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

Can Neutrophils Prevent Nosocomial Pneumonia after Serious Injury?

Nosocomial pneumonia is a leading cause of critical illness and mortality among seriously injured trauma patients. However, the link between injury and the development of nosocomial pneumonia is still not well recognized. Our work strongly suggests that mitochondrial damage-associated molecular patterns (mtDAMPs), especially mitochondrial formyl peptides (mtFPs) released by tissue injury, play a significant role in developing nosocomial pneumonia after a serious injury. Polymorphonuclear leukocytes (neutrophils, PMN) migrate toward the injury site by detecting mtFPs through formyl peptide receptor 1 (FPR1) to fight/contain bacterial infection and clean up debris. Activation of FPR1 by mtFPs enables PMN to reach the injury site; however, at the same time it leads to homo- and heterologous desensitization/internalization of chemokine receptors. Thus, PMN are not responsive to secondary infections, including those from bacteria-infected lungs. This may enable a progression of bacterial growth in the lungs and nosocomial pneumonia. We propose that the intratracheal application of exogenously isolated PMN may prevent pneumonia coupled with a serious injury.

Predictive Value of MRSA Nares Colonization in Diabetic Foot Infections: A Systematic Review and Bivariate Random Effects Meta-Analysis

The primary objective of this study was to assess the negative predictive value of methicillin-resistant Staphylococcus aureus (MRSA) nasal swabs in MRSA diabetic foot infections. MEDLINE and Cochrane Library were searched from inception to May 1, 2020. The following search string was used: (methicillin-resistant S. aureus OR MRSA) AND (nasal OR nares) AND (diabetic OR foot OR diabetic foot infections). All studies that contained data comparing MRSA nasal swab positivity to wound cultures from diabetic foot infections and met the inclusion criteria were included. Among the 86 relevant studies, 6 studies with 8706 diabetic patients were included. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline extension for Diagnostic Test Accuracy reviews was followed. The primary meta-analysis outcomes were the negative and positive predictive values of MRSA nasal swabs for MRSA diabetic foot infections. The pooled specificity and pooled sensitivity were determined by generating hierarchical summary receiver characteristic operating curves. In the bivariate meta-analysis, involving the 6 studies, pooled sensitivity and specificity was 41.7% (95% confidence interval = 32.9, 51) and 94.1% (95% confidence interval = 89.5, 96.8), respectively. In low-moderate MRSA prevalence levels (<15%), negative predictive value of MRSA nasal swab was >90% and positive predictive value was <55%. This meta-analysis suggests that in patients with diabetic foot infections, the nasal swab MRSA screen has a poor positive predictive value but an excellent negative predictive value in regions of low to moderate prevalence of MRSA diabetic foot infections.

Evaluation of the Cost-effectiveness of Infection Control Strategies to Reduce Hospital-Onset Clostridioides difficile Infection

Importance

Clostridioides difficile infection is the most common hospital-acquired infection in the United States, yet few studies have evaluated the cost-effectiveness of infection control initiatives targeting C difficile.

Objective

To compare the cost-effectiveness of 9 C difficile single intervention strategies and 8 multi-intervention bundles.

Design, Setting, and Participants

This economic evaluation was conducted in a simulated 200-bed tertiary, acute care, adult hospital. The study relied on clinical outcomes from a published agent-based simulation model of C difficile transmission. The model included 4 agent types (ie, patients, nurses, physicians, and visitors). Cost and utility estimates were derived from the literature.

Interventions

Daily sporicidal cleaning, terminal sporicidal cleaning, health care worker hand hygiene, patient hand hygiene, visitor hand hygiene, health care worker contact precautions, visitor contact precautions, C difficile screening at admission, and reduced intrahospital patient transfers.

Main Outcomes and Measures

Cost-effectiveness was evaluated from the hospital perspective and defined by 2 measures: cost per hospital-onset C difficile infection averted and cost per quality-adjusted life-year (QALY).

Results

In this agent-based model of a simulated 200-bed tertiary, acute care, adult hospital, 5 of 9 single intervention strategies were dominant, reducing cost, increasing QALYs, and averting hospital-onset C difficile infection compared with baseline standard hospital practices. They were daily cleaning (most cost-effective, saving $358 268 and 36.8 QALYs annually), health care worker hand hygiene, patient hand hygiene, terminal cleaning, and reducing intrahospital patient transfers. Screening at admission cost $1283/QALY, while health care worker contact precautions and visitor hand hygiene interventions cost $123 264/QALY and $5 730 987/QALY, respectively. Visitor contact precautions was dominated, with increased cost and decreased QALYs. Adding screening, health care worker hand hygiene, and patient hand hygiene sequentially to the daily cleaning intervention formed 2-pronged, 3-pronged, and 4-pronged multi-intervention bundles that cost an additional $29 616/QALY, $50 196/QALY, and $146 792/QALY, respectively.

Conclusions and Relevance

The findings of this study suggest that institutions should seek to streamline their infection control initiatives and prioritize a smaller number of highly cost-effective interventions. Daily sporicidal cleaning was among several cost-saving strategies that could be prioritized over minimally effective, costly strategies, such as visitor contact precautions.

Vancomycin-resistant enterococci (VRE) screening and isolation in the general medicine ward: a cost-effectiveness analysis

Background

Vancomycin-resistant enterococci (VRE) are a serious antimicrobial resistant threat in the healthcare setting. We assessed the cost-effectiveness of VRE screening and isolation for patients at high-risk for colonisation on a general medicine ward compared to no VRE screening and isolation from the healthcare payer perspective.

Methods

We developed a microsimulation model using local data and VRE literature, to simulate a 20-bed general medicine ward at a tertiary-care hospital with up to 1000 admissions, approximating 1 year. Primary outcomes were accrued over the patient's lifetime, discounted at 1.5%, and included expected health outcomes (VRE colonisations, VRE infections, VRE-related bacteremia, and deaths subsequent to VRE infection), quality-adjusted life years (QALYs), healthcare costs, and incremental cost-effectiveness ratio (ICER). Probabilistic sensitivity analysis (PSA) and scenario analyses were conducted to assess parameter uncertainty.

Results

In our base-case analysis, VRE screening and isolation prevented six healthcare-associated VRE colonisations per 1000 admissions (6/1000), 0.6/1000 VRE-related infections, 0.2/1000 VRE-related bacteremia, and 0.1/1000 deaths subsequent to VRE infection. VRE screening and isolation accrued 0.0142 incremental QALYs at an incremental cost of $112, affording an ICER of $7850 per QALY. VRE screening and isolation practice was more likely to be cost-effective (> 50%) at a cost-effectiveness threshold of $50,000/QALY. Stochasticity (randomness) had a significant impact on the cost-effectiveness.

Conclusion

VRE screening and isolation can be cost-effective in majority of model simulations at commonly used cost-effectiveness thresholds, and is likely economically attractive in general medicine settings. Our findings strengthen the understanding of VRE prevention strategies and are of importance to hospital program planners and infection prevention and control.

Comparing methods to estimate incremental inpatient costs and length of stay due to methicillin-resistant Staphylococcus aureus in Alberta, Canada

Background

Methicillin-resistant Staphylococcus aureus (MRSA) is an opportunistic bacterial organism resistant to first line antibiotics. Acquisition of MRSA is often classified as either healthcare-associated or community-acquired. It has been shown that both healthcare-associated and community-acquired infections contribute to the spread of MRSA within healthcare facilities. The objective of this study was to estimate the incremental inpatient cost and length of stay for individuals colonized or infected with MRSA. Common analytical methods were compared to ensure the quality of the estimate generated. This study was performed at Alberta Ministry of Health (Edmonton, Alberta), with access to clinical MRSA data collected at two Edmonton hospitals, and ministerial administrative data holdings.

Methods

A retrospective cohort study of patients with MRSA was identified using a provincial infection prevention and control database. A coarsened exact matching algorithm, and two regression models (semilogarithmic ordinary least squares model and log linked generalized linear model) were evaluated. A MRSA-free cohort from the same facilities and care units was identified for the matched method; all records were used for the regression models. Records span from January 1, 2011 to December 31, 2015, for individuals 18 or older at discharge.

