An Outbreak of Methicillin-ResistantStaphylococcus aureusInfections Related to Central Venous Catheters for Hemodialysis

Objectives:

To determine risk factors for hemodialysis catheter-related bloodstream infections (HCRBSIs) and investigate whether use of maximal sterile barrier precautions would prevent HCRBSIs.

Setting:

Tertiary-care medical center hemodialysis unit.

Design:

Open trial with historical comparison and case-control study of risk factors for HCRBSIs.

Methods:

Prospective surveillance was used to compare HCRBSI rates for 1 year before and after implementation of maximal sterile barrier precautions. A case–control study compared 50 case-patients with HCRBSI with 51 randomly selected control-patients.

Results:

The HCRBSI rate was 1.6% per 100 dialysis runs (CI95, 1.1%–2.3%) in the first year and 0.77% (CI95, 0.5%–1.1%) in the second year (P= .0106). The most frequent cause of HCRBSI was MRSA in the first year (15 of 32) and MSSA in the second year (13 of 18). Ten MRSA blood isolates in the first year were identical by PFGE. Diabetes mellitus was a risk factor for HCRBSI. Age, gender, site of hemodialysis central venous catheter (CVC), other underlying diseases, coma score, APACHE II score, serum albumin level, and cholesterol level were not associated with HCRBSI and did not change between the 2 years. Hospital stay was prolonged for case-patients (32.78 ± 20.96 days) versus control-patients (22.75 ± 17.33 days), but mortality did not differ.

Conclusions:

Use of maximal sterile barrier precautions during the insertion of CVCs reduced HCRBSIs in dialysis patients and seemed cost-effective. Diabetes mellitus was associated with HCRBSI. An outbreak of MRSA in the first year was likely caused by cross-infection via medical personnel.

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 ($5,878 vs $2,073; P = .003). When patients were stratified according to severity of illness as measured by the case mix index, a difference of $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.

Cost savings of universal decolonization to prevent intensive care unit infection: implications of the REDUCE MRSA trial

OBJECTIVE

To estimate and compare the impact on healthcare costs of 3 alternative strategies for reducing bloodstream infections in the intensive care unit (ICU): methicillin-resistant Staphylococcus aureus (MRSA) nares screening and isolation, targeted decolonization (ie, screening, isolation, and decolonization of MRSA carriers or infections), and universal decolonization (ie, no screening and decolonization of all ICU patients).

DESIGN

Cost analysis using decision modeling.

METHODS

We developed a decision-analysis model to estimate the health care costs of targeted decolonization and universal decolonization strategies compared with a strategy of MRSA nares screening and isolation. Effectiveness estimates were derived from a recent randomized trial of the 3 strategies, and cost estimates were derived from the literature.

RESULTS

In the base case, universal decolonization was the dominant strategy and was estimated to have both lower intervention costs and lower total ICU costs than either screening and isolation or targeted decolonization. Compared with screening and isolation, universal decolonization was estimated to save $171,000 and prevent 9 additional bloodstream infections for every 1,000 ICU admissions. The dominance of universal decolonization persisted under a wide range of cost and effectiveness assumptions.

CONCLUSIONS

A strategy of universal decolonization for patients admitted to the ICU would both reduce bloodstream infections and likely reduce healthcare costs compared with strategies of MRSA nares screening and isolation or screening and isolation coupled with targeted decolonization.

[Impact of an automated rapid MRSA/VRE identification technique in the surveillance of patients transferred from other medical centers]

INTRODUCTION

Identification of patients with methicillin resistant Staphylococcus aureus (MRSA) and vancomycin resistant Enterococci (VRE) is essential to limit the spread of these agents, through the use of isolation and contact precautions. Traditional microbiology has a long turn around time (3-5 days) extending the time of isolation, increasing complexity and cost of these patients.

OBJECTIVES

To implement a new real time polymerase chain reaction (PCR) GeneXpert R for SAMR and VRE detection. To compare costs and turn around time of PCR versus traditional cultures.

METHODS

Two periods were compared, in the first, traditional microbiology (standard group) was used, and in the second, only PCR was used (PCR group).

