Temporal Trends in the Incidence ofStaphylococcus aureusBacteremia in Olmsted County, Minnesota, 1998 to 2005: A Population‐Based Study

Abstract

Background There is a paucity of population-based studies on Staphylococcus aureus bacteremia (SAB) in the United States. We determined the incidence and trends of SAB in Olmsted County, Minnesota, over an 8-year period. Methods A retrospective, population-based, cohort study was done to evaluate the initial episodes of SAB occurring in adult residents of Olmsted County, Minnesota, from January 1, 1998 through December 31, 2005 using the microbiology databases at Mayo Clinic and Olmsted Medical Center. Results Among 247 evaluable adult patients with SAB, who were included in the incidence calculation, 57.9% were males and the median age was 72.1 years (range 19.5 - 98.5). Bacteremic episodes were classified according to acquisition site: 23.5% were nosocomial (NA-SAB); 58.7% were healthcare-associated (HCA-SAB); and 23.8% were community-acquired (CA-SAB). MRSA constituted 31.6% of the cases. No community-acquired MRSA bacteremia was noted. The age-adjusted incidence rate of SAB was 28.3/100,000 person-years for females, and 53.5/100,000 person-years for males, with an age- and gender-adjusted rate of 38.2/100,000 person-years. The age- and gender-adjusted incidence of NA-SAB, HCA-SAB, and CA-SAB was 9.0, 22.6 and 6.6/100,000 person-years, respectively. The age- and gender-adjusted incidence of MSSA was 25.4/100,000 and of MRSA was 12.4/100,000 person-years. Overall, the incidence rate increased with age, but not over calendar year. The exception was MRSA-B, which increased at a rate of 19.8% (± 5.5%) per year during the study period. Conclusions The incidence of SAB in adults remained stable in Olmsted County, Minnesota, from 1998 to 2005, but the proportion due to MRSA has significantly increased over the 8-year period.

Epidemiology of Staphylococcus aureus Blood and Skin and Soft Tissue Infections in the US Military Health System, 2005-2010

“…While these observations are in agreement with prior studies, 9,10,13,20,22 additional analyses are needed to determine if these characteristics are independent risk factors. The geographic distribution of community-onset SSTI rates may reflect both the influence of climate on SSTIs and the primary locations of military training, where rates of SSTIs are known to be high.…”

“…Regional populationbased studies of S aureus bacteremia reported stable incidence of S aureus bacteremia overall, but an increasing proportion of cases due to MRSA. 9,20 Similarly, Hersh et al 21 reported an increase in coded SSTI encounters from 32.1 to 48.1 per 1000 population from 1997 to 2005 coincident with the emer- 2 This incidence rate is lower than the 46 per 100 000 personyears observed in the current study for SSTIs in nonactive duty beneficiaries, but this may be due to the inability to separate health care-associated community-onset infections from community-associated infections in the current study, as well as different study populations and periods of observation.…”

Predictors of Mortality in Staphylococcus aureus Bacteremia

“…In Scandinavian countries, where data from the nationwide surveillance of SAB are routinely collected, the annual incidence is approximately 26/100,000 population (14,119,128). A similar low incidence of 19.7/100,000 population was reported in a Canadian study in 2008 (160), while in countries with a greater burden of methicillin-resistant S. aureus (MRSA), incidence rates are generally higher, between 35 and 39/100,000 population (38,56,233). In comparison, even higher rates, approximately 50/100,000 population, are inferred from surveillance data from the United States (143,201).…”

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

“…For example, in Quebec, Canada, the incidence of MRSA bacteremia increased from 0 per 100,000 person-years to 7.4 per 100,000 person-years from 1991 to2005, despite stable rates of methicillin-susceptible S. aureus (MSSA) bacteremia during the same period (10). Similar trends of increasing MRSA bacteremia incidence over this time period were seen in Minnesota from 1998 to 2005 (11); Calgary, Canada, from 2000 to 2006 (12); and Oxfordshire, United Kingdom, from 1997 to 2003 (13). In North America, epidemic community-associated clones of MRSA (e.g., USA300) have been largely responsible for the increase in the incidence of MRSA bacteremia (12,14), while in the United Kingdom, epidemic health care-associated clones of MRSA (United Kingdom EMRSA-15 and EMRSA-16) have been responsible (15).…”