The burden of MRSA in four German university hospitals

In the last few years, a dramatic increase of Methicillin-resistant Staphylococcus aureus (MRSA) detection in German hospitals can be recognized. Under this enormous pressure it is very important for infection control teams to assess the epidemiologic situation correctly. Therefore, a prospective multicenter hospital-based surveillance of MRSA cases was executed in four university hospitals with 1017–1333 beds in Germany. Routine surveillance data were recorded of all patients with MRSA isolates from clinical samples or screening cultures. Patients had been colonized or infected with MRSA during their hospital stay. In 2002 between 183 and 291 MRSA cases were treated in the respective hospitals (between 0.53 and 0.96 MRSA cases per 1000 patient days). Of these, 44.4% were MRSA infections. The most frequent type of MRSA infections were wound infections (56.9%) followed by pneumonia (21.0%) and bloodstream infections (15.1%). Of the infected patients 51.5% were already infected at admission. The median duration of isolation of MRSA patients in private rooms was between 11 and 16 days. Altogether 21,665 isolation days were observed in four hospitals; this means 1.52% of all patient days. On average, 9.0% of roommates were identified as MRSA carriers. Due to the high percentage of imported cases, the four university hospitals introduced a general screening for MRSA at admission in all ICUs and some further departments as well as an automatic alert system for readmitted patient with MRSA during their last hospital stay.     

Active screening in high-risk units is an effective and cost-avoidant method to reduce the rate of methicillin-resistant Staphylococcus aureus infection in the hospital.

OBJECTIVE: To evaluate the impact of active screening for methicillin-resistant Staphylococcus aureus (MRSA) on MRSA infection rates and cost avoidance in units where the risk of MRSA transmission is high. METHODS: During a 15-month period, all patients admitted to our adult medical and surgical intensive care units (ICUs) were screened for MRSA nasal carriage on admission and weekly thereafter. The overall rates of all MRSA infections and of nosocomial MRSA infection in the 2 adult ICUs and the general wards were compared with rates during the 15-month period prior to the start of routine screening. The percentage of patients colonized or infected with MRSA on admission and the cost avoidance of the surveillance program were also assessed. RESULTS: The overall rate of MRSA infections for all 3 areas combined decreased from 6.1 infections per 1,000 census-days in the preintervention period to 4.1 infections per 1,000 census-days in the postintervention period (P = .01). The decrease remained statistically significant when only nosocomial MRSA infections were examined (4.5 vs 2.8 infections per 1,000 census-days; P < .01), despite a corresponding increase during the postintervention period in the percentage of patients with onset of MRSA infection in the first 72 hours after admission to the general wards (46% to 81%; P < .005). A total of 3.7% of ICU patients were colonized or infected with MRSA on admission; MRSA would not have been detected in 91% of these patients if screening had not been performed. At a cost of Dollars 3,475/month for the program, we averted a mean of 2.5 MRSA infections/month for the ICUs combined, avoiding Dollars 19,714/month in excess cost in the ICUs. CONCLUSIONS: Even in a setting of increasing community-associated MRSA, active MRSA screening as part of a multi-factorial intervention targeted to high-risk units may be an effective and cost-avoidant strategy for achieving a sustained decrease of MRSA infections throughout the hospital.     

Dramatic results achieved with MRSA initiative

Program achieves 60% reduction in MRSA in one year, 80% in bloodstream infections. All hospital patients are swabbed, infected patients are isolated. Education efforts continued even after program was launched.     

Effect of targeted surveillance for control of methicillin-resistant Staphylococcus aureus in a community hospital system.

OBJECTIVE: To examine the cost associated with targeted surveillance for methicillin-resistant Staphylococcus aureus (MRSA) and the effect of such surveillance on the rate of nosocomial MRSA infection in a community hospital system. DESIGN: A before-and-after study comparing the rate of MRSA infection before (BES) and after (AES) the initiation of expanded surveillance. Cost-effectiveness was calculated as the difference between the cost savings associated with preventing nosocomial MRSA bacteremias and surgical site infections AES and the cost of MRSA cultures and contact isolation for patients colonized with MRSA. SETTING AND PARTICIPANTS: Patients in a 400-bed tertiary-care facility (Roper Hospital) and a 180-bed suburban hospital (St. Francis Hospital), both in Charleston, South Carolina.Interventions. Beginning in September 2001, patients were screened for MRSA colonization upon admission to the intensive care unit and weekly thereafter. In July 2002, surveillance was expanded to include targeted screening of patients admitted to general wards who were at risk of MRSA colonization. Colonized patients were placed in contact isolation. RESULTS: The mean rate of nosocomial MRSA infection decreased at Roper (0.76 cases per 1,000 patient-days BES and 0.45 per 1000 patient-days AES; P = .05) and at St. Francis (0.73 cases per 1,000 patient-days BES and 0.57 cases per 1000 patient-days AES; P=.35). Surveillance was cost-effective, preventing 13 nosocomial MRSA bacteremias and 9 surgical site infections, for a savings of 1,545,762 US dollars. CONCLUSIONS: Targeted surveillance for MRSA colonization was cost-effective and provided substantial benefits by reducing the rate of nosocomial MRSA infections in a community hospital system.     