Results

Of the models evaluated, the generalized linear model was found to perform the best. Based on this model, the incremental inpatient costs associated with hospital-acquired cases were the most costly at $31,686 (14,169 – 60,158) and $47,016 (23,125 – 86,332) for colonization and infection, respectively. Community-acquired MRSA cases also represent a significant burden, with incremental inpatient costs of $7397 (2924 – 13,180) and $14,847 (8445 – 23,207) for colonization and infection, respectively. All costs are adjusted to 2016 Canadian dollars. Incremental length of stay followed a similar pattern, where hospital-acquired infections had the longest incremental stays of 35.2 (16.3–69.5) days and community-acquired colonization had the shortest incremental stays of 3.0 (0.6–6.3) days.

Conclusions

MRSA, and in particular, hospital-acquired MRSA, places a significant but preventable cost burden on the Alberta healthcare system. Estimates of cost and length of stay varied by the method of analysis and source of infection, highlighting the importance of selecting the most appropriate method.

Direct Costs of a Contact Isolation Day: A Prospective Cost Analysis at a Swiss University Hospital

We prospectively evaluated direct costs of contact precautions using on-site observation. Additional mean costs per patient day were calculated for extra materials used, increased workload, and one-off isolation activities. The cost of contact precautions was $158.90 (95% confidence interval, $124.90‒$192.80) per patient day. Infect Control Hosp Epidemiol 2018;39:101-103.

Prevalence of methicillin-resistant Staphylococcus aureus carriage on admission among patients attending regional hospitals in Dar es Salaam, Tanzania

Background

Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen responsible for hospital and community acquired infection. Colonization with MRSA is associated with a high risk of developing infection. This study aimed to determine the rate of MRSA carriage on admission and the associated risk factors among patients attending regional hospitals, in Dar es Salaam, Tanzania.

Results

A total of 258 patients were included in this study. Nasal swabs were collected on admission to the hospital and after 48 h of hospital stay for detection of MRSA. Of 258 patients enrolled, 89 (34.5%) were colonized with S. aureus and out them 22 (24.7%) were carriers of MRSA, giving an overall MRSA nasal carriage rate of 8.5% (22/258). One patient acquired MRSA while admitted in the hospital. Most of the S. aureus isolates 85 (95.5%) were resistant to penicillin. Resistance to gentamycin, ciprofloxacin, kanamycin, linezolid and mupirocin were 14.6, 11.2, 11.2, 3.4 and 1.1%, respectively. The prevalence of inducible clindamycin resistance, constitutive clindamycin resistance, MS phenotype (resistance to erythromycin alone), and multidrug resistance was 21.3, 3.4, 12.4, and 16.9%, respectively. We observed a statistically significant association between MRSA and multiple drugs resistance among S. aureus isolates (p = 0.001). Of the risk factors investigated none were statistically significant associated with MRSA.

Conclusion

There is a high prevalence of MRSA among patients on admission at the two municipal hospitals in Dar es Salaam. The high prevalence of MRSA and the increased rates of resistance to commonly used antimicrobials among MRSA isolates call for attention to the importance of including the screening of MRSA in our hospitals setting in order to prevent further spread of MRSA strains to other patients and to the communities. Control and prevention strategies should be emphasized including decolonization.

[Molecular diagnosis of methicillin-resistent Staphylococcus aureus: Methods and efficacy]

Methicillin-resistant Staphylococcus aureus (MRSA) isolates are a serious public health problem whose ever-increasing rate is commensurate with the pressure it is exerting on the healthcare system. At present, more than 20% of clinical S. aureus isolates in German hospitals are methicillin-resistant, in Austria less than 10%. Strategies from low-prevalence countries show that this development is not necessarily inevitable. In the Scandinavian countries and the Netherlands, thanks to a rigorous prevention programme, MRSA prevalence has been kept at an acceptably low level (< 1-3%). Central to these search-and-destroy control strategies is an admission screening using several MRSA swabs taken from mucocutaneous colonisation sites of high-risk patients (MRSA surveillance). It has also been reported that the speed with which MRSA carriage is detected has an important role, as it is a key component of any effective strategy to prevent the pathogen from spreading. Since MRSA culturing involves a 2-3 day delay before the final results are available, rapid detection techniques (commonly referred to as MRSA rapid tests) using polymerase chain reaction (PCR) methods and, most recently, rapid culturing methods have been developed. The implementation of rapid tests reduces the time of detection of MRSA carriers from 48-72 to 2-5 h. Clinical evaluation data have shown that MRSA can thus be detected with very high sensitivity. Specificity, however, is sometimes impaired due to false-positive PCR signals occurring in mixed flora specimens. In order to rule out false-positive PCR results, a culture screen must always be carried out simultaneously. The data provide preliminary evidence that a PCR assay can reduce nosocomial MRSA transmission in high-risk patients or high-risk areas, whereas an approach that screens all patients admitted to the hospital is probably not effective. Information concerning the cost effectiveness of rapid MRSA tests is still sparse and thus the issue remains debated.

Cost Analysis of Universal Screening vs. Risk Factor-Based Screening for Methicillin-Resistant Staphylococcus aureus (MRSA)

Background

The literature remains conflicted regarding the most effective way to screen for MRSA. This study was designed to assess costs associated with universal versus risk factor-based screening for the reduction of nosocomial MRSA transmission.

Methods

The study was conducted at The Ottawa Hospital, a large multi-centre tertiary care facility with approximately 47,000 admissions annually. From January 2006-December 2007, patients underwent risk factor-based screening for MRSA on admission. From January 2008 to August 2009 universal MRSA screening was implemented. A comparison of costs incurred during risk factor-based screening and universal screening was conducted. The model incorporated probabilities relating to the likelihood of being tested and the results of polymerase chain reaction (PCR) testing with associated effects in terms of MRSA bacteremia and true positive and negative test results. Inputted costs included laboratory testing, contact precautions and infection control, private room costs, housekeeping, and length of hospital stay. Deterministic sensitivity analyses were conducted.

Results

The risk factor-based MRSA screening program screened approximately 30% of admitted patients and cost the hospital over $780 000 annually. The universal screening program screened approximately 83% of admitted patients and cost over $1.94 million dollars, representing an excess cost of $1.16 million per year. The estimated additional cost per patient screened was $17.76.

Conclusion

This analysis demonstrated that a universal MRSA screening program was costly from a hospital perspective and was previously known to not be clinically effective at reducing MRSA transmission. These results may be useful to inform future model-based economic analyses of MRSA interventions.

What To Think If the Results of the National Institutes of Health Randomized Trial of Methicillin-ResistantStaphylococcus aureusand Vancomycin-ResistantEnterococcusControl Measures Are Negative (and Other Advice to Young Epidemiologists): A Review and an Au Revoir

The incidence of methicillin-resistantStaphylococcus aureus(MRSA) and vancomycin-resistantEnterococcus(VRE) infections continues to rise in National Nosocomial Infections Surveillance system hospitals, and these pathogens are reportedly causing more than 100,000 infections and many deaths each year in US healthcare facilities. This has led some to insist that control measures are now urgently needed, but several recent articles have suggested that isolation of patients does not work, is not needed, or is unsafe, or that a single cluster-randomized trial could be used to decide such matters. At least 101 studies have reported controlling MRSA infection and 38 have reported controlling VRE infection by means of active detection by surveillance culture and use of isolation for all colonized patients in healthcare settings where the pathogens are epidemic or endemic, in academic and nonacademic hospitals, and in acute care, intensive care, and long-term care settings. MRSA colonization and infection have been controlled to exceedingly low levels in multiple nations and in the state of Western Australia for decades by use of active detection and isolation. Studies suggesting problems with using such data to control MRSA colonization and infection have their own problems, which are discussed. Randomized trials are epidemiologic tools that can sometimes provide erroneous results, and they have not been considered necessary for studying isolation before it is used to control other important infections, such as tuberculosis, smallpox, and severe acute respiratory syndrome. No single epidemiologic study should be considered definitive. One should always weigh all available evidence. Infection with antibiotic-resistant pathogens such as MRSA and VRE is controllable to a low level by active detection and isolation of colonized and infected patients. Effective measures should be used to minimize the morbidity and mortality attributable to these largely preventable infections.

