Methicillin-resistant Staphylococcus aureus prevention strategies in the ICU: a clinical decision analysis*

Impact of Povidone Application to Nares in Addition to Chlorhexidine Bath in Critically Ill Patients on Nosocomial Bacteremia and Central Line Blood Stream Infection

Nosocomial Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia results in a significant increase in morbidity and mortality in hospitalized patients. We aimed to analyze the impact of applying 10% povidone iodine (PI) twice daily to both nares in addition to chlorhexidine (CHG) bathing on nosocomial (MRSA) bacteremia in critically ill patients. A quality improvement study was completed with pre and post-design. The study period was from January 2018 until February 2020 and February 2021 and June 2021. The control period (from January 2018 to May 2019) consisted of CHG bathing alone, and in the intervention period, we added 10% PI to the nares of critically ill patients. Our primary outcome is rates of nosocomial MRSA bacteremia, and our secondary outcome is central line associated blood stream infection (CLABSI) and potential cost savings. There were no significant differences in rates of MRSA bacteremia in critically ill patients. Nosocomial MRSA bacteremia was significantly lower during the intervention period on medical/surgical areas (MSA). CLABSIs were significantly lower during the intervention period in critically ill patients. There were no Staphylococcus aureus CLABSIs in critical care area (CCA)during the intervention period. The intervention showed potential significant cost savings. The application of 10% povidone iodine twice a day in addition to CHG bathing resulted in a significant decrease in CLABSIs in critically ill patients and a reduction in nosocomial MRSA in the non-intervention areas. Further trials are needed to tease out individual patients who will benefit from the intervention.

Modelling the potential increase in eligible participants in clinical trials with inclusion of community intensive care unit patients in Alberta, Canada: a decision tree analysis

PURPOSE

Critical care research in Canada is conducted primarily in academically affiliated intensive care units (ICUs) with established research infrastructure. Efforts are made to engage community hospital ICUs in research, although the impacts of their inclusion in clinical research have never been explicitly quantified. We therefore sought to determine the number of additional eligible patients that could be recruited into critical care trials and the change in time to study completion if community ICUs were included in clinical research.

METHODS

We conducted a decision tree analysis using 2018 Alberta Health Services data. Patient demographics and clinical characteristics for all ICU patients were compared against eligibility criteria from ten landmark, randomized, multicentre critical care trials. Individual patients from academic and community ICUs were assessed for eligibility in each of the ten studies, and decision tree analysis models were built based on prior inclusion and exclusion criteria from those trials.

RESULTS

The number of potentially eligible patients for the ten trials ranged from 2,082 to 10,157. Potentially eligible participants from community ICUs accounted for 40.0% of total potentially eligible participants. The recruitment of community ICU patients in trials would have increased potential enrolment by an average of 64.0%. The inclusion of community ICU patients was predicted to decrease time to trial completion by a mean of 14 months (43% reduction).

CONCLUSION

Inclusion of community ICU patients in critical care research trials has the potential to substantially increase enrolment and decrease time to trial completion.

Nasal decolonization: What antimicrobials and antiseptics are most effective before surgery and in the ICU

BACKGROUND

Staphylococcus aureus colonization is a key risk factor for S. aureus infections in surgical patients and in hospitalized patients. Many studies have assessed various decolonization agents, protocols, and settings. This review summarizes key findings about nasal decolonization for 2 different patient populations: patients undergoing surgery and patients hospitalized in intensive care units.

METHODS

We reviewed major studies related to decolonization of patients colonized with S. aureus and who were either undergoing surgical procedures or were hospitalized in intensive care units. We focused on recent studies, particularly randomized controlled trials and robust quasi-experimental trials. We also reviewed select non-randomized trials when more rigorous trials were limited.

DISCUSSION/CONCLUSIONS

Mupirocin is the best-studied agent for decolonization. Its use reduces the risk of surgical site infection following orthopedic surgery (strongest data) and cardiac surgery. Mupirocin decolonization also reduces the incidence of S. aureus clinical cultures in the intensive care unit. Povidone-iodine is less well-studied. Current data suggest that it decreases the risk of surgical site infections after orthopedic surgical procedures. In contrast, povidone-iodine is less effective than mupirocin for reducing the incidence of S aureus clinical cultures in the intensive care unit. Both mupirocin and povidone-iodine have important limitations, highlighting the need for future decolonization research.

