All great truths are iconoclastic: selective decontamination of the digestive tract moves from heresy to level 1 truth

Amorphous Roxithromycin Loaded in-situ Gel for the Treatment of Staphylococcus aureus Induced Upper Respiratory Tract Infection

Objective

Upper respiratory tract infections are among the most prevalent respiratory diseases, imposing both financial and physical burdens on affected individuals. Roxithromycin (ROX), a primary drug for treating bacterial-induced respiratory tract infections, is typically administered orally due to its hydrophobic nature. However, the non-specific distribution resulting from oral administration reduces bioavailability and can cause side effects such as diarrhea.

Methods

In this study, we prepared a thermo-sensitive in-situ gel using a facile and highly reproducible method by simply mixing two types of poloxamers with ROX.

Results

The ROX can be well dissolved in the poloxamer matrix in amorphous state to give solution. Upon intranasal administration, the ROX solution undergoes a phase transition to form in-situ gel under body temperature. This gel remains in the nasal cavity for an extended period, releasing the drug directly to the site of infection and minimizing non-specific distribution. Pharmacokinetic experiments revealed that, compared to oral administration, the bioavailability of local nasal administration increased by 1.5 times, and the drug concentration in the local nasal cavity increased by 8 times. In contrast, concentrations in the liver and small intestine did not significantly differ from those following oral administration. In vivo antibacterial experiments also showed that the ROX in-situ gel has superior antibacterial efficacy and excellent biocompatibility.

Conclusion

These results suggest that the thermo-sensitive ROX in-situ gel is a promising formulation for treating bacterial upper respiratory tract infections.

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.

Selective Intestinal Decontamination as a Method for Preventing Infectious Complications (Review)

Infectious complications are the most common cause of death in patients with severe burns. To date, there is no generally accepted method for preventing such complications in burn injury. One of the possible prevention options is selective intestinal decontamination (SID). This method is based on the enteral administration of non-absorbable antimicrobial agents. The preventive effect of SID involves inhibition of intestinal microflora translocation through the mucous membranes, inasmuch as studies demonstrate that endogenous opportunistic microorganisms are a common cause of infectious complications in various critical conditions. The SID method was originally developed in the Netherlands for patients suffering from mechanical injury. Antimicrobial drugs were selected based on their high activity in relation to the main endogenous opportunistic pathogens and minimal activity against normal intestinal microflora components. The combination of polymyxin (B or E), tobramycin, and amphotericin B with intravenous cefotaxime was chosen as the first SID regimen. Other regimens were proposed afterwards, and the application field of the method was expanded. In particular, it became the method of choice for prevention of infectious complications in patients with severe burn injury. Clinical studies demonstrate efficacy of some SID regimens for preventing infectious complications in patients with thermal injury. Concomitant administration of SID and systemic preventive antibiotics and addition of oropharyngeal decontamination increases the method efficacy. SID is generally well-tolerated, but some studies show an increased risk of diarrhea with this preventive option. In addition, SID increases the risk of developing antibiotic resistance like any other antibiotic regimens.

Ventilator-Associated Pneumonia and PaO2/FIO2 Diagnostic Accuracy: Changing the Paradigm?

Background: Ventilator-associated pneumonia (VAP) is associated to longer stay and poor outcomes. Lacking definitive diagnostic criteria, worsening gas exchange assessed by PaO₂/F_IO₂ ≤ 240 in mmHg has been proposed as one of the diagnostic criteria for VAP. We aim to assess the adequacy of PaO₂/F_IO₂ ≤ 240 to diagnose VAP. Methods: Prospective observational study in 255 consecutive patients with suspected VAP, clustered according to PaO₂/F_IO₂ ≤ 240 vs. > 240 at pneumonia onset. The primary analysis was the association between PaO₂/F_IO₂ ≤ 240 and quantitative microbiologic confirmation of pneumonia, the most reliable diagnostic gold-standard. Results: Mean PaO₂/F_IO₂ at VAP onset was 195 ± 82; 171 (67%) cases had PaO₂/F_IO₂ ≤ 240. Patients with PaO₂/F_IO₂ ≤ 240 had a lower APACHE-II score at ICU admission; however, at pneumonia onset they had higher CPIS, SOFA score, acute respiratory distress syndrome criteria and incidence of shock, and less microbiological confirmation of pneumonia (117, 69% vs. 71, 85%, p = 0.008), compared to patients with PaO₂/FIO₂ > 240. In multivariate logistic regression, PaO₂/FIO₂ ≤ 240 was independently associated with less microbiological confirmation (adjusted odds-ratio 0.37, 95% confidence interval 0.15–0.89, p = 0.027). The association between PaO₂/F_IO₂ and microbiological confirmation of VAP was poor, with an area under the ROC curve 0.645. Initial non-response to treatment and length of stay were similar between both groups, while hospital mortality was higher in patients with PaO₂/F_IO₂ ≤ 240. Conclusion: Adding PaO₂/F_IO₂ ratio ≤ 240 to the clinical and radiographic criteria does not help in the diagnosis of VAP. PaO₂/F_IO₂ ratio > 240 does not exclude this infection. Using this threshold may underestimate the incidence of VAP.