Modeling Transmission of Methicillin-ResistantStaphylococcus AureusAmong Patients Admitted to a Hospital

Objective:

To determine the impact of the screening test, nursing workload, handwashing rates, and dependence of handwashing on risk level of patient visit on methicillin-resistantStaphylococcus aureus(MRSA) transmission among hospitalized patients.

Setting:

General medical ward.

Methods:

Monte Carlo simulation was used to model MRSA transmission (median rate per 1,000 patient-days). Visits by healthcare workers (HCWs) to patients were simulated, and MRSA was assumed to be transmitted among patients via HCWs.

Results:

The transmission rate was reduced from 0.89 to 0.56 by the combination of increasing the sensitivity of the screening test from 80% to 99% and being able to report results in 1 day instead of 4 days. Reducing the patient-to-nurse ratio from 4.3 in the day and 6.8 at night to 3.8 and 5.7, respectively, reduced the number of nosocomial infections from 0.89 to 0.85; reducing the ratio to 1 and 1, respectively, further reduced the number of nosocomial infections to 0.32. Increases in handwashing rates by 0%, 10%, and 20% for high-risk visits yielded reductions in nosocomial infections similar to those yielded by increases in handwashing rates for all visits (0.89, 0.36, and 0.24, respectively). Screening all patients for MRSA at admission reduced the transmission rate to 0.81 per 1,000 patient-days from 1.37 if no patients were screened.

Conclusion:

Within the ranges of parameters studied, the most effective strategies for reducing the rate of MRSA transmission were increasing the handwashing rates for visits involving contact with skin or bodily fluid and screening patients for MRSA at admission. (Infect Control Hosp Epidemiol 2005;26:607- 615)

Methicillin-ResistantStaphylococcus AureusCarriage Among Patients After Hospital Discharge

Background and Objective:

At the University Medical Center Utrecht (UMCU), follow-up implies an inventory of risk factors and screening for MRSA colonization among all MRSA-positive patients for at least 6 months. If risk factors or positive cultures persist or re-emerge, longer follow-up is indicated and isolation at readmission. This study investigated how long MRSA-positive patients remained colonized after hospital discharge and which risk factors were important. Furthermore, the results of eradication therapy were evaluated.

Design:

All patients who were positive for MRSA at the UMCU between January 1991 and January 2001 were analyzed regarding carriage state, presence of risk factors for prolonged carriage ofStaphylococcus aureus, and eradication treatment.

Results:

A total of 135 patients were included in the study. The median follow-up time was 1.2 years. Eighteen percent of the patients were dismissed from follow-up 1 year after discharge. Only 5 patients were dismissed after 6 months. Among patients with no risk factors, eradication treatment was effective for 95% within 1 year. Among patients with persistent risk factors, treatment was effective for 89% within 2 years.

Conclusions:

Based on these findings, eradication therapy should be prescribed for all MRSA carriers, independent of the presence of risk factors. MRSA-positive patients should be evaluated for 6 months for the presence of risk factors and MRSA carriage. Screening for risk factors is important because intermittent MRSA carriage was found in a significant number of our patients. Patients with negative MRSA cultures and without risk factors for 12 months can be safely dismissed from follow-up. (Infect Control Hosp Epidemiol 2005;26:629-633)

Duration of Colonization with Methicillin-ResistantStaphylococcus aureusAmong Patients in the Intensive Care Unit: Implications for Intervention

Objectives.

To determine the duration of methicillin-resistantStaphylococcus aureus(MRSA) colonization or infection before entry and during hospitalization in the intensive care unit (ICU) and the characteristics of patients who tested positive for MRSA.

Design.

Prospective observational cohort survey.

Setting.

A combined medical and coronary care ICU with 16 single-bed rooms in a 427-bed tertiary care Veteran Affairs Medical Center

Patients.

A total of 720 ICU patients associated with 845 ICU admissions were followed up for the detection of MRSA from January 13, 2003, to October 12, 2003. MRSA colonization was detected in patients by using active surveillance cultures (ASCs) of nasal swab specimens obtained within 48 hours of ICU entry and 3 times weekly thereafter. The duration of colonization during ICU stay and before ICU entry was calculated after a review of surveillance culture results, clinical culture results, and medical history.

Results.

Ninety-three (11.0%) of 845 ICU admissions involved patients who were colonized with MRSA at the time of ICU entry, and 21 admissions (2.5%) involved patients who acquired MRSA during ICU stay. ASCs were positive for MRSA in 84 (73.6%) of the 114 admissions associated with MRSA positivity and were the sole means of identifying MRSA in 50 cases (43.8%). More than half of the MRSA-associated admissions involved patients who were transferred from hospital wards. The total bed-days of care for 38 admissions involving patients who tested positive for MRSA before ICU entry (1131 days) was nearly 20% higher than the total bed-days of care for all admissions associated with MRSA positivity (970 days). Admissions involving MRSA-positive patients were associated with a longer length of hospitalization before ICU entry (P<.001), longer length of ICU stay (P<.001), longer overall length of hospitalization (P<.001), and greater inpatient mortality than admissions involving MRSA-negative patients (P<.001). A total of 22.8% of all bed-care days were dedicated to MRSA-positive patients in the ICU, and 55 (48.2%) of 114 admissions associated with MRSA positivity involved patients who were colonized for the duration of their ICU stay.

Conclusions.

In our unit, ASCs were an effective means to identify MRSA colonization among patients admitted to the ICU. Unfortunately, the majority of identified patients had long durations of stay in our own hospital before ICU entry, with prolonged MRSA colonization. Enhanced efforts to control MRSA will have to account for the prevalence of MRSA within hospital wards and to direct control efforts at these patients in the future.

Detection and Treatment of Antibiotic-Resistant Bacterial Carriage in a Surgical Intensive Care Unit: A 6-Year Prospective Survey

Objective:

To describe, during a 6-year period, multidrug-resistant bacterial carriage in an intensive care unit (ICU).

Design:

Prospective survey of 2,235 ICU patients with methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum beta-lactamase–producing Enterobacteriaceae (ESBL-E).

Setting:

A surgical ICU in a tertiary-care teaching hospital.

Patients:

All admitted patients.

Interventions:

Nasal and rectal swabs were performed at admission and weekly thereafter. There was nasal application of mupirocin for MRSA carriers and selective digestive decontamination with local antibiotics for ESBL-E carriers.

Results:

The swab compliance rate was 82% at admission and 51% during ICU stay. The rates of MRSA carriage or infection were 4.2 new cases per 100 admissions and 7.9 cases per 1,000 patient-days during ICU stay. The rates of ESBL-E carriage or infection were 0.4 new case per 100 admissions and 3.9 cases per 1,000 patient-days during ICU stay. Importation of MRSA increased significantly over time from 3.2 new cases per 100 admissions during the first 3 years to 5.5 during the last 3 years. The rate of ICU-acquired ESBL-E decreased from 5.5 cases per 1,000 patient-days during the first 3 years to 1.9 cases during the last 3 years. Nasal and digestive decontamination had low efficacy in eradicating carriage.

Conclusions:

MRSA remained poorly controlled throughout the hospital and was not just a problem in the ICU. MRSA thus requires more effective measures throughout the hospital. ESBL-E was mainly an ICU pathogen and our approach resulted in a clear decrease in the rate of acquisition in the ICU over time.

Staphylococcus aureus Bacteremia in Older Adults: Predictors of 7-Day Mortality and Infection With a Methicillin-Resistant Strain

Objectives.

To determine the predictors of 7-day mortality in older adult patients with Staphylococcus aureus bacteremia after controlling for comorbidity using the Charlson weighted index of comorbidity (WIC) and to identify the risk factors associated with bacteremia due to methicillin-resistant S. aureus (MRSA).

Design.

Retrospective cohort study from January 2003 until December 2004.

Setting.

Two tertiary care, university-affiliated hospitals.

Methods.

One hundred thirty-five hospitalized patients with S. aureus bacteremia were included in the study. All patients who were 60 years or older and had 1 or more blood cultures positive for S. aureus were included in the study. The primary outcome was death 7 days after the onset of S. aureus bacteremia.