RESULTS

MRSA or VRE were identified in 29.9% of patients in the PCR group and in 9.6% in the standard group. Turn around time was 15 ± 9 hours in PCR group and 53 ± 23 hours in standard group. PCR group had a net cost of USD 245 per patient and standard group USD 530 per patient.

DISCUSSION

PCR technique GeneXpert R for MRSA and VRE had a positive impact in the management of these patients and justifies its inclusion.

Health and economic burden of post-partum Staphylococcus aureus breast abscess

Objectives

To determine the health and economic burdens of post-partum Staphylococcus aureus breast abscess.

Study design

We conducted a matched cohort study (N = 216) in a population of pregnant women (N = 32,770) who delivered at our center during the study period from 10/1/03–9/30/10. Data were extracted from hospital databases, or via chart review if unavailable electronically. We compared cases of S. aureus breast abscess to controls matched by delivery date to compare health services utilization and mean attributable medical costs in 2012 United States dollars using Medicare and hospital-based estimates. We also evaluated whether resource utilization and health care costs differed between cases with methicillin-resistant and -susceptible S. aureus isolates.

Results

Fifty-four cases of culture-confirmed post-partum S. aureus breast abscess were identified. Breastfeeding cessation (41%), milk fistula (11.1%) and hospital readmission (50%) occurred frequently among case patients. Breast abscess case patients had high rates of health services utilization compared to controls, including high rates of imaging and drainage procedures. The mean attributable cost of post-partum S. aureus breast abscess ranged from $2,340–$4,012, depending on the methods and data sources used. Mean attributable costs were not significantly higher among methicillin-resistant vs. –susceptible S. aureus cases.

Conclusions

Post-partum S. aureus breast abscess is associated with worse health and economic outcomes for women and their infants, including high rates of breastfeeding cessation. Future study is needed to determine the optimal treatment and prevention of these infections.

MRSA screening in orthopaedic surgery: clinically valuable and cost effective? A prospective analysis of 8,867 patients

This study aimed at assessing the prevalence of MRSA colonisation in Trauma and Orthopaedics. Risk factors, decolonisation, and subsequent infection rates were investigated. Cost-analysis of the MRSA screening program was performed. The validity and effectiveness of the MRSA screening program was reviewed. A prospective analysis was made of all orthopaedic admissions in East Lancashire Hospital Trust. A total number of 13,155 swabs were taken in 8,867 patients in 2010. This MRSA screening program was compared to the ideal screening criteria set out by Wilson and Junger (WHO 1968). The MRSA prevalence in Trauma and Orthopaedics in 2010 was 0.47%. The decolonisation rate was 55%. There was no correlation between MRSA colonisation and subsequent infection. The total cost of MRSA screening at ELHT was calculated as a minimum of 184,170 Pounds. This could extrapolate to a national expense of around 16 million pounds in England and Wales in Orthopaedics alone. The MRSA screening program did not meet 4 out of 9 screening criteria of Wilson and Junger. The vast majority of Trauma and Orthopaedic patients are not at risk of MRSA colonisation or infection and therefore should not be screened. MRSA infection is a risk in certain high risk groups which should be screened. The MRSA screening program is ineffective when assessed to WHO standards. The program should be considered to be surveillance of MRSA, not an effective screening program for pathological MRSA infection.

Cost and effects of different admission screening strategies to control the spread of methicillin-resistant Staphylococcus aureus