Selective digestive or oropharyngeal decontamination and topical oropharyngeal chlorhexidine for prevention of death in general intensive care: systematic review and network meta-analysis

OBJECTIVES

To determine the effect on mortality of selective digestive decontamination, selective oropharyngeal decontamination, and topical oropharyngeal chlorhexidine in adult patients in general intensive care units and to compare these interventions with each other in a network meta-analysis.

DESIGN

Systematic review, conventional meta-analysis, and network meta-analysis. Medline, Embase, and CENTRAL were searched to December 2012. Previous meta-analyses, conference abstracts, and key journals were also searched. We used pairwise meta-analyses to estimate direct evidence from intervention-control trials and a network meta-analysis within a Bayesian framework to combine direct and indirect evidence.

INCLUSION CRITERIA

Prospective randomised controlled trials that recruited adult patients in general intensive care units and studied selective digestive decontamination, selective oropharyngeal decontamination, or oropharyngeal chlorhexidine compared with standard care or placebo.

RESULTS

Selective digestive decontamination had a favourable effect on mortality, with a direct evidence odds ratio of 0.73 (95% confidence interval 0.64 to 0.84). The direct evidence odds ratio for selective oropharyngeal decontamination was 0.85 (0.74 to 0.97). Chlorhexidine was associated with increased mortality (odds ratio 1.25, 1.05 to 1.50). When each intervention was compared with the other, both selective digestive decontamination and selective oropharyngeal decontamination were superior to chlorhexidine. The difference between selective digestive decontamination and selective oropharyngeal decontamination was uncertain.

CONCLUSION

Selective digestive decontamination has a favourable effect on mortality in adult patients in general intensive care units. In these patients, the effect of selective oropharyngeal decontamination is less certain. Both selective digestive decontamination and selective oropharyngeal decontamination are superior to chlorhexidine, and there is a possibility that chlorhexidine is associated with increased mortality.

Selective decontamination of the digestive tract: the mechanism of action is control of gut overgrowth

PURPOSE

Gut overgrowth is the pathophysiological event in the critically ill requiring intensive care. In relation to the risk of developing a clinically important outcome, gut overgrowth is defined as ≥10(5) potential pathogens including 'abnormal' aerobic Gram-negative bacilli (AGNB), 'normal' bacteria and yeasts, per mL of digestive tract secretion. Surveillance samples of throat and gut are the only samples to detect overgrowth. Gut overgrowth is the crucial event which precedes both primary and secondary endogenous infection, and a risk factor for the development of de novo resistance. Selective decontamination of the digestive tract (SDD) is an antimicrobial prophylaxis designed to control overgrowth.

METHODS

There have been 65 randomised controlled trials of SDD in 15,000 patients over 25 years and 11 meta-analyses, which are reviewed.

RESULTS AND CONCLUSIONS

These trials demonstrate that the full SDD regimen using parenteral and enteral antimicrobials reduces lower airway infection by 72 %, blood stream infection by 37 %, and mortality by 29 %. Resistance is also controlled. Parenteral cefotaxime which reaches high salivary and biliary concentrations eradicates overgrowth of 'normal' bacteria such as Staphylococcus aureus in the throat. Enteral polyenes control 'normal' Candida species. Enteral polymyxin and tobramycin, eradicate, or prevent gut overgrowth of 'abnormal' AGNB. Enteral vancomycin controls overgrowth of 'abnormal' methicillin-resistant S. aureus. SDD controls overgrowth by achieving high antimicrobial concentrations effective against 'normal' and 'abnormal' potential pathogens rather than by selectivity.

Selective digestive tract decontamination in critically ill patients

INTRODUCTION

Selective decontamination of the digestive tract (SDD) has been proposed to prevent endogenous and exogenous infections and to reduce mortality in critically ill patients. Although the efficacy of SDD has been confirmed by randomized controlled trials (RCTs) and systematic reviews, SDD has been the subject of intense controversy, based mainly on an insufficient evidence of efficacy and on concerns about resistance.

AREAS COVERED

This article reviews the philosophy, the current evidence on the efficacy of SDD and the issue of emergence of resistance. All SDD RCTs were searched using Embase and Medline, with no restriction of language, gender or age. Personal archives were also explored, including abstracts from major scientific meetings; references in papers and published meta-analyses on SDD were crosschecked. Up-to-date evidence of the impact of SDD on carriage, infections and mortality is presented, and the efficacy of SDD in selected patient groups was investigated, along with the problem of the emergence of resistance.