Results.

Twenty-one patients (15.6%) died within 7 days after the onset of S. aureus bacteremia. Seventy-four patients (56.1%) had MRSA bacteremia. Multivariate analysis identified 3 independent determinants of 7-day mortality: Charlson WIC score greater than 5 (odds ratio [OR], 3.6 [95% confidence interval {CI}, 1.1-11.2]; P = .03), previous hospitalization in the past 3 months (OR, 5.0 [95% CI, 1.1-25.1]; P = .04), and altered mental status at the onset of S. aureus bacteremia (OR, 13.6 [95% CI, 2.9-64.6]; P = .001). Multivariate analysis identified .previous hospitalization in the past 3 months (OR, 2.6 [95% CI, 1.1-5.9]; P = .02), residence in a long-term care facility (OR, 4.5 [95% CI, 1.7-12.3]; P = .003), and altered mental status at the onset of S. aureus bacteremia (OR, 2.5 [95% CI, 1.5-5.6]; P = .02) to be independently associated with the presence of MRSA.

Conclusions.

The Charlson WIC is significantly associated with increased mortality of S. aureus bacteremia in older adults. Previous hospitalization in the past 3 months, residence in a long-term care facility, and altered mental status should be used as a guidance for empirical vancomycin therapy and application of infection control measures in older adults with suspected S. aureus bacteremia.

Multidrug-resistant organism infections in US nursing homes: a national study of prevalence, onset, and transmission across care settings, October 1, 2010-December 31, 2011

OBJECTIVE

To understand the prevalence of multidrug-resistant organism (MDRO) infections among nursing home (NH) residents and the potential for their spread between NHs and acute care hospitals (ACHs).

METHODS

Descriptive analyses of MDRO infections among NH residents using all NH residents in the Long-Term Care Minimum Data Set (MDS) 3.0 between October 1, 2010 and December 31, 2011.

RESULTS

Analysis of MDS data revealed a very high volume of bidirectional patient flow between NHs and ACHs, indicating the need to study MDRO infections in NHs as well as in hospitals. A total of 4.24% of NH residents had an active MDRO diagnosis on at least 1 MDS assessment during the study period. This rate significantly varied by sex, age, urban/rural status, and state. Approximately 2% of NH discharges to ACHs involved a resident with an active diagnosis of infection due to MDROs. Conversely, 1.8% of NH admissions from an ACH involved a patient with an active diagnosis of infection due to MDROs. Among residents who acquired an MDRO infection during the study period, 57% became positive in the NH, 41% in the ACH, and 2% in other settings (eg, at a private home or apartment).

CONCLUSION

Even though NHs are the most likely setting where residents would acquire MDROs after admission to an NH (accounting for 57% of cases), a significant fraction of NH residents acquire MDRO infection at ACHs (41%). Thus, effective MDRO infection control for NH residents requires simultaneous, cooperative interventions among NHs and ACHs in the same community.

Methicillin-resistant Staphylococcus aureus multiple sites surveillance: a systemic review of the literature

Purpose

The objective of this study was to evaluate the optimal number of sampling sites for detection of methicillin-resistant Staphylococcus aureus (MRSA) colonization.

Methods

We performed a Medline search from January 1966 to February 2014 for articles that reported the prevalence of MRSA at different body sites. Studies were characterized by study design, country and period of the study, number of patients and/or isolates of MRSA, specimen type, sites of MRSA isolation, study population sampled, diagnostic testing method, and percentage of the MRSA isolates at each site in relation to the total number of sites.

Results

We reviewed 3,211 abstracts and 177 manuscripts, of which 17 met the criteria for analysis (n=52,642 patients). MRSA colonization prevalence varied from 8% to 99% at different body sites. The nasal cavity as a single site had MRSA detection sensitivity of 68% (34%–91%). The throat and nares gave the highest detection rates as single sites. A combination of two swabs improved MRSA detection rates with the best combination being groin/throat (89.6%; 62.5%–100%). A combination of three swab sites improved MRSA detection rate to 94.2% (81%–100%) with the best combination being groin/nose/throat. Certain combinations were associated with low detection rates. MRSA detection rates also varied with different culture methods.

Conclusion

A combination of three swabs from different body sites resulted in the highest detection rate for MRSA colonization. The use of three swab sites would likely improve the recognition and treatment of MRSA colonization, which may in turn reduce infection and transmission of MRSA to other patients.

Costs associated with implementation of a strict policy for controlling spread of highly resistant microorganisms in France

OBJECTIVE

To assess costs associated with implementation of a strict 'search and isolate' strategy for controlling highly drug-resistant organisms (HDRO).

DESIGN

Review of data from 2-year prospective surveillance (01/2012 to 12/2013) of HDRO.

SETTING

Three university hospitals located in northern Paris.

METHODS

Episodes were defined as single cases or outbreaks of glycopeptide-resistant enterococci (GRE) or carbapenemase-producing Enterobacteriacae (CPE) colonisation. Costs were related to staff reinforcement, costs of screening cultures, contact precautions and interruption of new admissions. Univariate analysis, along with simple and multiple linear regression analyses, was conducted to determine variables associated with cost of HDRO management.

RESULTS

Overall, 41 consecutive episodes were included, 28 single cases and 13 outbreaks. The cost (mean ± SD) associated with management of a single case identified within and/or 48 h after admission was €4443 ± 11,552 and €11,445 ± 15,743, respectively (p<0.01). In an outbreak, the total cost varied from €14,864 ± 17,734 for an episode with one secondary case (€7432 ± 8867 per case) to €136,525 ± 151,231 (€12,845 ± 5129 per case) when more than one secondary case occurred. In episodes of single cases, contact precautions and microbiological analyses represented 51% and 30% of overall cost, respectively. In outbreaks, cost related to interruption of new admissions represented 77-94% of total costs, and had the greatest financial impact (R(2)=0.98, p<0.01).

CONCLUSIONS

In HDRO episodes occurring at three university hospitals, interruption of new admissions constituted the most costly measure in an outbreak situation.

Review of a two-year methicillin-resistant Staphylococcus aureus screening program and cost-effectiveness analysis in Singapore

Background

Methicillin-resistant Staphylococcus aureus (MRSA) poses an increasingly large disease and economic burden worldwide. The effectiveness of screening programs in the tropics is poorly understood. The aims of this study are: (i) to analyze the factors affecting MRSA colonization at admission and acquisition during hospitalization and (ii) to evaluate the cost-effectiveness of a screening program which aims to control MRSA incidence during hospitalization.

Methods

We conducted a retrospective case–control study of patients admitted to the Communicable Disease Centre (CDC) in Singapore between Jan 2009 and Dec 2010 when there was an ongoing selective screening and isolation program. Risk factors contributing to MRSA colonization on admission and acquisition during hospital stay were evaluated using a logistic regression model. In addition, a cost-effectiveness analysis was conducted to determine the cost per disability-adjusted life year (DALY) averted due to implementing the screening and isolation program.

Results

The average prevalence rate of screened patients at admission and the average acquisition rate at discharge during the study period were 12.1 and 4.8 % respectively. Logistic regression models showed that older age (adjusted odds ratio (OR) 1.03, 95 % CI 1.02–1.04, p < 0.001) and dermatological conditions (adjusted OR 1.49, 95 % CI 1.11–1.20, p = 0.008) were independently associated with an increased risk of MRSA colonization at admission. Age (adjusted OR 1.02, 95 % CI 1.01–1.03, p = 0.002) and length of stay in hospital (adjusted OR 1.04, 95 % CI 1.03–1.06, p < 0.001) were independent factors associated with MRSA acquisition during hospitalization. The screening and isolation program reduced the acquisition rate by 1.6 % and was found to be cost saving. For the whole study period, the program cost US$129,916, while it offset hospitalization costs of US$103,869 and loss of productivity costs of US$50,453 with −400 $/DALY averted.

Discussion

This study is the first to our knowledge that evaluates the cost-effectiveness of screeningand isolation of MRSA patients in a tropical country. Another unique feature of the analysis is the evaluationof acquisition rates among specific types of patients (dermatological, HIV and infectious disease patients)and the comparison of the cost-effectiveness of screening and isolation between them.

