Methicillin-resistant Staphylococcus aureus nasal carriage among patients on haemodialysis with newly inserted central venous catheters

BACKGROUND

Although methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization is common among end-stage kidney disease patients undergoing haemodialysis, few studies were focused on MRSA nasal carriers among haemodialysis patients with central venous catheters (CVCs). The aim of this study is to evaluate the risk factors, various clinical outcomes and effect of decolonization for MRSA nasal colonization among patients on haemodialysis via CVCs.

METHODS

This was a single-centre non-concurrent cohort study of 676 patients who had new haemodialysis CVCs inserted. They were all screened for MRSA colonization via nasal swabs and were categorized into two groups: MRSA carriers and MRSA noncarriers. Potential risk factors and clinical outcomes were analysed in both groups. All MRSA carriers were given decolonization therapy and the effect of decolonization on subsequent MRSA infection was also performed.

RESULTS

Eighty-two patients (12.1%) were MRSA carriers. Multivariate analysis showed that MRSA carrier (OR 5.44; 95% CI 3.02-9.79), long-term care facility resident (OR 4.08; 95% CI 2.07-8.05), history of Staphylococcus aureus infection (OR 3.20; 95% CI 1.42-7.20) and CVC in situ > 21 days (OR 2.12; 95% CI 1.15-3.93) were independent risk factors for MRSA infection. There was no significant difference in all-cause mortality between MRSA carriers and noncarriers. The MRSA infection rates were similar between MRSA carriers with successful decolonization and those who had failed/incomplete decolonization in our subgroup analysis.

CONCLUSION

MRSA nasal colonization is an important cause of MRSA infection among haemodialysis patients with CVCs. However, decolonization therapy may not be effective in reducing MRSA infection.

Impact of the "Zero Resistance" program on acquisition of multidrug-resistant bacteria in patients admitted to Intensive Care Units in Spain. A prospective, intervention, multimodal, multicenter study

OBJECTIVE

To assess the impact of a multimodal interventional project ("Zero Resistance") on the acquisition of multidrug-resistant bacteria (MDR-B) during the patient's ICU stay.

DESIGN

Prospective, open-label, interventional, multicenter study.

SETTING

103 ICUs.

PATIENTS

Critically ill patients admitted to the ICUs over a 27-month period.

INTERVENTIONS

Implementation of a bundle of 10 recommendations to prevent emergence and spread of MDR-B in the ICU.

MAIN VARIABLE OF INTEREST

Rate of patients acquiring MDR-B during their ICU stay, with differentiation between colonization and infection.

RESULTS

A total of 139,505 patients were included. In 5409 (3.9%) patients, 6020 MDR-B on ICU admission were identified, and in 3648 (2.6%) patients, 4269 new MDR-B during ICU stay were isolated. The rate of patients with MDR-B detected on admission increased significantly (IRR 1.43, 95% CI 1.31-1.56) (p<0.001) during the study period, with an increase of 32.2% between the initial and final monthly rates. On the contrary, the rate of patients with MDR-B during ICU stay decreased non-significantly (IRR 0.93, 95% CI 0.83-1.03) (p=0.174), with a 24.9% decrease between initial and final monthly rates. According to the classification into colonization or infection, there was a highly significant increase of MDR-B colonizations detected on admission (IRR 1.69, 95% CI 1.52-1.83; p<0.0001) and a very significant decrease of MDR-B-infections during ICU stay (IRR 0.67, 95% CI 0.57-0.80, p<0.0001).

CONCLUSIONS

The implementation of ZR project-recommendations was associated with a significantly reduction an infection produced by MDR-B acquired during the patient's ICU stay.

Predictive Performance of Risk Factors for Multidrug-Resistant Pathogens in Nosocomial Pneumonia

Rationale: In 2017, the International European Respiratory Society/European Society of Intensive Care Medicine/European Society of Clinical Microbiology and Infectious Diseases/Latin American Thoracic Society (European) guidelines defined new risk factors for multidrug-resistant (MDR) pathogens in patients with nosocomial pneumonia.Objectives: To assess the predictive performance of these newly defined risk factors for MDR pathogens.Methods: We enrolled 507 adult patients with nosocomial pneumonia who were treated in six intensive care units at the Hospital Clinic of Barcelona in Spain. Of the 503 patients at high MDR pathogen and mortality risk, 275 (54%) had no septic shock and 228 (46%) had septic shock.Results: Admission to hospital settings with high rates of MDR pathogens (n = 421; 83%) and prior antibiotic use (n = 399; 79%) showed the highest prevalence in the overall population, with sensitivities of 92% and 85% and negative predictive values of 85% and 82%, respectively. However, low specificities and low positive predictive values were found. Previous respiratory MDR pathogen isolation was less common (n = 17; 3%) but presented a specificity and positive predictive value of 100%. The area under the receiver operating characteristic curve was less than 0.6 for all risk factors and combinations.Conclusions: The risk factors proposed by the European Respiratory Society/European Society of Intensive Care Medicine/European Society of Clinical Microbiology and Infectious Diseases/Latin American Thoracic Society showed low accuracy for predicting MDR pathogens in intensive care unit acquired pneumonia (ICU-AP). Admission to hospital settings with high rates of MDR pathogens and prior antibiotic use were the most prevalent risk factors, with a high sensitivity for predicting these microorganisms; prior positive cultures for MDR pathogens showed high specificity but very low sensitivity. Combinations of risk factors did not show any great accuracy for predicting these microorganisms. Further studies assessing combined strategies of risk stratification and complementary methods are now warranted.

Strategies to Prevent Healthcare-Associated Infections: A Narrative Overview

Healthcare-associated infections (HCAIs) are a major source of morbidity and mortality and are the second most prevalent cause of death. Furthermore, it has been reported that for every one-hundred patients admitted to hospital, seven patients in high-income economies and ten in emerging and low-income economies acquire at least one type of HCAI. Currently, almost all pathogenic microorganisms have developed antimicrobial resistance, and few new antimicrobials are being developed and brought to market. The literature search for this narrative review was performed by searching bibliographic databases (including Google Scholar and PubMed) using the search terms: "Strategies," "Prevention," and "Healthcare-Associated Infections," followed by snowballing references cited by critical articles. We found that although hand hygiene is a centuries-old concept, it is still the primary strategy used around the world to prevent HCAIs. It forms one of a bundle of approaches used to clean and maintain a safe hospital environment and to stop the transmission of contagious and infectious microorganisms, including multidrug-resistant microbes. Finally, antibiotic stewardship also has a crucial role in reducing the impact of HCAIs through conserving currently available antimicrobials.

Role of surveillance cultures in infection control

Hospital-acquired infections are a known menace to the primary disease, for which a patient is admitted. These infections are twenty times more common in developing countries than in the developed ones. Surveillance for colonised patients can be passive or active process. In many hospitals, active surveillance culture for certain sentinel organisms followed by contact precautions for the same is an important part of infection control policy. Specific measures can be taken on early detection of multidrug-resistant organism, allowing prevention of widespread transmission in hospitals. Cultures are the most conventional and economical microbiological method of detection. The cost of active surveillance is a major challenge, especially for developing nations. These nations lack basic infrastructure and have logistic issues. The guidelines regarding this are not very clearly delineated for developing countries. Each hospital has its own challenges and the process is to be tailor-made accordingly. The following review delineates the various aspects of active surveillance for the colonisation of various organisms and the advantages and disadvantages of the same.

