Monitoring antimicrobial use and resistance: comparison with a national benchmark on reducing vancomycin use and vancomycin-resistant enterococci

Evaluation of the initial timing of infection control pharmacist-driven audit and monitoring of vancomycin therapy in patients with infectious diseases: A retrospective observational study

BACKGROUND

Early monitoring and feedback on the treatment of infectious diseases are some of the methods for optimising antimicrobial treatment throughout the treatment period. Prospective audits and feedback interventions have also been shown to improve antimicrobial use and reduce antimicrobial resistance. We examined the appropriate use of antimicrobials by focusing on the initial timing for audits and feedback intervention of antimicrobial prescription by Infection Control Team pharmacists.

METHODS

We conducted a retrospective observational study in a university hospital in Tokyo, Japan from 1 January 2019 to 31 May 2021. We retrospectively enrolled patients with infections and those patients suspected of having an infection, who were administered vancomycin and assessed at our hospital. The definition of primary outcome was the maintenance of target vancomycin trough blood concentrations of 10-20 μg/ml during treatment. Multivariable logistic regression and multivariate linear regression analyses were performed to test the effectiveness of the initial timing of the intervention by Infection Control Team pharmacists as the explanatory variable.

RESULTS

A total of 638 patients were included in this study, with a median age of 69 years (interquartile range: 54-78 years). Multivariable logistic regression revealed that the maintenance of target vancomycin trough concentrations was not associated with the timing of the audit and the initiation of monitoring by Infection Control Team pharmacists (adjusted odds ratio: 0.99, 95% confidence interval: 0.99-1.00, p = 0.990). Multivariate linear regression revealed that the duration of vancomycin administration was significantly correlated with the timing of initiation of monitoring by Infection Control Team pharmacists (adjusted estimate: 0.0227, standard error: 0.0051, p = 0.012).

CONCLUSIONS

Our study showed that early initiation of a comprehensive audit and monitoring by Infection Control Team pharmacists did not affect the maintenance of the target vancomycin trough blood concentration. However, it reduced the duration of vancomycin administration.

Implementation of An Antibiotic Stewardship Intervention to Reduce Prescription of Fluoroquinolones: A Human Factors Analysis in Two Intensive Care Units

Antibiotic use is often the target of interventions in health care organizations that aim to decrease healthcare-associated infections (HAI) such as Clostridioides difficile (CDI); this is particularly important for fluoroquinolones (FQ), which are frequently used in critical care settings. In this study, using a multiple case study research approach, we conduct an in-depth analysis of an intervention aimed at limiting ICU prescriber access to FQ in two ICUs of two hospitals. The data collection and analysis were guided by a human factors engineering approach based on the SEIPS (Systems Engineering Initiative for Patient Safety) model and evidence-based implementation principles. Our results show some differences in the implementation of the FQ intervention between the two ICUs, such as level and method of FQ restriction, and training and communication with physicians and pharmacists. In both ICUs, several organizational learning mechanisms helped to quickly identify problems with the intervention and ensure that changes were made in a just-in-time manner (e.g. just-in-time training, removal of FQ in order set for pneumonia). Despite their organizational differences, both sites developed strategies to successfully implement the FQ intervention.

Impact of hospital antibiotic use on patient-level risk of death among 36,124,372 acute and medical admissions in England

OBJECTIVES

Initiatives to curb hospital antibiotic use might be associated with harm from under-treatment. We examined the extent to which variation in hospital antibiotic prescribing is associated with mortality risk in acute/general medicine inpatients.

METHODS

This ecological analysis examined Hospital Episode Statistics from 36,124,372 acute/general medicine admissions (≥16y) to 135 acute hospitals in England, 01/April/2010-31/March/2017. Random-effects meta-regression was used to investigate whether heterogeneity in adjusted 30-day mortality was associated with hospital-level antibiotic use, measured in defined-daily-doses (DDD)/1,000 bed-days. Models also considered DDDs/1,000 admissions and DDDs for narrow-spectrum/broad-spectrum antibiotics, parenteral/oral, and local interpretations of World Health Organization Access, Watch, and Reserve antibiotics.

RESULTS

Hospital-level antibiotic DDDs/1,000 bed-days varied 15-fold with comparable variation in broad-spectrum, parenteral, and Reserve antibiotic use. After extensive adjusting for hospital case-mix, the probability of 30-day mortality changed -0.010% (95% CI: -0.064,+0.044) for each increase of 500 hospital-level antibiotic DDDs/1,000 bed-days. Analyses of other metrics of antibiotic use showed no consistent association with mortality risk.

CONCLUSIONS

We found no evidence that wide variation in hospital antibiotic use is associated with adjusted mortality risk in acute/general medicine inpatients. Using low-prescribing hospitals as benchmarks could help drive safe and substantial reductions in antibiotic consumption of up-to one-third in this population.

Antimicrobial consumption in intensive care unit patients at level 1 trauma centre in India

PURPOSE

Increase in the antimicrobial resistance causes a concern globally. To mitigate the rapidly rising antimicrobial resistance in the health system globally antimicrobial stewardship programs (AMSP) have been advocated. Therefore, we aim to measure aggregate antibiotic consumption by both Defined Daily Dosage (DDD) and Days of Therapy (DOT) methods.

METHODS

As a part of Indian Council of Medical Research initiative to develop local AMSP, this prospective study of six months was conducted at a level -1 Trauma Centre of AIIMS, New Delhi. In this, we have included all the patients of polytrauma and neurosurgical Intensive care units between April to October 2019. Consumption of antibiotics data were collected manually daily by infection control practitioners. Data were presented as Days of Therapy (DOT) and Defined Daily Dose (DDD).

RESULTS

During the six months of study, antimicrobial consumption of ICU was compared with empirical therapy v/s culture-based therapy. Overall average antimicrobial consumption for the six months for both empirical therapy and culture-based therapy DDD/1000 patient days was 531.8 and 460.7 whereas DOT/1000 patient days 489.9 and 426.04 respectively.

CONCLUSIONS

Antimicrobial Stewardship activities aim to ensure judicious consumption of antimicrobials. Such data will be of value in establishing, evaluating and monitoring the function of the AMSP in the healthcare settings.

Decreasing ICU-associated Clostridioides difficile infection through fluoroquinolone restriction, the FIRST trial: a study protocol

INTRODUCTION

Clostridioides difficile infection (CDI) is one of the most common healthcare-associated infections in the USA, having high incidence in intensive care units (ICU). Antibiotic use increases risk of CDI, with fluoroquinolones (FQs) particularly implicated. In healthcare settings, antibiotic stewardship (AS) and infection control interventions are effective in CDI control, but there is little evidence regarding the most effective AS interventions. Preprescription authorisation (PPA) restricting FQs is a potentially promising AS intervention to reduce CDI. The FQ Restriction for the Prevention of CDI (FIRST) trial will evaluate the effectiveness of an FQ PPA intervention in reducing CDI rates in adult ICUs compared with preintervention care, and evaluate implementation effectiveness using a human-factors and systems engineering model.

METHODS AND ANALYSIS

This is a multisite, stepped-wedge, cluster, effectiveness-implementation clinical trial. The trial will take place in 12 adult medical-surgical ICUs with ≥10 beds, using Epic as electronic health record (EHR) and pre-existing AS programmes. Sites will receive facilitated implementation support over the 15-month trial period, succeeded by 9 months of follow-up. The intervention comprises a clinical decision support system for FQ PPA, integrated into the site EHRs. Each ICU will be considered a single site and all ICU admissions included in the analysis. Clinical data will be extracted from EHRs throughout the trial and compared with the corresponding pretrial period, which will constitute the baseline for statistical analysis. Outcomes will include ICU-onset CDI rates, FQ days of therapy (DOT), alternative antibiotic DOT, average length of stay and hospital mortality. The study team will also collect implementation data to assess implementation effectiveness using the Systems Engineering Initiative for Patient Safety model.

ETHICS AND DISSEMINATION

The trial was approved by the Institutional Review Board at the University of Wisconsin-Madison (2018-0852-CP015). Results will be made available to participating sites, funders, infectious disease societies, critical care societies and other researchers.

TRIAL REGISTRATION NUMBER

NCT03848689.

