De-escalation of antimicrobial therapy for bacteraemia due to difficult-to-treat Gram-negative bacilli

Comparison of antibiotic use and antibiotic resistance between a community hospital and tertiary care hospital for evaluation of the antimicrobial stewardship program in Japan

Assessment of risk-adjusted antibiotic use (AU) is recommended to evaluate antimicrobial stewardship programs (ASPs). We aimed to compare the amount and diversity of AU and antimicrobial susceptibility of nosocomial isolates between a 266-bed community hospital (CH) and a 963-bed tertiary care hospital (TCH) in Japan. The days of therapy/100 bed days (DOT) was measured for four classes of broad-spectrum antibiotics predominantly used for hospital-onset infections. The diversity of AU was evaluated using the modified antibiotic heterogeneity index (AHI). With 10% relative DOT for fluoroquinolones and 30% for each of the remaining three classes, the modified AHI equals 1. Multidrug resistance (MDR) was defined as resistance to ≥ 3 anti-Pseudomonas antibiotic classes. The DOT was significantly higher in the TCH than in the CH (10.85 ± 1.32 vs. 3.89 ± 0.93, p < 0.001). For risk-adjusted AU, the DOT was 6.90 ± 1.50 for acute-phase medical wards in the CH, and 8.35 ± 1.05 in the TCH excluding the hematology department. In contrast, the DOT of antibiotics for community-acquired infections was higher in the CH than that in the TCH. As quality assessment of AU, higher modified AHI was observed in the TCH than in the CH (0.832 ± 0.044 vs. 0.721 ± 0.106, p = 0.003), indicating more diverse use in the TCH. The MDR rate in gram-negative rods was 5.1% in the TCH and 3.4% in the CH (p = 0.453). No significant difference was demonstrated in the MDR rate for Pseudomonas aeruginosa and Enterobacteriaceae species between hospitals. Broad-spectrum antibiotics were used differently in the TCH and CH. However, an increased antibiotic burden in the TCH did not cause poor susceptibility, possibly because of diversified AU. Considering the different patient populations, benchmarking AU according to the facility type is promising for inter-hospital comparisons of ASPs.

Impact of antimicrobial de-escalation on mortality: a literature review of study methodology and recommendations for observational studies

Introduction: The safety of de-escalation of empirical antimicrobial therapy is largely based on observational data, with many reporting protective effects on mortality. As there is no plausible biological explanation for this phenomenon, it is most probably caused by confounding by indication.Areas covered: We evaluate the methodology used in observational studies on the effects of de-escalation of antimicrobial therapy on mortality. We extended the search for a recent systematic review and identified 52 observational studies. The heterogeneity in study populations was large. Only 19 (36.5%) studies adjusted for confounders and four (8%) adjusted for clinical stability during admission, all as a fixed variable. All studies had methodological limitations, most importantly the lack of adjustment for clinical stability, causing bias toward a protective effect.Expert opinion: The methodology used in studies evaluating the effects of de-escalation on mortality requires improvement. We depicted all potential confounders in a directed acyclic graph to illustrate all associations between exposure (de-escalation) and outcome (mortality). Clinical stability is an important confounder in this association and should be modeled as a time-varying variable. We recommend to include de-escalation as time-varying exposure and use inverse-probability-of-treatment weighted marginal structural models to properly adjust for time-varying confounders.

Modeling Antibiotic Use Strategies in Intensive Care Units: Comparing De-escalation and Continuation

Antimicrobial de-escalation refers to the treatment mechanism of switching from empiric antibiotics with good coverage to alternatives based on laboratory susceptibility test results, with the aim of avoiding unnecessary use of broad-spectrum antibiotics. In a previous study, we have developed multi-strain and multi-drug models in an intensive care unit setting, to evaluate the benefits and trade-offs of de-escalation in comparison with the conventional strategy called antimicrobial continuation. Our simulation results indicated that for a large portion of credible parameter combinations, de-escalation reduces the use of the empiric antibiotic but increases the probabilities of colonization and infections. In this paper, we first simplify the previous models to compare the long-term dynamical behaviors between de-escalation and continuation systems under a two-strain scenario. The analytical results coincide with our previous findings in the complex models, indicating the benefits and unintended consequences of de-escalation strategy result from the nature of this treatment mechanism, not from the complexity of the high-dimensional systems. By extending the models to three-strain scenarios, we find that de-escalation is superior than continuation in preventing outbreaks of invading strains that are resistant to empiric antibiotics. Thus decisions on antibiotic use strategies should be made specifically according to ICU conditions and intervention objectives.

