Hôpital Propre II Study Group. Methicillin-resistant Staphylococcus aureus in French hospitals: A 2-month survey in 43 hospitals, 1995

Relationship between the Prevalence of Methicillin-ResistantStaphylococcus aureusInfection and Indicators of Nosocomial Infection Control Measures A Population-Based Study in French Hospitals

Objective.

To assess whether infection control indicators are associated with the prevalence of methicillin-resistantStaphylococcus aureus(MRSA) infection in French hospitals.

Methods.

We linked the database for the 2006 national prevalence survey of nosocomial infection with the database of infection control indicators (comprised of ICALIN, an indicator of infection control organization, resources, and action, and ICSHA, an indicator of alcohol-based handrub consumption) recorded from hospitals by the Ministry of Health. Data on MRSA infection were obtained from the national prevalence survey database and included the site and origin of infection, the microorganism responsible, and its drug resistance profile. Because the prevalence of MRSA infection was low and often nil, especially in small hospitals, we restricted our analysis to hospitals with at least 300 Patients. We used a multilevel logistic regression model to assess the joint effects of patient-level variables (eg, age, sex, or infection) and hospital-level variables (infection control indicators).

Results.

Two hundred two hospitals had at least 300 patients, for a total of 128,631 Patients. The overall prevalence of MRSA infection was 0.34% (95% confidence interval [CI], 0.29%-0.39%). The mean value for ICSHA was 7.8 L per 1,000 patient-days (median, 6.1 L per 1,000 patient-days; range, 0-33 L per 1,000 patient-days). The mean value for ICALIN was 92 of a possible 100 points (median, 94.5;range, 67-100). Multilevel analyses showed that ICALIN scores were associated with the prevalence of MRSA infection (odds ratio for a score change of 1 standard deviation, 0.80;95% CI, 0.69-0.93). We found no association between prevalence of MRSA infection and ICSHA. Other variables significantly associated with the prevalence of MRSA infection were sex, vascular or urinary catheter, previous surgery, and the McCabe score.

Conclusions.

We found a significant association between the prevalence of MRSA infection and ICALIN that suggested that a higher ICALIN score may be predictive of a lower prevalence of MRSA infection.

Risk factors and mortality in patients with nosocomial Staphylococcus aureus bacteremia

BACKGROUND

Infections due to methicillin-resistant Staphylococcus aureus have become increasingly common in hospitals worldwide. S aureus continues to be a cause of nosocomial bacteremia.

METHODS

We analyzed the clinical significance (mortality) of MRSA and methicillin-susceptible S aureus bacteremia in a retrospective cohort study in a 2900-bed tertiary referral medical center. Survival and logistic regression analyses were used to determine the risk factors and prognostic factors of mortality.

RESULTS

During the 15-year period, 1148 patients were diagnosed with nosocomial S aureus bacteremia. After controlling potential risk factors for MRSA bacteremia on logistic regression analysis, service, admission days prior to bacteremia, age, mechanical ventilator, and central venous catheter (CVC) were independent risk factors for MRSA. The crude mortality rate of S aureus bacteremia was 44.1%. The difference between the mortality rates of MRSA (49.8%) and MSSA bacteremia (27.6%) was 22.2% (P < .001). Upon logistic regression analysis, the mortality with MRSA bacteremia was revealed to be 1.78 times higher than MSSA (P < .001). The other predicted prognostic factors included age, neoplasms, duration of hospital stay after bacteremia, presence of mechanical ventilator, and use of CVC.

CONCLUSIONS

Resistance to methicillin was an important independent prognostic factor for patients with S aureus bacteremia.

Development of a surveillance system for methicillin-resistant Staphylococcus aureus in German hospitals

OBJECTIVE

To determine the appropriate method to calculate the rate of methicillin-resistant Staphylococcus aureus (MRSA) infection and colonization (hereafter, MRSA rates) for interhospital comparisons, such that the large number of patients who are already MRSA positive on admission is taken into account.

