Short-duration selective decontamination of the digestive tract infection control does not contribute to increased antimicrobial resistance burden in a pilot cluster randomised trial (the ARCTIC Study)

OBJECTIVE

Selective decontamination of the digestive tract (SDD) is a well-studied but hotly contested medical intervention of enhanced infection control. Here, we aim to characterise the changes to the microbiome and antimicrobial resistance (AMR) gene profiles in critically ill children treated with SDD-enhanced infection control compared with conventional infection control.

DESIGN

We conducted shotgun metagenomic microbiome and resistome analysis on serial oropharyngeal and faecal samples collected from critically ill, mechanically ventilated patients in a pilot multicentre cluster randomised trial of SDD. The microbiome and AMR profiles were compared for longitudinal and intergroup changes. Of consented patients, faecal microbiome baseline samples were obtained in 89 critically ill children. Additionally, samples collected during and after critical illness were collected in 17 children treated with SDD-enhanced infection control and 19 children who received standard care.

RESULTS

SDD affected the alpha and beta diversity of critically ill children to a greater degree than standard care. At cessation of treatment, the microbiome of SDD patients was dominated by Actinomycetota, specifically Bifidobacterium, at the end of mechanical ventilation. Altered gut microbiota was evident in a subset of SDD-treated children who returned late longitudinal samples compared with children receiving standard care. Clinically relevant AMR gene burden was unaffected by the administration of SDD-enhanced infection control compared with standard care. SDD did not affect the composition of the oral microbiome compared with standard treatment.

CONCLUSION

Short interventions of SDD caused a shift in the microbiome but not of the AMR gene pool in critically ill children at the end mechanical ventilation, compared with standard antimicrobial therapy.

Is Zero Ventilator-Associated Pneumonia Achievable? Updated Practical Approaches to Ventilator-Associated Pneumonia Prevention

Ventilator-associated pneumonia (VAP) remains a significant clinical entity with reported incidence rates of 7% to 15%. Given the considerable adverse consequences associated with this infection, VAP prevention became a core measure required in most US hospitals. Many institutions took pride in implementing effective VAP prevention bundles that combined at least head of bed elevation, hand hygiene, chlorhexidine oral care, and subglottic drainage. Spontaneous breathing and awakening trials have also consistently been shown to shorten the duration of mechanical ventilation and secondarily reduce the occurrence of VAP.

Selective decontamination of the digestive tract: concept and application

Selective digestive decontamination (SDD) is a prophylactic strategy aimed at preventing or eradicating bacterial overgrowth in the intestinal flora that precedes the development of most infections in the Intensive Care Unit. SDD prevents serious infections, reduces mortality, is cost-effective, has no adverse effects, and its short- or long-term use is not associated with any significant increase in antimicrobial resistance. SDD is one of the most widely evaluated interventions in critically ill patients, yet its use is not widespread. The present article offers a narrative review of the most relevant evidence and an update of the pathophysiological concepts of infection control supporting the use of SDD.

Antimicrobial resistance and outcome in the critically ill patient: An opinion paper

Antimicrobial resistance (AMR) is associated with increased mortality and resources consumption in critically ill patients. However, the causality of AMR in this mortality remains unclear. This opinion paper aims to overview the effects of multidrug resistant (MDR) pathogens on the outcomes of critically ill patients, considering different variables as appropriateness of empirical antimicrobial therapy, severity of sepsis, comorbid conditions and frailty. Large studies based on national database associated MDR and increased mortality in critically ill patients. However, the patients carrying MDR pathogens, as compared with those carrying non-MDR pathogens, are those with co-morbid conditions, high risk of frailty and invasive procedures. In addition, inappropriate empirical antibiotics are more often used in these patients as well as withholding and withdrawing of life-sustained therapy. Future studies on AMR should report the rate of appropriateness of empirical antimicrobial therapy, withholding and withdrawing of life-sustained therapy.

Potential of Nuclear Imaging Techniques to Study the Oral Delivery of Peptides

Peptides are small biomolecules known to stimulate or inhibit important functions in the human body. The clinical use of peptides by oral delivery, however, is very limited due to their sensitive structure and physiological barriers present in the gastrointestinal tract. These barriers can be overcome with chemical and mechanical approaches protease inhibitors, permeation enhancers, and polymeric encapsulation. Studying the success of these approaches pre-clinically with imaging techniques such as fluorescence imaging (IVIS) and optical microscopy is difficult due to the lack of in-depth penetration. In comparison, nuclear imaging provides a better platform to observe the gastrointestinal transit and quantitative distribution of radiolabeled peptides. This review provides a brief background on the oral delivery of peptides and states examples from the literature on how nuclear imaging can help to observe and analyze the gastrointestinal transit of oral peptides. The review connects the fields of peptide delivery and nuclear medicine in an interdisciplinary way to potentially overcome the challenges faced during the study of oral peptide formulations.

Tales of the unexpected in antibiotic resistance

Since the 1990s few new antibiotics have become available; during the same period the appearance and spread of bacteria no longer susceptible to first- and second-line antibiotics has accelerated; indeed some bacterial infections untreatable with existing antibiotics. Control of antibiotic resistance is multifactorial, and includes restrictive antibiotic use and good infection control. The 2021 Lowbury lecture addresses three aspects of antibiotic resistance, with reference to the Netherlands, that illustrate the complexity of antibiotic resistance epidemiology. Initially selective decontamination of the digestive tract (SDD) was not adopted in the Netherlands because of concern about antibiotic resistance. However, three trials showed that SDD regimens, including 4 days of systemic cephalosporins, gave better clinical outcomes with no effect on antibiotic-resistant bacteria. Many predictions have been made about the impact of infections with antibiotic-resistant bacteria on human health. However, the situation is complex, because the risk factors for infection with multidrug-resistant bacteria are also risk factors for poor clinical outcome. A study in 8 Dutch hospitals estimated the mortality attributable to antibiotic resistance as close to zero. Concern about the emergence of resistance in Staphyloocccus aureus has limited the universal use of mupirocin to prevent surgical site infections. However, the risk may have been overstated, and universal decolonisation with mupirocin and chlorhexidine has now become standard of care in patients undergoing cardiothoracic or orthopaedic surgery in many Dutch hospitals. Prophylactic antibiotics can improve patient outcomes with acceptable risks of promoting resistance.