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.     

Trends in methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections: effect of the MRSA "search and isolate" strategy in a hospital in Italy with hyperendemic MRSA.

OBJECTIVE: To evaluate the secular trends in MRSA BSIs after the introduction of a nosocomial MRSA control intervention. DESIGN: Before-after study. SETTING: An 850-bed community hospital with an ICU and vascular surgery, neurosurgery, bone marrow transplantation, and AIDS units. MRSA is endemic at this hospital; the prevalence of methicillin resistance among patients with S. aureus infection is greater than 50%. PATIENTS: Among all inpatients, MRSA BSI was identified, its origin defined, and incidence rates calculated by ward and origin. INTERVENTION: A MRSA control program was implemented based on active surveillance cultures to identify MRSA-colonized patients, followed by isolation using contact precautions. Incidence rates of MRSA BSI during the intervention (i.e., July 1, 1997, to December 31, 2001) and preintervention (i.e., January 1, 1996, to June 30, 1997) periods were compared. RESULTS: Sixty-nine MRSA BSIs were identified. When compared with the preintervention period, the incidence rate of MRSA BSI was reduced from 0.64 to 0.30 per 1000 admissions (RR, 0.46; CI95, 0.25-0.87; P = .02) during the intervention period. The impact was greater in the ICU, with an 89% reduction (RR, 0.11; CI95, 0.01-0.98; P = .03), and for CVC-associated MRSA BSIs, with an 82% decrease (RR, 0.17; CI95, 0.05-0.55; P = .002). Methicillin resistance among S. aureus blood isolates decreased from 46% to 17% (RR, 0.36; CI95, 0.22-0.62; P = .0002). CONCLUSION: A reduction in MRSA bacteremia is achievable through use of the MRSA "search and isolate" intervention even in a hospital with high rates of endemic MRSA.     

Evidence for cost reduction based on pre-admission MRSA screening in general surgery

Colonization with methicillin-resistant Staphylococcus aureus (MRSA) is a risk factor for MRSA infection causing increased costs in patient's care and treatment. To evaluate cost efficiency, pre-admission MRSA screening and subsequent MRSA decolonization of patients admitted to the Department of General Surgery at the University Hospital of Münster were determined. In 2004, 2054 (89.3%) out of the total of 2299 hospital-admitted patients were screened for MRSA (1769 elective and 530 direct admissions); 1536 patients underwent pre-admission MRSA screening (86.8% of the 1769 elective admissions), of whom seven patients (0.5%) were MRSA-positive and five of these were successfully decolonized before admission. In case of direct admissions, i.e., emergency cases or transferral from other hospitals, 2.4% and 8.6% were MRSA-positive, respectively. There were 25 patients MRSA positive during their hospital stay, two of these were nosocomially acquired, which represent 0.1 nosocomial MRSA cases in 1000 in-patients. The average MRSA carrier was (65±15 years) older than the other patients (55±17 years), had a significantly higher rate of pulmonary disease, coronary heart disease and certain infections; and had a longer hospital stay (27 versus 10 days, p<0.05). The total costs of the MRSA screening were approximately 20,000€. Since the estimated costs for handling MRSA treatment and isolation during a hospital stay are 6000–10,000€ for each affected patient, we estimated that approximately 20,000€ could be saved by detecting and successfully decolonizing a total of five patients through pre-admission screening. In this calculation, additional costs due to the increased morbidity and mortality of MRSA carriers and the possible spread of MRSA through unrecognized colonization were not included. In conclusion, pre-admission screening for MRSA is an effective method to reduce the hospital burden of MRSA-colonized patients and the savings due to consistent decolonization before elective admission outweigh the costs of screening.     