DESIGN

A prospective, multicenter, hospital-based surveillance of MRSA-positive case patients from January through December 2004.

SETTING

Data from 31 hospitals participating in the German national nosocomial infections surveillance system (KISS) were recorded during routine surveillance by the infection control team at each hospital.

RESULTS

Data for 4,215 MRSA-positive case patients were evaluated. From this data, the following values were calculated. The median incidence density was 0.71 MRSA-positive case patients per 1,000 patient-days, and the median nosocomial incidence density was 0.27 patients with nosocomial MRSA infection or colonization per 1,000 patient-days (95% CI, 0.18-0.34). The median average daily MRSA burden was 1.13 MRSA patient-days per 100 patient-days (95% CI, 0.86-1.51), with the average daily MRSA burden defined as the total number of MRSA patient-days divided by the total number of patient-days times 100. The median MRSA-days-associated nosocomial MRSA infection and colonization rate, which describes the MRSA infection risk for other patients in hospitals housing large numbers of MRSA-positive patients and/or many patients who were MRSA positive on admission, was 23.1 cases of nosocomial MRSA infection and colonization per 1,000 MRSA patient-days (95% CI, 17.4-28.6). The values were also calculated for various MRSA screening levels.

CONCLUSIONS

The MRSA-days-associated nosocomial MRSA rate allows investigators to assess the extent of MRSA colonization and infection at each hospital, taking into account cases that have been imported from other hospitals, as well as from the community. This information provides an appropriate incentive for hospitals to introduce further infection control measures.

Multidrug-resistant organisms in cystic fibrosis: management and infection-control issues

Chronic infection and inflammation are the hallmarks of cystic fibrosis lung disease. As cystic fibrosis patients are living longer owing to more intense treatment, multidrug-resistant organisms are being isolated increasingly from patients' respiratory tracts. While the adverse effects of Pseudomonas aeruginosa and Burkholderia cepacia complex are well described, less is known about the clinical significance of other emerging multidrug-resistant organisms, such as methicillin-resistant Staphylococcus aureus and Stenotrophomonas maltophilia. Owing to multiple mechanisms of antimicrobial resistance, these organisms are difficult to treat and often require combination antibiotic therapy. Until more is known about their pathogenicity and effect on clinical outcomes, physicians should be aware of the potential transmissibility of these organisms and implement adequate infection control strategies.

Screening for multidrug-resistant bacteria as a predictive test for subsequent onset of nosocomial infection

OBJECTIVE

To investigate whether carriage of multidrug-resistant bacteria is a risk factor for nosocomial infection and whether detection of carriage is predictive of subsequent onset of nosocomial infection.

METHODS

In this observational cohort (study period, June 1998 through October 2002), nasal and rectal swab specimens from 412 consecutive patients admitted to the intensive care unit were tested for carriage of multidrug-resistant bacteria. Concomitantly, the bacteria responsible for any subsequent nosocomial infection, the date of infection, and some of the known clinical risk factors for nosocomial infection were noted. These factors were adjusted for potential confounders, using a Cox model stratified on the propensity score of multidrug-resistant bacteria carriage. The diagnostic characteristics of a carriage test, including the positive and negative diagnostic likelihood ratios, were calculated for all strata of the propensity score.

RESULTS

Forty-two patients were carrying multidrug-resistant bacteria. Nosocomial infection occurred in 95 patients, of whom 16 (38%) were carriers, and 79 (83%) were noncarriers (P=.01). After adjustment for potential confounders, statistical analysis revealed that carriage remained a risk factor for nosocomial infection (relative risk, 2.08 [95% confidence interval {CI}, 1.13-3.81]). Receipt of antibiotic treatment at the time of intensive care unit admission was found to be protective against nosocomial infection. A positive result of test for detection of carriage seemed to be an efficient predictor of subsequent nosocomial infection (positive diagnostic likelihood ratio, 2.05 [95% CI, 1.15-3.66]), although a negative test result was not a predictor of subsequent nosocomial infection (negative likelihood ratio, 0.91 [95% CI, 0.73-1.11]).