Eradication of Resistant and Susceptible Aerobic Gram-Negative Bacteria From the Digestive Tract in Critically Ill Patients; an Observational Cohort Study

Background

Selective Decontamination of the Digestive tract (SDD) aims to prevent nosocomial infections, by eradication of potentially pathogenic micro-organisms from the digestive tract.

Objectives

To estimate the rate of and the time to eradication of resistant vs. susceptible facultative aerobic gram-negative bacteria (AGNB) in patients treated with SDD.

Methods

This observational and retrospective study included patients admitted to the ICU between January 2001 and August 2017. Patients were included when treated with SDD (tobramycin, polymyxin B, and amphotericin B) and colonized in the upper or lower gastro-intestinal (GI) tract with at least one AGNB present on admission. Decontamination was determined after the first negative set of cultures (rectal and throat). An additional analysis was performed of two consecutive negative cultures.

Results

Of the 281 susceptible AGNB in the throat and 1,087 in the rectum on admission, 97.9 and 93.7%, respectively, of these microorganisms were successfully eradicated. In the upper GI-tract no differences in eradication rates were found between susceptible and resistant microorganisms. However, the median duration until eradication was significantly longer for aminoglycosides resistant vs. susceptible microorganisms (5 vs. 4 days, p < 0.01). In the lower GI-tract, differences in eradication rates between susceptible and resistant microorganisms were found for cephalosporins (90.0 vs. 95.6%), aminoglycosides (84.4 vs. 95.5%) and ciprofloxacin (90.0 vs. 95.2%). Differences in median duration until eradication between susceptible and resistant microorganisms were found for aminoglycosides and ciprofloxacin (both 5 days vs. 6 days, p = 0.001). Decontamination defined as two negative cultures was achieved in a lower rate (77–98% for the upper GI tract and 64–77% for the lower GI tract) and a median of 1 day later.

Conclusion

The vast majority of both susceptible and resistant microorganisms are effectively eradicated from the upper and lower GI tract. In the lower GI tract decontamination rates of susceptible microorganisms are significantly higher and achieved in a shorter time period compared to resistant strains.

Ventilator-Associated Events: Epidemiology, Risk Factors, and Prevention

The Centers for Disease Control and Prevention shifted the focus of safety surveillance in mechanically ventilated patients from ventilator-associated pneumonia to ventilator-associated events in 2013 to increase the objectivity and reproducibility of surveillance and to encourage quality improvement programs to focus on preventing a broader array of complications. Ventilator-associated events are associated with a doubling of the risk of dying. Prospective studies have found that minimizing sedation, increasing spontaneous awakening and breathing trials, and conservative fluid management can decrease event rates and the duration of ventilation. Multifaceted interventions to enhance these practices can decrease ventilator-associated event rates.

Modelling and Simulation of the Effect of Targeted Decolonisation on Incidence of Extended-Spectrum Beta-Lactamase-Producing Enterobacterales Bloodstream Infections in Haematological Patients

Introduction

Haematological patients are at higher risk of bloodstream infections (BSI) after chemotherapy. The aim of this study was to develop a simulation model assessing the impact of selective digestive decontamination (SDD) of haematological patients colonised with extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) on the incidence of ESBL-E BSI after chemotherapy.

Methods

A patient population was created by a stochastic simulation model mimicking the patients’ states of colonisation with ESBL-E during hospitalisation. A systematic literature search was performed to inform the model. All ESBL-E carriers were randomised (1:1) to either the intervention (targeted SDD) or the control group (placebo). ESBL-E BSI incidence was the outcome of the model. Sensitivity analyses were performed by prevalence of ESBL-E carriage at hospital admission (low: < 10%, medium: 10–25%, high: > 25%), duration of neutropenia after receiving chemotherapy, administration of antibiotic prophylaxis with quinolones, and time interval between SDD and chemotherapy.

Results

The model estimated that the administration of targeted SDD before chemotherapy reduces the incidence of ESBL-E BSI in the hospitalised haematological population up to 27%. The greatest benefit was estimated in high-prevalence settings, regardless of the duration of neutropenia, the time interval before chemotherapy, and the administration of antibiotic prophylaxis with quinolones (p < 0.05). In medium-prevalence settings, SDD was effective in patients receiving quinolone prophylaxis, with either 1-day time interval before chemotherapy and a neutropenia duration > 6 days (p < 0.05) or 7-day time interval before chemotherapy and a neutropenia duration > 9 days (p < 0.05). No benefit was observed in low-prevalence settings.

Conclusions

Our model suggests that targeted SDD could decrease the rate of ESBL-E BSI in haematological carriers before chemotherapy in the setting of high ESBL-E prevalence at hospital admission. These estimates require confirmation by well-designed multicentre RCTs, including the assessment of the impact on resistance/disruption patterns of gut microbiome.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-021-00550-3.