Nosocomial infection rates due to antibiotic-resistant bacteriae, e.g., methicillin-resistant Staphylococcus aureus (MRSA) remain high in most countries. Screening for MRSA carriage followed by barrier precautions for documented carriers (so-called screen and isolate (S&I)) has been successful in some, but not all settings. Moreover, different strategies have been proposed, but comparative studies determining their relative effects and costs are not available. We, therefore, used a mathematical model to evaluate the effect and costs of different S&I strategies and to identify the critical parameters for this outcome. The dynamic stochastic simulation model consists of 3 hospitals with general wards and intensive care units (ICUs) and incorporates readmission of carriers of MRSA. Patient flow between ICUs and wards was based on real observations. Baseline prevalence of MRSA was set at 20% in ICUs and hospital-wide at 5%; ranges of costs and infection rates were based on published data. Four S&I strategies were compared to a do-nothing scenario: S&I of previously documented carriers ("flagged" patients); S&I of flagged patients and ICU admissions; S&I of flagged and group of "frequent" patients; S&I of all hospital admissions (universal screening). Evaluated levels of efficacy of S&I were 10%, 25%, 50% and 100%. Our model predicts that S&I of flagged and S&I of flagged and ICU patients are the most cost-saving strategies with fastest return of investment. For low isolation efficacy universal screening and S&I of flagged and "frequent" patients may never become cost-saving. Universal screening is predicted to prevent hardly more infections than S&I of flagged and "frequent" patients, albeit at higher costs. Whether an intervention becomes cost-saving within 10 years critically depends on costs per infection in ICU, costs of screening and isolation efficacy.

[Pharmacoeconomic analysis of the treatment of methicillin-resistant Staphylococcus aureus with daptomycin or vancomycin]

INTRODUCTION

The increased morbidity, mortality and high costs associated with bacteremia caused by methicillin-resistant Staphylococcus aureus (MRSA) is a major public health problem. Pharmacoeconomic analysis was performed to compare the efficiency of daptomycin (DAP) against vancomycin (VAN) in the treatment of this infection.

METHODS

Retrospective, deterministic and probabilistic cost-effectiveness analysis. The effectiveness of the treatments was estimated from the results of a randomized clinical trial, which compared DAP (6 mg / kg IV daily) and VAN (1 g IV every 12 hours), both with or without gentamicin (1 mg / kg IV every 8 hours). Resource utilization was estimated from the clinical trial of the drug datasheets and Spanish sources, the unit costs were obtained also from Spanish sources. Monte Carlo probabilistic analysis and deterministic analysis were performed.

RESULTS

The clinical trial cure rates were higher with DAP (44.4%, 95% CI 43.5 to 45.4%) than with VAN (31.8%, 95% CI 30.9 to 32.7%) not statistically significant (p = 0.2203) but with economic impact. With DAP would occur less costs due to treatment failure (rescue antibiotics, additional tests, prolonged hospital stay and adverse reactions) than with VAN. In the base case the average cost of disease per patient was € 12,329 to € 12,696 with DAP and VAN (difference of 367 €). DAP treatment was dominant (more effective, with lower costs than VAN) both in the deterministic and probabilistic analysis. In the Monte Carlo simulation, DAP was the most cost-effective treatment in 100% of the 10,000 simulations, for a willingness to pay € 12,000 per additional cure (approximate cost of MRSA bacteraemia episode).

CONCLUSIONS

According to this model, daptomycin is more cost-effective than vancomycin in treating MRSA bacteremia. The higher cost of acquisition of daptomycin does not imply a higher cost of treating this infection.

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 potential economic value of a Staphylococcus aureus vaccine among hemodialysis patients

Staphylococcus aureus infections are a substantial problem for hemodialysis patients. Several vaccine candidates are currently under development, with hemodialysis patients being one possible target population. To determine the potential economic value of an S. aureus vaccine among hemodialysis patients, we developed a Markov decision analytic computer simulation model. When S. aureus colonization prevalence was 1%, the incremental cost-effectiveness ratio (ICER) of vaccination was ≤$25,217/quality-adjusted life year (QALY). Vaccination became more cost-effective as colonization prevalence, vaccine efficacy, or vaccine protection duration increased or vaccine cost decreased. Even at 10% colonization prevalence, a 25% efficacious vaccine costing $100 prevented 29 infections, 21 infection-related hospitalizations, and 9 inpatient deaths per 1000 vaccinated HD patients. Our results suggest that an S. aureus vaccine would be cost-effective (i.e., ICERs ≤ $50,000/QALY) among hemodialysis patients over a wide range of S. aureus prevalence, vaccine costs and efficacies, and vaccine protection durations and delineate potential target parameters for such a vaccine.