Impact of Chlorhexidine Bathing on Antimicrobial Utilization in Surgical Intensive Care Unit

BACKGROUND

This secondary analysis compared antimicrobial utilization among surgical intensive care unit patients randomized to every other day chlorhexidine bathing (chlorhexidine) versus daily soap and water bathing (soap-and-water) using data from the CHlorhexidine Gluconate BATHing trial.

MATERIALS AND METHODS

Antimicrobial utilization was quantified using defined daily dose (DDD)/100 patient-days and agent-days/100 patient-days for systemic antimicrobials. Antivirals (except oseltamivir), antiparasitics, and prophylaxis agents were excluded. The 2018 anatomic therapeutic chemical/DDD index was used to calculate DDD. Agent-days were calculated as the sum of calendar days where antimicrobials were administered. Patient-days were defined as time patients were at risk for health care-acquired infections plus up to 14 d. Primary analyses were conducted using linear regression adjusted for baseline Acute Physiology and Chronic Health Evaluation II scores.

RESULTS

Of 325 CHlorhexidine Gluconate BATHing trial patients, 312 (157 in soap-and-water and 155 in chlorhexidine) were included. The median (interquartile range) of total antimicrobial DDD/100 patient-days was 135.4 (75.2-231.8) for soap-and-water and 129.9 (49.2-215.3) for chlorhexidine. The median (interquartile range) of total antimicrobial agent-days/100 patient-days was 155.6 (83.3-243.2) for soap-and-water and 146.7 (66.7-217.4) for chlorhexidine. After adjusting for Acute Physiology and Chronic Health Evaluation II scores, chlorhexidine bathing was associated with a nonsignificant reduction in total antimicrobial DDD/100 patient-days (-3.9; 95% confidence interval, -33.9 to 26.1; P = 0.80) and total antimicrobial agent-days/100 patient-days (-10.3; 95% confidence interval, -34.7 to 14.1; P = 0.41).

CONCLUSIONS

Compared with daily soap and water bathing, every other day chlorhexidine bathing did not significantly reduce total antimicrobial utilization in surgical intensive care unit patients.

Impact of an Antimicrobial Stewardship Intervention on Within- and Between-Patient Daptomycin Resistance Evolution in Vancomycin-Resistant Enterococcus faecium

Vancomycin-resistant Enterococcus (VRE) is a leading cause of hospital-acquired infection, with limited treatment options. Resistance to one of the few remaining drugs, daptomycin, is a growing clinical problem and has previously been described in this hospital. In response to increasing resistance, an antimicrobial stewardship intervention was implemented to reduce hospital-wide use of daptomycin. To assess the impact of the intervention, daptomycin prescribing patterns and clinically reported culture results from vancomycin-resistant Enterococcus faecium (VREfm) bloodstream infections (BSIs) from 2011 through 2017 were retrospectively extracted and the impact of the intervention was estimated using interrupted time series analysis (ITS). We corrected for a change in MIC determination methodology by retesting 262 isolates using Etest and broth microdilution. Hospital-wide and within-patient resistance patterns of corrected daptomycin MICs are reported. Our data show that daptomycin prescriptions decreased from an average of 287 days of therapy/month preintervention to 151 days of therapy/month postintervention. Concurrently, the proportion of patients experiencing an increase in daptomycin MIC during an infection declined from 14.6% (7/48 patients) in 2014 to 1.9% (1/54 patients) in 2017. Hospital-wide resistance to daptomycin also decreased in the postintervention period, but this was not maintained. This study shows that an antimicrobial stewardship-guided intervention reduced daptomycin use and improved individual level outcomes but had only transient impact on the hospital-level trend.

Impact of an Unsolicited, Standardized Form-Based Antimicrobial Stewardship Intervention to Improve Guideline Adherence in the Management of Staphylococcus aureus Bacteremia

Background

Antimicrobial stewardship programs (ASPs) improve Staphylococcus aureus bacteremia (SAB) management. The objective of the current study was to evaluate the effect of unsolicited prospective audit and feedback (PAF) using a standardized SAB bundle form on the management of SAB.

Methods

Multicenter, pre-post quasi-experimental study of inpatients with SAB. The ASP developed an evidence-based SAB management bundle that included recommendations for infectious diseases consultation, blood culture clearance, appropriate empiric and definitive therapy, echocardiography, adequate treatment duration, and source control where applicable. ASP pharmacists performed PAF using a standardized form outlining bundle components. The primary outcome was bundle component adherence. Secondary outcomes were length of stay, 30-day readmission rate, and in-hospital and 30-day mortality rates.

Results

A total of 199 patients were included (preintervention group, 62; intervention group, 137). Bundle implementation with PAF resulted in significant improvements in infectious diseases consultation (56.5% in preintervention vs 93.4% in intervention group), appropriate definitive antibiotic therapy (83.9% vs 99.3%), ordering echocardiography (72.6% vs 95.6%), and adequate treatment duration (87.0% vs 100%) (all P < .001). Overall bundle adherence increased by 43.8% (P < .001). Readmission and 30-day mortality rates decreased, but this difference did not reach statistical significance.

Conclusions

Unsolicited PAF using a standardized SAB management bundle significantly improved adherence to evidence-based recommendations. This simple yet effective ASP-driven intervention can ensure consistent management of a highly morbid infection.

Catheter-related bloodstream infections with coagulase-negative staphylococci: are antibiotics necessary if the catheter is removed?

Background

Catheter-related bloodstream infections (CRBSI) with coagulase-negative Staphylococci (CoNS) are a common source of hospital-acquired bloodstream infections. The main objective of this study was to elucidate the role of systemic antibiotic therapy in the setting of catheter removal in adult patients with CoNS-CRBSI.

Methods

We conducted a retrospective cohort study on patients with CoNS-CRBSI diagnosed between 2008 and 2016 with follow-up for up to 12 months. The main inclusion criterion was a removed intravascular catheter with quantitative catheter tip culture growing CoNS and the same CoNS identified in the blood culture of a given patient. Outcomes were non-resolved infection (i.e. either presence of prolonged bacteremia or symptoms attributed to CoNS-CRBSI > 2 days after catheter removal), recurrence, mortality and length of hospitalization after catheter removal. We compared outcomes between a group with antibiotic treatment prescribed according to current IDSA guidelines (≥5 days, "treatment" group) and a "no-treatment" group.

Results

Our study population comprised 184 CoNS-CRBSI episodes. Seventy-six percent received antibiotic treatment ≥5 days, while 17% did not receive therapy. Non-resolved infections were absent from the patients who did not receive antibiotics. Severe neutropenia, hematologic cancer and immunosuppression were significantly more frequent in the treatment group. The subgroup analysis with 32 matched pairs showed no significant difference in frequency of non-resolved infection (0% in the no-treatment vs 15.6% in the ≥5 days treatment group, p = 0.06). The remaining outcomes were similar in the two groups.

Conclusions

Our findings indicate that withholding antimicrobial therapy in CoNS-CRBSI is neither associated with short-term complications nor with long-term recurrences.

Interventions to improve antibiotic prescribing practices for hospital inpatients

BACKGROUND

Antibiotic resistance is a major public health problem. Infections caused by multidrug-resistant bacteria are associated with prolonged hospital stay and death compared with infections caused by susceptible bacteria. Appropriate antibiotic use in hospitals should ensure effective treatment of patients with infection and reduce unnecessary prescriptions. We updated this systematic review to evaluate the impact of interventions to improve antibiotic prescribing to hospital inpatients.

OBJECTIVES

To estimate the effectiveness and safety of interventions to improve antibiotic prescribing to hospital inpatients and to investigate the effect of two intervention functions: restriction and enablement.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library), MEDLINE, and Embase. We searched for additional studies using the bibliographies of included articles and personal files. The last search from which records were evaluated and any studies identified incorporated into the review was January 2015.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and non-randomised studies (NRS). We included three non-randomised study designs to measure behavioural and clinical outcomes and analyse variation in the effects: non- randomised trials (NRT), controlled before-after (CBA) studies and interrupted time series (ITS) studies. For this update we also included three additional NRS designs (case control, cohort, and qualitative studies) to identify unintended consequences. Interventions included any professional or structural interventions as defined by the Cochrane Effective Practice and Organisation of Care Group. We defined restriction as 'using rules to reduce the opportunity to engage in the target behaviour (or increase the target behaviour by reducing the opportunity to engage in competing behaviours)'. We defined enablement as 'increasing means/reducing barriers to increase capability or opportunity'. The main comparison was between intervention and no intervention.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data and assessed study risk of bias. We performed meta-analysis and meta-regression of RCTs and meta-regression of ITS studies. We classified behaviour change functions for all interventions in the review, including those studies in the previously published versions. We analysed dichotomous data with a risk difference (RD). We assessed certainty of evidence with GRADE criteria.