Efficacy and safety of antimicrobial de-escalation as a clinical strategy

INTRODUCTION

De-escalation is a widely recommended strategy in regard to guidelines, with an associated adherence to guidelines being around 50%. This review discusses data supporting de-escalation and possible obstacles for its implementation. Areas covered: Although it does not have a consensual definition, de-escalation consists of reducing the spectrum of empirical antimicrobial treatment based on the microbiological findings. Many observational studies have suggested that this strategy is likely safe and efficient for treating various types of infection. However, randomized controlled trials published as of now have not shown any improvement on the outcomes. Regarding the adverse effects of de-escalation on ecological pressure and multidrug resistance emergence, the data are contradictory. The implementation of new techniques, such as rapid diagnosis, can help guide clinicians. Expert opinion: De-escalation should be included as part of a large antibiotic stewardship program to balance the risk and benefit of each administration, and each physician prescribing antibiotics should be challenged for the quality of her/his prescription on a daily basis. In the future, one of our duties will involve determining whether a delay of antimicrobial treatment - making it possible to improve diagnostic performance and obtain the first laboratory results - is either safe or unsafe for our patients.

Benefits and unintended consequences of antimicrobial de-escalation: Implications for stewardship programs

Sequential antimicrobial de-escalation aims to minimize resistance to high-value broad-spectrum empiric antimicrobials by switching to alternative drugs when testing confirms susceptibility. Though widely practiced, the effects de-escalation are not well understood. Definitions of interventions and outcomes differ among studies. We use mathematical models of the transmission and evolution of Pseudomonas aeruginosa in an intensive care unit to assess the effect of de-escalation on a broad range of outcomes, and clarify expectations. In these models, de-escalation reduces the use of high-value drugs and preserves the effectiveness of empiric therapy, while also selecting for multidrug-resistant strains and leaving patients vulnerable to colonization and superinfection. The net effect of de-escalation in our models is to increase infection prevalence while also increasing the probability of effective treatment. Changes in mortality are small, and can be either positive or negative. The clinical significance of small changes in outcomes such as infection prevalence and death may exceed more easily detectable changes in drug use and resistance. Integrating harms and benefits into ranked outcomes for each patient may provide a way forward in the analysis of these tradeoffs. Our models provide a conceptual framework for the collection and interpretation of evidence needed to inform antimicrobial stewardship.

Impact of antibiotic de-escalation on clinical outcomes in community-acquired pneumococcal pneumonia

BACKGROUND

Although antibiotic de-escalation is regarded as a measure that reduces selection pressure, adverse drug effects and costs, evidence supporting this practice in community-acquired pneumococcal pneumonia (CAPP) is lacking.

METHODS

We carried out a retrospective analysis of prospectively collected data of a cohort of hospitalized adults with CAPP. Pneumococcal aetiology was established in patients with one or more positive cultures for Streptococcus pneumoniae obtained from blood, sterile fluids or sputum, and/or a positive urinary antigen test. De-escalation therapy was considered when the initial antibiotic therapy was narrowed to penicillin, amoxicillin or amoxicillin/clavulanate within the first 72 h after admission. The primary outcomes were 30 day mortality and length of hospital stay (LOS). Adjustment for confounders was performed with multivariate and propensity score analyses.

RESULTS

Of 1410 episodes of CAPP, antibiotic de-escalation within the first 72 h after admission was performed in 166 cases. After adjustment, antibiotic de-escalation was not associated with a higher risk of mortality (OR = 0.83, 95% CI = 0.24-2.81), but it was found to be a protective factor for prolonged LOS (above the median) (OR = 0.46, 95% CI = 0.30-0.70). Similar results were found in patients classified into high-risk pneumonia severity index classes (IV-V), those with clinical instability and those with bacteraemia. No significant differences were documented in adverse drug reactions or readmission (<30 days).