替考拉宁与利奈唑胺治疗MRSA感染的临床比较

目的 评价替考拉宁与利奈唑胺随机对照治疗重症监护室MRSA感染患者的疗效和安全性.方法 对68例MRSA重症感染患者进行随机对照开放试验,分为替考拉宁组35例,剂量400mg/次,1次/12 h,3个剂量后,1次/d;利奈唑胺组33例,剂量600mg/次,1次/12 h,均为静脉滴注,疗程14～18 d;比较两组病例的疗效、细菌清除率、用药前后的肝肾功能改变.结果 替考拉宁与利奈唑胺治疗重症MRSA感染的临床有效率为88.6％和90.9％,细菌清除率为86.8％、88.2％,两组结果差异无统计学意义;患者治疗后14 d APACHEⅡ评分分别为(10.17±3.32)、(13.66±5.98)分,替考拉宁组优于利奈唑胺组,差异有统计学意义(P＜0.05);不良反应发生率分别为11.4％和18.2％,替考拉宁组的不良反应发生率小于利奈唑胺组,差异有统计学意义(P＜0.05).结论 替考拉宁和利奈唑胺在治疗MRSA所致重症感染均有良好疗效,替考拉宁的用药安全性更高.     

A purpose built MRSA cohort unit

The control of hospital-acquired infection, in particular methicillin-resistant Staphylococcus aureus (MRSA) remains a challenge. Our hospital has established a purpose built 11-bed cohort unit with on-site rehabilitation for care of patients colonized with MRSA, in an attempt to improve their quality of care. Prior to the opening of this unit a number of concerns were voiced and the aim of this study was to address these. First, to establish if patient cohorting reduces the likelihood of successful decolonization, second, to evaluate the risk of staff colonization, and finally to see if successful environmental control of MRSA is possible.A patient database was established detailing patient demographics, infection rates, eradication and reacquisition rates. Staff screening was performed weekly, at the start of a period of duty. Sixty environmental sites were screened before unit opening, at 48h, six weeks and at six months.There were 88 admissions in the first six months; 62 patients were colonized with MRSA, and 26 patients (10 surgical, 16 medical) had MRSA infections. Twenty-three of 88 patients (26%) were successfully decolonized, which compares favourably with an eradication rate of 20% for the rest of the hospital. Twenty staff members participated in weekly screening. Five staff members colonized with MRSA were detected and all were successfully decolonized. Environmental control was achieved with a combination of a daily detergent clean and a once weekly clean with phenolic disinfectant.Our preliminary data suggest that, despite cohorting patients colonized with MRSA, with proper education and supervised cleaning protocols, it is possible to control environmental MRSA load, successfully decolonize patients and limit the risk of staff colonization.     

Active surveillance for methicillin-resistant Staphylococcus aureus (MRSA) decreases the incidence of MRSA bacteremia.

OBJECTIVES: To evaluate the influence of performance of active surveillance cultures for methicillin-resistant Staphylococcus aureus (MRSA) on the incidence of nosocomial MRSA bacteremia in an endemic hospital. DESIGN: Before-after trial. SETTING: A 700-bed hospital. PATIENTS: All patients admitted to the hospital who were at high risk for MRSA bacteremia. INTERVENTION: Performance of surveillance cultures for detection of MRSA were recommended for all patients at high risk, and contact isolation was implemented for patients with positive results of culture. Each MRSA-positive patient received one course of eradication treatment. We compared the total number of surveillance cultures, the percentage of surveillance cultures with positive results, and the number of MRSA bacteremia cases before the intervention (from January 2002 through February 2003) after the start of the intervention (from July 2003 through October 2004). RESULTS: The number of surveillance cultures performed increased from a mean of 272.57 cultures/month before the intervention to 865.83 cultures/month after the intervention. The percentage of surveillance cultures with positive results increased from 3.13% before to 5.22% after the intervention (P < .001). The mean number of MRSA bacteremia cases per month decreased from 3.6 cases before the intervention to 1.8 cases after the intervention (P < 0.001). CONCLUSIONS: Active surveillance culture is important for identifying hidden reservoirs of MRSA. Contact isolation can prevent new colonization and infection and lead to a significant reduction of morbidity and healthcare costs.     