CONCLUSION

Carriage proved to be a risk factor for subsequent nosocomial infection. However, the carriage test was useful as a predictive tool only for patients with a positive test result.

Consideration of age at admission for selective screening to identify methicillin-resistant Staphylococcus aureus carriers to control dissemination in a medical ward

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) has become an increasingly important pathogen responsible for hospital-acquired infections. Our study was to evaluate the efficiency of our selective screening program for methicillin-resistant Staphylococcus aureus (MRSA) carriers at admission to nonintensive care units.

METHODS

During 6 months, all patients were screened at admission to an internal medicine ward, at which time they were classified as patients at risk of carriage (PRC) and those with no known risk factor. The amplitude of cross transmission was estimated using various indicators during this universal screening period and during the same calendar period of the preceding year (selective screening).

RESULTS

The prevalence of MRSA carriage at admission was 5.5%. Among the 22 carriers identified, only 10 were PRC. Age >80 years was significantly associated with MRSA carriage upon admission (OR, 3.5; P < .01). All estimation indicators of MRSA dissemination amplitude were significantly lower during universal screening (relative risks varied from 2.79 to 26.4 according to indicators), demonstrating the need to broaden our criteria defining PRC.

CONCLUSION

Adding patients >80 years of age to our PRC definition would increase screening sensitivity (15 carriers identified for 128 patients sampled) and would enable early implementation of barrier precautions for the additional carriers identified.

Colonisation à bactéries multirésistantes en service de médecine physique et réadaptation

The objective of this study was to evaluate the management of multiresistant bacteria infection in French rehabilitation units. We e-mailed a questionnaire to French rehabilitation practitioners asking them what they did and what they knew about multiresistant bacteria colonisation. Their answers are described and analysed. We received 60 answers representing most of the country's rehabilitation centers. Routine screening was rare, but multiresistant bacteria were often looked for when certain risk factors were present. Methicillin-resistant Staphylococcus aureus and multiresistant enterobacteria were the usual target germs. In general, respondents asked for evidence-based recommendations that are also applicable without too great a prejudice (for the rehabilitation as well as for the psychological state) for a patient hospitalised in a rehabilitation unit. The legal risks and the costs involved are also to be tested. Many questions lay unanswered, although the literature is rich in descriptions of this area. The opposition between the medical advice of isolation and the readaptation objectives of a rehabilitation unit are strong. This study aims to highlight the most important uncertainties so as to promote prospective studies and enlighten the legal authorities.

High prevalence of carriage of methicillin-resistant Staphylococcus aureus at hospital admission in elderly patients: implications for infection control strategies

BACKGROUND

Despite contact isolation precautions for patients with methicillin-resistant Staphylococcus aureus (MRSA), MRSA infections are increasing in many countries.

OBJECTIVE

To evaluate the role of a potential unrecognized reservoir of MRSA carried by patients in acute care wards, we determined the prevalence of MRSA at hospital admission, with special emphasis on screening-specimen yields.

SETTING

A 1100-bed teaching hospital in Paris, France.

METHODS

Nasal screening cultures were performed at admission to a tertiary-care teaching hospital for patients older than 75 years.

RESULTS

MRSA was isolated from 63 (7.9%) of 797 patients. On the multivariate analysis, variables significantly associated with MRSA carriage were presence of chronic skin lesions (adjusted odds ratio [AOR], 5.10; 95% confidence interval [CI95], 2.52-10.33); transfer from a nursing home, rehabilitation unit, or long-term-care unit (AOR, 4.52; CI95, 2.23-9.18); and poor chronic health status (AOR, 1.80; CI95, 1.02-3.18). Without admission screening, 84.1% of MRSA carriers would have been missed at hospital admission and 76.2% during their hospital stay. Furthermore, 81.1% of days at risk for MRSA dissemination would have been spent without contact isolation precautions had admission screening not been performed.