CONCLUSIONS

Antibiotic de-escalation seems to be safe and effective in reducing the duration of LOS, and did not adversely affect outcomes of patients with CAPP, even those with bacteraemia and severe disease, and those who were clinically unstable.

Is de-escalation of antimicrobials effective? A systematic review and meta-analysis

BACKGROUND

De-escalation therapy is a strategy used widely to treat infections while avoiding the use of broad-spectrum antimicrobials. However, there is a paucity of clinical evidence to demonstrate the effectiveness and safety of de-escalation therapy compared to conventional therapy.

METHODS

A systematic review and meta-analysis was conducted on de-escalation therapy for a variety of infections. A search of the MEDLINE (via PubMed), EMBASE, and Cochrane Library databases up to July 2015 for relevant studies was performed. The primary outcome was relevant mortality, such as 30-day mortality and in-hospital mortality. A meta-analysis was to be conducted for the pooled odds ratio using the random-effects model when possible. Both randomized controlled trials and observational studies were included in the analysis.

RESULTS

A total of 23 studies were included in the analysis. There was no difference in mortality for most infections, and some studies favored de-escalation over non-de-escalation for better survival. The quality of most studies included was not high.

CONCLUSIONS

This review and analysis suggests that de-escalation therapy is safe and effective for most infections, although higher quality studies are needed in the future.

Antibiotic de-escalation for bloodstream infections and pneumonia: systematic review and meta-analysis

Antibiotic de-escalation is an appealing strategy in antibiotic stewardship programmes. We aimed to assess its safety and effects using a systematic review and meta-analysis. We included randomized controlled trials (RCTs) and observational studies assessing adults with bacteraemia, microbiologically documented pneumonia or severe sepsis, comparing between antibiotic de-escalation and no de-escalation. De-escalation was defined as changing an initially covering antibiotic regimen to a narrower spectrum regimen based on antibiotic susceptibility testing results within 96 hours. The primary outcome was 30-day all-cause mortality. A search of published articles and conference proceedings was last updated in September 2015. Crude and adjusted ORs with 95% CI were pooled in random-effects meta-analyses. Sixteen observational studies and three RCTs were included. Risk of bias related to confounding was high in the observational studies. De-escalation was associated with fewer deaths in the unadjusted analysis (OR 0.53, 95% CI 0.39-0.73), 19 studies, moderate heterogeneity. In the adjusted analysis there was no significant difference in mortality (adjusted OR 0.83, 95% CI 0.59-1.16), 11 studies, moderate heterogeneity and the RCTs showed non-significant increased mortality with de-escalation (OR 1.73, 95% 0.97-3.06), three trials, no heterogeneity. There was a significant unadjusted association between de-escalation and survival in bacteraemia/severe sepsis (OR 0.45, 95% CI 0.30-0.67) and ventilator-associated pneumonia (OR 0.49, 95% CI 0.26-0.95), but not with other pneumonia (OR 0.97, 95% CI 0.45-2.12). Only two studies reported on the emergence of resistance with inconsistent findings. Observational studies suggest lower mortality with antibiotic susceptibility testing-based de-escalation for bacteraemia, severe sepsis and ventilator-associated pneumonia that was not demonstrated in RCTs.

Antimicrobial de-escalation of treatment for healthcare-associated pneumonia within the Veterans Healthcare Administration

OBJECTIVES

The objective of this study was to measure quantitatively antimicrobial de-escalation utilizing electronic medication administration data based on the spectrum of activity for antimicrobial therapy (i.e. spectrum score) to identify variables associated with de-escalation in a nationwide healthcare system.

METHODS

A retrospective cohort study of patients hospitalized for healthcare-associated pneumonia was conducted in Veterans Affairs Medical Centers (n = 119). Patients hospitalized for healthcare-associated pneumonia on acute-care wards between 5 and 14 days who received antimicrobials for ≥ 3 days during calendar years 2008-11 were evaluated. The spectrum score method was applied at the patient level to measure de-escalation on day 4 of hospitalization. De-escalation was expressed in aggregate and facility-level proportions. Logistic regression was used to assess variables associated with de-escalation. ORs with 95% CIs were reported.