Costs and benefits of rapid screening of methicillin-resistant Staphylococcus aureus carriage in intensive care units: a prospective multicenter study

INTRODUCTION

Pre-emptive isolation of suspected methicillin-resistant Staphylococcus aureus (MRSA) carriers is a cornerstone of successful MRSA control policies. Implementation of such strategies is hampered when using conventional cultures with diagnostic delays of three to five days, as many non-carriers remain unnecessarily isolated. Rapid diagnostic testing (RDT) reduces the amount of unnecessary isolation days, but costs and benefits have not been accurately determined in intensive care units (ICUs).

METHODS

Embedded in a multi-center hospital-wide study in 12 Dutch hospitals we quantified cost per isolation day avoided using RDT for MRSA, added to conventional cultures, in ICUs. BD GeneOhm™ MRSA PCR (IDI) and Xpert MRSA (GeneXpert) were subsequently used during 17 and 14 months, and their test characteristics were calculated with conventional culture results as reference. We calculated the number of pre-emptive isolation days avoided and incremental costs of adding RDT.

RESULTS

A total of 163 patients at risk for MRSA carriage were screened and MRSA prevalence was 3.1% (n=5). Duration of isolation was 27.6 and 21.4 hours with IDI and GeneXpert, respectively, and would have been 96.0 hours when based on conventional cultures. The negative predictive value was 100% for both tests. Numbers of isolation days were reduced by 44.3% with PCR-based screening at the additional costs of €327.84 (IDI) and €252.14 (GeneXpert) per patient screened. Costs per isolation day avoided were €136.04 (IDI) and €121.76 (GeneXpert).

CONCLUSIONS

In a low endemic setting for MRSA, RDT safely reduced the number of unnecessary isolation days on ICUs by 44%, at the costs of €121.76 to €136.04 per isolation day avoided.

Routine pre-cesarean Staphylococcus aureus screening and decolonization: a cost-effectiveness analysis

OBJECTIVES

To estimate the economic value of screening pregnant women for Staphylococcus aureus carriage before cesarean delivery.

STUDY DESIGN

Computer simulation model.

METHODS

We used computer simulation to assess the cost-effectiveness, from the third-party payer perspective, of routine screening for S aureus (and subsequent decolonization of carriers) before planned cesarean delivery. Sensitivity analyses explored the effects of varying S aureus colonization prevalence, decolonization treatment success rate (for the extent of the puerperal period), and the laboratory technique (agar culture vs polymerase chain reaction [PCR]) utilized for screening and pathogen identification from wound isolates.

RESULTS

Pre-cesarean screening and decolonization were only cost-effective when agar was used for both screening and wound cultures when the probability of decolonization success was ≥ 50% and colonization prevalence was ≥ 40%, or decolonization was ≥ 75% successful and colonization prevalence was ≥ 20%. The intervention was never cost-effective using PCR-based laboratory methods. The cost of agar versus PCR and their respective sensitivities and specificities, as well as the probability of successful decolonization, were important drivers of the economic and health impacts of preoperative screening and decolonization of pregnant women. The number needed to screen ranged from 21 to 2294, depending on colonization prevalence, laboratory techniques used, and the probability of successful decolonization.

CONCLUSIONS

Despite high rates of cesarean delivery, presurgical screening of pregnant women for S aureus and decolonization of carriers is unlikely to be cost-effective under prevailing epidemiologic circumstances.

Outcomes and costs associated with a history of vancomycin exposure in patients with MRSA-related complicated bacteremia and infective endocarditis

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is the primary cause of complicated bacteremia (CB) and infective endocarditis (IE). Studies have compared the costs of treatment with vancomycin to those of other agents, as well as the efficacy and tolerability of these treatments. However, a literature search found no published studies of the effects of vancomycin exposure on outcomes and hospital costs in patients with CB or IE due to MRSA.

OBJECTIVE

The aim of this study was to determine whether there is a quantitative relationship between the duration of vancomycin treatment or cumulative vancomycin exposure and outcomes or costs in patient with CB or IE due to MRSA.

METHODS

Electronic medical records of confirmed cases of MRSA-related CB or IE from July 1, 2006, to June 30, 2008, were retrospectively reviewed to identify patients with a history of vancomycin exposure or no vancomycin exposure. Those who received vancomycin were stratified by the amount of drug administered or the duration of treatment to determine the relationship between treatment and outcomes. Data collected included demographic information, treatment information, attributable mortality, MIC data, and hospital costs. Classification and regression tree analysis (CART) was used to determine whether a history of vancomycin exposure was associated with treatment failure, attributable mortality, or both. The Mann-Whitney U test and the Fisher exact test were used for univariate analyses, and logistic regression was used for multivariate modeling.