CONCLUSIONS

MRSA carriage at hospital admission is far more prevalent than MRSA-positive clinical specimens. This may contribute to failure of contact isolation programs. Screening cultures at admission help to identify the reservoir of unknown MRSA patients.

Methicillin-resistant Staphylococcus aureus in horses and horse personnel, 2000-2002

Methicillin-resistant Staphylococcus aureus was isolated from horses and horse personnel in a pattern suggestive of interspecies transmission of a human-origin clone.

Methicillin-resistant Staphylococcus aureus (MRSA) infection was identified in 2 horses treated at a veterinary hospital in 2000, prompting a study of colonization rates of horses and associated persons. Seventy-nine horses and 27 persons colonized or infected with MRSA were identified from October 2000 to November 2002; most isolations occurred in a 3-month period in 2002. Twenty-seven (34%) of the equine isolates were from the veterinary hospital, while 41 (51%) were from 1 thoroughbred farm in Ontario. Seventeen (63%) of 27 human isolates were from the veterinary hospital, and 8 (30%) were from the thoroughbred farm. Thirteen (16%) horses and 1 (4%) person were clinically infected. Ninety-six percent of equine and 93% of human isolates were subtypes of Canadian epidemic MRSA-5, spa type 7 and possessed SCCmecIV. All tested isolates from clinical infections were negative for the Panton-Valentine leukocidin genes. Equine MRSA infection may be an important emerging zoonotic and veterinary disease.

Risk factors for acquisition of methicillin-resistant Staphylococcus aureus (MRSA) by patients with cystic fibrosis

Methicillin-resistant Staphylococcus aureus (MRSA) is an increasing problem for patients with cystic fibrosis (CF). It has been associated with clinical deterioration in some patients with CF, creates additional infection control problems, and may affect acceptance onto transplant waiting lists. Recent attempts to eradicate the organism have met with only moderate success. An understanding of those factors which increase the risk of acquisition of MRSA by CF patients will aid the development of effective preventative strategies. We conducted a retrospective case-control study comparing a variety of risk factors for 15 MRSA-positive patients and 30 age-sex-matched MRSA-negative controls who attended the Regional Paediatric or Regional Adult Cystic Fibrosis Units in Leeds. During the year prior to initial isolation, MRSA-positive CF patients spent more days in hospital (mean 19.8 days versus 5.5 days, p=0.0003), received more treatment days of oral ciprofloxacin (43.5 days versus 13.9 days, p=0.03) more treatment days of oral/intravenous cephalosporins (42.7 days versus 15.4 days, p=0.04) and were more likely to be chronically infected with Aspergillus fumigatus (40% versus 10%, p=0.04) than the age-sex-matched MRSA-negative controls. There were no significant differences in observed clinical parameters (clinical and X-ray scores) with between the two groups. Minimising the number and length of hospital admissions and judicious use of antibiotics, particularly ciprofloxacin, should be the key components of any strategies designed to reduce the risk of MRSA acquisition by patients with CF.

An outbreak of methicillin-resistant Staphylococcus aureus surgical-site infections initiated by a healthcare worker with chronic sinusitis

An investigation was performed following two methicillin-resistant Staphylococcus aureus surgical-site infections in a 946-bed French general hospital. The investigation revealed that the outbreak involved 7 patients in 2 surgical wards and that infections were probably contracted in the operating theater from a healthcare worker suffering from chronic sinusitis.

Infections nosocomiales à Staphylococcus aureus résistant à la méthicilline en réanimation médicale polyvalente : facteurs de risque, morbidité et impact économique

OBJECTIVE

Methicillin resistance and infections caused by methicillin-resistant Staphylococcus aureus represent a growing problem and a challenge for health-care institutions. We evaluated risk factors, morbidity and cost of infections caused by methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) Staphylococcus aureus.