RESULTS

Among 9319 patients, the de-escalation proportion was 28.3% (95% CI 27.4-29.2), which varied 6-fold across facilities [median (IQR) facility-level de-escalation proportion 29.1% (95% CI 21.7-35.6)]. Variables associated with de-escalation included initial broad-spectrum therapy (OR 1.5, 95% CI 1.4-1.5 for each 10% increase in spectrum), collection of respiratory tract cultures (OR 1.1, 95% CI 1.0-1.2) and care in higher complexity facilities (OR 1.3, 95% CI 1.1-1.6). Respiratory tract cultures were collected from 35.3% (95% CI 32.7-37.7) of patients.

CONCLUSIONS

De-escalation of antimicrobial therapy was limited and varied substantially across facilities. De-escalation was associated with respiratory tract culture collection and treatment in a high complexity-level facility.

Appropriate initial antibiotic therapy in hospitalized patients with gram-negative infections: systematic review and meta-analysis

Background

The rapid global spread of multi-resistant bacteria and loss of antibiotic effectiveness increases the risk of initial inappropriate antibiotic therapy (IAT) and poses a serious threat to patient safety. We conducted a systematic review and meta-analysis of published studies to summarize the effect of appropriate antibiotic therapy (AAT) or IAT against gram-negative bacterial infections in the hospital setting.

Methods

MEDLINE, EMBASE, and Cochrane CENTRAL databases were searched until May 2014 to identify English-language studies examining use of AAT or IAT in hospitalized patients with Gram-negative pathogens. Outcomes of interest included mortality, clinical cure, cost, and length of stay. Citations and eligible full-text articles were screened in duplicate. Random effect models meta-analysis was used.

Results

Fifty-seven studies in 60 publications were eligible. AAT was associated with lower risk of mortality (unadjusted summary odds ratio [OR] 0.38, 95 % confidence interval [CI] 0.30-0.47, 39 studies, 5809 patients) and treatment failure (OR 0.22, 95 % CI 0.14–0.35; 3 studies, 283 patients). Conversely, IAT increased risk of mortality (unadjusted summary OR 2.66, 95 % CI 2.12–3.35; 39 studies, 5809 patients). In meta-analyses of adjusted data, AAT was associated with lower risk of mortality (adjusted summary OR 0.43, 95 % CI 0.23–0.83; 6 studies, 1409 patients). Conversely, IAT increased risk of mortality (adjusted summary OR 3.30, 95 % CI 2.42–4.49; 16 studies, 2493 patients). A limited number of studies suggested higher cost and longer hospital stay with IAT. There was considerable heterogeneity in the definition of AAT or IAT, pathogens studied, and outcomes assessed.

Discussion

Using a large set of studies we found that IAT is associated with a number of serious consequences,including an increased risk of hospital mortality. Infections caused by drug-resistant, Gram-negative organisms represent a considerable financial burden to healthcare systems due to the increased costs associated with the resources required to manage the infection, particularly longer hospital stays. However, there were insufficient data that evaluated AAT for the outcome of costs among patients with nosocomialGram-negative infections.

Conclusions

IAT in hospitalized patients with Gram-negative infections is associated with adverse outcomes. Technological advances for rapid diagnostics to facilitate AAT along with antimicrobial stewardship, surveillance, infection control, and prevention is needed.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1123-5) contains supplementary material, which is available to authorized users.

Resource-saving advice from an infectious diseases specialist team in a large university hospital: an exportable model?

AIM

To assess epidemiological features of patients for which a consultation by the infectious diseases consultation team was required, and the rate of clinical advice that led to resource-saving advice (R-SA): discontinuation of inappropriate therapy or prophylaxis, de-escalation and switch from parenteral to oral therapy.

MATERIALS & METHODS

An infectious diseases consultation team was implemented in a 1100-bed university hospital in Italy.

RESULTS

The most frequent infections for which an infectious diseases consultancy was required were pneumonia, bloodstream infections (17% by Candida) and urinary tract infections. In 828 patients (41.4%), interventions with the possibility of R-SA were suggested.