Anti-infectious decontamination strategies in Dutch intensive care units: A survey study on contemporary practice and heterogeneity

PURPOSE

Despite increasing evidence and updated national guidelines, practice of anti-infectious strategies appears to vary in the Netherlands. This study aimed to determine the variation of current practices of anti-infectious strategies in Dutch ICUs.

MATERIALS AND METHODS

In 2018 and 2019 an online survey of all Dutch ICUs was conducted with detailed questions on their anti-infectious strategies.

RESULTS

89% (63 of 71) of the Dutch ICUs responded to the online survey. The remaining ICUs were contacted by telephone. 47 (66%) of the Dutch ICUs used SDD, 14 (20%) used SOD and 10 (14%) used neither SDD nor SOD. Within these strategies considerable heterogeneity was observed in the start criteria of SDD/SOD, the regimen adjustments based on microbiological surveillance and the monitoring of the interventions.

CONCLUSIONS

The proportion of Dutch ICUs applying SDD or SOD increased over time. Considerable heterogeneity in the regimens was reported. The impact of the observed differences within SDD and SOD practices on clinical outcome remains to be explored.

Is selective decontamination (SDD/SOD) safe in the ICU context?

Multiple individual studies of selective digestive decontamination/selective oropharyngeal decontamination (SDD/SOD) among ICU patients appear to show potent infection prevention effects. Surprisingly, the event rates for multiple endpoints including ventilator-associated pneumonia, bacteraemia and candidaemia among concurrent control groups within SDD/SOD studies appear unusually high versus other rates in the literature. These paradoxical observations raise concern that the contextual effects of SDD/SOD, as postulated in the original SDD/SOD study, not only exist but also are strong. Until these effects are addressed within an optimally designed study, the safety of SDD/SOD within the 'whole of ICU' remains questionable.

Prevention of severe infectious complications after colorectal surgery using oral non-absorbable antimicrobial prophylaxis: results of a multicenter randomized placebo-controlled clinical trial

BACKGROUND

Surgical site infections (SSIs) are common complications after colorectal surgery. Oral non-absorbable antibiotic prophylaxis (OAP) can be administered preoperatively to reduce the risk of SSIs. Its efficacy without simultaneous mechanical cleaning is unknown.

METHODS

The Precaution trial was a double-blind, placebo-controlled randomized clinical trial conducted in six Dutch hospitals. Adult patients who underwent elective colorectal surgery were randomized to receive either a three-day course of preoperative OAP with tobramycin and colistin or placebo. The primary composite endpoint was the incidence of deep SSI or mortality within 30 days after surgery. Secondary endpoints included both infectious and non-infectious complications at 30 days and six months after surgery.

RESULTS

The study was prematurely ended due to the loss of clinical equipoise. At that time, 39 patients had been randomized to active OAP and 39 to placebo, which reflected 8.1% of the initially pursued sample size. Nine (11.5%) patients developed the primary outcome, of whom four had been randomized to OAP (4/39; 10.3%) and five to placebo (5/39; 12.8%). This corresponds to a risk ratio in the intention-to-treat analysis of 0.80 (95% confidence interval (CI) 0.23-2.78). In the per-protocol analysis, the relative risk was 0.64 (95% CI 0.12-3.46).

CONCLUSIONS

Observational data emerging during the study provided new evidence for the effectiveness of OAP that changed both the clinical and medical ethical landscape for infection prevention in colorectal surgery. We therefore consider it unethical to continue randomizing patients to placebo. We recommend the implementation of OAP in clinical practice and continuing monitoring of infection rates and antibiotic susceptibilities.

TRIAL REGISTRATION

The PreCaution trial is registered in the Netherlands Trial Register under NL5932 (previously: NTR6113) as well as in the EudraCT register under 2015-005736-17.

Selective decontamination of the digestive tract (SDD) in critically ill patients: a narrative review

Selective decontamination of the digestive tract (SDD) is an infection prevention measure for intensive care unit (ICU) patients that was proposed more than 30 years ago, and that is currently considered standard of care in the Netherlands, but only used sporadically in ICUs in other countries. In this narrative review, we first describe the rationale of the individual components of SDD and then review the evidence base for patient-centered outcomes, where we distinguish ICUs with low prevalence of antibiotic resistance from ICUs with moderate–high prevalence of resistance. In settings with low prevalence of antibiotic resistance, SDD has been associated with improved patient outcome in three cluster-randomized studies. These benefits were not confirmed in a large international cluster-randomized study in settings with moderate-to-high prevalence of antibiotic resistance. There is no evidence that SDD increases antibiotic resistance. We end with future directions for research.

Strategies for the eradication of extended-spectrum beta-lactamase or carbapenemase-producing Enterobacteriaceae intestinal carriage

Introduction: Among the multidrug resistant pathogens, extended-spectrum beta-lactamase (ESBL-E) or carbapenemase-producing Enterobacteriaceae (CPE) are currently considered the main threat due to the scarcity of therapeutic options and their rapid spread around the globe. In addition to developing new antibiotics and stopping transmission, recent research has focused on 'decolonization' strategies to eradicate the carriage of ESBL-E/CPE before infection occurs. Areas covered: In this narrative review, we aim to describe the current evidence of decolonization strategies for ESBL-E or CPE intestinal carriage. We first define decolonization and highlight the issues related to the lack of standardized definitions, then we summarize the available data on the natural history of colonization. Finally, we review the strategies assessed over the past 10 years for ESBL and CPE decolonization: oral antibiotics, probiotics and more recently fecal microbiota transplantation. We conclude by presenting the risks and uncertainties associated with these strategies. Expert opinion: The evidence available today is too low to recommend decolonization strategies for ESBL-E or CPE in routine clinical practice. The potential increase of resistance and the impact of microbiome manipulation should not be underestimated. Some of these decolonization strategies may nevertheless be effective, at least in temporarily suppressing colonization, which could be useful for specific populations such as high-risk patients. Effectiveness and long-term effects must be properly assessed through well-designed randomized controlled trials.