RESULTS

Data from 50 patients were evaluated (CB, 32; IE, 18). Overall rates of failure and attributable mortality were 32% and 16%, respectively. No significant differences were observed between the variables and costs. The CART break points for failure were ≥18.75 g and ≥14 days of vancomycin treatment in the previous 3 years; for attributable mortality, the CART break points were ≥45 g and ≥31 days. In the final multivariate model for failure, ≥18.75 g and ≥14 days of vancomycin treatment in the previous 3 years were predictors of failure (both, P = 0.002). Acute Physiology and Chronic Health Evaluation (APACHE) II score (P = 0.04), ≥45 g (P = 0.002), and ≥31 days of treatment (P = 0.002) in the previous 3 years were predictors of attributable mortality after adjustment for all covariates.

CONCLUSIONS

Using the present model, cumulative vancomycin amount and duration were associated with attributable mortality and clinical failure but not with costs.

Cost-effectiveness of preoperative screening and eradication of Staphylococcus aureus carriage

Background

Preoperative screening for nasal S. aureus carriage, followed by eradication treatment of identified carriers with nasal mupirocine ointment and chlorhexidine soap was highly effective in preventing deep-seated S. aureus infections. It is unknown how cost-effectiveness of this intervention is affected by suboptimal S. aureus screening. We determined cost-effectiveness of different preoperative S. aureus screening regimes.

Methods

We compared different screening scenarios (ranging from treating all patients without screening to treating only identified S. aureus carriers) to the base case scenario without any screening and treatment. Screening and treatment costs as well as costs and mortality due to deep-seated S. aureus infection were derived from hospital databases and prospectively collected data, respectively.

Results

As compared to the base case scenario, all scenarios are associated with improved health care outcomes at reduced costs. Treating all patients without screening is most cost-beneficial, saving €7339 per life year gained, as compared to €3330 when only identified carriers are treated. In sensitivity analysis, outcomes are susceptible to the sensitivity of the screening test and the efficacy of treatment. Reductions in these parameters would reduce the cost-effectiveness of scenarios in which treatment is based on screening. When only identified S. aureus carriers are treated costs of screening should be less than €6.23 to become the dominant strategy.

Conclusions

Preoperative screening and eradication of S. aureus carriage to prevent deep-seated S. aureus infections saves both life years and medical costs at the same time, although treating all patients without screening is the dominant strategy, resulting in most health gains and largest savings.

Beneficial effects of implementing guidelines on microbiology and costs of infected diabetic foot ulcers

AIMS/HYPOTHESIS

In 2003, guidelines for management of diabetic foot infection (DFI) were written by the authors' team according to the guidelines of the International Working Group on the Diabetic Foot. The effects of implementing these guidelines on the microbiology and costs of infected diabetic foot ulcers were assessed.

METHODS

From 2003 to 2007, potential beneficial effects of implementing these guidelines were assessed by comparison over time of bacteriological data (number of bacterial samples, number of microorganisms isolated in cultures, prevalence of multidrug-resistant organisms [MDRO] and colonising flora), and costs related to use of antimicrobial agents and microbiology laboratory workload.

RESULTS

The study included 405 consecutive diabetic patients referred to the Diabetic Foot Unit for a suspected DFI. From 2003 to 2007, a significant decrease was observed in the median number of bacteria species per sample (from 4.1 to 1.6), prevalence of MDRO (35.2% vs 16.3%) and methicillin-resistant Staphylococcus aureus (52.2% vs 18.9%) (p < 0.001). Moreover, prevalence of pathogens considered as colonisers dramatically fell from 23.1% to 5.8% of all isolates (p < 0.001). In parallel, implementation of guidelines was associated with a saving of euro14,914 (US$20,046) related to a reduced microbiology laboratory workload and euro109,305 (US$147,536) due to reduced prescription of extended-spectrum antibiotic agents.