Conclusions

Overall our results indicate high MRSA prevalence that can be cost effectively reduced by selective screening and isolation programs in Singapore.

Which Multidrug-Resitant Bacteria are Emerging in Patients with Hematological Malignancies?: One-Year Report

The aim of this retrospective, observational study was to evaluate the outcomes of bacteremia attacks during neutropenic episodes caused by chemotherapy in patients with hematological cancers by assessing mortality, involved pathogens, antimicrobial therapy and treatment responses. Patients who were older than 14 years of age and developed at least one neutropenic episode after chemotherapy to treat hematological cancer between November 2011 and November 2012 were included in the study. We retrospectively collected demographic, treatment, and survival data for 68 patients with 129 neutropenic episodes. The mean age was 59.36 ± 15.22 years (range 17-80 years), and 41 cases were male. The mean Multinational Association of Supportive Care in Cancer score was 19.56 ± 9.04. A total of 37 (28 %) bacteremia attacks were recorded in 20 cases (29 %). Fatality rates were 50 % in the six cases with bacteremia caused by carbapenem-resistant Gram-negative bacteria; death occurred in two patients with carbapenem-resistant Acinetobacter baumannii and in one patient with carbapenem-resistant Pseudomonas aeruginosa. Clinical and microbiological responses were achieved using PIP-TAZ or CEP-SUL treatment in 80 % (16/20) of the cases with bacteremia caused by carbapenem-sensitive Gram-negative bacteria (CS-GNB). During 547 colonization-days in 21 (30 %) vancomycin-resistant enterococci (VRE)-colonized cases among 68 patients, vancomycin-resistant Enterococcus faecium bacteremia developed in two patients. Non-carbapenem-based therapy can cure most bacteremia attacks caused by CS-GNB in patients with hematological cancer. However, bacteremia and other infections caused by drug-resistant pathogens, such as A. baumannii, P. aeruginosa, and VRE, are a growing concern in hematological patients.

Real-Time Polymerase Chain Reaction Detection of Methicillin-ResistantStaphylococcus aureus:Impact on Nosocomial Transmission and Costs

Objectives.

To assess the impact of real-time polymerase chain reaction (PCR) detection of methicillin-resistantStaphylococcus aureus(MRSA) on nosocomial transmission and costs.

Design.

Monthly MRSA detection rates were measured from April 1, 2000, through December 31, 2005. Time series analysis was used to identify changes in MRSA detection rates, and decision analysis was used to compare the costs of detection by PCR and by culture.

Setting.

A 1,200-bed, tertiary care hospital in Canada.

Patients.

Admitted patients at high risk for MRSA colonization. MRSA detection using culture-based screening was compared with a commercial PCR assay.

Results.

The mean monthly incidence of nosocomial MRSA colonization or infection was 0.37 cases per 1,000 patient-days. The time-series model indicated an insignificant decrease of 0.14 cases per 1,000 patient-days per month (95% confidence interval, —0.18 to 0.46) after the introduction of PCR detection (P= .39). The mean interval from a reported positive result until contact precautions were initiated decreased from 3.8 to 1.6 days (P<.001). However, the cost of MRSA control increased from Can$605,034 to Can$771,609. Of 290 PCR-positive patients, 120 (41.4%) were placed under contact precautions unnecessarily because of low specificity of the PCR assay used in the study; these patients contributed 37% of the increased cost. The modeling study predicted that the cost per patient would be higher with detection by PCR (Can$96) than by culture (Can$67).

Conclusion.

Detection of MRSA by the PCR assay evaluated in this study was more costly than detection by culture for reducing MRSA transmission in our hospital. The cost benefit of screening by PCR varies according to incidences of MRSA colonization and infection, the predictive values of the assay used, and rates of compliance with infection control measures.

Assessment of the Influence of Test Characteristics on the Clinical and Cost Impacts of Methicillin-ResistantStaphylococcus aureusScreening Programs in US Hospitals

Objective.

To compare the impacts of different methicillin-resistantStaphylococcus aureus(MRSA) screening test options (eg, polymerase chain reaction [PCR], rapid culture) and program characteristics on the clinical outcomes and budget of a typical US hospital.

Methods.

We developed an Excel-based decision-analytic model, using published literature to calculate and compare hospital costs and MRSA infection rates for PCR- or culture-based MRSA screening and then used multivariate sensitivity analysis to evaluate key variables. Same-day PCR testing for a representative 370-bed teaching hospital in the United States was assessed in different populations (high-risk patients, intensive care unit [ICU] patients, or all patients) and compared with other test options.

Results.

Different screening program populations (all patients, high-risk patients, ICU patients, or patients with previous MRSA colonization or infection only) represented a potential savings of $12,158-$76,624 per month over no program ($188,618). Analysis of multiple test options in high-risk population screening indicated that same-day PCR testing of high-risk patients resulted in fewer infections over 1,720 patient-days (2.9, compared with 3.5 for culture on selective media and 3.8 for culture on nonselective media) and the lowest total cost ($112,012). The costs of other testing approaches ranged from $113,742 to $123,065. Sensitivity analysis revealed that variations in transmission rate, conversion to infection, prevalence increases, and hospital size are important to determine program impact. Among test characteristics, turnaround time is highly influential.

Conclusion.

All screening options showed reductions in infection rates and cost impact improvement over no screening program. Among the options, same-day PCR testing for high-risk patients slightly edges out the others in terms of fewest infections and greatest potential cost savings.

Do Infection Control Measures Work for Methicillin-ResistantStaphylococcus aureus?

Objective:

To review evidence regarding the effectiveness of control measures in reducing transmission of methicillin-resistantStaphylococcus aureus(MRSA) in hospitals.

Design:

Literature review and surveillance cultures of hospitalized patients at high risk for MRSA colonization or infection.

Setting:

A 500-bed, university-affiliated, community teaching hospital.

Results:

The percentage of nosocomialS. aureusinfections caused by MRSA increased significantly between 1982 and 2002, despite the use of various isolation and barrier precaution policies. The apparent ineffectiveness of control measures may be due to several factors including the failure to identify patients colonized with MRSA For example, cultures of stool specimens submitted forClostridium difficiletoxin assays at one hospital found that 12% of patients had MRSA in their stool, and 41% of patients with unrecognized colonization were cared for without using barrier precautions. Other factors include the use of barrier precaution strategies that do not account for multiple reservoirs of MRSA, poor adherence of healthcare workers (HCWs) to recommended barrier precautions and handwashing, failure to identify and treat HCWs responsible for transmitting MRSA, and importation of MRSA by patients admitted from other facilities. Control programs that include active surveillance cultures (ASCs) of high-risk patients and use of barrier precautions have reduced MRSA prevalence rates and have been cost-effective. Using a staged approach to implementing ASCs can minimize logistic problems.

Conclusion:

MRSA control programs are effective if they include ASCs of high-risk patients, use of barrier precautions when caring for colonized or infected patients, hand hygiene, and treating HCWs implicated in MRSA transmission.

A Cost-Benefit Analysis of Gown Use in Controlling Vancomycin-ResistantEnterococcusTransmission Is It Worth the Price?

Objective:

To determine the net benefit and costs associated with gown use in preventing transmission of van-comycin-resistantEnterococcus(VRE).

Design:

A cost-benefit analysis measuring the net benefit of gowns was performed. Benefits, defined as averted costs from reduced VRE colonization and infection, were estimated using a matched cohort study. Data sources included a step-down cost allocation system, hospital informatics, and microbiology databases.

Setting:

The medical intensive care unit (MICU) at Barnes-Jewish Hospital, St. Louis, Missouri.

Patients:

Patients admitted to the MICU for more than 24 hours from July 1, 1997, to December 31, 1999.

Interventions:

Alternating periods when all healthcare workers and visitors were required to wear gowns and gloves versus gloves alone on entry to the rooms of patients colonized or infected with VRE.

Results:

On base-case analysis, 58 VRE cases were averted with gown use during 18 months. The annual net benefit of the gown policy was $419,346 and the cost per case averted of VRE was $1,897. The analysis was most sensitive to the level of VRE transmission.