CONCLUSION

Resource-saving advices were possible in 41% of cases. Recent surgery, having a central venous catheter, bloodstream, abdominal, surgical site or bone and joint infections were correlated to a higher probability of receiving R-SA.

Strategies for appropriate antibiotic use in intensive care unit

The comsumption of antibiotics is high, mainly in intensive care units. Unfortunately, most are inappropriately used leading to increased multi-resistant bacteria. It is well known that initial empirical therapy with broad-spectrum antibiotics reduce mortality rates. However the prolonged and irrational use of antimicrobials may also increase the risk of toxicity, drug interactions and diarrhea due to Clostridium difficile. Some strategies to rational use of antimicrobial agents include avoiding colonization treatment, de-escalation, monitoring serum levels of the agents, appropriate duration of therapy and use of biological markers. This review discusses the effectiveness of these strategies, the importance of microbiology knowledge, considering there are agents resistant to Staphylococcus aureus and Klebsiella pneumoniae, and reducing antibiotic use and bacterial resistance, with no impact on mortality.

De-escalation therapy among bacteraemic patients with community-acquired pneumonia

There is no evidence supporting the use of de-escalation therapy (DET) among patients with community-acquired pneumonia (CAP). We assessed the outcomes associated with DET among bacteraemic CAP patients. We performed a secondary analysis of the Community-Acquired Pneumonia Organization database, which contains data on 660 bacteraemic patients hospitalized because of CAP in 35 countries (2001-2013). Exclusion criteria were death within 72 h from admission and an inappropriate empirical antibiotic regimen. DET was defined as changing an appropriate empirical broad-spectrum regimen to a narrower-spectrum regimen according to culture results within 7 days from hospital admission. Two study groups were identified: patients whose antibiotic therapy was de-escalated (the DET group), and patients whose antibiotic therapy was not de-escalated (the N-DET group). The primary study outcome was 30-day mortality. Two hundred and sixty-one bacteraemic CAP patients were included. Gram-positive bacteria were responsible for 88.1% of the cases (Streptococcus pneumoniae, 75.9%). Gram-negative bacteria were responsible for for 7.3% of the cases. DET was performed in 165 patients (63.2%). The N-DET group was characterized by a more severe presentation at admission. After adjustment for confounders, DET was not associated with an increased risk of 30-day mortality. DET seems to be safe among bacteraemic patients with CAP. Randomized clinical trials are warranted to further explore these findings.

De-escalation versus continuation of empirical antimicrobial treatment in severe sepsis: a multicenter non-blinded randomized noninferiority trial

BACKGROUND

In patients with severe sepsis, no randomized clinical trial has tested the concept of de-escalation of empirical antimicrobial therapy. This study aimed to compare the de-escalation strategy with the continuation of an appropriate empirical treatment in those patients.

METHODS

This was a multicenter non-blinded randomized noninferiority trial of patients with severe sepsis who were randomly assigned to de-escalation or continuation of empirical antimicrobial treatment. Recruitment began in February 2012 and ended in April 2013 in nine intensive care units (ICUs) in France. Patients with severe sepsis were assigned to de-escalation (n = 59) or continuation of empirical antimicrobial treatment (n = 57). The primary outcome was to measure the duration of ICU stay. We defined a noninferiority margin of 2 days. If the lower boundary of the 95 % confidence interval (CI) for the difference in patients assigned to the de-escalation group was less than 2 days, as compared with that of patients assigned to the continuation group, de-escalation was considered to be noninferior to the continuation strategy. Secondary outcomes included mortality at 90 days, occurrence of organ failure, number of superinfections, and number of days with antibiotics during the ICU stay.

RESULTS

The median duration of ICU stay was 9 [interquartile range (IQR) 5-22] days in the de-escalation group and 8 [IQR 4-15] days in the continuation group, respectively (P = 0.71). The mean difference was 3.4 (95 % CI -1.7 to 8.5). A superinfection occurred in 16 (27 %) patients in the de-escalation group and six (11 %) patients in the continuation group (P = 0.03). The numbers of antibiotic days were 9 [7-15] and 7.5 [6-13] in the de-escalation group and continuation group, respectively (P = 0.03). Mortality was similar in both groups.