Is Zero Ventilator-Associated Pneumonia Achievable?: Practical Approaches to Ventilator-Associated Pneumonia Prevention

Ventilator-associated pneumonia (VAP) remains a significant clinical entity with reported incidence rates of 7% to 15%. Given the considerable adverse consequences associated with this infection, VAP prevention became a core measure required in most US hospitals. Many institutions implemented effective VAP prevention bundles that combined head of bed elevation, hand hygiene, chlorhexidine oral care, and subglottic drainage. More recently, spontaneous breathing and awakening trials have consistently been shown to shorten the duration of mechanical ventilation and secondarily reduce the occurrence of VAP. More recent data question the overall positive impact of prevention bundles, including some of their core component interventions.

The ecological effects of selective decontamination of the digestive tract (SDD) on antimicrobial resistance: a 21-year longitudinal single-centre study

Background

The long-term ecological effects on the emergence of antimicrobial resistance at the ICU level during selective decontamination of the digestive tract (SDD) are unknown. We determined the incidence of newly acquired antimicrobial resistance of aerobic gram-negative potentially pathogenic bacteria (AGNB) during SDD.

Methods

In a single-centre observational cohort study over a 21-year period, all consecutive patients, treated with or without SDD, admitted to the ICU were included. The antibiotic regime was unchanged over the study period. Incidence rates for ICU-acquired AGNB’s resistance for third-generation cephalosporins, colistin/polymyxin B, tobramycin/gentamicin or ciprofloxacin were calculated per year. Changes over time were tested by negative binomial regression in a generalized linear model.

Results

Eighty-six percent of 14,015 patients were treated with SDD. Most cultures were taken from the digestive tract (41.9%) and sputum (21.1%). A total of 20,593 isolates of AGNB were identified. The two most often found bacteria were Escherichia coli (N = 6409) and Pseudomonas (N = 5269). The incidence rate per 1000 patient-day for ICU-acquired resistance to cephalosporins was 2.03, for polymyxin B/colistin 0.51, for tobramycin 2.59 and for ciprofloxacin 2.2. The incidence rates for ICU-acquired resistant microbes per year ranged from 0 to 4.94 per 1000 patient-days, and no significant time-trend in incidence rates were found for any of the antimicrobials. The background prevalence rates of resistant strains measured on admission for cephalosporins, polymyxin B/colistin and ciprofloxacin rose over time with 7.9%, 3.5% and 8.0% respectively.

Conclusions

During more than 21-year SDD, the incidence rates of resistant microbes at the ICU level did not significantly increase over time but the background resistance rates increased. An overall ecological effect of prolonged application of SDD by counting resistant microorganisms in the ICU was not shown in a country with relatively low rates of resistant microorganisms.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2480-z) contains supplementary material, which is available to authorized users.

Monitoring of tobramycin serum concentrations in selected critically ill patients receiving selective decontamination of the digestive tract: a retrospective evaluation

INTRODUCTION

Selective decontamination of the digestive tract (SDD) is a strategy in mechanically ventilated patients to reduce mortality. Treatment consists of enterally administered non-absorbable antibiotics, i.e., tobramycin. However, most intensive care unit (ICU) patients with SDD appear to have detectable tobramycin serum concentrations. The Rijnstate Hospital implemented a protocol for therapeutic drug monitoring (TDM) of tobramycin in patients at risk. The aim of this study was to evaluate the necessity of TDM in these patients and to optimize the current protocol.

METHODS

This retrospective observational study included ICU patients with SDD treatment for ≥ 7 days and renal failure. These patients were considered eligible for monitoring of tobramycin. Tobramycin serum concentrations, relevant laboratory parameters (i.e., renal function, lactate), and patient data were extracted from the National Intensive Care Evaluation database and the hospital electronic patient data system.

RESULTS

In 23 subjects, a total of 43 tobramycin serum concentrations was determined. The median tobramycin serum concentration was 0.33 (IQR 0.17-0.49) mg/L of which 12 (27.9%) samples had concentrations < 0.2 mg/L, 30 (69.8%) had concentrations 0.2-1.0 mg/L and 1 (2.3%) had a toxic concentration > 1.0 mg/L. In 3 (7.0%) cases, an intervention was conducted based on the tobramycin serum concentration.

CONCLUSION

The majority (83.7%) of samples had detectable tobramycin serum concentrations. Monitoring of tobramycin serum concentrations can be considered necessary in patients at risk. However, the current protocol should be optimized to intercept patients more precise.

Drying technology strategies for colon-targeted oral delivery of biopharmaceuticals

In chronic intestinal diseases like inflammatory bowel disease, parenteral administration of biopharmaceuticals is associated with numerous disadvantages including immune reactions, infections, low patient compliance, and toxicity caused by high systemic bioavailability. One alternative that can potentially overcome these limitations is oral administration of biopharmaceuticals, where the local delivery will reduce the systemic exposure and furthermore the manufacturing costs will be lower. However, the development of oral dosage forms that deliver the biologically active form to the intestines is one of the greatest challenges for pharmaceutical technologists due to the sensitive nature of biopharmaceuticals. The present article discusses the various drug delivery technologies used to produce orally administered solid dosage forms of biopharmaceuticals with an emphasis on colon-targeted delivery. Solid oral dosage compositions containing different types of colon-targeting biopharmaceuticals are compiled followed by a review of currently applied and emerging drying technologies for biopharmaceuticals. The different drying technologies are compared in terms of their advantages, limitations, costs and their effect on product stability.