Survey of isolation room equipment and resources in an academic hospital

PURPOSE

The purpose of this paper, a point prevalence study, is to quantify the incidence of isolation and identify the type of communicable diseases in isolation. The paper evaluates isolation precaution communication, availability of personal protective equipment (PPE) as well as other equipment necessary for maintaining isolation precautions.

DESIGN/METHODOLOGY/APPROACH

A standardised audit tool was developed in accordance with the National Standards for the Prevention and Control of Healthcare Associated Infections (May 2009). Data were collected from 14 March 2017 to 16 March 2017, through observation of occupied isolation rooms in an academic hospital in Dublin, Ireland. The data were subsequently used for additional analysis and discussion.

FINDINGS

In total, 14 per cent (125/869) of the total inpatient population was isolated at the time of the study. The most common isolation precaution was contact precautions (96.0 per cent). In all, 88 per cent of known contact precautions were due to multi-drug resistant organisms. Furthermore, 96 per cent of patients requiring isolation were isolated, 92.0 per cent of rooms had signage, 90.8 per cent had appropriate signs and 93.0 per cent of rooms had PPE available. Finally, 31 per cent of rooms had patient-dedicated and single-use equipment and 2.4 per cent had alcohol wipes available.

PRACTICAL IMPLICATIONS

The audit tool can be used to identify key areas of noncompliance associated with isolation and inform continuous improvement and education.

ORIGINALITY/VALUE

Currently, the rate of isolation is unknown in Ireland and standard guidelines are not established for the evaluation of isolation rooms. This audit tool can be used as an assessment for isolation room compliance.

The relationship between Gram-negative colonization and bloodstream infections in neonates: a systematic review and meta-analysis

OBJECTIVES

Neonates admitted to neonatal intensive care units (NICU) are at significant risk of developing bloodstream infections (BSIs). Gram-negative bacteria (GNB) both colonize and infect, but the association between these entities is unclear. By conducting a systematic literature review, we aimed to explore the impact of factors on the association between GN colonization and GN-BSI at both baby-level and unit-level.

METHODS

We searched Medline, Embase, and Cochrane Library. Observational cohort studies published after 2000 up to June 2016 reporting data on the total number of neonates (0-28 days) colonized with GNB assessed by rectal/skin swab culture and the total number of neonates with GN-BSI (same bacteria) were included. Studies were excluded if data on skin/rectal colonization, neonates, and GNB could not be identified separately. Meta-analyses along with multivariate meta-regression with a random-effect model were performed to investigate factors associated with the GN colonization and GN-BSI at baby-level and unit-level.

RESULTS

Twenty-seven studies fulfilled our inclusion criteria, 15 for the baby-level and 12 for the unit-level analysis. Study heterogeneity was high, with suboptimal overall quality of reporting assessed by the STROBE-NI statement (44.8% of items adequately reported). In 1984 colonized neonates, 157 (7.9%) developed GN-BSI compared with 85 of 3583 (2.4%) non-colonized neonates. Considerable heterogeneity was observed across studies. Four factors were included in the meta-regression model: gross domestic product (GDP), pathogen, outbreak, and frequency of screening. There was no statistically significant impact of these factors on GN colonization and GN-BSI in baby-level. We were unable to perform the multivariate meta-regression because of insufficient reported data for unit-level.

CONCLUSIONS

Study limitations include the small number and the high heterogeneity of the included studies. While this report shows a correlation between colonization and BSI risk, these data currently do not support routine screening for GNB. Analysis of large cohorts of colonized neonates with clinical outcomes is still needed to define the major determinants leading from colonization to infection.

Hand hygiene compliance in a universal gloving setting

BACKGROUND

The use of gloves for every patient contact (ie, universal gloving) has been suggested as an infection prevention adjunct and alternative to contact precautions. However, gloves may carry organisms unless they are changed properly. In addition, hand hygiene is required before donning and after removing gloves, and there are scarce data regarding glove changing and hand hygiene in a universal gloving setting.

METHODS

This nonrandomized observational before-after study evaluated the effect of education and feedback regarding hand hygiene. Compliance with hand hygiene and glove use was directly observed in a universal gloving setting at a 10-bed intensive care unit in a Japanese tertiary care university teaching hospital.

RESULTS

A total of 6,050 hand hygiene opportunities were identified. Overall, hand hygiene compliance steadily increased from study period 1 (16.1%) to period 5 (56.8%), although there were indication-specific differences in the baseline compliance, the degree of improvement, and the reasons for noncompliance. There were decreases in the compliance with universal gloving and the incidence of methicillin-resistant Staphylococcus aureus.

CONCLUSION

It is difficult to properly perform glove use and hand hygiene in a universal gloving setting, given its complexity. Direct observation with specific feedback and education may be effective in improving compliance.

Current Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus in Elderly French People: Troublesome Clones on the Horizon

Objective: In 2015, we conducted at 44 healthcare facilities (HCFs) and 21 nursing homes (NHs) a 3-month bloodstream infection (BSI) survey, and a 1-day prevalence study to determine the rate of carriage of methicillin-resistant Staphylococcus aureus (MRSA) in 891 patients and 470 residents. We investigated the molecular characteristics of the BSI-associated and colonizing MRSA isolates, and assessed cross-transmission using double-locus sequence typing and pulsed-field gel electrophoresis protocol.

Results: The incidence of MRSA-BSI was 0.040/1000 patient-days (19 cases). The prevalence of MRSA carriage was 4.2% in patients (n = 39) and 8.7% in residents (n = 41) (p < 0.001). BSI-associated and colonizing isolates were similar: none were PVL-positive; 86.9% belonged to clonal complexes 5 and 8; 93.9% were resistant to fluoroquinolones. The qacA/B gene was carried by 15.8% of the BSI-associated isolates [3/3 BSI cases in intensive care units (ICUs)], and 7.7% of the colonizing isolates in HCFs. Probable resident-to-resident transmission was identified in four NHs.

Conclusion: Despite generally reassuring results, we identified two key concerns. First, a worryingly high prevalence of the qacA/B gene in MRSA isolates. Antisepsis measures being crucial to prevent healthcare-associated infections, our findings raise questions about the potential risk associated with chlorhexidine use in qacA/B⁺ MRSA carriers, particularly in ICUs. Second, NHs are a weak link in MRSA control. MRSA spread was not controlled at several NHs; because of their frequent contact with the community, conditions are favorable for these NHs to serve as reservoirs of USA300 clone for local HCFs.

Impact of active screening for methicillin-resistant Staphylococcus aureus (MRSA) and decolonization on MRSA infections, mortality and medical cost: a quasi-experimental study in surgical intensive care unit

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) is a leading pathogen of healthcare-associated infections in intensive care units (ICUs). Prior studies have shown that decolonization of MRSA carriers is an effective method to reduce MRSA infections in ICU patients. However, there is currently a lack of data on its effect on mortality and medical cost.