Economic evaluations of interventions to prevent and control health-care-associated infections: a systematic review

Almost 9 million health-care-associated infections have been estimated to occur each year in European hospitals and long-term care facilities, and these lead to an increase in morbidity, mortality, bed occupancy, and duration of hospital stay. The aim of this systematic review was to review the cost-effectiveness of interventions to limit the spread of health-care-associated infections), framed by WHO infection prevention and control core components. The Embase, National Health Service Economic Evaluation Database, Database of Abstracts of Reviews of Effects, Health Technology Assessment, Cinahl, Scopus, Pediatric Economic Database Evaluation, and Global Index Medicus databases, plus grey literature were searched for studies between Jan 1, 2009, and Aug 10, 2022. Studies were included if they reported interventions including hand hygiene, personal protective equipment, national-level or facility-level infection prevention and control programmes, education and training programmes, environmental cleaning, and surveillance. The British Medical Journal checklist was used to assess the quality of economic evaluations. 67 studies were included in the review. 25 studies evaluated methicillin-resistant Staphylococcus aureus outcomes. 31 studies evaluated screening strategies. The assessed studies that met the minimum quality criteria consisted of economic models. There was some evidence that hand hygiene, environmental cleaning, surveillance, and multimodal interventions were cost-effective. There were few or no studies investigating education and training, personal protective equipment or monitoring, and evaluation of interventions. This Review provides a map of cost-effectiveness data, so that policy makers and researchers can identify the relevant data and then assess the quality and generalisability for their setting.

Economic Analysis of Infectious Disease Consultation for Staphylococcus aureus Bacteremia Among Hospitalized Patients

IMPORTANCE

Staphylococcus aureus bacteremia is associated with a significant burden of mortality, morbidity, and health care costs. Infectious disease consultation may be associated with reduced mortality and bacteremia recurrence rates.

OBJECTIVE

To evaluate the cost-effectiveness of infectious disease consultation for Staphylococcus aureus bacteremia.

DESIGN, SETTING, AND PARTICIPANTS

In this economic evaluation, a decision-analytic model was constructed comparing infectious disease consult with no consult. The population was adult hospital inpatients with Staphylococcus aureus bacteremia diagnosed with at least 1 positive blood culture. Cost-effectiveness was calculated as deaths averted and incremental cost-effectiveness ratios. Uncertainty was addressed by plotting cost-effectiveness planes and acceptability curves for various willingness-to-pay thresholds. Costs and outcomes were calculated for a time horizon of 6 months. The analysis was performed from a societal perspective and included studies that had been published by January 2022.

INTERVENTIONS

Patients received or did not receive formal bedside consultation after positive blood cultures for Staphylococcus aureus bacteremia.

MAIN OUTCOMES AND MEASURES

The main outcomes were incremental difference in effectiveness (survival probabilities), incremental difference in cost (US dollars) and incremental cost-effectiveness ratios (US dollars/deaths averted).

RESULTS

This model included 1708 patients who received consultation and 1273 patients who did not. In the base-case analysis, the cost associated with the infectious disease consult strategy was $54 137.4 and the associated probability of survival was 0.77. For the no consult strategy, the cost was $57 051.2, and the probability of survival was 0.72. The incremental difference in cost between strategies was $2913.8, and the incremental difference in effectiveness was 0.05. Overall, consultation was associated with estimated savings of $55 613.4/death averted (incremental cost-effectiveness ratio, -$55613.4/death averted). In the probabilistic analysis, at a willingness-to-pay threshold of $50 000, infectious disease consult was cost-effective compared with no consult in 54% of 10 000 simulations. In cost-effectiveness acceptability curves, the consult strategy was cost-effective in 58% to 73%) of simulations compared with no consult for a willingness-to-pay threshold ranging from $0 to $150 000.

CONCLUSIONS AND RELEVANCE

These findings suggest that infectious disease consultation may be a cost-effective strategy for management of Staphylococcus aureus bacteremia and that it is associated with health care cost-savings.

The Cost-effectiveness of Cefazolin Compared With Antistaphylococcal Penicillins for the Treatment of Methicillin-Sensitive Staphylococcus aureus Bacteremia

Background

Methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia is associated with significant morbidity, mortality, and hospitalization costs. Cefazolin and antistaphylococcal penicillins (ASPs), such as nafcillin, are the preferred treatments for MSSA bacteremia. The aim of this study was to compare the cost-effectiveness of each approach.

Methods

We constructed a decision-analytic model comparing the use of cefazolin with ASPs for the treatment of MSSA bacteremia. Cost-effectiveness was determined by calculating deaths averted and incremental cost-effectiveness ratios (ICERs). Uncertainty was addressed by plotting cost-effectiveness planes and acceptability curves for various willingness-to-pay thresholds.

Results

In the base-case analysis, the cost associated with the cefazolin strategy was $38 863.1, and the associated probability of survival was 0.91. For the ASP strategy, the cost was $48 578.8, and the probability of survival was 0.81. The incremental difference in cost between the 2 strategies was $9715.7, with hospital length of stay being the main driver of cost, and the incremental difference in effectiveness was 0.10. Overall, cefazolin results in savings of $97 156.8 per death averted (ICER, $–97 156.8/death averted). In the probabilistic analysis, at a willingness-to-pay of $50 000, cefazolin had a 68% chance of being cost-effective compared with ASPs. In cost-effectiveness acceptability curves, the cefazolin strategy was cost-effective in 73.5%–81.8% of simulations compared with ASP for a willingness-to-pay ranging up to $50 000.