Aktuelle Daten und Trends zu Methicillin-resistenten Staphylococcus aureus (MRSA)

Nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a problem in hospital settings worldwide. The National Reference Centre for Staphylococci performs molecular typing on a representative sample set of MRSA isolates from German hospitals for assessing long-term trends thus following the dynamics of emergence and spread of MRSA clones. The article focuses on recent data concerning antibiotic resistance and epidemic MRSA in nosocomial settings and also reflects the impact of community-acquired MRSA and MRSA from zoonotic reservoirs. Identifying common and newly emerging clones is an on-going challenge in the changing epidemiology of MRSA and prevention of further spread needs molecular surveillance.     

Screening high-risk patients for methicillin-resistant Staphylococcus aureus on admission to the hospital: is it cost effective?

OBJECTIVES: To determine the cost-effectiveness of a policy of screening high-risk patients for methicillin-resistant Staphylococcus aureus (MRSA) colonization on admission to hospital. SETTING: 980-bed university-affiliated tertiary-care hospital. PATIENTS: Between June 1996 and May 1997, patients directly transferred from another hospital or nursing home, or who had been hospitalized in the previous 3 months, were screened for MRSA within 72 hours of hospital admission. DESIGN: Nasal, perineal, and wound swabs were obtained for MRSA screening using standard laboratory methods. Laboratory and nursing costs associated with screening patients for MRSA on admission to hospital were calculated. The costs associated with the implementation of recommended infection control measures for patients with MRSA also were determined. RESULTS: 3,673 specimens were obtained from 1,743 patients. MRSA was found on admission in 23 patients (1.3%), representing 36% of the 64 patients with MRSA identified in the hospital during the year. MRSA-colonized patients were more likely to have been transferred from a nursing home (odds ratio [OR], 6.4; P =.04) or to have had a previous history of MRSA colonization (OR, 13.1; P =.05). Laboratory and nursing costs were found to be $8.34 per specimen, for a total cost of $30,632 during the year. The average cost of implementing recommended infection control measures for patients colonized with MRSA was approximately $5,235 per patient. CONCLUSION: If early identification of MRSA in colonized patients prevents nosocomial transmission of the organism to as few as six new patients, the screening program would save money.     

Performance feedback of hand hygiene, using alcohol gel as the skin decontaminant, reduces the number of inpatients newly affected by MRSA and antibiotic costs

In March 2000 the Plastic Surgery Unit of our 600-bedded district general hospital agreed to be the pilot ward for the introduction of a new standard of hand hygiene, emphasizing the use of alcohol gel on socially clean hands between clinical contact with patients. Hand hygiene practice of healthcare workers (HCWs) was observed using Formic forms. The data from completed forms were scanned into an Excel database, and results fed back to HCWs in graphical form. The case notes of patients newly affected by methicillin-resistant Staphylococcus aureus (MRSA), likely to have been acquired as inpatients, were reviewed for one year before and after this performance feedback of hand hygiene. The cost of teicoplanin use (for MRSA infections) was also determined for the two periods. There was a significant reduction in the number of patients newly affected by MRSA (P<0.05), and in the use of teicoplanin, suggesting that performance feedback of hand hygiene reduces nosocomial MRSA infection rates and antibiotic use.     

MRSA in a large German University Hospital: Male gender is a significant risk factor for MRSA acquisition

Background: The continually rising number of hospital acquired infections and particularly MRSA (Methicillin-resistant Staphylococcus aureus) colonization poses a major challenge from both clinical and epidemiological perspectives. The assessment of risk factors is vital in determining the best prevention, diagnosis and treatment strategies. Materials and methods: We analyzed 798 cases of MRSA in a large German University Hospital over a 7-year period. Data was collected retro- and prospectively including patient age, sex, type of ward and duration of inpatient stay. In addition we analyzed all cases on ICU with regards to cross infection and MRSA genotyping via DNA MicroArray Technology. The years 2004 to 2007 were analyzed with a specific focus on gender.Results: Male gender is significantly correlated with increased risk of MRSA acquisition (p<0.001), the predominant setting for MRSA is on ICU. 75% of the MRSA positive patients are over 50 years of age (average age 59.8 years). The inpatient time was 4.15 times higher in MRSA carriers compared with non-MRSA cases, however this was not significant. MRSA genotyping on ICU showed mainly the subtypes ST 5, ST 22, ST 228, however cross contamination with identical genotypes was only detected in a minority of cases (5 out of 22).Conclusion: Unlike previous studies which show no or inconclusive evidence of gender as a risk factor, our data confirm that male gender is a significant risk factor for MRSA carrier status. Further research will be required to investigate the aetiology of these findings.     