METHODS

Using a quasi-experimental, interrupted time-series design with re-introduction of intervention, we evaluated the impact of active screening and decolonization on MRSA infections, mortality and medical costs in the surgical ICU of a university hospital in Taiwan. Regression models were used to adjust for effects of confounding variables.

RESULTS

MRSA infection rate decreased from 3.58 (baseline) to 0.42‰ (intervention period) (P <0.05), re-surged to 2.21‰ (interruption period) and decreased to 0.18‰ (re-introduction of intervention period) (P <0.05). Patients admitted to the surgical ICU during the intervention periods had a lower in-hospital mortality (13.5% (155 out of 1,147) versus 16.6% (203 out of 1,226), P = 0.038). After adjusting for effects of confounding variables, the active screening and decolonization program was independently associated with a decrease in in-hospital MRSA infections (adjusted odds ratio: 0.3; 95% CI: 0.1 to 0.8) and 90-day mortality (adjusted hazard ratio: 0.8; 95% CI: 0.7 to 0.99). Cost analysis showed that $22 medical costs can be saved for every $1 spent on the intervention.

CONCLUSIONS

Active screening for MRSA and decolonization in ICU settings is associated with a decrease in MRSA infections, mortality and medical cost.

Economic features of antibiotic resistance: the case of methicillin-resistant Staphylococcus aureus

This paper analyses and updates the economic information regarding methicillin-resistant Staphylococcus aureus (MRSA), including information that has been previously reviewed by other authors, and new information, for the purpose of facilitating health management and clinical decisions. The analysed articles reveal great disparity in the economic burden on MRSA patients; this is mainly due to the diversity of the designs of the studies, as well as the variability of the patients and the differences in health care systems. Regarding prophylactic strategies, the studies do not provide conclusive results that could unambiguously orientate health management. The studies addressing treatments noted that linezolid seems to be a cost-effective treatment for MRSA, mostly because it is associated with a shorter length of stay (LOS) in hospital. However, important variables such as antimicrobial susceptibility, infection type and resistance emergence should be included in these analyses before a conclusion is reached regarding which treatment is the best (most efficient). The reviewed studies found that rapid MRSA detection, using molecular techniques, is an efficient technique to control MRSA. As a general conclusion, the management of MRSA infections implicates important economic costs for hospitals, as they result in higher direct costs and longer LOS than those related to methicillin-susceptible S. aureus (MSSA) patients or MRSA-free patients; there is wide variability in those increased costs, depending on different variables. Moreover, the research reveals a lack of studies on other related topics, such as the economic implications of changes in MRSA epidemiology (community patients and lineages associated with farm animals).

Surveillance cultures in healthcare-associated pneumonia: sense or nonsense?

PURPOSE OF REVIEW

This review explores the usefulness of surveillance cultures in healthcare-associated pneumonia (HCAP).

RECENT FINDINGS

The definition of HCAP is controversial. Causative micro-organisms of HCAP resemble those found in hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP). Some types of surveillance cultures have proven useful in hospitalized patients. Whereas numerous studies have investigated the role of surveillance cultures in VAP, one may wonder whether surveillance culture implementation should belong in HCAP management guidelines.

SUMMARY

Studies exploring the usefulness of obtaining surveillance cultures in VAP are numerous, but are mostly retrospective, observational and/or quasi-experimental in nature. Surveillance cultures may be useful for antibiotic guidance, but positive predictive value and specificity of surveillance cultures are low, obviously negatively impacting on cost effectiveness, especially in the large population at risk for HCAP. On the other hand, multidrug-resistance is increasing and surveillance cultures for methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci in ICU-admitted patients appeared useful and cost-effective. Furthermore, surveillance cultures for the presence of multidrug-resistant Gram-negative bacilli might be useful for antibiotic guidance. Currently, neither community-acquired pneumonia, HCAP, HAP nor VAP guidelines incorporate surveillance cultures. In the future, surveillance cultures in populations at risk for HCAP may be able to differentiate HCAP from other kinds of pneumonia and authorize its reason for existence.

Hospital Staff Perceptions of a Legislative Mandate for Methicillin-Resistant Staphylococcus aureus Screening

Objective.

In August 2007, Illinois passed legislation mandating methicillin-resistant Staphylococcus aureus (MRSA) admission screening for intensive care unit patients. We assessed hospital staff perceptions of the implementation of this law.

Design.

Mixed-methods evaluation using structured focus groups and questionnaires.

Setting.

Eight Chicago-area hospitals.

Participants.

Three strata of staff (leadership, midlevel, and frontline) at each hospital.

Methods.

All participants completed a questionnaire and participated in a focus group. Focus group transcripts were thematically coded and analyzed. The proportion of staff agreeing with statements about MRSA and the legislation was compared across staff types.

Results.

Overall, 126 hospital staff participated in 23 focus groups. Fifty-six percent of participants agreed that the legislation had a positive effect at their facility; frontline staff were more likely to agree than midlevel and leadership staff (P < .01). Perceived benefits of the legislation included increased awareness of MRSA among staff and better knowledge of the epidemiology of MRSA colonization. Perceived negative consequences included the psychosocial effect of screening and contact precautions on patients and increased use of resources. Most participants (59%) would choose to continue the activities associated with the legislation but advised facilities in states considering similar legislation to educate staff and patients about MRSA screening and to draft clear implementation plans.

Conclusion.

Staff from Chicago-area hospitals perceived that mandatory MRSA screening legislation resulted in some benefits but highlighted implementation challenges. States considering similar initiatives might minimize these challenges by optimizing messaging to patients and healthcare staff, drafting implementation plans, and developing program evaluation strategies.

Cost-Effectiveness Analysis of Active Surveillance Screening for Methicillin-Resistant Staphylococcus aureus in an Academic Hospital Setting

Objective.

To evaluate the cost-effectiveness of 3 alternative active screening strategies for methicillin-resistant Staphylococcus aureus (MRSA): universal surveillance screening for all hospital admissions, targeted surveillance screening for intensive care unit admissions, and no surveillance screening.

Design.

Cost-effectiveness analysis using decision modeling.

Methods.

Cost-effectiveness was evaluated from the perspective of an 800-bed academic hospital with 40,000 annual admissions over the time horizon of a hospitalization. All input probabilities, costs, and outcome data were obtained through a comprehensive literature review. Effectiveness outcome was MRSA healthcare-associated infections (HAIs). One-way and probabilistic sensitivity analyses were conducted.

Results.

In the base case, targeted surveillance screening was a dominant strategy (ie, was associated with lower costs and resulted in better outcomes) for preventing MRSA HAL Universal surveillance screening was associated with an incremental cost-effectiveness ratio of $14,955 per MRSA HAL In one-way sensitivity analysis, targeted surveillance screening was a dominant strategy across most parameter ranges. Probabilistic sensitivity analysis also demonstrated that targeted surveillance screening was the most cost-effective strategy when willingness to pay to prevent a case of MRSA HAI was less than $71,300.

Conclusion.

Targeted active surveillance screening for MRSA is the most cost-effective screening strategy in an academic hospital setting. Additional studies that are based on actual hospital data are needed to validate this model. However, the model supports current recommendations to use active surveillance to detect MRSA.

