Comparison of strategies to reduce meticillin-resistant Staphylococcus aureus rates in surgical patients: a controlled multicentre intervention trial

Abstract

Objective: To compare the effect of two strategies (enhanced hand hygiene vs meticillin-resistant Staphylococcus aureus (MRSA) screening and decolonisation) alone and in combination on MRSA rates in surgical wards.

Design: Prospective, controlled, interventional cohort study, with 6-month baseline, 12-month intervention and 6-month washout phases.

Setting: 33 surgical wards of 10 hospitals in nine countries in Europe and Israel.

Participants: All patients admitted to the enrolled wards for more than 24 h.

Interventions: The two strategies compared were (1) enhanced hand hygiene promotion and (2) universal MRSA screening with contact precautions and decolonisation (intranasal mupirocin and chlorhexidine bathing) of MRSA carriers. Four hospitals were assigned to each intervention and two hospitals combined both strategies, using targeted MRSA screening.

Outcome measures: Monthly rates of MRSA clinical cultures per 100 susceptible patients (primary outcome) and MRSA infections per 100 admissions (secondary outcome). Planned subgroup analysis for clean surgery wards was performed.

Results: After adjusting for clustering and potential confounders, neither strategy when used alone was associated with significant changes in MRSA rates. Combining both strategies was associated with a reduction in the rate of MRSA clinical cultures of 12% per month (adjusted incidence rate ratios (aIRR) 0.88, 95% CI 0.79 to 0.98). In clean surgery wards, strategy 2 (MRSA screening, contact precautions and decolonisation) was associated with decreasing rates of MRSA clinical cultures (15% monthly decrease, aIRR 0.85, 95% CI 0.74 to 0.97) and MRSA infections (17% monthly decrease, aIRR 0.83, 95% CI 0.69 to 0.99).

Conclusions: In surgical wards with relatively low MRSA prevalence, a combination of enhanced standard and MRSA-specific infection control approaches was required to reduce MRSA rates. Implementation of single interventions was not effective, except in clean surgery wards where MRSA screening coupled with contact precautions and decolonisation was associated with significant reductions in MRSA clinical culture and infection rates.

Trial registration: clinicaltrials.gov identifier: NCT00685867.

Keywords: Infection Control < Infectious Diseases; Surgery.

Figure 1

Flow of study wards through each phase of the study, 10 hospitals in nine countries were enrolled and were allocated to one of the three study arms during the intervention phase. The enhanced hand hygiene arm used hand hygiene promotion; the screening and decolonisation arm used universal meticillin-resistant Staphylococcus aureus (MRSA) screening coupled with contact precautions and decolonisation therapy with intranasal mupirocin and chlorhexidine body washes for identified MRSA carriers; the combined arm used a combination of hand hygiene promotion and targeted MRSA screening.

Figure 2

Implementation of the interventions, the top panel (A) shows the monthly hand hygiene (HH) compliance rates for hospitals in the enhanced HH and combined arms that used HH promotion campaigns. The solid dots represent the observed compliance rates while the lines represent the predicted compliance rates based on the regression model. The bottom panel (B) shows the proportion of patients screened on admission to the study wards by study arm.

Figure 3

Adherence to contact precautions, decolonisation and isolation measures for meticillin-resistant Staphylococcus aureus (MRSA) carriers, this figure shows the distribution of monthly adherence to infection control measures for randomly audited patients known to be colonised or infected with MRSA for each study arm. The top panel (A) shows adherence to implementation of contact precautions, decolonisation therapy and isolation in single rooms. The middle panel (B) shows the presence of signage of MRSA status on the patients’ room, bed or nursing chart. The bottom panel (C) shows the availability of gowns, gloves and alcohol-based handrub in or at the entrance of the room. The horizontal line in each box represents the median, the box represents the interquartile range and the vertical lines represent the minimum and maximum values.

Figure 4

Nosocomial meticillin-resistant Staphylococcus aureus (MRSA) rates by study arm, the top panel (A) shows the nosocomial MRSA isolaton rates from clinical specimens. The middle panel (B) shows the nosocomial MRSA infection rates. The bottom panel (C) shows the nosocomial MRSA surgical site infection rates. The solid dots represent the observed MRSA rates while the lines represent the predicted MRSA rates based on the regression models.