MAIN RESULTS

This review includes 221 studies (58 RCTs, and 163 NRS). Most studies were from North America (96) or Europe (87). The remaining studies were from Asia (19), South America (8), Australia (8), and the East Asia (3). Although 62% of RCTs were at a high risk of bias, the results for the main review outcomes were similar when we restricted the analysis to studies at low risk of bias.More hospital inpatients were treated according to antibiotic prescribing policy with the intervention compared with no intervention based on 29 RCTs of predominantly enablement interventions (RD 15%, 95% confidence interval (CI) 14% to 16%; 23,394 participants; high-certainty evidence). This represents an increase from 43% to 58% .There were high levels of heterogeneity of effect size but the direction consistently favoured intervention.The duration of antibiotic treatment decreased by 1.95 days (95% CI 2.22 to 1.67; 14 RCTs; 3318 participants; high-certainty evidence) from 11.0 days. Information from non-randomised studies showed interventions to be associated with improvement in prescribing according to antibiotic policy in routine clinical practice, with 70% of interventions being hospital-wide compared with 31% for RCTs. The risk of death was similar between intervention and control groups (11% in both arms), indicating that antibiotic use can likely be reduced without adversely affecting mortality (RD 0%, 95% CI -1% to 0%; 28 RCTs; 15,827 participants; moderate-certainty evidence). Antibiotic stewardship interventions probably reduce length of stay by 1.12 days (95% CI 0.7 to 1.54 days; 15 RCTs; 3834 participants; moderate-certainty evidence). One RCT and six NRS raised concerns that restrictive interventions may lead to delay in treatment and negative professional culture because of breakdown in communication and trust between infection specialists and clinical teams (low-certainty evidence).Both enablement and restriction were independently associated with increased compliance with antibiotic policies, and enablement enhanced the effect of restrictive interventions (high-certainty evidence). Enabling interventions that included feedback were probably more effective than those that did not (moderate-certainty evidence).There was very low-certainty evidence about the effect of the interventions on reducing Clostridium difficile infections (median -48.6%, interquartile range -80.7% to -19.2%; 7 studies). This was also the case for resistant gram-negative bacteria (median -12.9%, interquartile range -35.3% to 25.2%; 11 studies) and resistant gram-positive bacteria (median -19.3%, interquartile range -50.1% to +23.1%; 9 studies). There was too much variance in microbial outcomes to reliably assess the effect of change in antibiotic use. Heterogeneity of intervention effect on prescribing outcomesWe analysed effect modifiers in 29 RCTs and 91 ITS studies. Enablement and restriction were independently associated with a larger effect size (high-certainty evidence). Feedback was included in 4 (17%) of 23 RCTs and 20 (47%) of 43 ITS studies of enabling interventions and was associated with greater intervention effect. Enablement was included in 13 (45%) of 29 ITS studies with restrictive interventions and enhanced intervention effect.

AUTHORS' CONCLUSIONS

We found high-certainty evidence that interventions are effective in increasing compliance with antibiotic policy and reducing duration of antibiotic treatment. Lower use of antibiotics probably does not increase mortality and likely reduces length of stay. Additional trials comparing antibiotic stewardship with no intervention are unlikely to change our conclusions. Enablement consistently increased the effect of interventions, including those with a restrictive component. Although feedback further increased intervention effect, it was used in only a minority of enabling interventions. Interventions were successful in safely reducing unnecessary antibiotic use in hospitals, despite the fact that the majority did not use the most effective behaviour change techniques. Consequently, effective dissemination of our findings could have considerable health service and policy impact. Future research should instead focus on targeting treatment and assessing other measures of patient safety, assess different stewardship interventions, and explore the barriers and facilitators to implementation. More research is required on unintended consequences of restrictive interventions.

Control of Vancomycin-Resistant Enterococci in the Neonatal Intensive Care Unit

Background and Objective:

Multidrug-resistant organisms (MDROs), such as vancomycin-resistant enterococci (VRE), cause serious infections, especially among high-risk patients in NICUs. When VRE was introduced and transmitted in our NICU despite recommended infection control practices, we instituted active surveillance cultures to determine their efficacy in detecting and controlling spread of VRE among high-risk infants.

Methods:

Active surveillance cultures, other infection control measures, and a mandatory in-service education module on preventing MDRO transmission were implemented. Cultures were performed on NICU admission and then weekly during their stay. Molecular DNA fingerprinting of VRE isolates facilitated targeting efforts to eliminate clonal spread of VRE. Repetitive sequence PCR (rep-PCR)-based DNA fingerprinting was used to compare isolates recovered from patients with VRE infection or colonization. Environmental VRE cultures were performed around VRE-colonized or -infected patients. DNA fingerprints were prepared from the products of rep-PCR amplification and analyzed using software to determine strain genetic relatedness.

Results:

Active surveillance cultures identified 65 patients with VRE colonization or infection among 1,820 admitted to the NICU. Rep-PCR performed on 60 VRE isolates identified 3 clusters. Cluster 1 included isolates from 21 patients and 4 isolates from the environment of the index patient. Clusters 2 and 3 included isolates from 23 and 3 patients, respectively. Similarity coefficients among the members of each cluster were 95% or greater.

Conclusions:

Control of transmission of multi-clonal VRE strains was achieved. Active surveillance cultures, together with implementation of other infection control measures, combined with rep-PCR DNA fingerprinting were instrumental in controlling VRE transmission in our NICU. (Infect Control Hosp Epidemiol 2005;26:646-649)

Implementing an Antibiotic Stewardship Program: Guidelines by the Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America

Evidence-based guidelines for implementation and measurement of antibiotic stewardship interventions in inpatient populations including long-term care were prepared by a multidisciplinary expert panel of the Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America. The panel included clinicians and investigators representing internal medicine, emergency medicine, microbiology, critical care, surgery, epidemiology, pharmacy, and adult and pediatric infectious diseases specialties. These recommendations address the best approaches for antibiotic stewardship programs to influence the optimal use of antibiotics.

Antimicrobial resistance: one world, one fight!

The lack of new antibiotic classes calls for a cautious use of existing agents. Yet, every 10 min, almost two tons of antibiotics are used around the world, all too often without any prescription or control. The use, overuse and misuse of antibiotics select for resistance in numerous species of bacteria which then renders antimicrobial treatment ineffective. Almost all countries face increased antimicrobial resistance (AMR), not only in humans but also in livestock and along the food chain. The spread of AMR is fueled by growing human and animal populations, uncontrolled contamination of fresh water supplies, and increases in international travel, migration and trade. In this context of global concern, 68 international experts attending the fifth edition of the World HAI Resistance Forum in June 2015 shared their successes and failures in the global fight against AMR. They underlined the need for a “One Health” approach requiring research, surveillance, and interventions across human, veterinary, agricultural and environmental sectors. This strategy involves concerted actions on several fronts. Improved education and increased public awareness are a well-understood priority. Surveillance systems monitoring infections need to be expanded to include antimicrobial use, as well as the emergence and spread of AMR within clinical and environmental samples. Adherence to practices to prevent and control the spread of infections is mandatory to reduce the requirement of antimicrobials in general care and agriculture. Antibiotics need to be banned as growth promoters for farm animals in countries where it has not yet been done. Antimicrobial stewardship programmes in animal husbandry have proved to be efficient for minimising AMR, without compromising productivity. Regarding the use of antibiotics in humans, new tools to provide highly specific diagnoses of pathogens can decrease diagnostic uncertainty and improve clinical management. Finally, infection prevention and control measures – some of them as simple as hand hygiene – are essential and should be extended beyond healthcare settings. Aside from regulatory actions, all people can assist in AMR reduction by limiting antibiotic use for minor illnesses. Together, we can all work to reduce the burden of AMR.