Conclusions

The use of cefazolin is a cost-effective strategy for the treatment of MSSA bacteremia and, when clinically appropriate, this strategy results in considerable health care cost-savings.

Impact of multicenter unified enhanced environmental cleaning and disinfection measures on nosocomial infections among patients in intensive care units

Objectives

Most Chinese hospitals have customized environmental cleaning policies and systems, with limited data availability based on evidence-based medicine. This study investigated the relationship between multidrug-resistant organism (MDRO) colonization in intensive care unit (ICU) patients and ICU surface bacterial contamination status.

Methods

This cross-sectional study comprised MDRO screening in ICU patients using bacterial cultivation by chromogenic medium; samples were collected before (control group) and after implementation of enhanced cleaning (cleaning group). Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to identify and analyze microorganisms; the relationships of MDRO colonization with infection and environmental bacteria were analyzed.

Results

In total, 196 patients were enrolled in the study (104 and 92 in control and cleaning groups, respectively); 1042 MDROs were subjected to screening before and after cleaning. After cleaning, the rate of MDRO detection on surfaces of frequently touched objects in ICUs decreased from 31.77% to 13.32%. There were fewer MDRO homologues in the cleaning group than in the control group. Moreover, the cleaning group had a shorter ICU stay and significantly lower mortality rate.

Conclusions

Enhanced environmental cleaning and disinfection could reduce environmental MDRO accumulation and suppress MDRO colonization in ICUs, thereby reducing nosocomial infections and improving adverse patient outcomes.

Health-Related Quality-of-Life and Cost Utility Analyses in Critical Care: A Systematic Review

OBJECTIVES

Cost utility analyses compare the costs and health outcome of interventions, with a denominator of quality-adjusted life year, a generic health utility measure combining both quality and quantity of life. Cost utility analyses are difficult to compare when methods are not standardized. It is unclear how cost utility analyses are measured/reported in critical care and what methodologic challenges cost utility analyses pose in this setting. This may lead to differences precluding cost utility analyses comparisons. Therefore, we performed a systematic review of cost utility analyses conducted in critical care. Our objectives were to understand: 1) methodologic characteristics, 2) how health-related quality-of-life was measured/reported, and 3) what costs were reported/measured.

DESIGN

Systematic review.

DATA SOURCES

We systematically searched for cost utility analyses in critical care in MEDLINE, Embase, American College of Physicians Journal Club, CENTRAL, Evidence-Based Medicine Reviews' selected subset of archived versions of UK National Health Service Economic Evaluation Database, Database of Abstracts of Reviews of Effects, and American Economic Association electronic databases from inception to April 30, 2020.

SETTING

Adult ICUs.

PATIENTS

Adult critically ill patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 8,926 citations, 80 cost utility analyse studies were eligible. The time horizon most commonly reported was lifetime (59%). For health utility reporting, health-related quality-of-life was infrequently measured (29% reported), with only 5% of studies reporting baseline health-related quality-of-life. Indirect utility measures (generic, preference-based health utility measurement tools) were reported in 85% of studies (majority Euro-quality-of-life-5 Domains, 52%). Methods of estimating health-related quality-of-life were seldom used when the patient was incapacitated: imputation (19%), assigning fixed utilities for incapacitation (19%), and surrogates reporting on behalf of incapacitated patients (5%). For cost utility reporting transparency, separate incremental costs and quality-adjusted life years were both reported in only 76% of studies. Disaggregated quality-adjusted life years (reporting separate health utility and life years) were described in only 34% of studies.

CONCLUSIONS

We identified deficiencies which warrant recommendations (standardized measurement/reporting of resource use/unit costs/health-related quality-of-life/methodological preferences) for improved design, conduct, and reporting of future cost utility analyses in critical care.

The cost-effectiveness of empirical antibiotic treatments for high-risk febrile neutropenic patients: A decision analytic model

PURPOSE

Febrile neutropenia has a significant clinical and economic impact on cancer patients. This study evaluates the cost-effectiveness of different current empiric antibiotic treatments.

METHODS

A decision analytic model was constructed to compare the use of cefepime, meropenem, imipenem/cilastatin, and piperacillin/tazobactam for treatment of high-risk patients. The analysis was performed from the perspective of U.S.-based hospitals. The time horizon was defined to be a single febrile neutropenia episode. Cost-effectiveness was determined by calculating costs and deaths averted. Cost-effectiveness acceptability curves for various willingness-to-pay thresholds (WTP), were used to address the uncertainty in cost-effectiveness.

