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Trends in Staphylococcus aureus bacteraemia and impacts of infection control practices including universal MRSA admission screening in a hospital in Scotland, 2006-2010: retrospective cohort study and time-series intervention analysis.

Lawes T, Edwards B, López-Lozano JM, Gould I - BMJ Open (2012)

Bottom Line: Rates of MSSA bacteraemia were not significantly affected by screening or antibiotic use.Declining clinical burdens from SAB were attributable to reductions in MRSA infections.Control of MSSA bacteraemia remains a priority.

View Article: PubMed Central - PubMed

Affiliation: Department of Paediatrics, Raigmore Hospital, Inverness, UK.

ABSTRACT

Objectives: To describe secular trends in Staphylococcus aureus bacteraemia (SAB) and to assess the impacts of infection control practices, including universal methicillin-resistant Staphylococcus aureus (MRSA) admission screening on associated clinical burdens.

Design: Retrospective cohort study and multivariate time-series analysis linking microbiology, patient management and health intelligence databases.

Setting: Teaching hospital in North East Scotland.

Participants: All patients admitted to Aberdeen Royal Infirmary between 1 January 2006 and 31 December 2010: n=420 452 admissions and 1 430 052 acute occupied bed days (AOBDs).

Intervention: Universal admission screening programme for MRSA (August 2008) incorporating isolation and decolonisation. PRIMARY AND SECONDARY MEASURES: Hospital-wide prevalence density, hospital-associated incidence density and death within 30 days of MRSA or methicillin-sensitive Staphylococcus aureus (MSSA) bacteraemia.

Results: Between 2006 and 2010, prevalence density of all SAB declined by 41%, from 0.73 to 0.50 cases/1000 AOBDs (p=0.002 for trend), and 30-day mortality from 26% to 14% (p=0.013). Significant reductions were observed in MRSA bacteraemia only. Overnight admissions screened for MRSA rose from 43% during selective screening to >90% within 4 months of universal screening. In multivariate time-series analysis (R(2) 0.45 to 0.68), universal screening was associated with a 19% reduction in prevalence density of MRSA bacteraemia (-0.035, 95% CI -0.049 to -0.021/1000 AOBDs; p<0.001), a 29% fall in hospital-associated incidence density (-0.029, 95% CI -0.035 to -0.023/1000 AOBDs; p<0.001) and a 46% reduction in 30-day mortality (-15.6, 95% CI -24.1% to -7.1%; p<0.001). Positive associations with fluoroquinolone and cephalosporin use suggested that antibiotic stewardship reduced prevalence density of MRSA bacteraemia by 0.027 (95% CI 0.015 to 0.039)/1000 AOBDs. Rates of MSSA bacteraemia were not significantly affected by screening or antibiotic use.

Conclusions: Declining clinical burdens from SAB were attributable to reductions in MRSA infections. Universal admission screening and antibiotic stewardship were associated with decreases in MRSA bacteraemia and associated early mortality. Control of MSSA bacteraemia remains a priority.

No MeSH data available.


Related in: MedlinePlus

Observed trends and multivariate transfer model predictions (sum of lagged explanatory variables) for prevalence density, hospital-associated (HA) incidence density, 30-day mortality in methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia and % Staphylococcus aureus bacteraemia (SAB) involving MRSA. CL, confidence limit.
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fig5: Observed trends and multivariate transfer model predictions (sum of lagged explanatory variables) for prevalence density, hospital-associated (HA) incidence density, 30-day mortality in methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia and % Staphylococcus aureus bacteraemia (SAB) involving MRSA. CL, confidence limit.

Mentions: In multivariate transfer function models, adjusting for changes in other aspects of care and prior trends (table 5 and figure 5), universal screening was associated with a 19% reduction in prevalence density (absolute change, 0.189 to 0.154 (−0.035, 95% CI −0.049 to −0.021)/1000 AOBDs; p<0.001), a 29% reduction in HA incidence density (0.100 to 0.071 (−0.029, 95% CI −0.035 to −0.023)/1000 AOBDs; p<0.001) and a 46% fall in 30-day mortality (34% to 18.4% (−15.6%, 95% CI −24.1% to −7.1%); p<0.001). Using targeted screening as the comparison, during universal screening, the number needed to screen to avoid one additional episode of MRSA bacteraemia was 1978. Rates of bacteraemia and 30-day mortality were also positively associated with hospital-wide consumption of fluoroquinolone and cephalosporin antibiotics 1–6 months earlier. Assuming an average regimen of seven defined daily doses, the number needed to treat to cause one additional case of MRSA bacteraemia was 179 for cephalosporins and 204 for fluoroquinolones. Compared with forecasted consumption, reduction in the use of these antibiotics following the ‘4C’ antibiotic stewardship intervention was projected to have reduced prevalence density of MRSA bacteraemia by 0.027 (0.15 to 0.039)/1000 AOBDs. No significant relationships were identified with % hand-hygiene compliance, and effect sizes for screening were comparable across all departments. Final models explained 45%–68% of variance, and in all models, residuals were randomly distributed.