CONCLUSIONS/INTERPRETATION

Implementation of guidelines for obtaining specimens for culture from patients with DFI is cost-saving and provides interesting quality indicators in the global management of DFI.

The potential economic value of a Staphylococcus aureus vaccine for neonates

The continuing morbidity and mortality associated with Staphylococcus aureus (S. aureus) infections, especially methicillin-resistant S. aureus (MRSA) infections, have motivated calls to make S. aureus vaccine development a research priority. We developed a decision analytic computer simulation model to determine the potential economic impact of a S. aureus vaccine for neonates. Our results suggest that a S. aureus vaccine for the neonatal population would be strongly cost-effective (and in many situations dominant) over a wide range of vaccine efficacies (down to 10%) for vaccine costs (or=1%).

Surgical site infections: Causative pathogens and associated outcomes

BACKGROUND

Surgical site infections (SSIs) are associated with substantial morbidity, mortality, and cost. Few studies have examined the causative pathogens, mortality, and economic burden among patients rehospitalized for SSIs.

METHODS

From 2003 to 2007, 8302 patients were readmitted to 97 US hospitals with a culture-confirmed SSI. We analyzed the causative pathogens and their associations with in-hospital mortality, length of stay (LOS), and cost.

RESULTS

The proportion of methicillin-resistant Staphylococcus aureus (MRSA) significantly increased among culture-positive SSI patients during the study period (16.1% to 20.6%, respectively, P < .0001). MRSA (compared with other) infections had higher raw mortality rates (1.4% vs 0.8%, respectively, P=.03), longer LOS (median, 6 vs 5 days, respectively, P < .0001), and higher hospital costs ($7036 vs $6134, respectively, P < .0001). The MRSA infection risk-adjusted attributable LOS increase was 0.93 days (95% confidence interval [CI]: 0.65-1.21; P < .0001), and cost increase was $1157 (95% CI: $641-$1644; P < .0001). Other significant independent risk factors increasing cost and LOS included illness severity, transfer from another health care facility, previous admission (<30 days), and other polymicrobial infections (P < .05).

CONCLUSION

SSIs caused by MRSA increased significantly and were independently associated with economic burden. Admission illness severity, transfer from another health care setting, and recent hospitalization were associated with higher mortality, increased LOS, and cost.

An economic model for the prevention of MRSA infections after surgery: non-glycopeptide or glycopeptide antibiotic prophylaxis?

AIM

Surgical site infection is commonly caused by Staphylococcus aureus. The multiresistant strains (MRSA) are resistant to most antibiotic prophylaxis regimens. Our aim was to explore whether there is a threshold of MRSA prevalence at which switching to routine glycopeptide-based antibiotic prophylaxis becomes cost-effective.

METHODS

An indicative model was designed to explore the cost-effectiveness of vancomycin, cephalosporin or a combination, in patients undergoing primary hip arthroplasty.

RESULTS

If the MRSA infection rate is equal to or above 0.25% and the rate of other infections with cephalosporin prophylaxis is equal to or above 0.2%, use of the combination antibiotic prophylaxis is optimal.

DISCUSSION

Modelling the cost-effectiveness of interventions for MRSA prevention is complex due to uncertainty around resistance and effectiveness of glycopeptides.

CONCLUSIONS

The indicative model provides a framework for evaluation. More work is needed to understand the impact of antibiotic resistance over time in these currently effective antibiotics.

Impact of rapid methicillin-resistant Staphylococcus aureus polymerase chain reaction testing on mortality and cost effectiveness in hospitalized patients with bacteraemia: a decision model

BACKGROUND

Patients hospitalized with Staphylococcus aureus bacteraemia have an unacceptably high mortality rate. Literature available to date has shown that timely selection of the most appropriate antibacterial may reduce mortality. One tool that may help with this selection is a polymerase chain reaction (PCR) assay that distinguishes methicillin (meticillin)-resistant S. aureus (MRSA) from methicillin-susceptible S. aureus (MSSA) in less than 1 hour. To date, no information is available evaluating the impact of this PCR technique on clinical or economic outcomes.