RESULTS

The base-case analysis results showed that treatments were equally effective but differed mainly in their cost. In increasing order: treatment with imipenem/cilastatin cost $52,647, cefepime $57,270, piperacillin/tazobactam $57,277, and meropenem $63,778. In the probabilistic analysis, mean costs were $52,554 (CI: $52,242-$52,866) for imipenem/cilastatin, $57,272 (CI: $56,951-$57,593) for cefepime, $57,294 (CI: $56,978-$57,611) for piperacillin/tazobactam, and $63,690 (CI: $63,370-$64,009) for meropenem. Furthermore, with a WTP set at $0 to $50,000, imipenem/cilastatin was cost-effective in 66.2% to 66.3% of simulations compared to all other high-risk options.

DISCUSSION

Imipenem/cilastatin is a cost-effective strategy and results in considerable health care cost-savings at various WTP thresholds. Cost-effectiveness analyses can be used to differentiate the treatments of febrile neutropenia in high-risk patients.

MRSA colonization and acquisition in the burn unit: A systematic review and meta-analysis

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most commonly encountered bacteria in the burn unit. In order to investigate the magnitude of this challenge, we assessed the prevalence of MRSA colonization on admission and the incidence of MRSA acquisition within burn units.

METHODS

We searched PubMed and EMBASE for studies reporting MRSA colonization among patients admitted in burn units.

RESULTS

We identified 16 articles that fulfilled our inclusion criteria and found an overall pooled prevalence of MRSA colonization upon the first 72 h of admission (colonization on admission) to the burn unit of 4.1% (95% CI: 2.7%-5.7%). MRSA acquisition in studies without a decolonization protocol was 21.2% (95% CI: 13.2%-30.5%) with a statistically significant downward trend over the years. Studies that implemented a decolonization protocol yielded a MRSA acquisition incidence rate of 4.5% (95% CI: 0.9%-10.6%). MRSA acquisition was higher among patients that have had inhalation injury (OR 3.96, 95% CI: 2.51-6.23), flame burns (OR 1.85, 95% CI: 1.25-2.73), or ICU admission (OR 3.12, 95% CI: 2.18-4.47).

CONCLUSION

Our study yielded that among burn victims, MRSA colonization prevalence on admission is not negligible and the risk of becoming MRSA colonized during hospitalization is higher when no decolonization protocols are implemented. Flame burns, admission to ICU, and inhalation injury were found to be associated with MRSA acquisition.

Population-level mathematical modeling of antimicrobial resistance: a systematic review

BACKGROUND

Mathematical transmission models are increasingly used to guide public health interventions for infectious diseases, particularly in the context of emerging pathogens; however, the contribution of modeling to the growing issue of antimicrobial resistance (AMR) remains unclear. Here, we systematically evaluate publications on population-level transmission models of AMR over a recent period (2006-2016) to gauge the state of research and identify gaps warranting further work.

METHODS

We performed a systematic literature search of relevant databases to identify transmission studies of AMR in viral, bacterial, and parasitic disease systems. We analyzed the temporal, geographic, and subject matter trends, described the predominant medical and behavioral interventions studied, and identified central findings relating to key pathogens.

RESULTS

We identified 273 modeling studies; the majority of which (> 70%) focused on 5 infectious diseases (human immunodeficiency virus (HIV), influenza virus, Plasmodium falciparum (malaria), Mycobacterium tuberculosis (TB), and methicillin-resistant Staphylococcus aureus (MRSA)). AMR studies of influenza and nosocomial pathogens were mainly set in industrialized nations, while HIV, TB, and malaria studies were heavily skewed towards developing countries. The majority of articles focused on AMR exclusively in humans (89%), either in community (58%) or healthcare (27%) settings. Model systems were largely compartmental (76%) and deterministic (66%). Only 43% of models were calibrated against epidemiological data, and few were validated against out-of-sample datasets (14%). The interventions considered were primarily the impact of different drug regimens, hygiene and infection control measures, screening, and diagnostics, while few studies addressed de novo resistance, vaccination strategies, economic, or behavioral changes to reduce antibiotic use in humans and animals.

CONCLUSIONS

The AMR modeling literature concentrates on disease systems where resistance has been long-established, while few studies pro-actively address recent rise in resistance in new pathogens or explore upstream strategies to reduce overall antibiotic consumption. Notable gaps include research on emerging resistance in Enterobacteriaceae and Neisseria gonorrhoeae; AMR transmission at the animal-human interface, particularly in agricultural and veterinary settings; transmission between hospitals and the community; the role of environmental factors in AMR transmission; and the potential of vaccines to combat AMR.