Conclusions:

Infection control policies (eg, gown use) initially increase the cost of health services delivery. However, such policies can be cost saving by averting nosocomial infections and the associated costs of treatment. The cost savings to the hospital plus the benefits to patients and their families of avoiding nosocomial infections make effective infection control policies a good investment.

Is Methicillin-Resistant Staphylococcus Aureus Colonization Associated with Worse Outcomes in COPD Hospitalizations?

BACKGROUND

Although methicillin-resistant Staphylococcus aureus (MRSA) colonization is common in chronic obstructive pulmonary disease (COPD) patients, its effect on the course of COPD hospitalization remains unknown.

METHODS

Records of 160 patients hospitalized at our institution January 1, 2008 to May 1, 2010 with acute exacerbations of COPD who were screened for MRSA were examined and outcomes from their hospitalizations were quantified.

RESULTS

Of the 160 patients, 33 (20.6%) were MRSA colonized on screening. These patients had similar demographics, spirometry, Charlson Indexes, and APACHE-II scores when compared to patients who were not MRSA colonized (n=127), but MRSA colonized patients had more hospitalizations within the 2 years prior to admission (2 [1-4.8] versus 1 [0-3], p = 0.03). While hospitalized, MRSA colonized patients had a longer length of stay (9 [5.3-15.5] versus 5 [3-7.8] days, p = 0.01) and more antibiotic days (7 [5-10.8] versus 5 [0-7] days, p = 0.01). They were also more likely to receive intensive care (51.5% versus 23.6%, p = 0.01) and to develop respiratory failure that required noninvasive ventilation (56.3% versus 38.2%, p = 0.05). Trends towards increased use of invasive mechanical ventilation and readmission within 30 days were also present.

CONCLUSIONS

COPD patients colonized with MRSA have longer hospitalizations, require longer courses of antibiotics, and are more likely to require intensive care.

Value of an active surveillance policy to document clearance of meticillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci amongst inpatients with prolonged admissions

This article reports the impact of an active surveillance policy to identify clearance of meticillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant enterococci (VRE) in known colonized inpatients with prolonged admissions in order to discontinue isolation precautions. Amongst 365 colonized patients with hospital admissions exceeding 30 days, clearance rates of 11% for MRSA and 18% for VRE were found after a median of 23 days and 26.5 days, respectively, resulting in a saving of 2152 patient-days of contact precautions over one year. This has proven to be a cost-beneficial policy.

Clinical, patient experience and cost impacts of performing active surveillance on known methicillin-resistant Staphylococcus aureus positive patients admitted to medical-surgical units

BACKGROUND

There is a large and growing body of evidence that methicillin-resistant Staphylococcus aureus (MRSA) screening programs are cost effective, but such screening represents a significant cost burden for hospitals. This study investigates the clinical, patient experience and cost impacts of performing active surveillance on known methicillin-resistant S aureus positive (MRSA+) patients admitted to 7 medical-surgical units of a large regional hospital, specifically to allow discontinuation of contact isolation.

METHODS

We conducted mixed-methods retrospective evaluation of a process improvement project that screened admitted patients with known MRSA+ status for continued MRSA colonization.

RESULTS

Of those eligible patients on our institution's MRSA+ list who did complete testing, 80.2% (130/162) were found to be no longer colonized, and only 19.8% (32/162) were still colonized. Forty-one percent (13/32) of interviewed patients in contact isolation for MRSA reported that isolation had affected their hospital stay, and 28% (9/32) of patients reported emotional distress resulting from their isolation. Total cost savings of the program are estimated at $101,230 per year across the 7 study units.

CONCLUSION

Our findings provide supporting evidence that a screening program targeting patients with a history of MRSA who would otherwise be placed in isolation has the potential to improve outcomes and patient experience and reduce costs.

Risk factors for methicillin-resistant Staphylococcus aureus in diabetic foot infections

Objective

The purpose of this study was to evaluate risk factors for methicillin-resistant Staphylococcus aureus (MRSA) in patients hospitalized for diabetic foot infections.

Methods

We reviewed hospital admissions for foot infections in patients with diabetes which had nasal swabs, and anaerobic and aerobic tissue cultures at the time of admission. Data collected included patient characteristics and medical history to determine risk factors for developing an MRSA infection in the foot.

Results

The prevalence of MRSA in these infections was 29.8%. Risk factors for MRSA diabetic foot infections were history of MRSA foot infection, MRSA nasal colonization, and multidrug-resistant organisms (p<0.05). Positive predictive value (PPV) and negative predictive value (NPV) of nasal colonization with MRSA to identify MRSA diabetic foot infections were 66.7% and 80.0% (sensitivity 41%, specificity 90%). Admission from a nursing home was not a significant risk factor.

Conclusion

Positive nasal swabs are not predictive of the infecting agent; however, a negative nasal swab rules out MRSA as the infecting agent in foot wounds with 90% accuracy.

Cost-benefit of infection control interventions targeting methicillin-resistant Staphylococcus aureus in hospitals: systematic review

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) incur significant costs. We aimed to examine the cost and cost-benefit of infection control interventions against MRSA and to examine factors affecting economic estimates. We performed a systematic review of studies assessing infection control interventions aimed at preventing spread of MRSA in hospitals and reporting intervention costs, savings, cost-benefit or cost-effectiveness. We searched PubMed and references of included studies with no language restrictions up to January 2012. We used the Quality of Health Economic Studies tool to assess study quality. We report cost and savings per month in 2011 US$. We calculated the median save/cost ratio and the save-cost difference with interquartile range (IQR) range. We examined the effects of MRSA endemicity, intervention duration and hospital size on results. Thirty-six studies published between 1987 and 2011 fulfilled inclusion criteria. Fifteen of the 18 studies reporting both costs and savings reported a save/cost ratio >1. The median save/cost ratio across all 18 studies was 7.16 (IQR 1.37-16). The median cost across all studies reporting intervention costs (n = 31) was 8648 (IQR 2025-19 170) US$ per month; median savings were 38 751 (IQR 14 206-75 842) US$ per month (23 studies). Higher save/cost ratios were observed in the intermediate to high endemicity setting compared with the low endemicity setting, in hospitals with <500-beds and with interventions of >6 months. Infection control intervention to reduce spread of MRSA in acute-care hospitals showed a favourable cost/benefit ratio. This was true also for high MRSA endemicity settings. Unresolved economic issues include rapid screening using molecular techniques and universal versus targeted screening.

Nasal MRSA screening for surgical patients: predictive value for postoperative infections caused by MRSA

PURPOSE

Postoperative methicillin-resistant Staphylococcus aureus (MRSA) infections are occasionally fatal. We hypothesized that nasal MRSA screening might predict the risk of postoperative MRSA infections. The aim of the current study was to elucidate the relationship between the positivity of nasal MRSA screening and postoperative MRSA infections.

METHODS

Six hundred and fourteen surgical patients who were admitted to the intensive care unit and underwent nasal MRSA screening between April 2006 and March 2011 were divided into MRSA-positive and -negative groups. The incidence of postoperative MRSA infections in the MRSA-positive and MRSA-negative groups were compared, and various risk factors for MRSA infections were evaluated.

RESULTS

The incidence of postoperative MRSA infections, such as pneumonia and enteritis, in the MRSA-positive group was significantly higher than that in the MRSA-negative group (41.9 vs. 3.1 %). The significant independent risk factors for postoperative MRSA infections were a positive MRSA screening, an operation lasting more than 300 min and an emergency operation. A positive MRSA screening was the most statistically significant risk factor for postoperative MRSA pneumonia and enteritis, but was not a risk factor for MRSA surgical site infections.

CONCLUSION

Nasal MRSA screening can help to identify patients who have an increased risk of developing postoperative MRSA infections, and would enable physicians to take a prompt action if these complications occur.

The outcome of non-carbapenem-based empirical antibacterial therapy and VRE colonisation in patients with hematological malignancies

BACKGROUND

Febrile neutropenia (FN) is generally a complication of cancer chemotherapy.