Control of Healthcare-AssociatedStaphylococcus aureusSurvey of Practices in North Carolina Hospitals

Although patients colonized or infected with methicillin-resistantStaphylococcus aureushave been placed on contact isolation for many years, more recent guidelines recommend enhanced control measures, such as routine active surveillance. We report here the results of a survey of 70 hospitals in North Carolina with regard to current management issues surrounding methicillin-resistantS. aureus.

Surveillance cultures in intensive care units: a nationwide survey on current practice providing future perspectives

PURPOSE

To explore the extent of surveillance culture (SC) implementation underlying motives for obtaining SC and decision making based on the results.

MATERIALS AND METHODS

A questionnaire was distributed to Heads of Department (HODs) and microbiologists within all intensive care departments in the Netherlands.

RESULTS

Response was provided by 75 (79%) of 95 HODs and 38 (64%) of 59 laboratories allied to an intensive care unit (ICU). Surveillance cultures were routinely obtained according to 55 (73%) of 75 HODs and 33 (87%) of 38 microbiologists. Surveillance cultures were obtained in more than 80% of higher-level ICUs and in 58% of lower-level ICUs (P < .05). Surveillance cultures were obtained twice weekly (88%) and sampled from trachea (87%), pharynx (74%), and rectum (68%). Thirty (58%) of 52 HODs obtained SC to optimize individual patient treatment. On suspicion of infection from an unknown source, microorganisms identified by SC were targeted according to 87%. One third of HODs targeted microorganisms identified by SC in the case of an infection not at the location where the SC was obtained. This was significantly more often than microbiologists in case of no infection (P = .02) or infection of unknown origin (P < .05).

CONCLUSIONS

Surveillance culture implementation is common in Dutch ICUs to optimize individual patients' treatment. Consensus is lacking on how to deal with SC results when the focus of infection is not at the sampled site.

The prevalence and significance of methicillin-resistant Staphylococcus aureus colonization at admission in the general ICU Setting: a meta-analysis of published studies

OBJECTIVE

To estimate the prevalence and significance of nasal methicillin-resistant Staphylococcus aureus colonization in the ICU and its predictive value for development of methicillin-resistant S. aureus infection.

DATA SOURCES

MEDLINE and EMBASE and reference lists of all eligible articles.

STUDY SELECTION

Studies providing raw data on nasal methicillin-resistant S. aureus colonization at ICU admission, published up to February 2013. Analyses were restricted in the general ICU setting. Medical, surgical, and interdisciplinary ICUs were eligible. ICU studies referring solely on highly specialized ICUs populations and reports on methicillin-resistant S. aureus outbreaks were excluded.

DATA EXTRACTION

Two authors independently assessed study eligibility and extrapolated data in a blinded fashion. The two outcomes of interest were the prevalence estimate of methicillin-resistant S. aureus nasal colonization at admission in the ICU and the sensitivity/specificity of colonization in predicting methicillin-resistant S. aureus-associated infections.

DATA SYNTHESIS

Meta-analysis, using a random-effect model, and meta-regression were performed. Pooled data extracted from 63,740 evaluable ICU patients provided an estimated prevalence of methicillin-resistant S. aureus nasal colonization at admission of 7.0% (95% CI, 5.8-8.3). Prevalence was higher for North American studies (8.9%; 95% CI, 7.1-10.7) and for patients screened using polymerase chain reaction (14.0%; 95% CI, 9.6-19). A significant per year increase in methicillin-resistant S. aureus colonization was also noted. In 17,738 evaluable patients, methicillin-resistant S. aureus infections (4.1%; 95% CI, 2.0-6.8) developed in 589 patients. The relative risk for colonized patients was 8.33 (95% CI, 3.61-19.20). Methicillin-resistant S. aureus nasal carriage had a high specificity (0.96; 95% CI, 0.90-0.98) but low sensitivity (0.32; 95% CI, 0.20-0.48) to predict methicillin-resistant S. aureus-associated infections, with corresponding positive and negative predictive values at 0.25 (95% CI, 0.11-0.39) and 0.97 (95% CI, 0.83-1.00), respectively.

CONCLUSIONS

Among ICU patients, 5.8-8.3% of patients are colonized by methicillin-resistant S. aureus at admission, with a significant upward trend. Methicillin-resistant S. aureus colonization is associated with a more than eight-fold increase in the risk of associated infections during ICU stay, and methicillin-resistant S. aureus infection develops in one fourth of patients who are colonized with methicillin-resistant S. aureus at admission to the ICU.

Utility of surveillance cultures for antimicrobial resistant organisms in infants transferred to the neonatal intensive care unit

BACKGROUND

Infections with antibiotic resistant organisms (AROs) are an important source of morbidity and mortality among infants hospitalized in the neonatal intensive care unit (NICU). To identify potential reservoirs of AROs in the NICU, active surveillance strategies have been adopted by many NICUs to detect infants colonized with AROs. However, the yield, risks, benefits and costs of different strategies have not been fully evaluated.

METHODS

We conducted a retrospective study in 2 level III NICUs from 2004 to 2010 to investigate the yield of surveillance cultures obtained from infants transferred to the NICU from other hospitals. Cultures were processed for methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci and antibiotic-resistant gram-negative rods. Risk factors, selected outcomes and laboratory costs associated with ARO colonization were assessed.

RESULTS

Among 1751 infants studied, the rate of colonization for methicillin-resistant S. aureus, vancomycin-resistant enterococci and antibiotic-resistant gram-negative rods was 3%, 1.7% and 1%, respectively. Age at transfer was the strongest predictor of ARO colonization; infants transferred at ≥ 7 days of life had 5.8 increased odds of ARO colonization compared with infants <7 days of age. Transferred infants who were colonized had similar rates of mortality, ARO infection and duration of hospitalization compared with those who were not colonized. The laboratory cost of surveillance cultures during the study period was $58,425.

CONCLUSIONS

The rate of colonization with AROs at transfer was low particularly in infants <7 days old. Future studies should examine the safety of targeted surveillance strategies focused on older infants.

Predictors of methicillin-resistant Staphylococcus aureus colonization at hospital admission

BACKGROUND

The best strategy for active surveillance for methicillin-resistant Staphylococcus aureus (MRSA) remains unclear. We attempted to identify a risk factor score to predict MRSA colonization at hospital admission.

METHODS

Data on 9 variables reported as risk factors for MRSA colonization were analyzed, and a risk factor score to predict MRSA colonization was generated using multivariable logistic regression and receiver operating characteristic curve analyses. This risk score was then prospectively validated.

RESULTS

Four risk factors (nursing home residence, diabetes, hospitalization in the past year, and chronic skin condition/infection) were significantly associated with MRSA colonization (c-statistic = 0.846). A cut-off score of 8 or greater would result in screening 20% of admissions and would detect 71% of MRSA-colonized patients. In the prospective validation study, a cut-off score of 8 or greater required screening 21% of admissions and detected 54% of MRSA. Nursing home residence was the best predictor of MRSA colonization.

CONCLUSION

A similar risk factor-based screening strategy could be used to predict MRSA colonization in other institutions. Our data support routine screening of nursing home patients at hospital admission.