The Cost-Effectiveness of Corticosteroids for the Treatment of Community-Acquired Pneumonia

BACKGROUND

The use of corticosteroids as adjunct treatment for community-acquired pneumonia (CAP) is associated with potential clinical benefits. The aim of this study was to evaluate the cost-effectiveness of this approach.

METHODS

We constructed a decision-analytic model comparing the use of corticosteroids + antibiotics with that of placebo + antibiotics for the treatment of CAP. Cost-effectiveness was determined by calculating deaths averted and incremental cost-effectiveness ratios. Uncertainty was addressed by plotting cost-effectiveness planes and acceptability curves for various willingness-to-pay thresholds.

RESULTS

In the base-case analysis, corticosteroids + antibiotics resulted in savings of $142,795 per death averted. In the probabilistic analysis, at a willingness to pay of $50,000, corticosteroids + antibiotics had a 86.4% chance of being cost-effective compared with placebo + antibiotics. In cost-effectiveness acceptability curves, the corticosteroids + antibiotics strategy was cost-effective in 87.6% to 94.3% of simulations compared with the placebo + antibiotics strategy for a willingness to pay ranging from $0 to $50,000. In patients with severe CAP (Pneumonia Severity Index classes IV/V) the corticosteroids + antibiotics strategy resulted in savings of $70,587 and had a 82.6% chance of being cost-effective compared with the placebo + antibiotics strategy.

CONCLUSIONS

The use of corticosteroids + antibiotics is a cost-effective strategy and results in considerable health care cost-savings, especially among patients with severe CAP (Pneumonia Severity Index classes IV/V).

The Cost-Effectiveness of Rapid Diagnostic Testing for the Diagnosis of Bloodstream Infections with or without Antimicrobial Stewardship

Bloodstream infections are associated with considerable morbidity and health care costs. Molecular rapid diagnostic tests (mRDTs) are a promising complement to conventional laboratory methods for the diagnosis of bloodstream infections and may reduce the time to effective therapy among patients with bloodstream infections. The concurrent implementation of antimicrobial stewardship programs (ASPs) may reinforce these benefits. The aim of this study was to evaluate the cost-effectivenesses of competing strategies for the diagnosis of bloodstream infection alone or combined with an ASP. To this effect, we constructed a decision-analytic model comparing 12 strategies for the diagnosis of bloodstream infection. The main arms compared the use of mRDT and conventional laboratory methods with or without an ASP. The baseline strategy used as the standard was the use of conventional laboratory methods without an ASP, and our decision-analytic model assessed the cost-effectivenesses of 5 principal strategies: mRDT (with and without an ASP), mRDT with an ASP, mRDT without an ASP, conventional laboratory methods with an ASP, and conventional laboratory methods without an ASP. Furthermore, based on the availability of data in the literature, we assessed the cost-effectivenesses of 7 mRDT subcategories, as follows: PCR with an ASP, matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) analysis with an ASP, peptide nucleic acid fluorescent in situ hybridization (PNA-FISH) with an ASP, a blood culture nanotechnology microarray system for Gram-negative bacteria (BC-GP) with an ASP, a blood culture nanotechnology microarray system for Gram-positive bacteria (BC-GN) with an ASP, PCR without an ASP, and PNA-FISH without an ASP. Our patient population consisted of adult inpatients in U.S. hospitals with suspected bloodstream infection. The time horizon of the model was the projected life expectancy of the patients. In a base-case analysis, cost-effectiveness was determined by calculating the numbers of bloodstream infection deaths averted, the numbers of quality-adjusted life years gained, and incremental cost-effectiveness ratios (ICERs). In a probabilistic analysis, uncertainty was addressed by plotting cost-effectiveness planes and acceptability curves for various willingness-to-pay thresholds. In the base-case analysis, MALDI-TOF analysis with an ASP was the most cost-effective strategy, resulting in savings of $29,205 per quality-adjusted life year and preventing 1 death per 14 patients with suspected bloodstream infection tested compared to conventional laboratory methods without an ASP (ICER, -$29,205/quality-adjusted life year). BC-GN with an ASP (ICER, -$23,587/quality-adjusted life year), PCR with an ASP (ICER, -$19,833/quality-adjusted life year), and PCR without an ASP (ICER, -$21,039/quality-adjusted life year) were other cost-effective options. In the probabilistic analysis, mRDT was dominant and cost-effective in 85.1% of simulations. Importantly, mRDT with an ASP had an 80.0% chance of being cost-effective, while mRDT without an ASP had only a 41.1% chance. In conclusion, our findings suggest that mRDTs are cost-effective for the diagnosis of patients with suspected bloodstream infection and can reduce health care expenditures. Notably, the combination of mRDT and an ASP can result in substantial health care savings.