OBJECTIVE

To evaluate the effect of a rapid PCR assay on mortality and economics compared with traditional empiric therapy, using a literature-derived model.

METHODS

A literature search for peer-reviewed European (EU) and US publications regarding treatment regimens, outcomes and costs was conducted. Information detailing the rates of infection, as well as the specificity and sensitivity of a rapid PCR assay (Xpert MRSA/SA Blood Culture PCR) were obtained from the peer-reviewed literature. Sensitivity analysis varied the prevalence rate of MRSA from 5% to 80%, while threshold analysis was applied to the cost of the PCR test. Hospital and testing resource consumption were valued with direct medical costs, adjusted to year 2009 values. Adjusted life-years were determined using US and WHO life tables. The cost-effectiveness ratio was defined as the cost per life-year saved. Incremental cost-effectiveness ratios (ICERs) were calculated to determine the additional cost necessary to produce additional effectiveness. All analyses were performed using TreeAge Software (2008).

RESULTS

The mean mortality rates were 23% for patients receiving empiric vancomycin subsequently switched to semi-synthetic penicillin (SSP) for MSSA, 36% for patients receiving empiric vancomycin treatment for MRSA, 59% for patients receiving empiric SSP subsequently switched to vancomycin for MRSA and 12% for patients receiving empiric SSP for MSSA. Furthermore, with an MRSA prevalence of 30%, the numbers of patients needed to test in order to save one life were 14 and 16 compared with empiric vancomycin and SSP, respectively. The absolute mortality difference for MRSA prevalence rates of 80% and 5% favoured the PCR testing group at 2% and 10%, respectively, compared with empiric vancomycin and 18% and 1%, respectively, compared with empiric SSP. In the EU, the cost-effectiveness ratios for empiric vancomycin- and SSP-treated patients were Euro 695 and Euro 687 per life-year saved, respectively, compared with Euro 636 per life-year saved for rapid PCR testing. In the US, the cost-effectiveness ratio was $US 898 per life-year saved for empiric vancomycin and $US 820 per life-year saved for rapid PCR testing. ICERs demonstrated dominance of the PCR test in all instances. Threshold analysis revealed that PCR testing would be less costly overall, even at greatly inflated assay prices.

CONCLUSIONS

Rapid PCR testing for MRSA appears to have the potential to reduce mortality rates while being less costly than empiric therapy in the EU and US, across a wide range of MRSA prevalence rates and PCR test costs.

Clinical and financial outcomes due to methicillin resistant Staphylococcus aureus surgical site infection: a multi-center matched outcomes study

BACKGROUND

The clinical and financial outcomes of SSIs directly attributable to MRSA and methicillin-resistance are largely uncharacterized. Previously published data have provided conflicting conclusions.

METHODOLOGY

We conducted a multi-center matched outcomes study of 659 surgical patients. Patients with SSI due to MRSA were compared with two groups: matched uninfected control patients and patients with SSI due to MSSA. Four outcomes were analyzed for the 90-day period following diagnosis of the SSI: mortality, readmission, duration of hospitalization, and hospital charges. Attributable outcomes were determined by logistic and linear regression.

PRINCIPAL FINDINGS

In total, 150 patients with SSI due to MRSA were compared to 231 uninfected controls and 128 patients with SSI due to MSSA. SSI due to MRSA was independently predictive of readmission within 90 days (OR = 35.0, 95% CI 17.3-70.7), death within 90 days (OR = 7.27, 95% CI 2.83-18.7), and led to 23 days (95% CI 19.7-26.3) of additional hospitalization and $61,681 (95% 23,352-100,011) of additional charges compared with uninfected controls. Methicillin-resistance was not independently associated with increased mortality (OR = 1.72, 95% CI 0.70-4.20) nor likelihood of readmission (OR = 0.43, 95% CI 0.21-0.89) but was associated with 5.5 days (95% CI 1.97-9.11) of additional hospitalization and $24,113 (95% 4,521-43,704) of additional charges.

CONCLUSIONS/SIGNIFICANCE

The attributable impact of S. aureus and methicillin-resistance on outcomes of surgical patients is substantial. Preventing a single case of SSI due to MRSA can save hospitals as much as $60,000.