Evaluation of a consultant audit and feedback programme to improve the quality of antimicrobial prescribing in acute medical admissions

Objectives

This study aims to evaluate the effectiveness and acceptability of a pharmacist-led antimicrobial stewardship intervention, consisting of consultant performance audit and feedback, on antimicrobial prescribing quality.

Methods

From October 2010 to September 2012, the prescribing performance of medical consultant teams rotating on the acute medical admissions unit was measured against four quality indicators. Measurements were taken at baseline then at quarterly intervals during which time consultants received feedback. Proportion of prescriptions adhering to each indicator was compared with baseline using paired sample z-test (significance level P &lt; 0.01, Bonferroni corrected). Consultants’ views were explored using anonymous questionnaires.

Key findings

Overall, 2609 antimicrobial prescriptions were reviewed. Improvement from baseline was statistically significant in all follow-up periods for two indicators: ‘antimicrobials should have a documented indication in the medical notes’ and ‘antimicrobials should adhere to guideline choice or have a justification for deviation’, reaching 6.0% (95% CI 2.5, 9.6) and 8.7% (95% CI 3.7, 13.7), respectively. Adherence to the indicator ‘antimicrobials should have a documented stop/review prompt’ improved significantly in all but the first follow-up period. For the indicator: ‘antimicrobial assessed by antimicrobial specialists as unnecessary’, improvement was statistically significant in the first (−4.7%, 95% CI −8.0, −1.4) and fourth (−4.2%, 95% CI −7.7%, −0.8%) periods. Service evaluation showed support for the pharmacist-led stewardship activities.

Conclusions

There were significant and sustained improvements in prescribing quality as a result of the intervention. Consultants’ engagement and acceptance of stewardship activities were demonstrated.

Antibiotic stewardship in Germany: a cross-sectional questionnaire survey of 355 intensive care units

PURPOSE

Little information is available on antibiotic prescription management in German hospitals. The objective of this cross-sectional study was to determine the prevalence and components of antibiotic stewardship measures in German intensive care units (ICUs).

METHODS

A questionnaire survey was sent to all ICUs participating in the German nosocomial infection surveillance system (n = 579) in October 2011. Data on antibiotic management structures were collected and analyzed by structural hospital and ICU factors.

RESULTS

The questionnaire was completed by 355 German ICUs (response rate 61 %). Common measures used (>80 % of the ICUs) were personnel restrictions for antibiotic prescriptions, routine access to bacterial resistance data, and pharmacy reports on antibiotic costs and consumption. A small proportion of ICUs (14 %) employed physicians specialized in the prescription of antimicrobial medication. Hospitals with their own microbiological laboratory report participation in surveillance networks for antimicrobial use (34 %) and bacterial resistance (32 %) twice as often as hospitals with external laboratories (15 and 14 %, respectively, p < 0.001). Also, non-profit and public hospitals participate more often in surveillance networks for bacterial resistance than private hospitals (>23 % vs. 11 %, p < 0.05).

CONCLUSIONS

While the majority of ICUs report to have some antibiotic policies established, the contents and composition of these policies vary. Organizational-level control strategies to improve antibiotic management are common in Germany. However, strategies widely considered effective, such as the systematic cross-institutional surveillance of antimicrobial use and bacterial resistance in a standardized manner or the employment of infectious disease specialists, are scarce. This study provides a benchmark for future antibiotic stewardship programs.

Utility of prior screening for methicillin-resistant Staphylococcus aureus in predicting resistance of S. aureus infections

BACKGROUND

Screening for methicillin-resistant Staphylococcus aureus (MRSA) is intended to reduce nosocomial spread by identifying patients colonized by MRSA. Given the widespread use of this screening, we evaluated its potential clinical utility in predicting the resistance of clinical isolates of S. aureus.

METHODS

We conducted a 2-year retrospective cohort study that included patients with documented clinical infection with S. aureus and prior screening for MRSA. We determined test characteristics, including sensitivity and specificity, of screening for predicting the resistance of subsequent S. aureus isolates.

RESULTS

Of 510 patients included in the study, 53 (10%) had positive results from MRSA screening, and 79 (15%) of infecting isolates were resistant to methicillin. Screening for MRSA predicted methicillin resistance of the infecting isolate with 99% (95% confidence interval [CI] 98%-100%) specificity and 63% (95% CI 52%-74%) sensitivity. When screening swabs were obtained within 48 hours before isolate collection, sensitivity increased to 91% (95% CI 71%-99%) and specificity was 100% (95% CI 97%-100%), yielding a negative likelihood ratio of 0.09 (95% CI 0.01-0.3) and a negative predictive value of 98% (95% CI 95%-100%). The time between swab and isolate collection was a significant predictor of concordance of methicillin resistance in swabs and isolates (odds ratio 6.6, 95% CI 1.6-28.2).

INTERPRETATION

A positive result from MRSA screening predicted methicillin resistance in a culture-positive clinical infection with S. aureus. Negative results on MRSA screening were most useful for excluding methicillin resistance of a subsequent infection with S. aureus when the screening swab was obtained within 48 hours before collection of the clinical isolate.

A multicentre evaluation of the effectiveness and safety of high-dose daptomycin for the treatment of infective endocarditis

OBJECTIVES

Despite significant medical advances, infective endocarditis (IE) remains an infection associated with high morbidity and mortality. The objective was to assess the safety and efficacy of high-dose daptomycin, defined as ≥ 8 mg/kg/day, in patients with confirmed or suspected staphylococcal and/or enterococcal IE.

METHODS

This was a multicentre, retrospective observational study (2005-11). Adult patients, not undergoing haemodialysis, with blood cultures positive for staphylococci or enterococci and a definitive or possible diagnosis of IE, who received daptomycin ≥ 8 mg/kg/day (based on total body weight) for ≥ 72 h were included.

RESULTS

Seventy patients met the inclusion criteria and comprised 33 (47.1%) with right-sided IE (RIE), 35 (50%) with left-sided IE (LIE) and 2 with both RIE and LIE. Several patients had concomitant sites of infection, with bone/joint infection being most prevalent (12.9%). Sixty-five patients received daptomycin as salvage therapy. Pathogens were isolated from 64 patients, with methicillin-resistant Staphylococcus aureus as the most common organism (84.4%), followed by vancomycin-resistant Enterococcus faecium (7.8%). The median (IQR) daptomycin dose was 9.8 mg/kg/day (8.2-10.0 mg/kg/day), and was similar in RIE and LIE patients (9.8 and 9.3 mg/kg/day, respectively). A total of 24 (34.3%) received combination therapy. For those patients with pathogens isolated (n = 64), the organism was eradicated in 57 (89.1%) patients. Among 64 clinically evaluable patients, 55 (85.9%) achieved clinical success. No patients required discontinuation of high-dose daptomycin due to creatine phosphokinase elevations.

CONCLUSIONS

Patients with both RIE and LIE had successful outcomes with high-dose daptomycin therapy. Additional clinical trials evaluating high daptomycin dosages in patients with IE are warranted.

Interventions to improve antibiotic prescribing practices for hospital inpatients

BACKGROUND

The first publication of this review in Issue 3, 2005 included studies up to November 2003. This update adds studies to December 2006 and focuses on application of a new method for meta-analysis of interrupted time series studies and application of new Cochrane Effective Practice and Organisation of Care (EPOC) Risk of Bias criteria to all studies in the review, including those studies in the previously published version. The aim of the review is to evaluate the impact of interventions from the perspective of antibiotic stewardship. The two objectives of antibiotic stewardship are first to ensure effective treatment for patients with bacterial infection and second support professionals and patients to reduce unnecessary use and minimize collateral damage.

OBJECTIVES

To estimate the effectiveness of professional interventions that, alone or in combination, are effective in antibiotic stewardship for hospital inpatients, to evaluate the impact of these interventions on reducing the incidence of antimicrobial-resistant pathogens or Clostridium difficile infection and their impact on clinical outcome.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE from 1980 to December 2006 and the EPOC specialized register in July 2007 and February 2009 and bibliographies of retrieved articles. The main comparison is between interventions that had a restrictive element and those that were purely persuasive. Restrictive interventions were implemented through restriction of the freedom of prescribers to select some antibiotics. Persuasive interventions used one or more of the following methods for changing professional behaviour: dissemination of educational resources, reminders, audit and feedback, or educational outreach. Restrictive interventions could contain persuasive elements.