Low incidence of multidrug-resistant bacteria and nosocomial infection due to a preventive multimodal nosocomial infection control: a 10-year single centre prospective cohort study in neurocritical care

Background

Nosocomial infection (NI) control is an important issue in neurocritical care due to secondary brain damage and the increased morbidity and mortality of primary acute neurocritical care patients. The primary aim of this study was to determine incidence of nosocomial infections and multidrug-resistant bacteria and seek predictors of nosocomial infections in a preventive multimodal nosocomial infection protocol in the neurointensive care unit (NICU). The secondary aim focused on their impact on stay, mortality and cost in the NICU.

Methods

A10-year, single-centre prospective observational cohort study was conducted on 3464 acute brain disease patients. There were 198 (5.7%) patients with nosocomial infection (wound 2.1%, respiratory 1.8%, urinary 1.0%, bloodstream 0.7% and other 0.1%); 67 (1.9%) with Extended spectrum beta-lactamase (ESBL); 52 (1.5%) with Methicillin-resistant Staphylococcus aureus (MRSA), nobody with Vancomycin-resistant enterococcus (VRE). The protocol included hygienic, epidemiological status and antibiotic policy. Univariate and multivarite logistic regression analysis was used for identifying predictors of nosocomial infection.

Results

From 198 NI patients, 153 had onset of NI during their NICU stay (4.4%; wound 1.0%, respiratory 1.7%, urinary 0.9%, bloodstream 0.6%, other 0.1%); ESBL in 31 (0.9%) patients, MRSA in 30 (0.9%) patients. Antibiotics in prophylaxis was given to 63.0% patients (59.2 % for operations), in therapy to 9.7% patients. Predictors of NI in multivariate logistic regression analysis were airways (OR 2.69, 95% CI 1.81-3.99, p<0.001), urine catheters (OR 2.77, 95% CI 1.00-7.70, p=0.050), NICU stay (OR 1.14, 95% CI 1.12-1.16, p<0.001), transfusions (OR 1.79, 95% CI 1.07-2.97, p=0.025) antibiotic prophylaxis (OR 0.50, 95% CI 0.34-0.74, p<0.001), wound complications (OR 2.30, 95% CI 1.33-3.97, p=0.003). NI patients had longer stay (p<0.001), higher mortality (p<0.001) and higher TISS sums (p<0.001) in the NICU.

Conclusions

The presented preventive multimodal nosocomial infection control management was efficient; it gave low rates of nosocomial infections (4.2%) and multidrug-resistant bacteria (ESBL 0.9%, MRSA 0.9% and no VRE). Strong predictors for onset of nosocomial infection were accesses such as airways and urine catheters, NICU stay, antibiotic prophylaxis, wound complications and transfusion. This study confirmed nosocomial infection is associated with worse outcome, higher cost and longer NICU stay.

Diversity, evolution and medical applications of insect antimicrobial peptides

Antimicrobial peptides (AMPs) are short proteins with antimicrobial activity. A large portion of known AMPs originate from insects, and the number and diversity of these molecules in different species varies considerably. Insect AMPs represent a potential source of alternative antibiotics to address the limitation of current antibiotics, which has been caused by the emergence and spread of multidrug-resistant pathogens. To get more insight into AMPs, we investigated the diversity and evolution of insect AMPs by mapping their phylogenetic distribution, allowing us to predict the evolutionary origins of selected AMP families and to identify evolutionarily conserved and taxon-specific families. Furthermore, we highlight the use of the nematode Caenorhabditis elegans as a whole-animal model in high-throughput screening methods to identify AMPs with efficacy against human pathogens, including Acinetobacter baumanii and methicillin-resistant Staphylococcus aureus. We also discuss the potential medical applications of AMPs, including their use as alternatives for conventional antibiotics in ectopic therapies, their combined use with antibiotics to restore the susceptibility of multidrug-resistant pathogens, and their use as templates for the rational design of peptidomimetic drugs that overcome the disadvantages of therapeutic peptides.

The article is part of the themed issue ‘Evolutionary ecology of arthropod antimicrobial peptides’.

Preoperative Staphylococcus Aureus Screening and Targeted Decolonization in Cardiac Surgery

BACKGROUND

We assessed the impact of preoperative Staphylococcus aureus screening and targeted decolonization on the incidence of postoperative methicillin-resistant S aureus (MRSA) colonization, intensive care unit MRSA transmission, and surgical site infections in cardiac surgery patients.

METHODS

We reviewed medical records for all adult patients during two periods: preintervention (January 2007 to April 2010) and intervention (January 2011 to December 2014). In the intervention period, we performed nasal screening for methicillin-sensitive S aureus and MRSA using polymerase chain reaction within 30 days of the operation. Colonized patients received intranasal mupirocin twice daily and chlorhexidine baths daily for 5 days; patients colonized with MRSA also received prophylactic vancomycin plus cefazolin with contact isolation precautions. Nasal surveillance for MRSA was performed on intensive care unit admission and weekly thereafter. Multivariable logistic regression models were constructed to determine risk factors for postoperative MRSA colonization, and surgical site infections and the impact of our screening program was assessed in these models. Poisson regression was used to assess MRSA transmission.