DESIGN

We performed an un-matched case-control study in an 20-bed medical intensive care unit from 1994-2001 at Nantes teaching hospital, France. All patients with pneumonia, bacteraemia and urinary MRSA (cases) or MSSA (controls) nosocomial infections were included in the study.

RESULTS

Twenty four patients with MRSA infection were compared to 64 patients with MSSA infections. Patients with MRSA infection were older (56 vs. 45 years, P < 0.01), had longer length of stay (47 vs. 35 days, P < 0.05) and were infected later (22 vs. 10 days, P < 0.00001) than patients with MSSA infection. No difference was observed between the two groups according to the Omega index, acute simplify index and mortality. MRSA infections involved extra cost due to antimicrobial treatment (184 vs. 72 Euros, P < 0.005) and length of stay (37,278 vs. 27,755 Euros, P < 0.05).

CONCLUSION

Patient infected by MRSA seems to be different from patient infected by MSSA but without consequence on Omega index and mortality. But methicillin-resistance involves extra cost due to antimicrobial treatment and length of stay.

Elimination of epidemic methicillin-resistant Staphylococcus aureus from a university hospital and district institutions, Finland

From August 1991 to October 1992, two successive outbreaks of methicillin-resistant Staphylococcus aureus (MRSA) occurred at a hospital in Finland. During and after these outbreaks, MRSA was diagnosed in 202 persons in our medical district; >100 cases involved epidemic MRSA. When control policies failed to stop the epidemic, more aggressive measures were taken, including continuous staff education, contact isolation for MRSA-positive patients, systematic screening for persons exposed to MRSA, cohort nursing of MRSA-positive and MRSA-exposed patients in epidemic situations, and perception of the 30 medical institutions in that district as one epidemiologic entity brought under surveillance and control of the infection control team of Turku University Hospital. Two major epidemic strains, as well as eight additional strains, were eliminated; we were also able to prevent nosocomial spread of other MRSA strains. Our data show that controlling MRSA is possible if strict measures are taken before the organism becomes endemic. Similar control policies may be successful for dealing with new strains of multiresistant bacteria, such as vancomycin-resistant strains of S. aureus.

[Evaluation of the efficacy of a multiresistant bacteria control programme in a teaching hospital, studying the evolution of methicillin-resistant Staphylococcus aureus incidence]

Methicillin-resistant Staphylococcus aureus (MRSA) constitute the most important multiresistant bacteria (MRB) recovered in French hospitals. Our objective was to measure these MRSA diffusion in our hospital to evaluate the MRB control programme which had been implemented in the beginning of 1999. This study was conducted in a teaching hospital containing 1800 beds, from February 1999 to January 2001. All MRSA isolated in clinical samples were included. Duplicates (same bacteria in the same patient) were excluded. The detection of methicillin-resistance was performed at 30 degrees C, by disk diffusion method. Incidence densities were determined with their 95% confidence interval (CI 95%). Their evolution by four-month period was evaluated with the chi-square test for trend. During the two-year period, 866 MRSA were isolated. The global incidence was 0,88 per 1000 patient-days (PD) (IC 95% = left open bracket 0,83-0,93 right open bracket ). For cases acquired in our hospital the incidence was 0,66 per 1000 PD, whereas it was 0,26 per 1000 PD for imported cases. Concerning the evolution of incidences, no significant trend was observed for global incidence. The incidence of acquired MRSA decreased during the first year, but increased thereafter. The incidence of imported MRSA increased with a significant trend (p < 10(-5)). The number of these imported MRSA isolated in our hospital was twice fold higher in 2000. This study emphasizes an important actual problem : the increase of patient colonization pressure at the time of admission in hospitals. This increase, which can be due in part to a community transmission, is responsible for a reduction of the efficacy of MRSA control programmes.