EXPERT OPINION

SDD significantly reduces the number of infections of the lower respiratory tract and bloodstream, multiple organ failure and mortality. It also controls resistance, particularly when the full protocol of parenteral and enteral antimicrobials is used.

SCT in patients with carbapenem resistant Klebsiella pneumoniae: a single center experience with oral gentamicin for the eradication of carrier state

Following an outbreak of carbapenem resistant Klebsiella pneumoniae (CRKP) bacteremia among inpatients in the Hemato-oncology and BMT unit, we studied the course of this infection in patients undergoing intensive chemotherapy and SCT. In addition, we conducted a pilot study aimed to eradicate CRKP colonization in the gastrointestinal tract, using oral gentamicin. Adult patients admitted to the BMT unit, identified as CRKP carriers on surveillance rectal cultures, were included in the study. Oral gentamicin at a dose of 80 mg q.i.d. was administered to all identified carriers until eradication. Among 15 colonized patients included in the study, the eradication rate achieved was 66% (10/15); discontinuation of persistent bacteremia occurred in 62.5% (5/8) and nosocomial spread of CRKP carrier state ceased. Administration of intensive chemotherapy and SCT is feasible, although associated with increased risk. Hematological patients in need of intensive chemotherapy/SCT should not be denied the required treatment on the basis of being CRKP carriers. Oral gentamicin treatment for eradication of CRKP from the gastrointestinal reservoir could serve as additional tool in the combat against the nosocomial spread and severe infections caused by this difficult-to-treat organism.

Physicians' and nurses' opinions on selective decontamination of the digestive tract and selective oropharyngeal decontamination: a survey

Introduction

Use of selective decontamination of the digestive tract (SDD) and selective oropharyngeal decontamination (SOD) in intensive care patients has been controversial for years. Through regular questionnaires we determined expectations concerning SDD (effectiveness) and experience with SDD and SOD (workload and patient friendliness), as perceived by nurses and physicians.

Methods

A survey was embedded in a group-randomized, controlled, cross-over multicenter study in the Netherlands in which, during three 6-month periods, SDD, SOD or standard care was used in random order. At the end of each study period, all nurses and physicians from participating intensive care units received study questionnaires.

Results

In all, 1024 (71%) of 1450 questionnaires were returned by nurses and 253 (82%) of 307 by physicians. Expectations that SDD improved patient outcome increased from 71% and 77% of respondents after the first two study periods to 82% at the end of the study (P = 0.004), with comparable trends among nurses and physicians. Nurses considered SDD to impose a higher workload (median 5.0, on a scale from 1 (low) to 10 (high)) than SOD (median 4.0) and standard care (median 2.0). Both SDD and SOD were considered less patient friendly than standard care (medians 4.0, 4.0 and 6.0, respectively). According to physicians, SDD had a higher workload (median 5.5) than SOD (median 5.0), which in turn was higher than standard care (median 2.5). Furthermore, physicians graded patient friendliness of standard care (median 8.0) higher than that of SDD and SOD (both median 6.0).

Conclusions

Although perceived effectiveness of SDD increased as the trial proceeded, both among physicians and nurses, SOD and SDD were, as compared to standard care, considered to increase workload and to reduce patient friendliness. Therefore, education about the importance of oral care and on the effects of SDD and SOD on patient outcomes will be important when implementing these strategies.

Trial registration

ISRCTN35176830.

[Decontamination. A treatment without indications]

The prevention of ventilator-associated pneumonia (VAP) is a priority in the Intensive Care Unit (ICU). To achieve this goal, clinical practice guidelines recommend the simultaneous application of a heterogeneous group of preventive measures of proven effectiveness. That is why we are presently seeing a reduction in VAP incidence to values previously considered unreachable. Better compliance with clinical practice guidelines has resulted in VAP rates approaching zero in multiple studies. Faced with the measures recommended in these guidelines, selective digestive decontamination (SDD), used together with other infection control practices, has shown efficacy in hospitals with high baseline incidence of pneumonia. However, its effectiveness in hospitals with good compliance of clinical practice guidelines and lower rates of VAP is highly unlikely. A serious drawback of DDS is the risk of favoring the selection of resistant microorganisms that can spread easily through the ICU and the hospital. With current standards of infection prevention, DDS is an unnecessary and risky measure, which should not be used on a widespread basis. Those situations in which the DDS may increase the effectiveness of properly implemented standard measures are still unknown.