RESULTS

Comparing 2,826 preintervention and 4,038 intervention patients, cases differed in age, diabetes mellitus, preoperative infection, preoperative length of stay, and bypass time (all p ≤ 0.03). Intervention patients had risk-adjusted reductions in MRSA colonization (odds ratio 0.53, 95% confidence interval [CI]: 0.37 to 0.76, p < 0.001), transmission (incidence rate ratio 0.29, 95% CI: 0.13 to 0.65, p = 0.002), and surgical site infections (odds ratio 0.58, 95% CI: 0.40 to 0.86, p = 0.007). Increased duration of preoperative decolonization therapy was associated with decreased postoperative MRSA colonization (odds ratio 0.73, 95% CI: 0.53 to 1.00, p = 0.05).

CONCLUSIONS

Preoperative S aureus screening with targeted decolonization was associated with reduced MRSA colonization, transmission, and surgical site infections. Duration of preoperative therapy correlated with decreased frequency of postoperative MRSA colonization.

Staphylococcus aureus in the Intensive Care Unit: Are These Golden Grapes Ripe for a New Approach?

Staphylococcus aureus is the leading cause of infection in the setting of critical illness and injury. This pathogen causes life-threatening infection in otherwise healthy individuals and also complicates the clinical course of patients requiring intensive care as a result of their primary medical or surgical disease processes. S. aureus infection in the intensive care unit (ICU) most commonly manifests as sepsis, ventilator-associated pneumonia, and infection of surgical sites and indwelling medical devices. With the epidemic spread of methicillin-resistant S. aureus, many cases of staphylococcal infection in the ICU are now classified as drug resistant, prompting hospital-based screening for methicillin-resistant S. aureus and implementation of both isolation practices and decolonization strategies in ICU patients. The genetic adaptability of S. aureus, heterogeneity of disease presentation, clinical course, and outcome between individual S. aureus-infected ICU patients remains enigmatic, suggesting a need to define disease classification subtypes that inform disease progression and therapy. We propose that S. aureus infection in the ICU now presents a unique opportunity for individualized risk stratification coupled with the investigation of novel approaches to mitigate disease. Given our increasing knowledge of the molecular pathogenesis of S. aureus disease, we suggest that the application of molecular pathological epidemiology to S. aureus infection can usher in a new era of highly focused personalized therapy that may be particularly beneficial in the setting of critical illness and injury.

The Effect of Universal Decolonization With Screening in Critical Care to Reduce MRSA Across an Entire Hospital

OBJECTIVE To describe the effect of universal methicillin-resistant Staphylococcus aureus (MRSA) decolonization therapy in a large intensive care unit (ICU) on the rates of MRSA cases and acquisitions in a UK hospital. DESIGN Descriptive study. SETTING University Hospitals Birmingham (UHB) NHS Foundation Trust is a tertiary referral teaching hospital in Birmingham, United Kingdom, that provides clinical services to nearly 1 million patients every year. METHODS A break-point time series analysis and kernel regression models were used to detect significant changes in the cumulative monthly numbers of MRSA bacteremia cases and acquisitions from April 2013 to August 2016 across the UHB system. RESULTS Prior to 2014, all ICU patients at UHB received universal MRSA decolonization therapy. In August 2014, UHB discontinued the use of universal decolonization due to published reports in the United Kingdom detailing the limited usefulness and cost-effectiveness of such an intervention. Break-point time series analysis of MRSA acquisition and bacteremia data indicated that break points were associated with the discontinuation and subsequent reintroduction of universal decolonization. Kernel regression models indicated a significant increase (P<.001) in MRSA acquisitions and bacteremia cases across UHB during the period without universal decolonization. CONCLUSION We suggest that routine decolonization for MRSA in a large ICU setting is an effective strategy to reduce the spread and incidence of MRSA across the whole hospital. Infect Control Hosp Epidemiol 2017;38:430-435.