Admission Screening of Methicillin-Resistant Staphylococcus aureus with Rapid Molecular Detection in Intensive Care Unit: A Three-Year Single-Centre Experience in Hong Kong

Background. The admission screening of methicillin-resistant Staphylococcus aureus (MRSA) by rapid molecular assay is considered to be an effective method in reducing the transmission of MRSA in intensive care unit (ICU). Method. The admission screening on patients from ICU once on their admissions by BD GeneOhm MRSA assay has been introduced to Prince of Wales Hospital, Hong Kong, since 2008. The assay was performed on weekdays and reported on the day of testing. Patients pending for results were under standard precautions until the negative screening results were notified, while contact precautions were implemented for MRSA-positive patients. In this study, we compared the MRSA transmission rate in molecular screening periods (2008 to 2010) with the historical culture periods (2006 to 2007) as control. Results. A total of 4679 samples were tested; the average carriage rate of MRSA on admission was 4.45%. By comparing with the historical culture periods, the mean incidence ICU-acquired MRSA infection was reduced from 3.67 to 1.73 per 1000 patient bed days. Conclusion. The implementation of admission screening of MRSA with molecular method in intensive care unit could reduce the MRSA transmission, especially in the area with high MRSA prevalence situation in Hong Kong.

Successful reduction of hospital-acquired methicillin-resistant Staphylococcus aureus in a urology ward: a 10-year study

BACKGROUND

To eradicate hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) using a stepwise infection control strategy that includes an avoidance of antimicrobial prophylaxis (AMP) based on surgical wound classification and an improvement in operative procedures in gasless single-port urologic surgery.

METHODS

The study was conducted at an 801-bed university hospital. Since 2001, in the urology ward, we have introduced the stepwise infection control strategy. In 2007, surveillance cultures for MRSA in all urological patients were commenced. The annual incidence of MRSA was calculated as a total number of newly identified MRSA cases per 1,000 patient days. Trend analysis was performed using a Poisson regression.

RESULTS

Over the study period, 139,866 patients, including 10,201 urology patients, were admitted to our hospital. Of these patients, 3,719 patients, including 134 ones in the urology ward, were diagnosed with MRSA throughout the entire hospital. Although the incidence of MRSA increased throughout the entire hospital (p = 0.002), it decreased significantly in the urology ward (p < 0.0001). Of the 134 cases, 45 (33.6%) were classified as "imported," and 89 (66.4%) as "acquired." In the urology ward, the incidence of acquired MRSA decreased significantly over time (p < 0.0001), whereas the incidence of imported MRSA did not change over time (p = 0.66). A significant decrease (p < 0.0001) in the incidence of clinically significant MRSA infection over time was found.

CONCLUSIONS

Stepwise infection control strategy that includes a reduction or avoidance of antimicrobial prophylaxis in minimally invasive surgery can contribute to a reduction in hospital-acquired MRSA.

TRIAL REGISTRATION

Current study has approved by the institutional ethical review board (No.1141).

Surveillance and management of multidrug-resistant microorganisms

Multidrug-resistant organisms are an established and growing worldwide public health problem and few therapeutic options remain available. The traditional antimicrobials (glycopeptides) for multidrug-resistant Gram-positive infections are declining in efficacy. New drugs that are presently available are linezolid, daptomicin and tigecycline, which have well-defined indications for severe infections, and talavancin, which is under Phase III trial for hospital-acquired pneumonia. Unfortunately the therapies available for multidrug-resistant Gram-negatives, including carbapenem-resistant Pseudomonas aeruginosa, Acinetobacter baumannii and Enterobacteriaceae, are limited to only colistin and tigecycline. Both of these drugs are still not registered for severe infections, such as hospital acquired pneumonia. Consequently, as confirmed by scientific evidence, a multidisciplinary approach is needed. Surveillance, infection control procedures, isolation and antimicrobial stewardship should be implemented to reduce multidrug-resistant organism diffusion.

Methicillin-resistant Staphylococcus aureus risk profiling: who are we missing?

Background

Targeted screening of patients at high risk for methicillin-resistant Staphylococcus aureus (MRSA) carriage is an important component of MRSA control programs, which rely on prediction tools to identify those high-risk patients. Most previous risk studies reported a substantial rate of patients who are eligible for screening, but failed to be enrolled. The characteristics of these missed patients are seldom described. We aimed to determine the rate and characteristics of patients who were missed by a MRSA screening programme at our institution to see how the failure to include these patients might impact the accuracy of clinical prediction tools.

Findings

From March-June 2010 all patients admitted to 13 internal medicine wards at the University of Geneva Hospital (HUG) were prospectively screened for MRSA carriage. Of 1968 patients admitted to the ward, 267 patients (13.6%) failed to undergo appropriate MRSA screening. Forty-one (2.4%) screened patients were MRSA carriers at admission. On multivariate regression, patients who were missed by screening were more likely to be aged < 50 years (OR 2.4 [1.4-3.9]), transferred to internal medicine from another ward in the hospital (OR 2.8 [1.1-7.1]), and have a history of malignancy (OR 3.2[2.1-5.1]). There was no significant difference in the rate of previous MRSA carriage between screened and unscreened patients.

Conclusions

Our findings highlight the potential bias that “missed” patients may introduce into MRSA risk scores. Reporting on the proportions and characteristics of missed patients is essential for accurate interpretation of MRSA prediction tools.

Molecular and epidemiologic predictors of Staphylococcus aureus colonization site in a population with limited nosocomial exposure

BACKGROUND

The anterior naris has been considered the most consistent location of asymptomatic Staphylococcus aureus colonization. However, recent studies have shown that a substantial number of individuals, ranging from 7% to 32% of colonized individuals, are exclusive throat carriers. Most of these studies have been carried out in a health care setting, limiting their generalizability to nonhospitalized populations.

METHODS

To evaluate anatomic carriage sites of S aureus in individuals outside of a health care setting, we combined the results of 2 cross-sectional studies conducted in Iowa.

RESULTS

S aureus was carried by 103 of 340 individuals (30.3%), including 31 (30.1%) exclusive throat carriers, 44 (42.7%) exclusive nose carriers, and 28 (27.2%) colonized in both sites. Nonwhite race (adjusted odds ratio [OR], 4.91; 95% confidence interval [CI], 1.26-18.3) and younger age (≥30 years: OR, 0.23; 95% CI, 0.10-0.54) were associated with increased odds of exclusive throat carriage, whereas nonwhite race (OR, 5.14; 95% CI, 1.62-16.3) and spring or summer sampling season (OR, 2.62; 95% CI, 1.32-5.18) were associated with increased odds of exclusive nasal carriage.

CONCLUSIONS

These findings suggest that including a throat swab in addition to a nasal swab could play an important role in the success of surveillance programs, particularly among younger adults.

Reduction of methicillin-resistant Staphylococcus aureus infection among veterans in Atlanta

OBJECTIVE

Describe local changes in the incidence of community-onset and hospital-onset methicillin-resistant Staphylococcus aureus (MRSA) infection and evaluate the impact of MRSA active surveillance on hospital-onset infection.

DESIGN

Observational study using prospectively collected data.