SELECTION CRITERIA

We included randomized clinical trials (RCTs), controlled clinical trials (CCT), controlled before-after (CBA) and interrupted time series studies (ITS). Interventions included any professional or structural interventions as defined by EPOC. The intervention had to include a component that aimed to improve antibiotic prescribing to hospital inpatients, either by increasing effective treatment or by reducing unnecessary treatment. The results had to include interpretable data about the effect of the intervention on antibiotic prescribing or microbial outcomes or relevant clinical outcomes.

DATA COLLECTION AND ANALYSIS

Two authors extracted data and assessed quality. We performed meta-regression of ITS studies to compare the results of persuasive and restrictive interventions. Persuasive interventions advised physicians about how to prescribe or gave them feedback about how they prescribed. Restrictive interventions put a limit on how they prescribed; for example, physicians had to have approval from an infection specialist in order to prescribe an antibiotic. We standardized the results of some ITS studies so that they are on the same scale (percent change in outcome), thereby facilitating comparisons of different interventions. To do this, we used the change in level and change in slope to estimate the effect size with increasing time after the intervention (one month, six months, one year, etc) as the percent change in level at each time point. We did not extrapolate beyond the end of data collection after the intervention. The meta-regression was performed using standard weighted linear regression with the standard errors of the coefficients adjusted where necessary.

MAIN RESULTS

For this update we included 89 studies that reported 95 interventions. Of the 89 studies, 56 were ITSs (of which 4 were controlled ITSs), 25 were RCT (of which 5 were cluster-RCTs), 5 were CBAs and 3 were CCTs (of which 1 was a cluster-CCT).Most (80/95, 84%) of the interventions targeted the antibiotic prescribed (choice of antibiotic, timing of first dose and route of administration). The remaining 15 interventions aimed to change exposure of patients to antibiotics by targeting the decision to treat or the duration of treatment. Reliable data about impact on antibiotic prescribing data were available for 76 interventions (44 persuasive, 24 restrictive and 8 structural). For the persuasive interventions, the median change in antibiotic prescribing was 42.3% for the ITSs, 31.6% for the controlled ITSs, 17.7% for the CBAs, 3.5% for the cluster-RCTs and 24.7% for the RCTs. The restrictive interventions had a median effect size of 34.7% for the ITSs, 17.1% for the CBAs and 40.5% for the RCTs. The structural interventions had a median effect of 13.3% for the RCTs and 23.6% for the cluster-RCTs. Data about impact on microbial outcomes were available for 21 interventions but only 6 of these also had reliable data about impact on antibiotic prescribing.Meta-analysis of 52 ITS studies was used to compare restrictive versus purely persuasive interventions. Restrictive interventions had significantly greater impact on prescribing outcomes at one month (32%, 95% confidence interval (CI) 2% to 61%, P = 0.03) and on microbial outcomes at 6 months (53%, 95% CI 31% to 75%, P = 0.001) but there were no significant differences at 12 or 24 months. Interventions intended to decrease excessive prescribing were associated with reduction in Clostridium difficile infections and colonization or infection with aminoglycoside- or cephalosporin-resistant gram-negative bacteria, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis. Meta-analysis of clinical outcomes showed that four interventions intended to increase effective prescribing for pneumonia were associated with significant reduction in mortality (risk ratio 0.89, 95% CI 0.82 to 0.97), whereas nine interventions intended to decrease excessive prescribing were not associated with significant increase in mortality (risk ratio 0.92, 95% CI 0.81 to 1.06).

AUTHORS' CONCLUSIONS

The results show that interventions to reduce excessive antibiotic prescribing to hospital inpatients can reduce antimicrobial resistance or hospital-acquired infections, and interventions to increase effective prescribing can improve clinical outcome. This update provides more evidence about unintended clinical consequences of interventions and about the effect of interventions to reduce exposure of patients to antibiotics. The meta-analysis supports the use of restrictive interventions when the need is urgent, but suggests that persuasive and restrictive interventions are equally effective after six months.

Benchmarking antimicrobial drug use in hospitals

Measuring and monitoring antibiotic use in hospitals is believed to be an important component of the strategies available to antimicrobial stewardship programs to address acquired antimicrobial resistance. Recent efforts to organize large numbers of hospitals into networks allow for interhospital comparisons of a variety of healthcare processes and outcomes, a process often called 'benchmarking'. For comparisons of antimicrobial use to be valid, usage figures must be risk-adjusted to account for differences in patient mix and hospital characteristics. The purpose of this review is to describe recent methods to benchmark antimicrobial drug use and to critically assess the potential advantages and the remaining challenges. While many methodological challenges remain, and the clinical outcomes resulting from benchmarking programs have yet to be determined, recent developments suggest that benchmarking antimicrobial drug use will become an important component of antimicrobial stewardship program activities.

Trends in aminoglycoside use and gentamicin-resistant gram-negative clinical isolates in US academic medical centers: implications for antimicrobial stewardship

OBJECTIVE

To measure trends in aminoglycoside antibiotic use and gentamicin-resistant clinical isolates across a network of hospitals and compare network-level relationships with those of individual hospitals.

DESIGN

Longitudinal observational investigation.

SETTING

US academic medical centers.

PARTICIPANTS

Adult inpatients.

METHODS

Adult aminoglycoside use was measured from 2002 or 2003 through 2009 in 29 hospitals. Hospital-wide antibiograms assessed gentamicin resistance by proportions and incidence rates for Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli. Mixed-effects analysis of variance was used to assess the significance of changes in aminoglycoside use and changes in resistance rates and proportions. Generalized estimating equations were used to assess the relationship between aminoglycoside use and resistance.

RESULTS

Mean aminoglycoside use declined by 41%, reflecting reduced gentamicin (P < .0001) and tobramycin (P < .005) use; amikacin use did not change. The rate and proportion of gentamicin-resistant P. aeruginosa decreased by 48% (P < .0001) and 31% (P < .0001), respectively. The rate and proportion of gentamicin-resistant E. coli increased by 166% and 124%, respectively (P < .0001), and they were related to increasing quinolone resistance in E. coli. Resistance among K. pneumoniae and A. baumannii did not change. Relationships between aminoglycoside use and resistance at the network level were highly variable at the individual hospital level.

CONCLUSIONS

Mean aminoglycoside use declined in this network of US hospitals and was associated with significant and opposite changes in rates of resistance for some organisms and no change for others. At the individual hospital level, antibiograms appear to be an unreliable reflection of antibiotic use, at least for aminoglycosides.

Surveillance of broad-spectrum antibiotic prescription in Singaporean hospitals: a 5-year longitudinal study

BACKGROUND

Inappropriate prescription of antibiotics may contribute towards higher levels antimicrobial resistance. A key intervention for improving appropriate antibiotic prescription is surveillance of prescription. This paper presents the results of a longitudinal surveillance of broad-spectrum antibiotic prescription in 5 public-sector hospitals in Singapore from 2006 to 2010.

METHODOLOGY/PRINCIPAL FINDINGS

Quarterly antibiotic prescription data were obtained and converted to defined daily doses (DDDs) per 1,000 inpatient-days. The presence of significant trends in antibiotic prescription over time for both individual and combined hospitals was tested by regression analysis and corrected for autocorrelation between time-points. Excluding fluoroquinolones, there was a significant increase in prescription of all monitored antibiotics from an average of 233.12 defined daily doses (DDD)/1,000 inpatient-days in 2006 to 254.38 DDD/1,000 inpatient-days in 2010 (Coefficient = 1.13, 95%CI: 0.16-2.09, p = 0.025). Increasing utilization of carbapenems, piperacillin/tazobactam, and Gram-positive agents were seen in the majority of the hospitals, while cephalosporins were less prescribed over time. The combined expenditure for 5 hospitals increased from USD9.9 million in 2006 to USD16.7 million in 2010.