OBJECTIVES

We retrospectively evaluated the febrile neutropenia episodes and their outcomes with respect to modification rates of non-carbapenem-based empirical antibacterial therapy and vancomycin-resistant enterococcus (VRE) colonisation that caused to VRE bacteremia in patients with hematological malignancies.

METHODS

All consecutive patients, who were older than 14 years of age and developed febrile neutropenia episodes due to hematological malignancies from September 2010 to November 2011 at the hematology department were included into the study.

RESULTS

In total, 86 consecutive neutropenic patients and their 151 febrile episodes were evaluated. The mean MASCC prognostic index score was 18,72 ± 9,43. Among 86 patients, 28 patients experienced a total of 30 bacteremia episodes of bacterial origin. Modification rates of both, empirical monotherapy and combination therapies, were found similar, statistically (P = 0,840).

CONCLUSIONS

Our results suggest that initiating of non-carbapenem based therapy does not provide high response rates in the treatment of febrile neutropenia attacks. Furthermore, non-carbapenem-based empirical therapy provides benefit in regard to cost-effectiveness and antimicrobial stewardship when local antibiotic resistance patterns of gram-negative bacteria are considered. Patients who are colonized with VRE are more likely to develop bacteremia with VRE strains as a result of invasive procedures and severe damage of mucosal barriers observed in this group of patients.

Quantifying the impact of extranasal testing of body sites for methicillin-resistant Staphylococcus aureus colonization at the time of hospital or intensive care unit admission

OBJECTIVE

Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of healthcare-associated infections. Recent legislative mandates require nares screening for MRSA at hospital and intensive care unit (ICU) admission in many states. However, MRSA colonization at extranasal sites is increasingly recognized. We conducted a systematic review of the literature to identify the yield of extranasal testing for MRSA.

DESIGN

We searched MEDLINE from January 1966 through January 2012 for articles comparing nasal and extranasal screening for MRSA colonization. Studies were categorized by population tested, specifically those admitted to ICUs and those admitted to hospitals with a high prevalence (6% or greater) or low prevalence (less than 6%) of MRSA carriers. Data were extracted using a standardized instrument.

RESULTS

We reviewed 4,381 abstracts and 735 articles. Twenty-three articles met the criteria for analysis ((n = 39,479 patients). Extranasal MRSA screening increased the yield by approximately one-third over nares alone. The yield was similar at ICU admission (weighted average, 33%; range, 9%-69%) and hospital admission in high-prevalence (weighted average, 37%; range, 9%-86%) and low-prevalence (weighted average, 50%; range, 0%-150%) populations. For comparisons between individual extranasal sites, testing the oropharynx increased MRSA detection by 21% over nares alone; rectum, by 20%; wounds, by 17%; and axilla, by 7%.

CONCLUSIONS

Extranasal MRSA screening at hospital or ICU admission in adults will increase MRSA detection by one-third compared with nares screening alone. Findings were consistent among subpopulations examined. Extranasal testing may be a valuable strategy for outbreak control or in settings of persistent disease, particularly when combined with decolonization or enhanced infection prevention protocols.

Transmission rates, screening methods and costs of MRSA--a systematic literature review related to the prevalence in Germany

Methicillin-resistant Staphylococcus aureus (MRSA) infections represent a serious challenge for health care institutions, which is inherent in the combination of prevalence, transmission rates and costs. Furthermore, performing an MRSA screening requires information on the complex system of effectiveness, accuracy and costs of different screening methods. The purpose of this study was to give an overview of parameters with decisive significance for the burden of MRSA and the selection of a specific MRSA screening strategy. A systematic literature search for peer-reviewed health economic studies associated with MRSA was performed (from 1995 to the present). Eighty-seven different studies met all inclusion and exclusion criteria. Primary outcomes included the prevalence of MRSA, MRSA transmission rates, performance characteristics of MRSA screening methods, costs for pre-emptive isolation precautions and costs per MRSA case. The prevalence rates reported for all inpatients (1.2-5.3 %) as well as for inpatients with risk factors or patients in risk areas (3.85-20.6 %) vary greatly. The range of cross-transmission rates per day reported for patients with MRSA in isolation is 0.00081-0.009 and for carriers not in isolation is 0.00137-0.140, respectively. For polymerase chain reaction (PCR) methods, the mean sensitivity and specificity were 91.09 and 95.79 %, respectively. Culture methods show an average sensitivity of 89.01 % and an average specificity of 93.21 %. The turn-around time for PCR methods averages 15 h, while for the culture method, it can only be estimated as 48-72 h. This review filtered important parameters and cost drivers, and covered them with literature-based averages. These findings serve as an ideal evidence base for further health economic considerations of the cost-effectiveness of different MRSA screening methods.

Is screening patients for antibiotic-resistant bacteria justified in the Indian context?

Infection with multi-antibiotic-resistant bacteria is a common clinical problem in India. In some countries and centres, screening patients to detect colonisation by these organisms is used to determine specific interventions such as decolonisation treatment, prophylactic antibiotics prior to surgical interventions or for selection of empirical antibiotic therapy, and to isolate patients so that transmission of these difficult to treat organisms to other patients could be prevented. In India, there is no national guideline or recommendation for screening patients for multi-drug-resistant (MDR) bacteria such as MRSA (methicillin-resistant Staphylococcus aureus), VRE (vancomycin-resistant enterococcus), ESBL (extended spectrum beta-lactamase) or MBL (metallo-beta-lactamase) producers. The present article discusses the relevance of screening patients for multi-antibiotic-resistant bacteria in the Indian context. Literature has been reviewed about antibiotic resistance in India, screening methodology, economic debate about screening. The percentages of strains from various hospitals in India which were reported to be MRSA was between 8 and 71%, those for ESBL between 19 and 60% and carbapenem-resistant Gram-negative bacilli between 5.3 and 59%. There exists culture-based technology for the detection of these resistant organisms from patient samples. For some pathogens, such as MRSA and VRE Polymerase chain reaction-based tests are also becoming available. Screening for MDR bacteria is an option which may be used after appraisal of the resources available, and after exploring possibility of implementing the interventions that may be required after a positive screening test result.

[Generalized or targeted screening for carriage of MRSA on admission to a geriatric hospital]

OBJECTIVES

To confirm previously risk factors for MRSA carriage in our geriatric patient population and to suggest a simplified risk score with a combination of these risk factors, to test the Novel Score and to check if a targeted MRSA screening on admission is possible to reduce the screening workload and cost.

DESIGN

a prospective in-hospital cohort study.

SUBJECTS

1125 geriatric patients were screened for MRSA carriage within 24 hours after admission to a geriatric hospital.

METHODS

Risk factors, based on recently published risk scores (Preop Score and Ger Score) were determined.

RESULTS

Prevalence of MRSA carriage was 8.44%. In a multivariate analysis age > or = 87 year (OR 1,864; 95% CI 1,145-3,035), presence of a long-term catheter (OR 2,813; 95% CI 1,562-5,065) and prior carriage of MRSA (OR 13,25; 95% CI 8,007-21,926) remained predictors of MRSA carriage. The Novel Score (cut-off > or = 1) had a sensitivity of 73.7%, a specificity of 64%, PPV 15.9%, NPV 96.3% and AUC of 0.688. The Novel Score allows reduction of the screening load by 57.2%, but misses 26% of positive cases. 16% of MRSA carriers develop an infection that needs to be treated with vancomycin.

CONCLUSION

With targeted MRSA screening on admission based on a risk score a substantial reduction of workload and costs is possible compared to generalized screening for MRSA. Because MRSA carriers can be missed with a risk score, the epidemiological context and the risk of transmission and infection with MRSA must be taken in to account when introducing a targeted screening.

The management of infection and colonization due to methicillin-resistant Staphylococcus aureus: A CIDS/CAMM position paper

Methicillin-resistant Staphylococcus aureus (MRSA) is being seen with greater frequency in most hospitals and other health care facilities across Canada. The organism may cause life-threatening infections and has been associated with institutional outbreaks. Several studies have confirmed that MRSA infection is associated with increased morbidity and mortality compared with infections caused by susceptible strains, even when the presence of comorbidities is accounted for. Treatment of MRSA infection is complicated by the fact that these organisms are resistant to multiple antimicrobial agents, so treatment options are limited. The effectiveness of decolonization therapy (attempting to eradicate MRSA carriage) is also uncertain. This paper reviews the medical management of MRSA infections, discusses the potential role of decolonization and provides an overview of evidence to support recommended infection control practices.