SETTING

Atlanta Veterans Affairs Medical Center (AVAMC).

PATIENTS

All patients seen at the AVAMC over an 8-year period with clinically and microbiologically proven MRSA infection.

METHODS

All clinical cultures positive for MRSA were prospectively identified, and corresponding clinical data were reviewed. MRSA infections were classified into standard clinical and epidemiologic categories. The Veterans Health Administration implemented the MRSA directive in October 2007, which required active surveillance cultures in acute care settings.

RESULTS

The incidence of community-onset MRSA infection peaked in 2007 at 5.45 MRSA infections per 1,000 veterans and decreased to 3.14 infections per 1,000 veterans in 2011 ([Formula: see text] for trend). Clinical and epidemiologic categories of MRSA infections did not change throughout the study period. The prevalence of nasal MRSA colonization among veterans admitted to AVAMC decreased from 15.8% in 2007 to 11.2% in 2011 ([Formula: see text] for trend). The rate of intensive care unit (ICU)-related hospital-onset MRSA infection decreased from October 2005 through March 2007, before the MRSA directive. Rates of ICU-related hospital-onset MRSA infection remained stable after the implementation of active surveillance cultures. No change was observed in rates of non-ICU-related hospital-onset MRSA infection.

CONCLUSIONS

Our study of the AVAMC population over an 8-year period shows a consistent trend of reduction in the incidence of MRSA infection in both the community and healthcare settings. The etiology of this reduction is most likely multifactorial.

Meticillin-resistant Staphylococcus aureus screening in Wales: survey of practices in adult critical care units in Welsh hospitals

Screening for meticillin-resistant Staphylococcus aureus (MRSA) carriage in critical care units remains a controversial issue. This cross-sectional study reviewed the MRSA screening policies in adult critical care units in Welsh hospitals. Data were collected by structured questionnaires. The study showed a degree of variability in practice from universal screening to no screening at all. It is recommended that local MRSA policies should be reviewed, bearing in mind the local prevalence of colonization and infection; and compliance with basic infection control strategies should not only be directed at MRSA infection, but also at other healthcare-associated infections.

Costs of healthcare- and community-associated infections with antimicrobial-resistant versus antimicrobial-susceptible organisms

OBJECTIVE

We compared differences in the hospital charges, length of hospital stay, and mortality between patients with healthcare- and community-associated bloodstream infections, urinary tract infections, and pneumonia due to antimicrobial-resistant versus -susceptible bacterial strains.

METHODS

A retrospective analysis of an electronic database compiled from laboratory, pharmacy, surgery, financial, and patient location and device utilization sources was undertaken on 5699 inpatients who developed healthcare- or community-associated infections between 2006 and 2008 from 4 hospitals (1 community, 1 pediatric, 2 tertiary/quaternary care) in Manhattan. The main outcome measures were hospital charges, length of stay, and mortality among patients with antimicrobial-resistant and -susceptible infections caused by Staphylococcus aureus, Enterococcus faecium, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii.

RESULTS

Controlling for multiple confounders using linear regression and nearest neighbor matching based on propensity score estimates, resistant healthcare- and community-associated infections, when compared with susceptible strains of the same organism, were associated with significantly higher charges ($15,626; confidence interval [CI], $4339-$26,913 and $25,573; CI, $9331-$41,816, respectively) and longer hospital stays for community-associated infections (3.3; CI, 1.5-5.4). Patients with resistant healthcare-associated infections also had a significantly higher death rate (0.04; CI, 0.01-0.08).

CONCLUSIONS

With careful matching of patients infected with the same organism, antimicrobial resistance was associated with higher charges, length of stay, and death rates. The difference in estimates after accounting for censoring for death highlight divergent social and hospital incentives in reducing patient risk for antimicrobial resistant infections.

Ten-year decrease of acquired methicillin-resistant Staphylococcus aureus (MRSA) bacteremia at a single institution: the result of a multifaceted program combining cross-transmission prevention and antimicrobial stewardship

Background

In France, the proportion of MRSA has been over 25% since 2000. Prevention of hospital-acquired (HA) MRSA spread is based on isolation precautions and antibiotic stewardship. At our institution, before 2000, the Infection Disease and the Infection Control teams had failed to reduce HA-MRSA rates.

Objectives and methods

We implemented a multifaceted hospital-wide prevention program and measured the effects on HA-MRSA colonization and bacteremia rates between 2000 and 2009. From 2000 to 2003, active screening and decontamination of ICU patients, hospital wide alcohol based hand rubs (ABHR) use, control of specific classes of antibiotics, compliance audits, and feed-backs to the care providers were successively implemented. The efficacy of the program was assessed by HA-MRSA colonized and bacteremic patient rates per 1000 patient-days in patients hospitalized for more than twenty-four hours.

Results

Compliance with the isolation practices increased between 2000 and 2009. Consumption of ABHR increased from 6.8 L to 27.5 L per 1000 patient-days. The use of antibiotic Defined Daily Doses (DDD) per 1000 patient-days decreased by 31%. HA-MRSA colonization decreased by 84% from 1.09 to 0.17 per 1000 patient-days and HA-MRSA bacteremia by 93%, from 0.15 to 0.01 per 1000 patient-days (p < 10⁻⁷ for each rate).

Conclusions

In an area highly endemic for MRSA, a multifaceted prevention program allows for sustainable reduction in HA-MRSA bacteremia rates.

Multicenter evaluation of the LightCycler MRSA advanced test, the Xpert MRSA Assay, and MRSASelect directly plated culture with simulated workflow comparison for the detection of methicillin-resistant Staphylococcus aureus in nasal swabs

Rapid detection of nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) followed by appropriate infection control procedures reduces MRSA infection and transmission. We compared the performance and workflow of two Food and Drug Administration-approved nucleic acid amplification assays, the LightCycler MRSA Advanced Test and the Xpert MRSA test, with those of directly plated culture (MRSASelect) using 1202 nasal swabs collected at three U.S. sites. The sensitivity of the LightCycler test (95.2%; 95% CI, 89.1% to 98.4%) and Xpert assay (99%; 95% CI, 94.8% to 100%) did not differ compared with that of culture; the specificity of the two assays was identical (95.5%; 95% CI, 94.1% to 96.7%) compared with culture. However, sequencing performed on 71 samples with discordant results among the three methods confirmed the presence of MRSA in 40% of samples that were positive by both molecular methods but negative by culture. Workflow analysis from all sites including batch runs revealed average hands-on sample preparation times of 1.40, 2.35, and 1.44 minutes per sample for the LightCycler, Xpert, and MRSASelect methods, respectively. Discrete event simulation analysis of workflow efficiencies revealed that the LightCycler test used less hands-on time for the assay when greater than eight batched samples were run. The high sensitivity and specificity, low hands-on time, and efficiency gains using batching capabilities make the LightCycler test suitable for rapid batch screening of MRSA colonization.

Certification in infection control matters: Impact of infection control department characteristics and policies on rates of multidrug-resistant infections

BACKGROUND

The study objective is to describe infection control policies aimed at multidrug-resistant organisms (MDRO) in California hospitals and assess the relationship among these policies, structural characteristics, and rates of methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) bloodstream infections and Clostridium difficile infections.

