A prospective survey of current methicillin-resistant Staphylococcus aureus control measures

An integrative review of infection prevention and control programs for multidrug-resistant organisms in acute care hospitals: a socio-ecological perspective

BACKGROUND

The infection rates of multidrug-resistant organisms (MDRO) are increasing in Canada and the United States. The prevention and control of MDRO infections remain an important issue in acute care hospitals. Although comprehensive infection prevention and control programs have been recommended, there is little evidence to date of their effectiveness or of what aspects are most important.

OBJECTIVES

Our objectives were to review and critique the literature on the relationship between an MDRO infection and control program and MDRO rates in acute care hospitals.

METHODS

Studies including original research published between January 1, 1998, and May 14, 2009, were identified through MEDLINE, CINAHL, EMBASE, PUBMED, The Cochrane Library, and expert consultation. A comprehensive search strategy was developed with a librarian to find studies that covered the main subject areas of this integrative review.

RESULTS

Of the 1,382 papers retrieved, 47 were reviewed, and 32 studies met the inclusion criteria. The interventions in the included studies were assessed using the tier 1/tier 2 framework. A total of 18 (56.25%) studies had an administrative measure as an intervention; 20 (62.5%) studies had education and training of health care personnel; 8 (25.0%) studies had judicious use of antimicrobial agents; 17 (53.1%) studies used surveillance; 24 (75.0%) studies had infection control precautions to prevent transmission; 7 studies (21.9%) introduced environmental measures; and 9 (28.1%) studies used patient decolonization. Although all the 32 studies were quasiexperimental studies, only 2 (5.9%) studies provided sample size calculations, and only 5 studies reported confounding factors. Whereas 27 used an interrupted time series design and 2 were controlled pre- and post-intervention designs, 3 were pre- and post-intervention without control groups.

CONCLUSION

This integrative review demonstrated that the evidence of the relationship between MDRO infection prevention and control programs and the rates of MDRO is weak. Although major methodologic weaknesses exist in the published literature making it not possible to exclude other plausible explanations for the reduction of the acquisition of MDRO, the overall evidence does support the use of multiple interventions to reduce the rates of MDRO in acute care hospitals. Whereas it is unclear which bundles of interventions are effective, there is a clear suggestion that multiple simultaneous interventions can be effective in reducing MDRO infections. In addition, despite the limitations of interrupted time series, multiple studies employing active surveillance cultures were associated with reduced MDRO infections. Future individual reports of outbreaks and intervention studies should be written in a standardized manner using the recommended Outbreak Reports and Intervention Studies of Nosocomial Infection (ORION) guidelines. Further research is needed on the proposed tier 1/tier 2 framework clearly indicating all the interventions implemented.

Isolation measures in the hospital management of methicillin resistant Staphylococcus aureus (MRSA): systematic review of the literature

OBJECTIVE

To evaluate the evidence for the effectiveness of isolation measures in reducing the incidence of methicillin resistant Staphylococcus aureus (MRSA) colonisation and infection in hospital inpatients.

DESIGN

Systematic review of published articles.

DATA SOURCES

Medline, Embase, CINAHL, Cochrane Library, System for Information on Grey Literature in Europe (SIGLE), and citation lists (1966-2000).

REVIEW METHODS

Articles reporting MRSA related outcomes and describing an isolation policy were selected. No quality restrictions were imposed on studies using isolation wards or nurse cohorting. Other studies were included if they were prospective or employed planned comparisons of retrospective data.

RESULTS

46 studies were accepted; 18 used isolation wards, nine used nurse cohorting, and 19 used other isolation policies. Most were interrupted time series, with few planned formal prospective studies. All but one reported multiple interventions. Consideration of potential confounders, measures to prevent bias, and appropriate statistical analysis were mostly lacking. No conclusions could be drawn in a third of studies. Most others provided evidence consistent with a reduction of MRSA acquisition. Six long interrupted time series provided the strongest evidence. Four of these provided evidence that intensive control measures including patient isolation were effective in controlling MRSA. In two others, isolation wards failed to prevent endemic MRSA.

CONCLUSION

Major methodological weaknesses and inadequate reporting in published research mean that many plausible alternative explanations for reductions in MRSA acquisition associated with interventions cannot be excluded. No well designed studies exist that allow the role of isolation measures alone to be assessed. None the less, there is evidence that concerted efforts that include isolation can reduce MRSA even in endemic settings. Current isolation measures recommended in national guidelines should continue to be applied until further research establishes otherwise.

Control of endemic MRSA-what is the evidence? A personal view

Although there is extensive literature on the control of MRSA, when that concerning epidemics is excluded, only a limited amount remains regarding the control of endemic MRSA. Several guidelines have been recently published recommending stringent control measures, which are often suggested based on their success in controlling MRSA outbreaks in hospitals with few MRSA or in containing MRSA cases introduced into a hospital with no MRSA. In these settings, multiple measures are usually introduced with apparently successful results. However, results may not be generalizable to other settings and we do not know the minimum effective measures required for MRSA containment. This paper aims critically to review the literature to determine whether evidence exists for the value of the infection control measures that are widely recommended in the endemic setting. Much of this literature is based on observational studies, with few randomized, controlled trials having been conducted. More well-designed studies are required before many of the principles on which we build infection control programmes can be regarded as evidence based.

The effect of moving to a new hospital facility on the prevalence of methicillin-resistant Staphylococcus aureus

BACKGROUND

The influence of hospital design on nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) is unknown. Our hospital's relocation to a new building with radically different ward design allowed us to study this question. Our old hospital facility had open bay wards and intensive care units, and few poorly located sinks for handwashing (bed:sink ratio 4:1). Our new hospital facility had optimized hand-washing geography and distribution of ward beds into mostly single or double rooms (bed:sink ratio 1.3:1).

METHODS

We compared the prevalence of MRSA in the 2 institutions by obtaining nasal swabs from all patients on 8 selected wards and intensive care units at 2 time points both before and after the move. In addition, passive surveillance rates of MRSA for all hospitalized patients for 2 years both before and after the move were compared. Hand hygiene practices, although unrelated to the study periods, were directly observed.

RESULTS

Eight of 123 patients cultured before the move were MRSA positive, compared to 5 of 138 patients cultured after the move (P=NS). MRSA prevalence determined by passive surveillance of all hospitalized patients before and after the move was also unchanged. An insignificant increase in the frequency of hand-hygiene performance following the move (20% to 23%) was observed.

CONCLUSION

Radical facility design changes, which would be permissive of optimal infection control practices, were not sufficient, by themselves, to reduce the nosocomial spread of MRSA in our institution.

Methicillin resistant Staphylococcus aureus (MRSA) in the intensive care unit

Methicillin resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen that causes severe morbidity and mortality worldwide. MRSA strains are endemic in many American and European hospitals and account for 29%-35% of all clinical isolates. Recent studies have documented the increased costs associated with MRSA infection, as well as the importance of colonisation pressure. Surveillance strategies have been proposed especially in high risk areas such as the intensive care unit. Pneumonia and bacteraemia account for the majority of MRSA serious clinical infections, but intra-abdominal infections, osteomyelitis, toxic shock syndrome, food poisoning, and deep tissue infections are also important clinical diseases. The traditional antibiotic therapy for MRSA is a glycopeptide, vancomycin. New antibiotics have been recently released that add to the armamentarium for therapy against MRSA and include linezolid, and quinupristin/dalfopristin, but cost, side effects, and resistance may limit their long term usefulness.