The Role of the Environment and Colonization in Healthcare-Associated Infections

Healthcare-associated infections (HAIs) can be caused by endogenous host microbial flora or by exogenous microbes, including those found in the hospital environment. Efforts to decrease endogenous pathogens via decolonization and skin antisepsis may decrease the risk of infection in some settings. Controlling the spread of potential pathogens from the environment requires meticulous attention to cleaning and disinfection practices. In addition to selection of the appropriate cleaning agent, use of tools that assess the adequacy of cleaning and addition of no-touch cleaning technology may decrease environmental contamination. Hand hygiene is also a critical component of preventing transmission of pathogens from the environment to patients via healthcare worker hands.

Use of Colistin in Critically Ill Patients

Due to lack of better therapeutic options, colistin use for extensively drug-resistant Gram-negative organisms was revived in the past two decades, including in patients in intensive-care units (ICU). There are multiple knowledge gaps pertaining to the clinical use and utility of colistin in critically-ill patients, but due to lack of options, it is used in these high risk patients. In this chapter, we critically review the various topics pertaining to colistin use in critically-ill patients, while highlighting the (lack of) controlled evidence supporting common current practices pertaining to colistin use by clinicians.

Recovery of gut microbiota of healthy adults following antibiotic exposure

To minimize the impact of antibiotics, gut microorganisms harbour and exchange antibiotics resistance genes, collectively called their resistome. Using shotgun sequencing-based metagenomics, we analysed the partial eradication and subsequent regrowth of the gut microbiota in 12 healthy men over a 6-month period following a 4-day intervention with a cocktail of 3 last-resort antibiotics: meropenem, gentamicin and vancomycin. Initial changes included blooms of enterobacteria and other pathobionts, such as Enterococcus faecalis and Fusobacterium nucleatum, and the depletion of Bifidobacterium species and butyrate producers. The gut microbiota of the subjects recovered to near-baseline composition within 1.5 months, although 9 common species, which were present in all subjects before the treatment, remained undetectable in most of the subjects after 180 days. Species that harbour β-lactam resistance genes were positively selected for during and after the intervention. Harbouring glycopeptide or aminoglycoside resistance genes increased the odds of de novo colonization, however, the former also decreased the odds of survival. Compositional changes under antibiotic intervention in vivo matched results from in vitro susceptibility tests. Despite a mild yet long-lasting imprint following antibiotics exposure, the gut microbiota of healthy young adults are resilient to a short-term broad-spectrum antibiotics intervention and their antibiotics resistance gene carriage modulates their recovery processes.

Long-term use of selective digestive decontamination in an ICU highly endemic for bacterial resistance

BACKGROUND

We examined whether long-term use of selective digestive tract decontamination (SDD) was effective in reducing intensive care unit (ICU)-acquired infection and antibiotic consumption while decreasing colistin-, tobramycin-, and most of the antibiotic-resistant colonization rates in a mixed ICU with a high endemic level of multidrug-resistant bacteria (MDRB).

METHODS

In this cohort study, which was conducted in a 30-bed medical-surgical ICU, clinical outcomes before (1 year, non-SDD group) and after (4 years) implementation of SDD were compared. ICU patients who were expected to require tracheal intubation for > 48 hours were given a standard prophylactic SDD regimen. Oropharyngeal and rectal swabs were obtained on admission and once weekly thereafter.

RESULTS

ICU-acquired infections occurred in 110 patients in the non-SDD group and in 258 in the SDD group. A significant (P <  0.001) reduction of infections caused by MDRB (risk ratio [RR], 0.31; 95% CI, 0.23-0.41) was found after SDD and was associated with low rates of colistin- and tobramycin-resistant colonization. Colistin- and tobramycin-acquired increasing rate of ICU colonization resistance by 1000 days, adjusted by the rate of resistances at admission, was nonsignificant (0.82; 95% CI, 0.56 to 1.95; 1.13; 95% CI, 0.75 to 1.70, respectively). SDD was also a protective factor for ICU-acquired infections caused by MDR gram-negative pathogens and Acinetobacter baumannii in the multivariate analysis. In addition, a significant (P <  0.001) reduction of ventilator-associated pneumonia (VAP) (RR, 0.43; 95% CI, 0.32-0.59) and secondary bloodstream infection (BSI) (RR, 0.35; 95% CI, 0.24-0.52) was found. A decrease in antibiotic consumption was also observed.

CONCLUSIONS

Treatment with SDD during 4 years was effective in an ICU setting with a high level of resistance, with clinically relevant reductions of infections caused by MDRB, and with low rates of colistin- and tobramycin-resistant colonization with nonsignificant increasing rate of ICU colonization resistance by 1000 days, adjusted by the rate of resistances at ICU admission. In addition, VAP and secondary BSI rates were significantly lower after SDD. Notably, a decrease in antimicrobial consumption was also observed.

National laboratory-based surveillance system for antimicrobial resistance: a successful tool to support the control of antimicrobial resistance in the Netherlands

An important cornerstone in the control of antimicrobial resistance (AMR) is a well-designed quantitative system for the surveillance of spread and temporal trends in AMR. Since 2008, the Dutch national AMR surveillance system, based on routine data from medical microbiological laboratories (MMLs), has developed into a successful tool to support the control of AMR in the Netherlands. It provides background information for policy making in public health and healthcare services, supports development of empirical antibiotic therapy guidelines and facilitates in-depth research. In addition, participation of the MMLs in the national AMR surveillance network has contributed to sharing of knowledge and quality improvement. A future improvement will be the implementation of a new semantic standard together with standardised data transfer, which will reduce errors in data handling and enable a more real-time surveillance. Furthermore, the scientific impact and the possibility of detecting outbreaks may be amplified by merging the AMR surveillance database with databases from selected pathogen-based surveillance programmes containing patient data and genotypic typing data.