Ethical concerns in isolating patients with methicillin-resistant Staphylococcus aureus on the rehabilitation ward: a case report

Concern about methicillin-resistant Staphylococcus aureus (MRSA) is increasing in rehabilitation facilities. Those affected are often isolated to prevent the spread of MRSA to other patients. Because this isolation often interferes with the traditional rehabilitative approach, rehabilitation team members find themselves in an ethical dilemma as to how to approach these patients. Some patients may feel that strict isolation protocols violate their rights. We report a case showing the ethical dilemmas that an MRSA-positive patient brings to the rehabilitation setting. Isolation techniques make it difficult to treat rehabilitation patients using the current standards of care without compromising the medical ethics principles of autonomy and beneficence. Further study is required to establish protocols for patients with MRSA in the rehabilitation setting.

[The importance of detecting methicillin-resistant Staphylococcus aureus in an intensive care setting]

In recent years, the fight against nosocomial infections has constituted a major public health challenge. Measures aimed at preventing the spread of multiresistant bacteria (MRB) through carriage combine the more or less systematic detection of carriers and precautions concerning isolation. In the light of published data, elements for the evaluation of a cost-efficiency ratio for measures concerning detection and isolation in intensive care are presented. The high levels of methicillin-resistant Staphylococcus aureus (MRSA) observed in hospitals constitute the principal target. Although isolation precautions appear to be effective, the value of detecting MRSA remains a subject of debate. Such detection has several objectives: the identification of carriers, assistance in the implementation of isolation precautions, the eradication of carriage and the evaluation of strategy. These different objectives are discussed.

[Staphylococci resistant to antibiotic therapy]

Increasing frequency in antibiotic resistance in Staphylococcus aureus is worrying. In this review, we briefly describe the mechanisms of resistance to antibiotics in staphylococci and we report the current incidence of antibiotic resistance in France. Methicillin-resistance is mostly confined to hospitals. However, spread of multiply resistant strains of staphylococci to the community is a putative threat. Strains with diminished susceptibility to glycopeptides are rare but possibly underestimated because of the in vitro difficulties to detect glycopeptide resistance. A continuous resistance survey is necessary. The problem of multiresistance is different for hospital and community staphylococci. The later strains still remain susceptible to many antibiotics, apart from some exceptions. By contrast, incidence of multiply resistance in hospitals remains high. After a recent decrease, incidence of oxacillin resistance seems to be stabilized. A new and recent feature is the great variety of resistance phenotypes which can be found in methicillin-resistant strains, in particular with gentamicin susceptibility.

Prevalence of methicillin-resistant Staphylococcus aureus carriage at the time of admission in two acute geriatric wards

Studies on methicillin-resistant Staphylococcus aureus (MRSA) in the elderly have been concerned with patients hospitalized in nursing homes or long-term care facilities. Our objective was to estimate the prevalence of MRSA at the time of admission in two acute geriatric wards with high endemic MRSA incidence in a French teaching hospital. A prospective screening of MRSA carriers was conducted by swabbing nares and wounds during five weeks for all patients on the day of admission. For each patient demographic, administrative, clinical and therapeutic data were recorded. Their associations with MRSA carriage were studied by logistic regression analysis. On the day of admission, 35 patients (14.6%) were MRSA carriers. Variables independently associated with carriage were hospitalization within the six last months (OR = 4.64; P < 0.001) and the existence of wounds or bedsores (OR = 2.864; P = 0.02). The high prevalence of MRSA carriage at the time of admission could explain in part the high incidence of MRSA in these wards. A systematic selective screening targeted on patients with high risk of carriage should be helpful to implement barrier precautions and reduce cross-transmission.

Duration of colonization by methicillin-resistant Staphylococcus aureus after hospital discharge and risk factors for prolonged carriage

To investigate persistent carriage of methicillin-resistant Staphylococcus aureus (MRSA), we conducted a prospective 10-month study of MRSA carriage in previous carriers who were readmitted to our hospital. Four screening specimens, 2 from the skin and 2 from the nares, were obtained within 3 days after admission, in addition to diagnostic specimens requested by physicians. Of the 78 patients included in our study, 31 (40%) were persistent carriers of MRSA, with an estimated median time of 8.5 months to MRSA clearance. In the multivariate analysis, the only factor significantly associated with persistent carriage was the presence of a break in the skin at readmission (odds ratio, 4.34; P=.004); however, a trend was found for admission from a chronic-care institution (odds ratio, 3.65; P=.06). Our data confirm that prolonged carriage of MRSA can occur after hospital discharge, support routine screening for MRSA at readmission of previously MRSA-positive patients, and suggest that a particularly high index of suspicion for MRSA carriage should be maintained if these patients have a break in the skin.