CONCLUSIONS/SIGNIFICANCE

The rate of prescription of broad-spectrum antibiotics in Singaporean hospitals is much higher compared to those of European hospitals. This may be due to high rates of antimicrobial resistance. The increase in expenditure on monitored antibiotics over the past 5 years outstripped the actual increase in DDD/1,000 inpatient-days of antibiotics prescribed. Longitudinal surveillance of antibiotic prescription on a hospital and countrywide level is important for detecting trends for formulating interventions or policies. Further research is needed to understand the causes for the various prescription trends and to act on these where necessary.

Benchmarking risk-adjusted adult antibacterial drug use in 70 US academic medical center hospitals

BACKGROUND

Antimicrobial stewardship programs are advised to measure and risk-adjust antimicrobial use to facilitate interhospital comparisons, a process called benchmarking. The purpose of this investigation was to evaluate a new benchmarking strategy for antibacterials.

METHODS

Hospital-wide adult antibacterial drug use in 2009 was measured as days of therapy (DOT) and length of therapy (LOT) from billing records in 70 US academic medical centers (AMCs). Patients were assigned to 1 of 35 clinical service lines (CSL) based on their Medicare Severity Diagnosis Related Group. Expected (E) use was determined by indirect standardization and compared with observed (O) use.

RESULTS

Of 1,791 ,180 discharged adults, 63.7% received antibacterial drugs; the range by CSL was 14.3% (psychiatry) to 99.7% (lung transplant). Mean ± SD hospital-wide use was 839 ± 106 DOTs (range, 594-1109) and 536 ± 53.0 LOT (range, 427-684) per 1000 patient-days. The ventilator support CSL had the most DOT per discharge, 39.4 ± 9.4 days; the LOT was 21.5 ± 4.5 days. The hospital-wide O/E ratio range was 0.7-1.45; in 5 AMCs the ratio exceeded the 90% confidence interval (CI) and was below the 90% CI in 6. Variability in use was explained by the proportion of treated patients within each CSL and mean LOT and DOT per discharge.

CONCLUSIONS

Adult antibacterial drug use was benchmarked to expected use adjusted for patient mix, and outlier hospitals were identified. Differences between expected and observed use reflect usage patterns that were benchmarked and are targets for evaluation and intervention.

Integrated Multilevel Surveillance of the World's Infecting Microbes and Their Resistance to Antimicrobial Agents

Microbial surveillance systems have varied in their source of support; type of laboratory reporting (patient care or reference); inclusiveness of reports filed; extent of microbial typing; whether single hospital, multihospital, or multicountry; proportion of total medical centers participating; and types, levels, integration across levels, and automation of analyses performed. These surveillance systems variably support the diagnosis and treatment of patients, local or regional infection control, local or national policies and guidelines, laboratory capacity building, sentinel surveillance, and patient safety. Overall, however, only a small fraction of available data are under any surveillance, and very few data are fully integrated and analyzed. Advancing informatics and genomics can make microbial surveillance far more efficient and effective at preventing infections and improving their outcomes. The world's microbiology laboratories should upload their reports each day to programs that detect events, trends, and epidemics in communities, hospitals, countries, and the world.

Synthesis and combinational antibacterial study of 5''-modified neomycin

A library of 5″-modified neomycin derivatives were synthesized for an antibacterial structure-activity optimization strategy. Two leads exhibited prominent activity against both methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). Antibacterial activities were measured when combined with other clinically used antibiotics. Significant synergistic activities were observed which may lead to the development of novel therapeutic practices in the battle against infectious bacteria.

Surprising alteration of antibacterial activity of 5"-modified neomycin against resistant bacteria

A facile synthetic protocol for the production of neomycin B derivatives with various modifications at the 5'' position has been developed. The structural activity relationship (SAR) against aminoglycoside resistant bacteria equipped with various aminoglycoside-modifying enzymes (AMEs) was investigated. Enzymatic and molecular modeling studies reveal that the superb substrate promiscuity of AMEs allows the resistant bacteria to cope with diverse structural modifications despite the observation that several derivatives show enhanced antibacterial activity compared to the parent neomycin. Surprisingly, when testing synthetic neomycin derivatives against other human pathogens, two leads exhibit prominent activity against both methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) that are known to exert a high level of resistance against clinically used aminoglycosides. These findings can be extremely useful in developing new aminoglycoside antibiotics against resistant bacteria. Our result also suggests that new biological and antimicrobial activities can be obtained by chemical modifications of old drugs.

Multidrug-resistant hospital-associated infections in a pediatric intensive care unit: a cross-sectional survey in a Thai university hospital

OBJECTIVE

To determine the incidence and associated factors of multidrug-resistant hospital-associated infections (MDR-HAI) in a pediatric intensive care unit (PICU) of a university hospital in Thailand.

METHOD

A prospective study was performed in the PICU of King Chulalongkorn Memorial Hospital during the period May-December 2005. Children aged < or = 15 years who developed a PICU-related HAI were studied.

RESULTS

Forty-four patients (median age 6 months; male:female = 1.4:1) developed 58 episodes of PICU-related HAI. The HAI rate was 28.3 per 1000 patient-days. Thirty episodes (52%) were MDR-HAI. The following were found more frequently in MDR-HAI when compared to non-MDR-HAI: Acinetobacter baumannii (50% vs. 23%, p = 0.04), female sex (60% vs. 29%, p = 0.02), admission to the PICU with a medical condition (90% vs. 64%, p = 0.03), PICU stay longer than 7 days prior to the development of HAI (67% vs. 36%, p = 0.03), and previous use of broad-spectrum antibiotics (83% vs. 43%, p = 0.002). Independent risk factors for MDR-HAI included female sex (OR = 5.5, p = 0.03) and previous use of a broad-spectrum antibiotic (OR = 9.7, p = 0.01).

CONCLUSION

The incidence of MDR-HAI was high in the PICU. Female sex and previous use of a broad-spectrum antibiotic were independent risk factors for MDR-HAI.

Review: Novel targets in the management of pneumonia

Community-acquired pneumonia (CAP) is the leading cause of death from infectious diseases in the US. It accounts each year for 500,000 hospitalizations and 45,000 deaths and represents one of the most common causes of intensive care unit (ICU) admission. The mortality rate due to severe CAP has shown little improvement in the past three decades, remaining between 21% and 58% in patients admitted to the intensive care unit. Antimicrobial agents are the cornerstone of therapy against CAP, but there are some novel antibiotic and nonantibiotic therapies that have been recently tested that may potentially impact outcomes of patients with severe CAP. We will review the most recent data regarding novel therapies in patients with the highest risk of death such as those with severe CAP.

Acquired vancomycin resistance in clinically relevant pathogens

Acquired resistance to vancomycin is an increasing problem in pathogenic bacteria. It is best studied and most prevalent among Enterococcus and still remains rare in other pathogenic bacteria. Different genotypes of vancomycin resistance, vanA–G, have been described. The different van gene clusters consist of up to nine genes encoding proteins of different functions; their interplay leads to an alternative cell wall precursor less susceptible to glycopeptide binding. Variants of vanA and vanB types are found worldwide, with vanA predominating; their reservoir is Enterococcus faecium. Within this species a subpopulation of hospital-adapted types exists that acquired van gene clusters and which is responsible for outbreaks of vancomycin-resistant enterococci all over the world. Acquisition of vanA by methicillin-resistant Staphylococcus aureus (MRSA) is worrisome and seven cases have been described. Nonsusceptibility to glycopeptides also occurs independently from van genes and is a growing therapeutic challenge, especially in MRSA.

Vancomycin revisited: a reappraisal of clinical use

Vancomycin has been used for decades to treat serious systemic gram positive infections. Extensive use over time has demonstrated vancomycin is not nephrotoxic even when used in high dosage, i.e., twice the usual dose. Since vancomycin is not nephrotoxic, there is no rationale for dosing vancomycin based on serum vancomycin levels. Since vancomycin is eliminated by GFR, vancomycin dosing should be based on creatinine clearance. Vancomycin obeys "concentration dependent" kinetics and higher than usual doses may be useful in some infections (eg, osteomyelitis). Widespread vancomycin use has resulted in increased VRE prevalence worldwide. Among staphylococci, vancomycin induced cell wall thickening results in "permeability mediated" resistance to vancomycin, as well as other anti-staphylococcal antibiotics. "Permeability mediated" resistance accounts for the common clinical observation that MRSA infections treated with vancomycin often resolve slowly or not at all. Other effective MRSA antibiotics are available (eg, linezolid, daptomycin, minocycline, or tigecycline) and are more reliably effective, do not increase staphylococcal resistance or increase VRE prevalence.