Economic Consequences of the Demography of MRSA Patients and the Impact of Broad-Spectrum Antimicrobials

Background: Studies have determined the societal impact of methicillin-resistant Staphylococcus aureus (MRSA) by modelling its impact on labour supply and productivity. In addition, most of the studies on the topic conclude that the problem of resistance should be counteracted on the macro level by reducing overall antibacterial consumption. Objective: Two major questions have been raised in the present work. Firstly, is MRSA impairing labour supply and productivity? Secondly, is it the overall use of antibacterials that may be seen as crucial to the spread of MRSA infections? Methods: The age distribution of MRSA patients is compared with the age distribution of the entire patient population at a German teaching hospital. In addition, the age distribution of MRSA patients was applied to the age distribution of the German population in the year 2050 in order to identify the effects of the double-ageing process on the spread of MRSA. Furthermore, recent epidemiological studies were reviewed on the impact of overall antibacterial consumption on MRSA infection rates. Results: Based on available data, we show that patients infected or colonized with MRSA are, for the most part, beyond retirement age and thus not responsible for changes in labour supply or productivity. Application of age distribution of MRSA patients to the age distribution of the German population in the year 2050 gives a 24% increase in the number of MRSA cases to a total of 182 778 due to an ageing population. In addition, we show that a 32% reduction in the cost of MRSA to the German healthcare system could be reached if use of fluoroquinolones and third-generation cephalosporins was reduced by just 10% and, correspondingly, use of antiseptics for hand disinfection was increased by 10%. Conclusions: MRSA is a phenomenon that, to a larger degree, affects the elderly population rather than the labour force. When it comes to policy options to counteract MRSA on the macro level, most economic research on the topic is biased in assuming that the overall use of antibacterials is responsible for the spread of MRSA infections.     

The population impact of MRSA in a country: the national survey of MRSA in Wales, 1997

Continuous data collection on all new isolates of MRSA via CoSurv has taken place in Wales since January 1996. In order to audit this data collection, and to address some of the issues that it does not include, a survey of MRSA was carried out. Questionnaires were completed by infection control teams. Rates were calculated using hospital throughput denominators. Results from the one-day prevalence survey, the two-week incidence survey, and the follow-up survey carried out on new MRSA patients identified in the incidence survey, are presented. Results were found to be broadly similar to those collected via routine surveillance. MRSA was found frequently and disproportionately in the elderly, with higher rates in male than female patients. The highest incidence of total and invasive MRSA was in males aged 75 and over (total: 12.5/1000 finished consultant episodes; invasive: 2.8/1000). Although there was a large community reservoir of MRSA, most appeared to have been acquired in hospital, since most patients had a history of hospitalization, often with multiple hospital admissions. Community-based isolates from cases with no hospital history tended to have been from ulcers. Prevalence and incidence of MRSA was relatively low compared with hospital throughput (mean prevalence: 2.4/100 occupied beds; mean incidence: 3.6/1000 finished consultant episodes), there was also quite large variation between sites, even when screening samples were removed. Patients with MRSA had strikingly long stays before isolation of the organism (prevalence survey: 39 days; incidence survey: 31 days) and highest incidence occurred in elderly care wards. The outcome survey showed that approximately half of the patients were treated with some type of antimicrobial therapy for MRSA. Decontamination therapy was associated with clearance of MRSA only when controlling for sex of the patient. The majority of patients were discharged still with MRSA, mostly to their own homes. The survey emphasizes the need to continue surveillance to detect any changes, to allow guidelines based on evidence to be developed and to monitor the effectiveness of such guidelines.     

The Dutch MRSA policy should be retained

The Dutch methicillin-resistant Staphylococcus aureus (MRSA) 'search and destroy' policy is effective. MRSA should be banned from hospitals: MRSA infections are associated with increased mortality and costs. In addition, widespread use of vancomycin for treating MRSA infections encourages the spread and development of vancomycin-resistant micro-organisms.     