Curiosities of the methicillin-resistant Staphylococcus aureus survey - possibility of pseudo-outbreak and transmission to household contacts

Methicillin-resistant Staphylococcus aureus (MRSA) is currently one of the most prevalent antibiotic-resistant pathogens in hospitals, but it is also emerging as a community-acquired pathogen. We analysed the clinical and microbiological data of the patients in a county teaching hospital regarding MRSA. During the examination period (1996-2010), four outbreaks and one pseudo-outbreak occurred. It also became evident that health care workers and their families are possibly at risk of becoming carriers of MRSA. The importance of the molecular epidemiological investigation (pulsed-field gel-electrophoresis (PFGE)) typing and hygienic measures in order to detect and control MRSA outbreaks must be emphasised. Following infection control guidelines seems to be cost-effective method of controlling the nosocomial transmission of MRSA.

Epidemiology and virulence insights from MRSA and MSSA genome analysis

Staphylococcus aureus is a major human pathogen responsible for a wide diversity of infections ranging from localized to life threatening diseases. From 1961 and the emergence of methicillin-resistant S. aureus (MRSA), this bacterium has shown a particular capacity to survive and adapt to drastic environmental changes and since the beginning of the 1990s it has spread worldwide. Until recently, S. aureus was considered as the prototype of a nosocomial pathogen but it has now been recognized as an agent responsible for outbreaks in the community. Several recent reports suggest that the epidemiology of MRSA is changing. Understanding of pathogenicity, virulence and emergence of epidemic clones within MRSA populations is not clearly defined, despite several attempts to identify common molecular features between strains that share similar epidemiological and/or virulence behavior. These studies included: pattern profiling of bacterial adhesins, analysis of clonal complex groups, molecular genotyping and enterotoxin content analysis. To date, all approaches failed to find a correlation between molecular determinants and clinical outcomes. We hypothesize that the capacity of the bacterium to become more invasive or virulent is determined by genetics. The utilization of massively parallel methods of analysis is therefore ideal to study the contribution of genetics. Therefore, this article focuses on the entire genome including coding sequences as well as noncoding sequences. This high resolution approach allows the monitoring micro- and macroevolution of MRSA and identification of specific genomic markers of evolution of invasive or highly virulent phenotypes.

Quantifying cost-effectiveness of controlling nosocomial spread of antibiotic-resistant bacteria: the case of MRSA

Background

The costs and benefits of controlling nosocomial spread of antibiotic-resistant bacteria are unknown.

Methods

We developed a mathematical algorithm to determine cost-effectiveness of infection control programs and explored the dynamical interactions between different epidemiological variables and cost-effectiveness. The algorithm includes occurrence of nosocomial infections, attributable mortality, costs and efficacy of infection control and how antibiotic-resistant bacteria affect total number of infections: do infections with antibiotic-resistant bacteria replace infections caused by susceptible bacteria (replacement scenario) or occur in addition to them (addition scenario). Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia was used for illustration using observational data on S. aureus bacteremia (SAB) in our hospital (n = 189 between 2001–2004, all being methicillin-susceptible S. aureus [MSSA]).

Results

In the replacement scenario, the costs per life year gained range from € 45,912 to € 6590 for attributable mortality rates ranging from 10% to 50%. Using € 20,000 per life year gained as a threshold, completely preventing MRSA would be cost-effective in the replacement scenario if attributable mortality of MRSA is ≥21%. In the addition scenario, infection control would be cost saving along the entire range of estimates for attributable mortality.

Conclusions

Cost-effectiveness of controlling antibiotic-resistant bacteria is highly sensitive to the interaction between infections caused by resistant and susceptible bacteria (addition or replacement) and attributable mortality. In our setting, controlling MRSA would be cost saving for the addition scenario but would not be cost-effective in the replacement scenario if attributable mortality would be <21%.

Impact of active surveillance and contact isolation on transmission of methicillin-resistant Staphylococcus aureus in intensive care units in an area with high prevalence

BACKGROUND/PURPOSE

Previous research has suggested that active surveillance and early initiation of contact isolation (ASI) can control the nosocomial spread of methicillin-resistant Staphylococcus aureus (MRSA), especially among intensive care unit (ICU) patients. However, these interventions have never been implemented in Taiwan.

METHODS

This study was conducted from September 2005 to October 2006 to evaluate the effect of ASI on the spread of MRSA in two medical centers in Taiwan with a high prevalence of MRSA. One ICU from each hospital was selected as a study site. In phase I (the first 6 months), only active surveillance was introduced. In phase II (the final 6 months), ASI for patients who had positive MRSA cultures was implemented.

RESULTS

The incidence of acquiring MRSA during ICU stay did not differ significantly during phases I and II in hospital A (p = 0.940) and hospital B (p = 0.810). The independent risk factors for acquiring MRSA in the ICU were length of stay and presence of respiratory tract diseases.

CONCLUSION

This study demonstrated that, given the current resource limitations, ASI alone could not reduce MRSA transmission in two ICUs in Taiwan, where the MRSA prevalence was high.

Methicillin-resistant Staphylococcus aureus in Canada: a historical perspective and lessons learned

The history of methicillin-resistant Staphylococcus aureus (MRSA) in Canada has many similarities to MRSA evolution worldwide, but especially to that in the United States and United Kingdom. Reports of MRSA occurred as early as 1964, and community isolates were cited in the 1970s. Nosocomial outbreaks were becoming common by 1978 and flourished gradually thereafter. Endemic institutional MRSA became predominant in the 1990s, threatening large teaching hospitals in particular. In the last decade, both hospital-acquired and community-acquired MRSA have created major medical problems in Canada. More recently, an epidemic of Canadian community-acquired MRSA-10, has led to heightened public health concerns. Canadian contributions to MRSA science are numerous, with organized surveillance continuing to mature across the nation. A typing system for epidemic clones is now available and is being judiciously applied. Estimated costs for MRSA surveillance, treatment, and control are extraordinary, paralleling the dramatic rise in the number of MRSA isolations. Whereas surveillance continues to form an essential aspect of MRSA management, control, eradication, and overall diminution, MRSA reservoirs deserve much greater attention. Such efforts, however, must be as widely publicized in the community and in patient homes as they are in medical institutions responsible for both acute and long-term care.

Characterization of the best anatomical sites in screening for methicillin-resistant Staphylococcus aureus colonization

The purpose of this study was to identify differences in the sensitivity of anatomical sites sampling for methicillin-resistant Staphylococcus aureus (MRSA) colonization related to age, gender, clinical situation, and acquisition source as a base for screening protocols. We used a database that included all MRSA-positive cultures (Carmel Medical Center, 2003-2006) taken from nares, throat, perineum, and infection sites. The study population of 597 patients was divided into: "screening sample" (SS), which were cases of routine screening, and "clinical diagnostic sample" (CDS), which were patients with concurrent MRSA infection. MRSA acquisition sources were classified as internal medicine, surgical, referral patients, or intensive care unit (ICU). CDS patients were older than SS patients (median age 78 vs. 74 years, p = 0.0002), more commonly throat colonized (47.5% vs. 31.8%, p = 0.0001), and colonized in more multiple sites (65.7% vs. 43.3% were colonized in three sites in the CDS and SS groups, respectively, p < 0.001) than SS patients. In the SS, group throat colonization was higher in internal medicine wards than in the ICU (odds ratio [OR] = 3.98, p < 0.0001). In the CDS group, perineal colonization was more common in referral patients than in the ICU (OR = 4.52, p < 0.05). Patient age was the most influential factor on nares and multiple sites colonization in the SS and CDS groups, respectively. Our data support multiple sites sampling. Throat cultures are crucial in MRSA-infected patients and internal medicine ward patients. Multiple body sites colonization is more likely in older or MRSA-infected patients, affecting decisions regarding eradication using topical antibiotics.