[Debates in intensive medicine: Pro: selective decontamination]

Selective decontamination of the digestive tract (SDD) has been proven to prevent infections of endogenous development and reduce mortality in critically ill patients under prolonged mechanical ventilation. Historical arguments against its use, like the development of bacterial resistance or the selection of resistant microorganisms and the absence of influence on mortality have not been confirmed. Moreover, recent clinical trials designed to evaluate these variables, show remarkable reductions in the incidence of resistant bacteria and a significant beneficial effect on mortality. Furthermore, no increases in workload or costs have been documented. A few studies with post-trial and intermediate range follow-up periods didn't find increases in resistance. Implementation of SDD requires motivation and leadership in order to achieve cooperation of other related hospital specialists, training of several categories of healthcare professionals, and continuous monitoring of results. In order to facilitate the use of SDD in the critically ill, this preventive measure should be incorporated in guidelines of national and international scientific societies and working groups involved in the care of the critically ill patient. The general implementation of SDD in our intensive care units must be accompanied by a registry in order to be able to monitor the effect on the incidence of infection and bacterial resistance. For this purpose, the Spanish national ICU infection and resistance surveillance programme ENVIN-HELICS, active over the last 15 years, constitutes both a more than adequate tool, and the convenient reference data base.

[Selective decontamination of the digestive tract: repercussions on microbiology laboratory workload and costs, and antibiotic resistance trends]

INTRODUCTION

This study determines the workload and cost of implementing selective digestive decontamination in the microbiology laboratory, and reports the impact on microbial flora and bacterial resistance trends in the intensive care unit (ICU).

METHODS

The total microbiological workload and cost were quantified, as well as the part charged to the petitioning service, in the year before and the year after introducing the procedure. Changes in microbial flora were evaluated and bacterial resistance trends were analyzed over 12 years in 21 sentinel antimicrobial/microorganism combinations.

RESULTS

The workload ascribed to the ICU increased by 10% and cost increased by 1.8% in the period after introduction of the procedure (non-significant differences). The increased workload resulting from epidemiological surveillance cultures was compensated by significant reductions in quantitative endotracheal aspirate cultures, blood cultures, exudate cultures, identification tests with antibiograms, and serologies. The procedure has been associated with a significant decrease in Acinetobacter isolates and a significant increase in Enterococcus. Three significant trends of increased resistance were detected, all of them in Pseudomonas aeruginosa (imipenem, tobramycin, and ciprofloxacin).

CONCLUSIONS

In our hospital, implementation of selective digestive decontamination did not cause a significant increase in the workload or costs in the microbiology laboratory. Selective digestive decontamination was associated with a significant decrease in Acinetobacter, an increase in Enterococcus, and higher resistance to imipenem, tobramycin and ciprofloxacin in P. aeruginosa.

Ventilator-associated pneumonia in patients undergoing major heart surgery: an incidence study in Europe

Introduction

Patients undergoing major heart surgery (MHS) represent a special subpopulation at risk for nosocomial infections. Postoperative infection is the main non-cardiac complication after MHS and has been clearly related to increased morbidity, use of hospital resources and mortality. Our aim was to determine the incidence, aetiology, risk factors and outcome of ventilator-associated pneumonia (VAP) in patients who have undergone MHS in Europe.

Methods

Our study was a prospective study of patients undergoing MHS in Europe who developed suspicion of VAP. During a one-month period, participating units submitted a protocol of all patients admitted to their units who had undergone MHS.

Results

Overall, 25 hospitals in eight different European countries participated in the study. The number of patients intervened for MHS was 986. Fifteen patients were excluded because of protocol violations. One or more nosocomial infections were detected in 43 (4.4%) patients. VAP was the most frequent nosocomial infection (2.1%; 13.9 episodes per 1000 days of mechanical ventilation). The microorganisms responsible for VAP in this study were: Enterobacteriaceae (45%), Pseudomonas aeruginosa (20%), methicillin-resistant Staphylococcus aureus (10%) and a range of other microorganisms. We identified the following significant independent risk factors for VAP: ascending aorta surgery (odds ratio (OR) = 6.22; 95% confidence interval (CI) = 1.69 to 22.89), number of blood units transfused (OR = 1.08 per unit transfused; 95% CI = 1.04 to 1.13) and need for re-intervention (OR = 6.65; 95% CI = 2.10 to 21.01). The median length of stay in the intensive care unit was significantly longer (P < 0.001) in patients with VAP than in patients without VAP (23 days versus 2 days). Death was significantly more frequent (P < 0.001) in patients with VAP (35% versus 2.3%).

Conclusions

Patients undergoing aortic surgery and those with complicated post-intervention courses, requiring multiple transfusions or re-intervention, constitute a high-risk group probably requiring more active preventive measures.

Survival benefit of the full selective digestive decontamination regimen

PURPOSE

We assessed the impact of the full protocol of selective decontamination of the digestive tract (SDD) using parenteral and enteral antimicrobials on mortality.

MATERIALS AND METHODS

A systematic review was performed searching MEDLINE, EMBASE, the Cochrane Register of Controlled Trials, previous meta-analyses, and conferences proceedings. We included all randomized controlled trials (RCTs) comparing the full protocol of SDD, including oropharyngeal and intestinal administration of antibiotics combined with the parenteral component, with no treatment or placebo. The primary end points were overall mortality, mortality attributable to infection, early, and late mortality.