METHODS

Data on infection control policies, structural characteristics, and MDRO rates were collected through a 2010 survey of California infection control departments. Bivariate and multivariable Poisson and negative binomial regressions were conducted.

RESULTS

One hundred eighty hospitals provided data (response rate, 54%). Targeted MRSA screening upon admission was reported by the majority of hospitals (87%). The majority of hospitals implemented contact precautions for confirmed MDRO and C difficile patients; presumptive isolation/contact precautions for patients with pending screens were less frequently implemented. Few infection control policies were associated with lower MDRO rates. Hospitals with a certified infection control director had significantly lower rates of MRSA bloodstream infections (P < .05).

CONCLUSION

Although most California hospitals are involved in activities to decrease MDRO, there is variation in specific activities utilized with the most focus placed on MRSA. This study highlights the importance of certification and its significant impact on infection rates. Additional research is needed to confirm these findings.

Clinical effectiveness and cost benefit of universal versus targeted methicillin-resistant Staphylococcus aureus screening upon admission in hospitals

OBJECTIVE

To conduct an exploratory study to evaluate the clinical effectiveness and cost benefit of universal versus targeted screening for methicillin-resistant Staphylococcus aureus (MRSA) to prevent hospital-acquired MRSA infections.

DESIGN

Prospective, interventional study, using a case-control design, difference-in-differences, and cost-benefit analyses.

SETTING

Two community hospitals in Wisconsin.

PATIENTS

Consecutive sample of 15,049 adult admissions from April 2009 to July 2010.

INTERVENTIONS

MRSA surveillance performed by polymerase chain reaction (PCR) on samples collected from all adult patients (aged over 18 years) within 30 days before or upon an admission to the hospital. During a 9-month baseline period, targeted screening was conducted at both hospitals. During the 5-month intervention period, all patients admitted to the intervention hospital were screened for MRSA. Infection control measures were consistent at both hospitals.

RESULTS

Universal screening was associated with an increase in admission screening of 43.58 percentage points (P< .01), an increase in MRSA detection of 2.95 percentage points (P< .01), and a small, nonsignificant decline in hospital-acquired MRSA infections of 0.12 percentage points (P< .01). The benefit-to-cost ratio was 0.50, indicating that for every dollar spent on universal versus targeted screening, only $0.50 is recovered in avoided costs of hospital-acquired MRSA infection.

CONCLUSION

Compared with targeted screening, universal screening increased the rate of detection of MRSA upon hospital admission but did not significantly reduce the rate of hospital-acquired MRSA infection. Universal screening was associated with higher costs of care and was not cost beneficial.

Trends in Staphylococcus aureus bacteraemia and impacts of infection control practices including universal MRSA admission screening in a hospital in Scotland, 2006-2010: retrospective cohort study and time-series intervention analysis

OBJECTIVES

To describe secular trends in Staphylococcus aureus bacteraemia (SAB) and to assess the impacts of infection control practices, including universal methicillin-resistant Staphylococcus aureus (MRSA) admission screening on associated clinical burdens.

DESIGN

Retrospective cohort study and multivariate time-series analysis linking microbiology, patient management and health intelligence databases.

SETTING

Teaching hospital in North East Scotland.

PARTICIPANTS

All patients admitted to Aberdeen Royal Infirmary between 1 January 2006 and 31 December 2010: n=420 452 admissions and 1 430 052 acute occupied bed days (AOBDs).

INTERVENTION

Universal admission screening programme for MRSA (August 2008) incorporating isolation and decolonisation. PRIMARY AND SECONDARY MEASURES: Hospital-wide prevalence density, hospital-associated incidence density and death within 30 days of MRSA or methicillin-sensitive Staphylococcus aureus (MSSA) bacteraemia.

RESULTS

Between 2006 and 2010, prevalence density of all SAB declined by 41%, from 0.73 to 0.50 cases/1000 AOBDs (p=0.002 for trend), and 30-day mortality from 26% to 14% (p=0.013). Significant reductions were observed in MRSA bacteraemia only. Overnight admissions screened for MRSA rose from 43% during selective screening to >90% within 4 months of universal screening. In multivariate time-series analysis (R(2) 0.45 to 0.68), universal screening was associated with a 19% reduction in prevalence density of MRSA bacteraemia (-0.035, 95% CI -0.049 to -0.021/1000 AOBDs; p<0.001), a 29% fall in hospital-associated incidence density (-0.029, 95% CI -0.035 to -0.023/1000 AOBDs; p<0.001) and a 46% reduction in 30-day mortality (-15.6, 95% CI -24.1% to -7.1%; p<0.001). Positive associations with fluoroquinolone and cephalosporin use suggested that antibiotic stewardship reduced prevalence density of MRSA bacteraemia by 0.027 (95% CI 0.015 to 0.039)/1000 AOBDs. Rates of MSSA bacteraemia were not significantly affected by screening or antibiotic use.

CONCLUSIONS

Declining clinical burdens from SAB were attributable to reductions in MRSA infections. Universal admission screening and antibiotic stewardship were associated with decreases in MRSA bacteraemia and associated early mortality. Control of MSSA bacteraemia remains a priority.

Screening and control of methicillin-resistant Staphylococcus aureus in 186 intensive care units: different situations and individual solutions

Introduction

Controversy exists about the benefit of screening for prevention of methicillin-resistant Staphylococcus aureus (MRSA) in intensive care units (ICUs) and recent studies have shown conflicting results. The aim of this observational study was to describe and evaluate the association between MRSA incidence densities (IDs) and screening and control measures in ICUs participating in the German Nosocomial Infection Surveillance System.

Methods

The surveillance module for multidrug-resistant bacteria collects data on MRSA cases in ICUs with the aim to provide a national reference and a tool for evaluation of infection control management. The median IDs of MRSA cases per 1000 patient-days (pd) with the interquartile range (IQR) were calculated from the pooled data of 186 ICUs and correlated with parameters derived from a detailed questionnaire regarding ICU structure, microbiological diagnostics and MRSA screening and control measures. The association between questionnaire results and MRSA cases was evaluated by generalized linear regression models.

Results

One hundred eighty-six ICUs submitted data on MRSA cases for 2007 and 2008 and completed the questionnaire. During the period of analysis, 4935 MRSA cases occurred in these ICUs; of these, 3928 (79.6%) were imported and 1007 MRSA cases (20.4%) were ICU-acquired. Median MRSA IDs were 3.23 (IQR 1.24-5.73), 2.24 (IQR 0.63-4.30) and 0.64 (IQR 0.17-1.39) per 1000 pd for all cases, imported and ICU-acquired MRSA cases, respectively. MRSA IDs as well as implemented MRSA screening and control measures varied widely between ICUs. ICUs performing universal admission screening had significantly higher MRSA IDs than ICUs performing targeted or no screening. Separate regression models for ICUs with different screening strategies included the incidence of imported MRSA cases, the type of ICU, and the length of stay in independent association with the number of ICU-acquired MRSA cases.

Conclusions

The analysis shows that MRSA IDs and structural parameters differ considerably between ICUs. In response, ICUs have combined screening and control measures in many ways to achieve various individual solutions. The incidence of imported MRSA cases might be helpful for consideration in the planning of MRSA control programmes.