CONCLUSION

As compared to the continuation of the empirical antimicrobial treatment, a strategy based on de-escalation of antibiotics resulted in prolonged duration of ICU stay. However, it did not affect the mortality rate.

Optimal screening strategies for healthcare associated infections in a multi-institutional setting

Health institutions may choose to screen newly admitted patients for the presence of disease in order to reduce disease prevalence within the institution. Screening is costly, and institutions must judiciously choose which patients they wish to screen based on the dynamics of disease transmission. Since potentially infected patients move between different health institutions, the screening and treatment decisions of one institution will affect the optimal decisions of others; an institution might choose to “free-ride” off the screening and treatment decisions of neighboring institutions. We develop a theoretical model of the strategic decision problem facing a health care institution choosing to screen newly admitted patients. The model incorporates an SIS compartmental model of disease transmission into a game theoretic model of strategic decision-making. Using this setup, we are able to analyze how optimal screening is influenced by disease parameters, such as the efficacy of treatment, the disease recovery rate and the movement of patients. We find that the optimal screening level is lower for diseases that have more effective treatments. Our model also allows us to analyze how the optimal screening level varies with the number of decision makers involved in the screening process. We show that when institutions are more autonomous in selecting whom to screen, they will choose to screen at a lower rate than when screening decisions are more centralized. Results also suggest that centralized screening decisions have a greater impact on disease prevalence when the availability or efficacy of treatment is low. Our model provides insight into the factors one should consider when choosing whether to set a mandated screening policy. We find that screening mandates set at a centralized level (i.e. state or national) will have a greater impact on the control of infectious disease.

Healthcare associated infections are a major cause of morbidity and mortality. Screening patients on admission to the hospital may reduce prevalence by identifying infected individuals; infected individuals can then be treated or isolated to prevent further spread. Because screening is costly, institutions must weigh the benefits of reduced prevalence against the costs of screening. However, patients move between institutions carrying disease with them; consequently, when choosing who to screen, institutions must also consider the rates at which neighboring institutions screen patients as well. We develop a theoretical model that describes this strategic decision process. Using this model we are able to analyze the screening decision problem along three dimensions: (1) how disease specific parameters, such as the effectiveness of treatment, influence the optimal screening level, (2) how the degree of centralization in screening policy (e.g. local, state or federal) influences the optimal screening level, and (3) how these two sets of factors combine to influence the optimal screening level. Our model highlights factors to consider when choosing to implement screening policy, and results are of use to policy makers wishing to reduce the prevalence of infectious disease.

De-escalation of empirical therapy is associated with lower mortality in patients with severe sepsis and septic shock

PURPOSES

We set out to assess the safety and the impact on in-hospital and 90-day mortality of antibiotic de-escalation in patients admitted to the ICU with severe sepsis or septic shock.

METHODS

We carried out a prospective observational study enrolling patients admitted to the ICU with severe sepsis or septic shock. De-escalation was defined as discontinuation of an antimicrobial agent or change of antibiotic to one with a narrower spectrum once culture results were available. To control for confounding variables, we performed a conventional regression analysis and a propensity score (PS) adjusted-multivariable analysis.

RESULTS

A total of 712 patients with severe sepsis or septic shock at ICU admission were treated empirically with broad-spectrum antibiotics. Of these, 628 were evaluated (84 died before cultures were available). De-escalation was applied in 219 patients (34.9%). By multivariate analysis, factors independently associated with in-hospital mortality were septic shock, SOFA score the day of culture results, and inadequate empirical antimicrobial therapy, whereas de-escalation therapy was a protective factor [Odds-Ratio (OR) 0.58; 95% confidence interval (CI) 0.36-0.93). Analysis of the 403 patients with adequate empirical therapy revealed that the factor associated with mortality was SOFA score on the day of culture results, whereas de-escalation therapy was a protective factor (OR 0.54; 95% CI 0.33-0.89). The PS-adjusted logistic regression models confirmed that de-escalation therapy was a protective factor in both analyses. De-escalation therapy was also a protective factor for 90-day mortality.

CONCLUSIONS

De-escalation therapy for severe sepsis and septic shock is a safe strategy associated with a lower mortality. Efforts to increase the frequency of this strategy are fully justified.