Decolonization in Prevention of Health Care-Associated Infections

Colonization with health care-associated pathogens such as Staphylococcus aureus, enterococci, Gram-negative organisms, and Clostridium difficile is associated with increased risk of infection. Decolonization is an evidence-based intervention that can be used to prevent health care-associated infections (HAIs). This review evaluates agents used for nasal topical decolonization, topical (e.g., skin) decolonization, oral decolonization, and selective digestive or oropharyngeal decontamination. Although the majority of studies performed to date have focused on S. aureus decolonization, there is increasing interest in how to apply decolonization strategies to reduce infections due to Gram-negative organisms, especially those that are multidrug resistant. Nasal topical decolonization agents reviewed include mupirocin, bacitracin, retapamulin, povidone-iodine, alcohol-based nasal antiseptic, tea tree oil, photodynamic therapy, omiganan pentahydrochloride, and lysostaphin. Mupirocin is still the gold standard agent for S. aureus nasal decolonization, but there is concern about mupirocin resistance, and alternative agents are needed. Of the other nasal decolonization agents, large clinical trials are still needed to evaluate the effectiveness of retapamulin, povidone-iodine, alcohol-based nasal antiseptic, tea tree oil, omiganan pentahydrochloride, and lysostaphin. Given inferior outcomes and increased risk of allergic dermatitis, the use of bacitracin-containing compounds cannot be recommended as a decolonization strategy. Topical decolonization agents reviewed included chlorhexidine gluconate (CHG), hexachlorophane, povidone-iodine, triclosan, and sodium hypochlorite. Of these, CHG is the skin decolonization agent that has the strongest evidence base, and sodium hypochlorite can also be recommended. CHG is associated with prevention of infections due to Gram-positive and Gram-negative organisms as well as Candida. Conversely, triclosan use is discouraged, and topical decolonization with hexachlorophane and povidone-iodine cannot be recommended at this time. There is also evidence to support use of selective digestive decontamination and selective oropharyngeal decontamination, but additional studies are needed to assess resistance to these agents, especially selection for resistance among Gram-negative organisms. The strongest evidence for decolonization is for use among surgical patients as a strategy to prevent surgical site infections.

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.

Beyond the Intensive Care Unit (ICU): Countywide Impact of Universal ICU Staphylococcus aureus Decolonization

A recent trial showed that universal decolonization in adult intensive care units (ICUs) resulted in greater reductions in all bloodstream infections and clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) than either targeted decolonization or screening and isolation. Since regional health-care facilities are highly interconnected through patient-sharing, focusing on individual ICUs may miss the broader impact of decolonization. Using our Regional Healthcare Ecosystem Analyst simulation model of all health-care facilities in Orange County, California, we evaluated the impact of chlorhexidine baths and mupirocin on all ICU admissions when universal decolonization was implemented for 25%, 50%, 75%, and 100% of ICU beds countywide (compared with screening and contact precautions). Direct benefits were substantial in ICUs implementing decolonization (a median 60% relative reduction in MRSA prevalence). When 100% of countywide ICU beds were decolonized, there were spillover effects in general wards, long-term acute-care facilities, and nursing homes resulting in median 8.0%, 3.0%, and 1.9% relative MRSA reductions at 1 year, respectively. MRSA prevalence decreased by a relative 3.2% countywide, with similar effects for methicillin-susceptible S. aureus. We showed that a large proportion of decolonization's benefits are missed when accounting only for ICU impact. Approximately 70% of the countywide cases of MRSA carriage averted after 1 year of universal ICU decolonization were outside the ICU.

Universal vs Risk Factor Screening for Methicillin-Resistant Staphylococcus aureus in a Large Multicenter Tertiary Care Facility in Canada

OBJECTIVE To assess the clinical effectiveness of a universal screening program compared with a risk factor-based program in reducing the rates of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) among admitted patients at the Ottawa Hospital. DESIGN Quasi-experimental study. SETTING Ottawa Hospital, a multicenter tertiary care facility with 3 main campuses, approximately 47,000 admissions per year, and 1,200 beds. METHODS From January 1, 2006 through December 31, 2007 (24 months), admitted patients underwent risk factor-based MRSA screening. From January 1, 2008 through August 31, 2009 (20 months), all patients admitted underwent universal MRSA screening. To measure the effectiveness of this intervention, segmented regression modeling was used to examine monthly nosocomial MRSA incidence rates per 100,000 patient-days before and during the intervention period. To assess secular trends, nosocomial Clostridium difficile infection, mupirocin prescriptions, and regional MRSA rates were investigated as controls. RESULTS The nosocomial MRSA incidence rate was 46.79 cases per 100,000 patient-days, with no significant differences before and after intervention. The MRSA detection rate per 1,000 admissions increased from 9.8 during risk factor-based screening to 26.2 during universal screening. A total of 644 new nosocomial MRSA cases were observed in 1,448,488 patient-days, 323 during risk factor-based screening and 321 during universal screening. Secular trends in C. difficile infection rates and mupirocin prescriptions remained stable after the intervention whereas population-level MRSA rates decreased. CONCLUSION At Ottawa Hospital, the introduction of universal MRSA admission screening did not significantly affect the rates of nosocomial MRSA compared with risk factor-based screening. Infect. Control Hosp. Epidemiol. 2015;37(1):41-48.