The economic impact of methicillin-resistant Staphylococcus aureus in Canadian hospitals

OBJECTIVES

To determine the costs associated with the management of hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA), and to estimate the economic burden associated with MRSA in Canadian hospitals.

DESIGN

Patient-specific costs were used to determine the attributable cost of MRSA associated with excess hospitalization and concurrent treatment. Excess hospitalization for infected patients was identified using the Appropriateness Evaluation Protocol, a criterion-based chart review process to determine the need for each day of hospitalization. Concurrent treatment costs were identified through chart review for days in isolation, antimicrobial therapy, and MRSA screening tests. The economic burden to Canadian hospitals was estimated based on 3,167,521 hospital discharges for 1996 and 1997 and an incidence of 4.12 MRSA cases per 1,000 admissions.

SETTING

A tertiary-care, university-affiliated teaching hospital in Toronto, Ontario, Canada.

PATIENTS

Inpatients with at least one culture yielding MRSA between April 1996 and March 1998.

RESULTS

A total of 20 patients with MRSA infections and 79 colonized patients (with 94 admissions) were identified. This represented a rate of 2.9 MRSA cases per 1,000 admissions. The mean number of additional hospital days attributable to MRSA infection was 14, with 11 admissions having at least 1 attributable day. The total attributable cost to treat MRSA infections was $287,200, or $14,360 per patient The cost for isolation and management of colonized patients was $128,095, or $1,363 per admission. Costs for MRSA screening in the hospital were $109,813. Assuming an infection rate of 10% to 20%, we determined the costs associated with MRSA in Canadian hospitals to be $42 million to $59 million annually.

CONCLUSIONS

These results indicate that there is a substantial economic burden associated with MRSA in Canadian hospitals. These costs will continue to rise if the incidence of MRSA increases further.

Comparison of systematic versus selective screening for methicillin-resistant Staphylococcus aureus carriage in a high-risk dermatology ward

OBJECTIVE

To compare two strategies for screening methicillin-resistant Staphylococcus aureus (MRSA) carriers in a high-risk dermatology ward: systematic screening of all admitted patients versus selective screening of patients at risk.

DESIGN

The two strategies were applied prospectively during two consecutive periods. In period A (8.5 months), only patients transferred from other wards, or with a history of prior hospitalization, or presenting chronic wounds or disease with denuded skin were considered at high risk of MRSA carriage and sampled. In period B (7.5 months), all admitted patients were systematically screened. End-points were the number of patients having a MRSA-positive screening sample on admission during period B and having none of the risk factors used in period A, the rate of imported MRSA cases, and the rate of acquired cases.

SETTING

A 1,032-bed university hospital with a 19-bed inpatient dermatology ward, a referral center for toxic epidermal necrolysis and severe extensive dermatoses.

PATIENTS

The study included 729 dermatology inpatients (370 in period A and 359 in period B).

RESULTS

During period A, screening samples were obtained on admission for 30% of patients (77% of the patients at risk) and identified 25 MRSA carriers. During period B, 90.5% of admitted patients were screened, and 26 MRSA carriers were detected on admission; all of these patients belonged to at least one predefined category at risk for carriage. Overall rates of imported and acquired cases were similar between the two periods (6.8% vs 7.5%, and 2.9% vs 2.4%, respectively).

CONCLUSIONS

A screening strategy targeted to patients at risk of harboring MRSA has similar sensitivity and is more cost-effective than a strategy of systematic screening to identify MRSA carriers on admission.