RESULTS

Twenty-one RCTs on 4902 patients were included. Overall mortality was significantly reduced (odds ratio [OR], 0.71; 95% confidence interval [CI]; 0.61-0.82; P < .001). There was a nonsignificant reduction in infection-related mortality (6 RCTs; OR, 0.40; 95% CI, 0.10-1.59; P = .19) and early mortality (4 RCTs; OR, 0.64; 95% CI, 0.34-1.19; P = 0.16), and a significant reduction in late mortality (5 RCTs; OR, 0.56; 95% CI, 0.40-0.77; P < .001). The subgroup analysis showed a significant mortality reduction in successfully decontaminated patients (OR, 0.58; 95% CI, 0.45-0.77; P < .001), and when parenteral and enteral antimicrobials were administered to every patient receiving treatment in the intensive care unit (OR, 0.59; 95% CI, 0.42-0.82; P < .001).

CONCLUSIONS

The findings strongly indicated that the full protocol of SDD reduces mortality in critically ill patients, in particular when successful decontamination is obtained. Eighteen patients should be treated with SDD to prevent one death.

Febrile neutropenia

This review summarizes the current status and diagnostic-therapeutic challenges in febrile neutropenia. Patients with neutropenia-associated infections have a poor prognosis. A large meta-analysis of trials assessing prophylactic antibiotics has shown significant survival benefits; clinical significance of resistance is unclear. Administering broad-spectrum antibiotics to established febrile neutropenic patients has become selective, vancomycin is withheld unless absolutely necessary, and low-risk patients are identified with biological markers. Such patients are now managed with oral antibiotics at home or even without antibiotics. Protracted prolonged neutropenia is the setting par excellence for invasive fungal infections. Conventional amphotericin B administered to such risk patients reduces the incidence of fungal infections. New antifungal drugs have heightened efficacy and lowered toxicity. Novel antifungal diagnostic tests include imaging, particularly the CT "halo" sign (aspergillosis), and serology (glucan, galactomannan), and provide earlier diagnosis and treatment and better outcomes. Negative tests may indicate withholding antifungal therapy. High intermittent dosing of liposomal amphotericin B seems as safe and as effective as standard dosing regimens, but at half the drug acquisition cost. The use of nonantibiotic agents has offered alternative management strategies. Recombinant interleukin-11 reduces bacteremia, through a cytoprotective mechanism on the gut. rhIL-11 releases C-reactive protein and causes shedding of soluble TNF receptor-1, modulating the immunological milieu and the systemic inflammatory response. Other candidate molecules include RANTES and long-pentraxin 3. Recombinant growth factors reduce febrile episodes, permitting completion of chemotherapy, increase overall survival, and minimize infection mortality.

Perioperative goal directed haemodynamic therapy--do it, bin it, or finally investigate it properly?

The literature concerning the use of goal directed haemodynamic therapy (GDHT) in high risk surgical patients has been importantly increased by the study of Lopes and colleagues. Using a minimally invasive assessment of fluid status and pulse pressure variation monitoring during mechanical ventilation, improvements were seen in post-operative complications, duration of mechanical ventilation, and length of hospital and intensive care unit (ICU) stay. Many small studies have shown improved outcome using various GDHT techniques but widespread implementation has not occurred. Those caring for perioperative patients need to accept the published evidence base or undertake a larger, multi-centre study.

Oral probiotic and prevention of Pseudomonas aeruginosa infections: a randomized, double-blind, placebo-controlled pilot study in intensive care unit patients

INTRODUCTION

Preventing carriage of potentially pathogenic micro-organisms from the aerodigestive tract is an infection control strategy used to reduce the occurrence of ventilator-associated pneumonia in intensive care units. However, antibiotic use in selective decontamination protocols is controversial. The purpose of this study was to investigate the effect of oral administration of a probiotic, namely Lactobacillus, on gastric and respiratory tract colonization/infection with Pseudomonas aeruginosa strains. Our hypothesis was that an indigenous flora should exhibit a protective effect against secondary colonization.

METHODS

We conducted a prospective, randomized, double-blind, placebo-controlled pilot study between March 2003 and October 2004 in a 17-bed intensive care unit of a teaching hospital in Clermont-Ferrand, France. Consecutive patients with a unit stay of longer than 48 hours were included, 106 in the placebo group and 102 in the probiotic group. Through a nasogastric feeding tube, patients received either 109 colony-forming units unity forming colony of Lactobacillus casei rhamnosus or placebo twice daily, from the third day after admission to discharge. Digestive tract carriage of P. aeruginosa was monitored by cultures of gastric aspirates at admission, once a week thereafter and on discharge. In addition, bacteriological analyses of respiratory tract specimens were conducted to determine patient infectious status.

