living conditions, poor hygiene, household crowding, lesser use of washing, and sanitation facilities that are seen in lower SES individuals, which are associated with higher infectious disease rates. 17 However, another study needs to be done in the community to quantify the different reasons for higher prevalence of MRSA in lower SES. According to FDA guidance documents, diabetes mellitus is a complicating factor in SSTIs.…”