Risk factors for positive admission surveillance cultures for methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci in a neurocritical care unit

OBJECTIVE

Hospitals are under increasing pressure to perform active surveillance cultures for methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. This study aimed to identify patients at low and high risk for positive admission surveillance cultures for methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus in a neurocritical care unit using readily ascertainable historical factors.

DESIGN

Before/after study with nested case/control study.

SETTING

Neurocritical care unit of an academic hospital.

PATIENTS

During the intervention period (July 2007 to June 2008), after implementation of an admission surveillance culture screening program for methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus, 2,059 patients were admitted to the neurocritical care unit for a total of 5,957 patient days.

INTERVENTIONS

Cases had positive methicillin-resistant Staphylococcus aureus or vancomycin-resistant Enterococcus admission surveillance cultures within 48 hrs of hospital admission. Controls had negative cultures.

MEASUREMENTS AND MAIN RESULTS

Admission surveillance cultures grew methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus in 35 of 823 (4.3%) and 19 of 766 (2.5%) patients, respectively. Factors significantly associated with both methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus colonization were intravenous antibiotics and hospitalization in the past year, immunocompromised health status, intravenous drug use, long-term hemodialysis, and known prior carrier status. Transfer from an outside hospital and residence in a long-term care facility in the past year were associated with vancomycin-resistant Enterococcus colonization. Classification and regression tree analysis was used to identify variables that best predicted positive methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus surveillance cultures. A classification and regression tree model with six of these variables yielded an overall cross-validated predictive accuracy of 87.12% to detect methicillin-resistant Staphylococcus aureus colonization. For vancomycin-resistant Enterococcus, a four-variable classification and regression tree model (intravenous antibiotics, hospitalization and long-term patient care in the past year, and not being "admitted same day of procedure") optimized the predictive accuracy (94.91%). There were no cases of vancomycin-resistant Enterococcus colonization in patients admitted same day of procedure.

CONCLUSIONS

Colonization with methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus in neurocritical care patients can be predicted with a high predictive accuracy using decision trees that include four to six readily attainable risk factors. In our setting, in the absence of these risk factors and in patients admitted from home for neurosurgical procedures, routine admission surveillance cultures to the intensive care unit may not be cost-effective.

Challenges of applying the SHEA/HICPAC metrics for multidrug-resistant organisms to a real-world setting

OBJECTIVE

To test in a real-world setting the recommendations for measuring infection with multidrug-resistant organisms (MDRO) from the Society for Healthcare Epidemiology of America (SHEA) and the Centers for Disease Control and Prevention's Healthcare Infection Control Practices Advisory Committee (HICPAC).

METHODS

Using data from 3 hospital settings within a healthcare network, we applied the SHEA/HICPAC recommendations to measure methicillin-resistant Staphylococcus aureus (MRSA) infection and colonization. Data were obtained from the hospitals' electronic surveillance system and were supplemented by manual medical record review as necessary. Additionally, we tested (1) different definitions for nosocomial incidence, (2) the effect of excluding patients not at risk from the denominator for hospital-onset incidence, and (3) the appropriate time period to use when including or excluding patients with a prior history of MRSA infection or colonization from nosocomial rates. Negative binomial regression models were used to test for differences between rate definitions. A rating scale was created for each metric, assessing the extent to which manual or electronic data elements were required.

RESULTS

There was no statistically significant difference between using 72 hours or 3 calendar days as the cutoff to define hospital-onset incidence. Excluding patients not at risk from the denominator when calculating hospital-onset incidence led to statistically significant increases in rates. When excluding patients with a prior history of MRSA infection or colonization from nosocomial incidence rates, rates were similar regardless of whether we looked at 1, 2, or 3 years' worth of prior data.

CONCLUSIONS

The SHEA/HICPAC MDRO metrics are useful but can be challenging to implement. We include in our description of the data sources and processes required to calculate these metrics information that may simplify the process for institutions.

Cost and health outcomes associated with mandatory MRSA screening in a special care nursery

PURPOSE

Methicillin-resistant Staphylococcus aureus (MRSA) rates continue to rise and pose a threat to patient health and limited hospital resources. In 2007, Illinois passed a legislative mandate requiring active surveillance cultures to screen for MRSA in all patients in hospital intensive care units. However, professional guidelines do not support mandated universal surveillance cultures, and funding to cover screening costs was not included. The purpose of the study was to examine the costs (personnel, screening test, and supply) associated with the mandated universal MRSA screening and to examine the infant health-related outcomes and costs associated with implementing MRSA screening in a special care nursery.

SUBJECTS

Personnel-54 observations of staff members in a community-based hospital in a large midwestern city. Infants-445 infants admitted from January 2008 through January 2009.

METHODS

Time and motion (related to screening activities by registered nurses) based on observations of staff during MRSA screenings, and abstraction of health and cost data from the infant log, infant medical records, and financial reports.

MAIN OUTCOME MEASURES

Costs (laboratory tests, personnel, and supplies) and infant health outcomes.

DESIGN

A prospective descriptive study.

RESULTS

Mandatory screening leads to increased costs, problems related to false-positives, and unintended consequences (eg, decision whether to treat non-MRSA organisms identified on screening cultures, possibility of legal implications, adverse family psychosocial affects, and questionable validity of the polymerase chain reaction test). The average total costs of laboratory, supply, and personnel were $15,270.12 ($34.31 per infant or $19.58 per screen).

CONCLUSIONS

A screening test for MRSA with a high positive predictive value, low cost, and quick turnaround (<24 hours) is greatly needed for neonates. Our findings indicate that mandatory universal MRSA screening is not warranted when the incidence of MRSA is low. Just as health care providers require evidence when determining best practices, legislators should require adequate evidence before passing policy.

Review of a three-year meticillin-resistant Staphylococcus aureus screening programme

The Newcastle upon Tyne Hospitals NHS Foundation Trust (NuTH) implemented a seek and destroy (S&D) programme in 2006 to minimise meticillin-resistant Staphylococcus aureus (MRSA) colonisation and/or infection of patients. Using a phased introduction, all patient specialties were included in the scheme by September 2008, well in advance of the mandatory Department of Health, England (DoH) requirement for all patients to be screened. NuTH screens nose, throat and perineum samples from approximately 15,000 patients per month using a chromogenic culture method, showing a mean MRSA prevalence of 2.4%. Provision of seven-day microbiology and infection control services ensured that the turnaround time to prescribing decolonisation therapy was <24 h. Analysis of 168,073 results identified the necessity for inclusion of all three screening sites to maximise recovery of MRSA. Appraisal of the S&D policy demonstrated that MRSA detection rates did not increase despite an exponential increase in workload owing to mandatory inclusion of low risk areas in the screening programme. Review of data during a typical one-month period indicated that only seven day-case patients would not have been identified as MRSA carriers using our targeted S&D approach compared with the DoH universal screening. Detection of these additional patients incurred total laboratory costs of £20,000 and generated a further 4200 associated negative screens in one month alone. Our study indicates that a screening strategy based upon clinical risk is more pragmatic and more cost-effective than the universal programme currently required in England.