Decreasing incidence of Staphylococcus aureus bacteremia over 9 years: greatest decline in community-associated methicillin-susceptible and hospital-acquired methicillin-resistant isolates.

BACKGROUND: The impact of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) emergence on the epidemiology of S aureus bacteremia (SAB) is not well documented. METHODS: This was an observational study of adult (aged ≥18 years) inpatients with SAB in a single 808-bed teaching hospital during 2002-2003, 2005-2006, 2008-2009, and 2010 with period-stratified SAB rate, onset mode, patient characteristics, and outcome. RESULTS: We encountered a total of 1,098 cases over the entire study period. The rate decreased steadily over time (from 6.64/10(3) discharges in 2002-2003 to 6.49/10(3) in 2005-2006, 5.24/10(3) in 2008-2009, and 5.00/10(3) in 2010; P = .0001), with a greater decline in community-associated cases (0.99/10(3), 0.77/10(3), 0.58/10(3), and 0.40/10(3), respectively; P = .0005) compared with health care-associated cases (5.65/10(3), 5.72/10(3), 4.66/10(3), and 4.60/10(3), respectively; P = .005). The decline was principally in MSSA (3.11/10(3), 2.21/10(3), 2.24/10(3), and 1.75/10(3), respectively; P = .00006), including both community-associated (P = .0002) and health care-associated cases (P = .006). Although overall rate changes in MRSA were not significant (P = .09), hospital-onset MRSA decreased markedly (P < .00001), whereas CA-MRSA increased (P = .03). The all-cause 100-day mortality rate did not change significantly (25.6% for 2002-2003, 25.2% for 2005-2006, 28.1% for 2008-2009, and 32.2% for 2010; P = .10). Differences in MSSA/MRSA-associated mortality decreased (20.1% vs 30.6%, P = .03 for 2002-2003; 18.1% vs 28.9%, P = .05 for 2005-2006; 21.7% vs 32.9%, P = .05 for 2008-2009; and 29.3% vs 34.9, P = .5 for 2010). CONCLUSIONS: SAB incidence is decreasing, with the greatest decline in community-associated MSSA and hospital-onset MRSA cases. Most health care-associated cases currently are community-onset. MRSA/MSSA-related mortality is comparable. These changes are likely related to the emergence of CA-MRSA and the inpatient-to-outpatient shift in health care.

Differences in patient risk factors and source of candidaemia caused by Candida albicans and Candida glabrata.

There is an increasing frequency of candidaemia caused by Candida glabrata which has decreased in vitro susceptibility to fluconazole. Differences in risk factors for candidaemia caused by C. glabrata and C. albicans have not been formally evaluated in a diverse patient group. We performed a retrospective study of adult inpatients from January 1, 2003 to April 30, 2008 with C. glabrata and C. albicans candidaemia at a single tertiary care centre in Detroit, Michigan to evaluate for differences in risk factors and presumed source of infection in these groups. Patients' underlying conditions, risk factors and source of infection (probable or definite) were compared. Among 119 patients, 80 (67.2%) were C. albicans and 39 (32.8%) C. glabrata. Using logistic regression analysis, patients with C. glabrata infection were more likely to have diabetes mellitus (OR 2.43; 95% CI, 1.06-5.54) and abdominal source of infection (OR 4.53, 95% CI, 1.72-11.92). Mortality rates in the two groups were similar. Patients with C. glabrata candidaemia are more likely to be diabetic and have an abdominal source of infection compared with patients with C. albicans.

Molecular analysis of 2 cases of methicillin-resistant Staphylococcus aureus cholecystitis and a review of the literature.

We present 2 cases of methicillin-resistant Staphylococcus aureus (MRSA) acalculous cholecystitis and review the literature. We performed pulsed field gel electrophoresis, typing of the staphylococcal cassette chromosome mec element, and Panton-Valentine leukocidin testing on the isolates. One each was closely related to USA100 and USA300, indicating that both healthcare- and community-associated strains may cause MRSA cholecystitis.