Surveillance of antimicrobial use and antimicrobial resistance in German intensive care units (SARI): a summary of the data from 2001 through 2004

Objective:

To report the experience gained over 4 years in working with the German SARI project (Surveillance of Antimicrobial Use and Antimicrobial Resistance in Intensive Care Units), and to compare SARI with data from the Swedish STRAMA and the US AUR surveillance system.

Methods:

Prospective unit and laboratory based surveillance was carried out in 40 German ICUs from 2001 through 2004. WHO 2004 definitions of defined daily doses (DDD) per 1,000 patient days (pd) were used to express antimicrobial consumption (AD). Apart from the proportion of resistant isolates (RP), the incidence density of resistant isolates (RD) was calculated on the basis of the number of resistant isolates per 1,000 pd. To determine the changes over time, the Wilcoxon signed rank test for paired samples was used.

Results:

From 1/2001 through 12/2004, 40 ICUs provided data on 53,399 isolates, a total of 789,569 DDD and 597,592 pd. Total AD ranged from 427 to 2,798, with the median being 1,351. There was no statistically significant change in total antimicrobial use, but a statistically significant decrease was observed in the use of aminoglycosides. RD was highest for MRSA with 4.4 resistant isolates/1,000 pd followed by imipenem resistant Pseudomonas aeruginosa with 1.7 resistant isolates/1,000 pd. The corresponding RPs were 21.5% and 23.2%. Over the 4-year period (2001–2004), significant increases were seen in the RDs of third generation cephalosporin and ciprofloxacin resistant Escherichia coli. In 2004, the mean RD reached 0.28 and 1.41, respectively. In comparison, the RP of selected pathogens was highest in the US ICUs and lowest in Swedish ICUs, with the exception of imipenem resistant P. aeruginosa.

Conclusion:

Antibiotic consumption remained stable over a period of 4 years, (the mean being 1,321 DDD/1,000 pd). The same applied to the situation regarding resistance in Staphylococcus aureus, enterococci and P. aeruginosa. For most pathogens the RP was higher in SARI ICUs than in Swedish ICUs, but lower than in US ICUs.

Vancomycin for treatment of invasive, multi-drug resistant Staphylococcus aureus infections

Staphylococcus aureus is a bacterial pathogen responsible for a variety of serious infections and is a frequent cause of nosocomial disease. During the last 60 years, S. aureus has developed increasing in vitro resistance to virtually all antimicrobials. In contrast, vancomycin has maintained a high degree of activity in vitro against this pathogen, although slight changes with in vitro activity could vastly change clinical activity. As a result, vancomycin has become the mainstay of therapy for invasive infections due to methicillin-resistant strains. However, clinical strains of S. aureus with intermediate resistance to vancomycin were reported in 1996, followed in 2002 with reports of isolates that were fully resistant. Although many authorities believe vancomycin remains the drug of choice for most staphylococcal-resistant infections, important issues surrounding its clinical application remain. These include the need for multiple daily dosing, intravenous administration, requirements for serum concentration monitoring, increasing resistance in vitro, modest efficacy rates and (less frequently) treatment-limiting adverse effects. This review addresses these important topics.

Does vancomycin prescribing intervention affect vancomycin-resistant enterococcus infection and colonization in hospitals? A systematic review

Background

Vancomycin resistant enterococcus (VRE) is a major cause of nosocomial infections in the United States and may be associated with greater morbidity, mortality, and healthcare costs than vancomycin-susceptible enterococcus. Current guidelines for the control of VRE include prudent use of vancomycin. While vancomycin exposure appears to be a risk factor for VRE acquisition in individual patients, the effect of vancomycin usage at the population level is not known. We conducted a systematic review to determine the impact of reducing vancomycin use through prescribing interventions on the prevalence and incidence of VRE colonization and infection in hospitals within the United States.

Methods

To identify relevant studies, we searched three electronic databases, and hand searched selected journals. Thirteen studies from 12 articles met our inclusion criteria. Data were extracted and summarized for study setting, design, patient characteristics, types of intervention(s), and outcome measures. The relative risk, 95% confidence interval, and p-value associated with change in VRE acquisition pre- and post-vancomycin prescription interventions were calculated and compared. Heterogeneity in study results was formally explored by stratified analysis.

Results

No randomized clinical trials on this topic were found. Each of the 13 included studies used a quasi-experimental design of low hierarchy. Seven of the 13 studies reported statistically significant reductions in VRE acquisition following interventions, three studies reported no significant change, and three studies reported increases in VRE acquisition, one of which reported statistical significance. Results ranged from a reduction of 82.5% to an increase of 475%. Studies of specific wards, which included sicker patients, were more likely to report positive results than studies of an entire hospital including general inpatients (Fisher's exact test 0.029). The type of intervention, endemicity status, type of study design, and the duration of intervention were not found to significantly modify the results. Among the six studies that implemented vancomycin reduction strategies as the sole intervention, two of six (33%) found a significant reduction in VRE colonization and/or infection. In contrast, among studies implementing additional VRE control measures, five of seven (71%) reported a significant reduction.

Conclusion

It was not possible to conclusively determine a potential role for vancomycin usage reductions in controlling VRE colonization and infection in hospitals in the United States. The effectiveness of such interventions and their sustainability remains poorly defined because of the heterogeneity and quality of studies. Future research using high-quality study designs and implementing vancomycin as the sole intervention are needed to answer this question.

Measurement of Adult Antibacterial Drug Use in 130 US Hospitals: Comparison of Defined Daily Dose and Days of Therapy

BACKGROUND

Hospitals are advised to measure antibiotic use and monitor its relationship to resistance. The World Health Organization's recommended metric is the defined daily dose (DDD). An alternative measure is the number of days of therapy (DOT). The purpose of this study was to contrast these measures.

METHODS

We measured the use of 50 antibacterial drugs that were administered to adults who were discharged from 130 US hospitals during 1 August 2002-31 July 2003.

RESULTS

Of 1,795,504 patients, 1,074,174 received at least 1 dose of an antibacterial drug (59.8%). The mean (+/- standard deviation) of total antibacterial drug use measured by the number of DDDs per 1000 patient-days and the number of DOTs per 1000 patient-days were not significantly different (792+/-147 and 776+/-120, respectively; P=.137), although the correlation was poor (r=0.603). For some individual drugs, such as levofloxacin and linezolid, there was no significant difference between DDDs per 1000 patient-days and DOTs per 1000 patient-days, because the administered daily dosage was nearly equivalent to the DDD. When the administered dosage exceeded the DDD, such as for ampicillin-sulbactam and cefepime, estimates of use based on DDDs per 1000 patient-days significantly exceeded those based on DOTs per 1000 patient-days (P<.001). When the administered dosage was less than the DDD, such as for piperacillin-tazobactam and ceftriaxone, estimates of use based on DDDs per 1000 patient-days were significantly lower than those based on DOTs per 1000 patient-days (P<.001).

CONCLUSION

The measurement of aggregate hospital antibiotic use by DDDs per 1000 patient-days and DOTs per 1000 patient-days is discordant for many frequently used antibacterial drugs, because the administered dose is dissimilar from the DDD recommended by the World Health Organization. DDD methods are useful for benchmarking purposes but cannot be used to make inferences about the number of DOTs or relative use for many antibacterial drugs.

In vitro activity of tigecycline against quinolone-resistant Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci

Tigecycline is a glycylcycline with promising broad-spectrum activity, including resistant Gram-positive organisms. This study characterizes in vitro activity of tigecycline against quinolone-resistant Streptococcus pneumoniae (QRSP), methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE). An in vitro pharmacodynamic model generated specific bacterial kill profiles for tigecycline against clinical isolates of QRSP, MRSA and VRE. Tigecycline produced a 6.6 log total reduction and cleared QRSP from the pharmacodynamic model by 18 h. Tigecycline and vancomycin were unable to achieve 3-log reductions in the MRSA and VRE isolates; log reductions in MRSA and VRE were 1.5 and 1.2 logs for tigecycline and 2.8 and zero for vancomycin, respectively. Area under the concentration time curve to minimum inhibitory concentration (AUC/MIC) values for tigecycline ranged from 79 to 158 microg h/mL and tigecycline concentrations remained above the MIC (T>MIC) throughout the simulated dosing interval. Tigecycline showed in vitro activity against the QRSP, MRSA and VRE isolates studied. Low MIC values, prolonged elimination half-life and the associated post-antibiotic effect (PAE) observed with tigecycline are desirable attributes that make it a potentially attractive option for treating resistant Gram-positive organisms.