RESULTS

The occurrence of P. aeruginosa respiratory colonization and/or infection was significantly delayed in the probiotic group, with a difference in median delay to acquisition of 11 days versus 50 days (P = 0.01), and a nonacquisition expectancy mean of 69 days versus 77 days (P = 0.01). The occurrence of ventilator-associated pneumonia due to P. aeruginosa in the patients receiving the probiotic was less frequent, although not significantly reduced, in patients in the probiotic group (2.9%) compared with those in the placebo group (7.5%). After multivariate Cox proportional hazards modelling, the absence of probiotic treatment increased the risk for P. aeruginosa colonization in respiratory tract (adjusted hazard ratio = 3.2, 95% confidence interval - 1.1 to 9.1).

CONCLUSION

In this pilot study, oral administration of a probiotic delayed respiratory tract colonization/infection by P. aeruginosa.

TRIAL REGISTRATION

The trial registration number for this study is NCT00604110.

Impact of Selective Decontamination of the Digestive Tract on Carriage and Infection Due to Gram-Negative and Gram-Positive Bacteria: A Systematic Review of Randomised Controlled Trials

Meta-analyses of randomised controlled trials of selective digestive decontamination have clinical outcome measures, mainly pneumonia and mortality. This meta-analysis has a microbiological endpoint and explores the impact of selective digestive decontamination on Gram-negative and Gram-positive carriage and severe infections. We searched electronic databases, Cochrane Register of Controlled Trials, previous meta-analyses and conference proceedings with no language restrictions. We included randomised controlled trials which compared the selective digestive decontamination protocol with no treatment or placebo. Three reviewers independently applied selection criteria, performed the quality assessment and extracted the data. The outcome measures were carriage and severe infection due to Gram-negative and Gram-positive bacteria. Odds ratios were pooled with the random effect model. Fifty-four randomised controlled trials comprising 9473 patients were included; 4672 patients received selective digestive decontamination and 4801 were controls. Selective digestive decontamination significantly reduced oropharyngeal carriage (odds ratio [OR] 0.13, 95% confidence interval [CI] 0.07 to 0.23), rectal carriage (OR 0.15, 95% CI 0.07 to 0.31), overall infection (OR 0.17, 95% CI 0.10 to 0.28), lower respiratory tract infection (OR 0.11, 95% CI 0.06 to 0.20) and bloodstream infection (OR 0.35, 95% CI 0.21 to 0.67) due to Gram-negative bacteria. Reduction in Gram-positive carriage was not significant. Gram-positive lower airway infections were significantly reduced (OR 0.52, 95% CI 0.34 to 0.78). Gram-positive bloodstream infections were not significantly increased (OR 1.03, 95% CI 0.75 to 1.41). The association of parenteral and enteral antimicrobials was superior to enteral antimicrobials in reducing carriage and severe infections due to Gram-negative bacteria. This meta-analysis confirms that selective digestive decontamination mainly targets Gram-negative bacteria; it does not show a significant increase in Gram-positive infection.

Systemic tobramycin concentrations during selective decontamination of the digestive tract in intensive care unit patients on continuous venovenous hemofiltration

Objective

To study whether selective decontamination of the digestive tract (SDD) results in detectable serum tobramycin concentrations in intensive care unit (ICU) patients with acute renal failure treated with continuous venovenous hemofiltration (CVVH).

Design and setting

Prospective, observational, single-center study in a mixed medical–surgical ICU.

Patients

Adult ICU patients receiving SDD for at least 3 days and being treated with CVVH because of acute renal failure.

Measurements and results

Tobramycin serum concentrations were measured at the 3rd day after start of CVVH and every 3 days thereafter. Detectable serum concentrations of tobramycin were found in 12 (63%) of 19 patients and in 15 (58%) of the 26 samples. With a toxic tobramycin concentration defined as more than 2.0 mg/l, we found one patient with a toxic concentration of 3.0 mg/l. In three other patients tobramycin concentrations of ≥ 1.0 mg/l were found.

Conclusions

In patients with acute renal failure treated with CVVH, administration of SDD with tobramycin can lead to detectable and potentially toxic serum tobramycin concentrations.

[Selective digestive decontamination. Why don't we apply the evidence in the clinical practice?]

Selective digestive decontamination (SDD) is a prophylactic strategy whose objective is to reduce the incidence of infections, mainly mechanical ventilation associated pneumonia in patients who require intensive cares, preventing or eradicating the oropharyngeal and gastrointestinal carrier state of potentially pathogenic microorganisms. Fifty-four randomized clinical trials (RCTs) and 9 meta-analysis have evaluated SDD. Thirty eight RCTs show a significant reduction of the infections and 4 of mortality. All the meta-analyses show a significant reduction of the infections and 5 out of the 9 meta-analyses report a significant reduction in mortality. Thus, 5 patients from the ICU with SDD must be treated to prevent pneumonia and 12 patients from the ICU should be treated to prevent one death. The data that show benefit of the SDD on mortality have an evidence grade 1 or recommendation grade A (supported by at least two level 1 investigations). The aim of this review is to explain the pathogeny of infections in critical patients, describe selective digestive decontamination, analyze the evidence available on it efficacy and the potential adverse effects and discuss the reasons published by the experts who advise against the use of SDD, even though it is recognized as the best intervention evaluated in intensive cares to reduce morbidity and mortality of the infections.