Is Selective Digestive Decontamination Useful for Critically Ill Patients?

In this study we review the rationale for using selective digestive decontamination (SDD) in critically ill patients, and its effects on clinical outcomes and rates of infection with antimicrobial-resistant microorganisms. SDD consists of the application of nonabsorbable antibiotics to the oropharynx and through a nasogastric or nasoenteral tube, in association with a 4-day course of an intravenous third-generation cephalosporin. The enteral component aims at preventing oral and rectal colonization with potentially pathogenic nosocomial aerobic gram-negative bacilli and yeasts while preserving normal protective anaerobic enteral flora. The short-course systemic component aims at eradicating oral endogenous gram-positive bacteria. SDD decreases the risk of nosocomial infections, and reduces by one-quarter the mortality of patients on mechanical ventilation in settings with low prevalence of antibiotic resistance. Evidence from randomized trials suggests that SDD does not increase rates of antimicrobial-resistant microorganisms, and may reduce resistance rates to some antibiotics. However, several limitations decrease our confidence on these data, particularly for settings with high baseline rates of antimicrobial-resistant microorganisms. Although SDD has a clear potential to improve clinical outcomes of critically patients, its long-term ecologic effects on rates of antimicrobial resistant require appropriate assessment by large multinational cluster randomized trials. Before these results are available, the use of SDD cannot be recommended in most parts of the world, except in settings with very low baseline prevalence of antibiotic resistance.

Ventilator-Associated Events and Their Prevention

The Centers for Disease Control and Prevention shifted the focus of safety surveillance in mechanically ventilated patients from ventilator-associated pneumonia to ventilator-associated events (VAEs) in 2013. The shift was designed to increase the objectivity and reproducibility of surveillance and to encourage quality-improvement programs to tackle a broader array of complications in mechanically ventilated patients. Prospective intervention studies have found that minimizing sedation, increasing the use of spontaneous awakening and breathing trials, and conservative fluid management can lower VAE rates and decrease duration of mechanical ventilation. Additional strategies to prevent VAEs include early mobility programs, low tidal volume ventilation, and restrictive transfusion thresholds.

Selective decontamination of the digestive tract and oropharynx: after 30 years of debate is the definitive answer in sight?

PURPOSE OF REVIEW

Selective digestive or oropharyngeal decontamination has been being used as a means to prevent infections and death in intensive care patients for the past 30 years. It remains controversial and its use is limited. In this review, we summarize the recently published data on efficacy of selective decontamination and effects on antibiotic resistances.

RECENT FINDINGS

The most recent meta-analysis shows a reduced mortality when selective digestive or oropharyngeal decontamination are compared with either standard care or oropharyngeal chlorhexidine. Selective decontamination is associated with reduced bacteraemia, and although this effect is greater with selective digestive decontamination compared with selective oropharyngeal decontamination, there is not a mortality difference between these two interventions. Reanalysis of infection data suggests, however, that selective decontamination may also have effects on concurrent control groups. Current evidence generally shows that antibiotic resistance is decreased although much of these data come from the Netherlands (an area with low endemic antibiotic resistance rates). There are currently two huge cluster randomized clinical trials, one in early recruitment, one in development, which will hopefully provide definitive answers in the years to come.

SUMMARY

Current evidence suggests that selective decontamination reduces mortality without increasing antibiotic resistances; this will be tested again in two huge international trials.

Current status of selected oral peptide technologies in advanced preclinical development and in clinical trials

The development of oral dosage forms that allows absorption of therapeutic peptides to the systemic circulation is one of the greatest challenges for the pharmaceutical industry. Currently, a number of technologies including either mixtures of penetration enhancers or protease inhibitors and/or nanotechnology-based products are under clinical development. Typically, these formulations are presented in the form of enteric-coated tablets or capsules. Systems undergoing preclinical investigation include further advances in nanotechnology, including intestinal microneedle patches, as well as their combination with regional delivery to the colon. This review critically examines four selected promising oral peptide technologies at preclinical stage and the twelve that have progressed to clinical trials, as indicated in www.clinicaltrials.gov. We examined these technologies under the criteria of peptide selection, formulation design, system components and excipients, intestinal mechanism of action, efficacy in man, and safety issues. The conclusion is that most of the technologies in clinical trials are incremental rather than paradigm-shifting and that even the more clinically advanced oral peptide drugs examples of oral bioavailability appear to yield oral bioavailability values of only 1-2% and are, therefore, only currently suitable for a limited range of peptides.