Compliance with Institutional Guidelines on the Use of Vancomycin in a Medical Intensive Care Unit

Purpose

The University of Michigan implemented guidelines and restrictions for the use of vancomycin in 1995, based on recommendations from the Centers for Disease Control and Prevention. This study evaluated vancomycin use in the University of Michigan's Medical Intensive Care Unit (MICU), and assessed compliance with these institutional guidelines.

Methods

The primary objective of the study was to assess compliance with institutional guidelines. All patients admitted to the MICU who received vancomycin during the period of October 2002 through January 2003 were included in the study. Patients were identified retrospectively and patient medical records were accessed to gather pertinent information. Approval of the Institutional Review Board was obtained.

Results

Fifty-one patients received a total of 71 courses of vancomycin therapy (55 empiric, 16 definitive). Fifty-five (77.5%) of the 71 total courses of vancomycin therapy met institutional criteria. All courses of definitive therapy met specific criteria. Thirty-nine (71%) of the 55 courses of empiric therapy met criteria. Of the courses of empiric therapy which did not fulfill criteria, 12 were from patients exhibiting signs of sepsis and received vancomycin for more than 72 hours, and nine involved immunocompromised patients.

Conclusions

The implementation of guidelines and restrictions is essential to limiting and preventing resistance, but are only effective if designed with the specific hospital's patient population in mind. The results of this study suggest that immunocompromised patients may require a different approach than what is allowed by existing criteria.

Guidelines for the control and prevention of meticillin-resistant Staphylococcus aureus (MRSA) in healthcare facilities

Meticillin-resistant Staphylococcus aureus (MRSA) remains endemic in many UK hospitals. Specific guidelines for control and prevention are justified because MRSA causes serious illness and results in significant additional healthcare costs. Guidelines were drafted by a multi-disciplinary group and these have been finalised following extensive consultation. The recommendations have been graded according to the strength of evidence. Surveillance of MRSA should be undertaken in a systematic way and should be fed back routinely to healthcare staff. The inappropriate or unnecessary use of antibiotics should be avoided, and this will also reduce the likelihood of the emergence and spread of strains with reduced susceptibility to glycopeptides, i.e. vancomycin-intermediate S. aureus/glycopeptide-intermediate S. aureus (VISA/GISA) and vancomycin-resistant S. aureus (VRSA). Screening for MRSA carriage in selected patients and clinical areas should be performed according to locally agreed criteria based upon assessment of the risks and consequences of transmission and infection. Nasal and skin decolonization should be considered in certain categories of patients. The general principles of infection control should be adopted for patients with MRSA, including patient isolation and the appropriate cleaning and decontamination of clinical areas. Inadequate staffing, especially amongst nurses, contributes to the increased prevalence of MRSA. Laboratories should notify the relevant national authorities if VISA/GISA or VRSA isolates are identified.

Comparison of censored regression and standard regression analyses for modeling relationships between antimicrobial susceptibility and patient- and institution-specific variables

In order to identify patients likely to be infected with resistant bacterial pathogens, analytic methods such as standard regression (SR) may be applied to surveillance data to determine patient- and institution-specific factors predictive of an increased MIC. However, the censored nature of MIC data (e.g., MIC < or = 0.5 mg/liter or MIC > 8 mg/liter) imposes certain limitations on the use of SR. In order to investigate the nature of these limitations, simulations were performed to compare a regression tailored for censored data (censored regression [CR]) and one tailored for an SR. By using a model relating piperacillin-tazobactam MICs against Enterobacter spp. to patient age and hospital bed capacity, 200 simulations of 500 isolates were performed. Various MIC censoring patterns were imposed by using 26 left- or right-censored (L,R) pairs (i.e., MICs < or = 2 mg/liter(L) [2L] or MICs > 2 mg/liter(R) [2R], respectively). Data were fit by CR and SR for which censored MICs were either (i) excluded, (ii) replaced by 2L or 2R, or (iii) replaced by 2(L - 1) or 2(R + 1). Total censoring for the 26 pairs ranged from 7 to 86%. By CR, deviations of average parameter estimates from the true parameter values were <0.10 log2 (mg/liter) for all parameters for each of the 26 pairs. By SR, these deviations were >0.10 log2 (mg/liter) for at least 18 of the 26 pairs for all but one parameter. Two-standard-error confidence intervals for individual parameters contained as little as 0% of cases for all SR approaches but > or = 91.5% of cases for the CR approach. When censored MIC data are modeled, CR may reduce or eliminate biased parameter estimates obtained by SR.

Guidelines for the control of glycopeptide-resistant enterococci in hospitals

The increase since the mid 1980s in glycopeptide resistant enterococci (GRE) raised concerns about the limited options for antimicrobial therapy, the implications for ever-increasing numbers of immunocompromised hospitalised patients, and fuelled fears, now realised, for the transfer of glycopeptide resistance to more pathogenic bacteria, such as Staphylococcus aureus. These issues underlined the need for guidelines for the emergence and control of GRE in the hospital setting. This Hospital Infection Society (HIS) and Infection Control Nurses Association (ICNA) working party report reviews the literature relating to GRE prevention and control. It provides guidance on microbiological investigation, treatment and management, including antimicrobial prescribing and infection control measures. Evidence identified to support recommendations has been categorized. A risk assessment approach is recommended and areas for research and development identified.

Antimicrobial stewardship programs in health care systems

Antimicrobial stewardship programs in hospitals seek to optimize antimicrobial prescribing in order to improve individual patient care as well as reduce hospital costs and slow the spread of antimicrobial resistance. With antimicrobial resistance on the rise worldwide and few new agents in development, antimicrobial stewardship programs are more important than ever in ensuring the continued efficacy of available antimicrobials. The design of antimicrobial management programs should be based on the best current understanding of the relationship between antimicrobial use and resistance. Such programs should be administered by multidisciplinary teams composed of infectious diseases physicians, clinical pharmacists, clinical microbiologists, and infection control practitioners and should be actively supported by hospital administrators. Strategies for changing antimicrobial prescribing behavior include education of prescribers regarding proper antimicrobial usage, creation of an antimicrobial formulary with restricted prescribing of targeted agents, and review of antimicrobial prescribing with feedback to prescribers. Clinical computer systems can aid in the implementation of each of these strategies, especially as expert systems able to provide patient-specific data and suggestions at the point of care. Antibiotic rotation strategies control the prescribing process by scheduled changes of antimicrobial classes used for empirical therapy. When instituting an antimicrobial stewardship program, a hospital should tailor its choice of strategies to its needs and available resources.

An antibiotic order form intervention does not improve or reduce vancomycin use

OBJECTIVES

To determine whether a paper-based antibiotic ordering system is an effective antibiotic stewardship measure.

METHODS

An antibiotic order form (AOF) was introduced in July 2001 at a pediatric tertiary care hospital. Vancomycin courses prescribed before and after the AOF introduction were retrospectively reviewed based on Hospital Infection Control Practices Advisory Committee guidelines. The impact of the AOF on the appropriateness of vancomycin prescribing was evaluated in univariate and multivariable analyses that adjusted for other factors associated with appropriateness of vancomycin use. The density of vancomycin use after introduction of the AOF was also assessed.

RESULTS

Compliance with the AOF was poor (<50%) during the planned study period; therefore an additional 2 months of improved compliance (70-80%) were included. Rates of inappropriate vancomycin use increased during the study periods: 35% before AOF; 39% post-AOF; and 51% during the improved compliance period. On adjusted analysis, vancomycin utilization was significantly more inappropriate after introduction of the AOF. Vancomycin doses per 1000 patient days increased after introduction of the AOF.

CONCLUSIONS

Inappropriate vancomycin use and vancomycin use overall increased after the introduction of an AOF. An AOF intervention did not have its intended effect of improving and reducing vancomycin use.