Relative effects of barrier precautions and topical antibiotics on nosocomial bacterial transmission: results of multi-compartment models

Nosocomial bacterial infections in critically ill patients are generally preceded by asymptomatic carriage (i.e. colonization) at one, or even several, body sites such as the skin, the gastro-intestinal and the respiratory tract. Different routes of transmission between the colonized sites create a complex epidemiology, which is additionally complicated by the smallness of the patient population size and the rapid patient turnover, characteristic for intensive care units (ICUs). Naturally occurring large fluctuations in the prevalence of colonization make it very difficult to determine the efficacy of control measures that aim to reduce the prevalence of antibiotic-resistant bacteria in ICUs. Theoretical models can sharpen our intuition through carefully designed thought experiments. In this spirit, we introduce and investigate two models that incorporate the fact that patients may be colonized at multiple body sites. Our study can be applied to several pathogens commonly found in ICUs, such Pseudomonas Aeruginosa, enteric Gram-negative bacteria, MRSA and enterococci. We evaluate the effects of barrier precautions (improved hygiene, use of gloves and gowns, etc.) and of administration of nonabsorbable antibiotics on the prevalence of colonization in ICUs and find that the effect of the controversial, though widely used, antibiotic prophylaxis can only be substantial if the patient-to-patient transmission has already been reduced to a subcritical level by barrier precautions. Taking into account that the very use of antibiotics may increase the selection for resistant strains and may thereby only add to the ever increasing problem of antibiotic resistance, our findings hence represent a firm theoretical argument against the routine use of topical antimicrobial prophylaxis for infection control.

Review article: bacterial translocation in the critically ill--evidence and methods of prevention

BACKGROUND

Delayed sepsis, systemic inflammatory response syndrome (SIRS) and multiorgan failure remain major causes of morbidity and mortality on intensive care units. One factor thought to be important in the aetiology of SIRS is failure of the intestinal barrier resulting in bacterial translocation and subsequent sepsis.

AIM

This review summarizes the current knowledge about bacterial translocation and methods to prevent it.

METHODS

Relevant studies during 1966-2006 were identified from a literature search. Factors, which detrimentally affect intestinal barrier function, are discussed, as are methods that may attenuate bacterial translocation in the critically ill patient.

RESULTS

Methodological problems in confirming bacterial translocation have restricted investigations to patients undergoing laparotomy. There are only limited data available relating to specific interventions that might preserve intestinal barrier function or limit bacterial translocation in the intensive care setting. These can be categorized broadly into pre-epithelial, epithelial and post-epithelial interventions.

CONCLUSIONS

A better understanding of factors that influence translocation could result in the implementation of interventions which contribute to improved patient outcomes. Glutamine supplementation, targeted nutritional intervention, maintaining splanchnic flow, the judicious use of antibiotics and directed selective gut decontamination regimens hold some promise of limiting bacterial translocation. Further research is required.

Selective decontamination of the digestive tract reduces bacterial bloodstream infection and mortality in critically ill patients. Systematic review of randomized, controlled trials

A systematic review and meta-analysis of randomized controlled trials (RCTs) of selective decontamination of the digestive tract (SDD) was undertaken to evaluate the impact of this procedure on bacterial bloodstream infection and mortality. Data sources were Medline, Embase, Cochrane Register of Controlled Trials, previous meta-analyses, and conference proceedings, without restriction of language or publication status. RCTs were retrieved that compared oropharyngeal and/or intestinal administration of antibiotics as part of the SDD protocol, with or without a parenteral component, with no treatment or placebo in the controls. The three outcome measures were patients with bloodstream infection, causative micro-organisms, and total mortality. Fifty-one RCTs conducted between 1987 and 2005, comprising 8065 critically ill patients were included in the review; 4079 patients received SDD and 3986 were controls. SDD significantly reduced overall bloodstream infections [odds ratio (OR), 0.73; 95% confidence interval (CI), 0.59-0.90; P=0.0036], gram-negative bloodstream infections (OR, 0.39; 95% CI, 0.24-0.63; P<0.001) and overall mortality (OR, 0.80; 95% CI, 0.69-0.94; P=0.0064), without affecting gram-positive bloodstream infections (OR, 1.06; 95% CI, 0.77-1.47). The subgroup analysis showed an even larger impact of SDD using parenteral and enteral antimicrobials on overall bloodstream infections, bloodstream infections due to gram-negative bacteria and overall mortality with ORs of 0.63 (95% CI, 0.46-0.87; P=0.005), 0.30 (95% CI, 0.16-0.56; P<0.001), and 0.74 (95% CI, 0.61-0.91; P=0.0034), respectively. Twenty patients need to be treated with SDD to prevent one gram-negative bloodstream infection and 22 patients to prevent one death.