Pilot Study of the Pharmacokinetics of Cefotaxime in Critically Ill Patients with Acute Kidney Injury Treated with Continuous Renal Replacement Therapy

The objective of this study was to describe the pharmacokinetics of cefotaxime (CTX) in critically ill patients with acute kidney injury (AKI) when treated with continuous renal replacement therapy (CRRT) in the intensive care unit (ICU). This single-center prospective observational pilot study was performed among ICU-patients with AKI receiving ≥48 h concomitant CRRT and CTX. CTX was administered intravenously 1,000 mg (bolus) every 6 h for 4 days. CRRT was performed as continuous venovenous hemofiltration (CVVH). Plasma concentrations of CTX and its active metabolite desacetylcefotaxime (DAC) were measured during CVVH treatment. CTX plasma levels and patient data were used to construct concentration-time curves. By using this data, the duration of plasma levels above 4 mg/liter (four times the MIC) was calculated and analyzed. Twenty-seven patients were included. The median CTX peak level was 55 mg/liter (range, 19 to 98 mg/liter), the median CTX trough level was 12 mg/liter (range, 0.8 to 37 mg/liter), and the median DAC plasma level was 15 mg/liter (range, 1.5 to 48 mg/liter). Five patients (19%) had CTX plasma levels below 4 mg/liter at certain time points during treatment. In at least 83% of the time any patient was treated with CTX, the CTX plasma level stayed above 4 mg/liter. A dosing regimen of 1,000 mg of CTX given four times daily is likely to achieve adequate plasma levels in patients with AKI treated with CVVH. Dose reduction might be a risk for suboptimal treatment.

Fighting antibiotic resistance in the intensive care unit using antibiotics

Antibiotic resistance is a global and increasing problem that is not counterbalanced by the development of new therapeutic agents. The prevalence of antibiotic resistance is especially high in intensive care units with frequently reported outbreaks of multidrug-resistant organisms. In addition to classical infection prevention protocols and surveillance programs, counterintuitive interventions, such as selective decontamination with antibiotics and antibiotic rotation have been applied and investigated to control the emergence of antibiotic resistance. This review provides an overview of selective oropharyngeal and digestive tract decontamination, decolonization of methicillin-resistant Staphylococcus aureus and antibiotic rotation as strategies to modulate antibiotic resistance in the intensive care unit.

Decolonization and decontamination: what's their role in infection control?

PURPOSE OF REVIEW

Hospital-acquired infections cause up to 19% of infections in paediatric patients contributing to the spread of antimicrobial resistance. This review evaluates the effect of decolonization and decontamination in hospitalized children and neonates as an adjunct to standard infection control measures.

RECENT FINDINGS

Few studies on decolonization and decontamination are available in children. The evidence about the effectiveness of daily chlorhexidine washcloths on bacteraemia in paediatric patients relies on a single randomized controlled trial, in neonates with central venous access in a single retrospective observational study. It is uncertain whether nasal mupirocin reduces methicillin-resistant Staphylococcus aureus carriage and infections in neonates, whereas oral chlorhexidine mouthwashes have not proven effective in children in intensive care settings. Scanty evidence demonstrates a reduction in the rate of ventilation-acquired pneumonia with digestive tract decontamination in paediatric patients and no studies are available in neonates. These strategies have not been extensively tested in resource-poor countries.

SUMMARY

Strong evidence about the efficacy of decolonization and decontamination interventions exists in adult medicine but not in paediatric patients. There is an urgent need to understand how these interventions could be adapted to neonates and resource-poor settings in which the prevalence of hospital-acquired infections is higher.

Selective oropharyngeal decontamination versus selective digestive decontamination in critically ill patients: a meta-analysis of randomized controlled trials

BACKGROUND

Selective digestive decontamination (SDD) and selective oropharyngeal decontamination (SOD) are associated with reduced mortality and infection rates among patients in intensive care units (ICUs); however, whether SOD has a superior effect than SDD remains uncertain. Hence, we conducted a meta-analysis of randomized controlled trials (RCTs) to compare SOD with SDD in terms of clinical outcomes and antimicrobial resistance rates in patients who were critically ill.

METHODS

RCTs published in PubMed, Embase, and Web of Science were systematically reviewed to compare the effects of SOD and SDD in patients who were critically ill. Outcomes included day-28 mortality, length of ICU stay, length of hospital stay, duration of mechanical ventilation, ICU-acquired bacteremia, and prevalence of antibiotic-resistant Gram-negative bacteria. Results were expressed as risk ratio (RR) with 95% confidence intervals (CIs), and weighted mean differences (WMDs) with 95% CIs. Pooled estimates were performed using a fixed-effects model or random-effects model, depending on the heterogeneity among studies.

RESULTS

A total of four RCTs involving 23,822 patients met the inclusion criteria and were included in this meta-analysis. Among patients whose admitting specialty was surgery, cardiothoracic surgery (57.3%) and neurosurgery (29.7%) were the two main types of surgery being performed. Pooled results showed that SOD had similar effects as SDD in day-28 mortality (RR = 1.03; 95% CI: 0.98, 1.08; P = 0.253), length of ICU stay (WMD = 0.00 days; 95% CI: -0.2, 0.2; P = 1.00), length of hospital stay (WMD = 0.00 days; 95% CI: -0.65, 0.65; P = 1.00), and duration of mechanical ventilation (WMD =1.01 days; 95% CI: -0.01, 2.02; P = 0.053). On the other hand, compared with SOD, SDD had a lower day-28 mortality in surgical patients (RR =1.11; 95% CI: 1.00, 1.22; P = 0.050), lower incidence of ICU-acquired bacteremia (RR = 1.38; 95% CI: 1.24, 1.54; P = 0.000), and lower rectal carriage of aminoglycosides (RR = 2.08; 95% CI: 1.68, 2.58; P = 0.000), ciprofloxacin-resistant Gram-negative bacteria (RR = 1.84; 95% CI: 1.48, 2.29; P = 0.000), and respiratory carriage of third-generation cephalosporin-resistant Gram-negative bacteria (RR = 2.50; 95% CI: 1.78, 3.5; P = 0.000).