MRSA bloodstream infections in hospitals in Frankfurt/Main, Germany, 2010 : Results of the mandatory notification and suggestions for improvement

Since 1?July?2009 in accordance with the statuary order based on the German law for infectious diseases (Infektionsschutzgesetz), MRSA in blood and liquor must be notified to the public health authorities. The aim of extension of the notification to report is to improve the surveillance of nosocomial infections and the prevention of nosocomial MRSA infections. In addition to MRSA detection, data on symptoms and risk factors, e.g., medical devices, must also be reported. In this report, data of bloodstream MRSA infections in hospitals in Frankfurt/Main, Germany, for the first complete year (2010)were evaluated. In 2010, 58 MRSA-positive bloodstream infections were reported by the 17 hospitals in Frankfurt to the health protection authorities, i.e., 0.0360 MRSA/1,000 patient-days (range: 0- 0.109/1,000 patient-days). However, 10 of these infections initially had not been reported to the public health department in charge for the hospitals, but to the health departments according to the patient's addresses. Although most of the infections were reported from large hospitals (>100,000 patient-days/year), the highest incidences (0.0416/1,000 patient-days) were reported from small hospitals (<50,000 patient-days/year). Of the blood specimen, 13 (22.4%) were drawn on the first day of hospital stay, thus, indicating an imported infection. While 90% of the patients with MRSA in the bloodstream suffered from fever, 80% had sepsis and 34.5% suffered from pneumonia. Medical devices, such as central venous catheters and PEG, were reported from 60% of the patients. In the MRE network Rhine-Main region, the public health authorities asked for some more detailed information, such as risk factors for MRSA colonization (history for MRSA, recent hospital stay or antibiotic therapy, skin disorders, dialysis, residence in a retirements home), and for screening results as well as for the MRSA management, i.e., isolation of the patient and, if necessary, the contact patient. In 55% of the cases, the patients were identified by the clinics themselves as being patients with MRSA risk factors, mainly because of a history of MRSA (29%), recent hospital stay (71%), and antibiotic therapy during the last 6 months (52%). Screening was performed in 31 (53%) of the patients, most of them (71%) with positive MRSA nose swab. If the patients were screened, significantly fewer contact patients had to be screened and isolated later. Thus, to improve surveillance data on MRSA bloodstream infections, the notification route to the public health authorities responsible for the clinic hosting the patient must be strictly obeyed in order to avoid underreporting und underassessment of nosocomial infection. Although asking for clinical symptoms may be useful to validate the result in some cases, focus should be placed on risk factors and risk management, including screening and isolation. Only then can the aim of improving surveillance and reduction of nosocomial MRSA infection be achieved.     

Modelling the usefulness of a dedicated cohort facility to prevent the dissemination of MRSA

The aim of this retrospective study was to determine whether or not a surgical dedicated cohort facility, mainly dedicated to the care of orthopaedic patients, can control the risk of infection caused by methicillin-resistant Staphylococcus aureus (MRSA). We tested this hypothesis on the orthopaedic surgery ward of a university-affiliated public hospital with 1228 beds by determining whether there was a significant correlation between the colonization pressure exerted by MRSA and the number of cases of acquired MRSA. This was then used as a tool to predict the number of patients contaminated with MRSA in hospitals with and without dedicated cohort facilities. We found that the relative risk of MRSA acquisition increased with the colonization pressure exerted by MRSA imported cases. This statistical model enabled us to predict that the risk of MRSA acquisition would increase by 160% per year in the absence of a dedicated cohort facility. We conclude that these units are useful to control the spread of MRSA in hospitals.     

Risk factors and costs associated with methicillin-resistant Staphylococcus aureus bloodstream infections.

OBJECTIVES: To compare the cost of hospitalization of patients with methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) versus patients with methicillin-sensitive S. aureus (MSSA) BSI, controlling for severity of underlying illness; and to identify risk factors associated with MRSA BSI. DESIGN: Retrospective case-control study based on medical chart review. SETTING: A 640-bed, tertiary-care hospital in Seattle, Washington. PATIENTS: All patients admitted to the hospital between January 1, 1997, and December 31, 1999, with S. aureus BSI confirmed by culture. RESULTS: Twenty patients with MRSA BSI were compared with 40 patients with MSSA BSI. Univariate analysis identified 5 risk factors associated with MRSA BSI. Recent hospital admission (P = .006) and assisted living (P = .004) remained significant in a multivariate model. Costs were significantly higher per patient-day of hospitalization for MRSA BSI than for MSSA BSI (dollar 5,878 vs dollar 2,073; P = .003). When patients were stratified according to severity of illness as measured by the case mix index, a difference of dollar 5,302 per patient-day was found between the two groups for all patients with a case mix index greater than 2 (P < .001). CONCLUSION: These observations suggest that MRSA BSI significantly increases hospitalization costs compared with MSSA BSI, even when controlling for the severity of the patient's underlying illness. As MRSA BSI was also found to be significantly associated with a group of patients who have repeated hospitalizations, such infections contribute substantially to the increasing cost of medical care.