Trends in Staphylococcus aureus bacteraemia and impacts of infection control practices including universal MRSA admission screening in a hospital in Scotland, 2006-2010: retrospective cohort study and time-series intervention analysis.

Lawes T, Edwards B, López-Lozano JM, Gould I - BMJ Open (2012)

Observed trends and multivariate transfer model predictions (sum of lagged explanatory variables) for prevalence density, hospital-associated (HA) incidence density, 30-day mortality in methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia and % Staphylococcus aureus bacteraemia (SAB) involving MRSA. CL, confidence limit.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3378947&req=5

fig5: Observed trends and multivariate transfer model predictions (sum of lagged explanatory variables) for prevalence density, hospital-associated (HA) incidence density, 30-day mortality in methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia and % Staphylococcus aureus bacteraemia (SAB) involving MRSA. CL, confidence limit.
Mentions: In multivariate transfer function models, adjusting for changes in other aspects of care and prior trends (table 5 and figure 5), universal screening was associated with a 19% reduction in prevalence density (absolute change, 0.189 to 0.154 (−0.035, 95% CI −0.049 to −0.021)/1000 AOBDs; p<0.001), a 29% reduction in HA incidence density (0.100 to 0.071 (−0.029, 95% CI −0.035 to −0.023)/1000 AOBDs; p<0.001) and a 46% fall in 30-day mortality (34% to 18.4% (−15.6%, 95% CI −24.1% to −7.1%); p<0.001). Using targeted screening as the comparison, during universal screening, the number needed to screen to avoid one additional episode of MRSA bacteraemia was 1978. Rates of bacteraemia and 30-day mortality were also positively associated with hospital-wide consumption of fluoroquinolone and cephalosporin antibiotics 1–6 months earlier. Assuming an average regimen of seven defined daily doses, the number needed to treat to cause one additional case of MRSA bacteraemia was 179 for cephalosporins and 204 for fluoroquinolones. Compared with forecasted consumption, reduction in the use of these antibiotics following the ‘4C’ antibiotic stewardship intervention was projected to have reduced prevalence density of MRSA bacteraemia by 0.027 (0.15 to 0.039)/1000 AOBDs. No significant relationships were identified with % hand-hygiene compliance, and effect sizes for screening were comparable across all departments. Final models explained 45%–68% of variance, and in all models, residuals were randomly distributed.

Bottom Line: Rates of MSSA bacteraemia were not significantly affected by screening or antibiotic use.Declining clinical burdens from SAB were attributable to reductions in MRSA infections.Control of MSSA bacteraemia remains a priority.

View Article: PubMed Central - PubMed

Affiliation: Department of Paediatrics, Raigmore Hospital, Inverness, UK.

ABSTRACT

Objectives: To describe secular trends in Staphylococcus aureus bacteraemia (SAB) and to assess the impacts of infection control practices, including universal methicillin-resistant Staphylococcus aureus (MRSA) admission screening on associated clinical burdens.

Design: Retrospective cohort study and multivariate time-series analysis linking microbiology, patient management and health intelligence databases.

Setting: Teaching hospital in North East Scotland.

Participants: All patients admitted to Aberdeen Royal Infirmary between 1 January 2006 and 31 December 2010: n=420 452 admissions and 1 430 052 acute occupied bed days (AOBDs).

Intervention: Universal admission screening programme for MRSA (August 2008) incorporating isolation and decolonisation. PRIMARY AND SECONDARY MEASURES: Hospital-wide prevalence density, hospital-associated incidence density and death within 30 days of MRSA or methicillin-sensitive Staphylococcus aureus (MSSA) bacteraemia.

Results: Between 2006 and 2010, prevalence density of all SAB declined by 41%, from 0.73 to 0.50 cases/1000 AOBDs (p=0.002 for trend), and 30-day mortality from 26% to 14% (p=0.013). Significant reductions were observed in MRSA bacteraemia only. Overnight admissions screened for MRSA rose from 43% during selective screening to >90% within 4 months of universal screening. In multivariate time-series analysis (R(2) 0.45 to 0.68), universal screening was associated with a 19% reduction in prevalence density of MRSA bacteraemia (-0.035, 95% CI -0.049 to -0.021/1000 AOBDs; p<0.001), a 29% fall in hospital-associated incidence density (-0.029, 95% CI -0.035 to -0.023/1000 AOBDs; p<0.001) and a 46% reduction in 30-day mortality (-15.6, 95% CI -24.1% to -7.1%; p<0.001). Positive associations with fluoroquinolone and cephalosporin use suggested that antibiotic stewardship reduced prevalence density of MRSA bacteraemia by 0.027 (95% CI 0.015 to 0.039)/1000 AOBDs. Rates of MSSA bacteraemia were not significantly affected by screening or antibiotic use.

Conclusions: Declining clinical burdens from SAB were attributable to reductions in MRSA infections. Universal admission screening and antibiotic stewardship were associated with decreases in MRSA bacteraemia and associated early mortality. Control of MSSA bacteraemia remains a priority.

No MeSH data available.


Related in: MedlinePlus