CONCLUSION

SOD has similar effects as SDD in clinical outcomes, but has higher incidence of ICU-acquired bacteremia, and higher carriage of antibiotic-resistant Gram-negative bacteria. However, due to the high cost of SDD and the increased risk of development of antibiotic resistance with the widespread use of cephalosporins in SDD, we would recommend SOD as prophylactic antibiotic regimens in patients in the ICU. More well-designed, large-scale RCTs are needed to confirm our findings.

Selective decontamination and antibiotic resistance in ICUs

Selective digestive decontamination (SDD) and selective oropharyngeal decontamination (SOD) have been associated with reduced mortality and lower ICU-acquired bacteremia and ventilator-associated pneumonia rates in areas with low levels of antibiotic resistance. However, the effect of selective decontamination (SDD/SOD) in areas where multidrug-resistant Gram-negative bacteria are endemic is less clear. It will be important to determine whether SDD/SOD improves patient outcome in such settings and how these measures affect the epidemiology of multidrug-resistant Gram-negative bacteria. Here we review the current evidence on the effects of SDD/SOD on antibiotic resistance development in individual ICU patients as well as the effect on ICU ecology, the latter including both ICU-level antibiotic resistance and antibiotic resistance development during long-term use of SDD/SOD.

Infection control measures to decrease the burden of antimicrobial resistance in the critical care setting

PURPOSE OF REVIEW

The prevalence of multidrug-resistant organisms (MDROs) in ICUs is increasing worldwide. This review assesses the role of infection control measures, excluding antibiotic stewardship programs, in reducing the burden of resistance in ICUs.

RECENT FINDINGS

The knowledge base about the effect of increased hand hygiene compliance in reducing the burden of methicillin-resistant Staphylococcus aureus in ICUs has been improved. Universal decolonization with chlorhexidine body washing was associated with significant reduction in MDRO prevalence, but vigilance for emerging chlorhexidine resistance is required. A significant reduction of resistance for Gram-negative bacilli has been demonstrated with the use of selective decontamination, but further clinical trials are necessary before definitive conclusions can be drawn regarding long-term risk/benefit ratios.

SUMMARY

In the recent years, several high-quality clinical studies have assessed the ability of various infection control measures in reducing the burden of antimicrobial resistance. Significant progress has been made in identifying interventions effective in preventing transmission of MDROs in ICUs, in particular, decolonization. However, it still remains impossible to determine the exact and relative importance of different infection control measures. Any approach must ultimately be tailored to the local epidemiology of the targeted ICU.

Colistin and tobramycin resistance during long- term use of selective decontamination strategies in the intensive care unit: a post hoc analysis

Introduction

Selective decontamination of the digestive tract (SDD) and selective oropharyngeal decontamination (SOD) have been shown to improve intensive care unit (ICU) patients’ outcomes. The aim of this study was to determine the effects of long-term use of SDD and SOD on colistin and tobramycin resistance among gram-negative bacteria.

Methods

We performed a post hoc analysis of two consecutive multicentre cluster-randomised trials with crossover of interventions. SDD and SOD were alternately but continuously used during 7 years in five Dutch ICUs participating in two consecutive cluster-randomised trials. In both trials, to measure colistin and tobramycin resistance among gram-negative bacteria, rectal and respiratory samples were obtained monthly from all patients present in the ICU.

Results

The prevalence of tobramycin resistance in respiratory and rectal samples decreased significantly during long-term use of SOD and SDD. (rectal samples risk ratio (RR) 0.35 (0.23 to 0.53); respiratory samples RR 0.48 (0.32 to 0.73), SDD compared to standard care). Colistin resistance in rectal and respiratory samples did not change (rectal samples RR 0.63 (0.29 to 1.38); respiratory samples RR 1.26 (0.35 to 4.57), SDD compared to standard care).

Conclusions

In this study, in a setting with low antimicrobial resistance rates, the prevalence of resistance against colistin and tobramycin among gram-negative isolates did not increase during a mean of 7 years of SDD or SOD use.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-0838-4) contains supplementary material, which is available to authorized users.

The views of health care professionals about selective decontamination of the digestive tract: an international, theoretically informed interview study

PURPOSE

Selective decontamination of the digestive tract (SDD) as a prophylactic intervention improves hospital-acquired infection and survival rates. Uptake of SDD is low and remains controversial. This study applied the theoretical domains framework to assess intensive care unit clinicians' views about SDD in regions with limited or no adoption of SDD.

MATERIALS AND METHODS

Participants were health professionals with "decisional authority" for the adoption of SDD. Semistructured interviews were conducted as the first round of a Delphi study. Views about SDD adoption, delivery, and further SDD research were explored. Directed content analysis of interview data identified subthemes, which informed item development for subsequent Delphi rounds. Linguistic features of interview data were also explored.

RESULTS

One hundred forty-one participants provided interview data. Fifty-six subthemes were identified; 46 were common across regions. Beliefs about consequences were the most widely elaborated theme. Linguistic features of how participants discussed SDD included caution expressed when discussing the risks and benefits and words such as "worry," "anxiety," and "fear" when discussing potential antibiotic resistance associated with SDD.

CONCLUSIONS

We identified salient beliefs, barriers, and facilitators to SDD adoption and delivery. What participants said about SDD and the way in which they said it demonstrated the degree of clinical caution, uncertainty, and concern that SDD evokes.

Gut instinct

Barriers to the use of selective digestive decontamination include concerns about emergence of resistant organisms, over-estimation of current performance in preventing ventilator-associated pneumonia (VAP), alternative methods of preventing VAP, and misunderstanding of mechanisms of action. A definitive cluster-randomised trial should be undertaken that incorporates practitioner concerns and effect-size preferences.