Selective Digestive Tract Decontamination—Will It Prevent Infection with Multidrug-Resistant Gram-Negative Pathogens but Still Be Applicable in Institutions where Methicillin-Resistant Staphylococcus aureus and Vancomycin-Resistant Enterococci Are Endemic?

The purposes of selective decontamination of the digestive tract are to treat infections that may be incubating at the time a patient is admitted to an intensive care unit (ICU), by intravenous administration of antibiotics during the first days of a stay in the ICU, and to prevent ICU-acquired infections, by topical application of antibiotics in the oropharynx and the gastrointestinal tract. Despite multiple trials in which a considerable reduction in the incidence of ventilator-associated pneumonia was demonstrated, major objections against the routine use of selective decontamination of the digestive tract have included a lack of demonstrated reductions in mortality rates and in length of stay (in individual trials), a lack of cost-efficacy data, and the threat of selection of multidrug-resistant bacteria. Recently, 2 controlled, randomized studies reported significant reductions in mortality rates among patients in ICUs who underwent selective decontamination of the digestive tract in combination with reduced selection of antibiotic-resistant pathogens. However, those studies were performed in settings where levels of antibiotic resistance are low, and some methodological issues remain unresolved. If these beneficial results are confirmed, the question of how to balance these benefits against the expected enhanced selection of methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and, possibly, multidrug-resistant gram-negative bacteria will emerge.

Effects of long-term routine use of selective digestive decontamination on antimicrobial resistance

OBJECTIVE

To assess the distribution of bacterial species and antimicrobial resistance in an ICU during long-term use of selective digestive decontamination (SDD) in the context of national reference data.

DESIGN AND SETTING

Five-year prospective observational study in a 24-bed interdisciplinary surgical ICU of a university hospital (study ICU) participating in the project "Surveillance of Antimicrobial Use and Antimicrobial Resistance in German Intensive Care Units" (SARI; reference ICUs).

PATIENTS

Resistance data were obtained from all patients; patients intubated for at least 2 days received SDD (colistin, tobramycin, amphotericin B).

INTERVENTIONS AND MEASUREMENTS

SDD was performed in 1,913 of 7,270 patients. Antimicrobial resistance was examined in 4,597 (study ICU) and 46,346 (reference ICUs) isolates.

RESULTS

Methicillin-resistant Staphylococcus aureus (MRSA) remained stable (2.76 and 2.58 isolates/1000 patient days) in the study ICU; this was below the German average (4.26 isolates/1000 patient days). Aminoglycoside- and betalactam-resistant Gram-negative rods did not increase during SDD use. Aminoglycoside resistance of Pseudomonas aeruginosa was 50% below the mean value of SARI (0.24 vs. 0.52 isolates/1,000 patient days). The relative frequency of enterococci and coagulase-negative staphylococci (CNS) was higher than in the SARI ICUs (23.2% vs. 17.3%, and 25.0% vs. 20.6%, respectively).

CONCLUSION

Routine 5-year-use of SDD was not associated with increased antimicrobial resistance in our ICU with low baseline resistance rates. Vigorous surveillance and control measures to search and destroy MRSA were considered a mandatory component of the SDD program. The relative increase in enterococci and CNS is of concern requiring further investigation.

[New approaches to intensive care for sepsis]

In Germany, the mortality from sepsis remains high, and up to 60,000 patients die from it each year. Thus, sepsis is the third most common cause of death. More deaths occur only from coronary heart disease and acute myocardial infarction. In the last 3-4 years, substantial progress in sepsis therapy has been made. Based on these achievements, there is hope of reducing sepsis mortality by 25% in the next few years. Implementing new medical evidence in this context into daily clinical intensive care remains a major hurdle. The early diagnosis of sepsis prior to the onset of clinical deterioration is of particular interest, because this would increase the possibility of early and specified treatment, which is in turn the major determining factor of mortality in septic patients.

High mortality of invasive pneumococcal disease compared with meningococcal disease in critically ill children

OBJECTIVE

To ascertain outcome, patterns of disease, incidence of concurrent infection, superinfection and penicillin resistance in children requiring intensive care for Streptococcus pneumoniae infection and compare it to a similar disease pattern, namely Neisseria meningitidis b infection.

DESIGN AND SETTING

Prospective cohort study in a regional paediatric intensive care unit (PICU).

PATIENTS AND PARTICIPANTS

Children with invasive pneumococcal and meningococcal disease requiring intensive care.

MEASUREMENTS AND RESULTS

The study included 22 children with invasive pneumococcal disease (IPD), median age 14 months (interquartile range 3-52), median Paediatric Index of Mortality (PIM) 0.051 (0.028-0.066), median length of PICU stay 8.5 days (4-13). Four patients died, three (13.5%) attributable to IPD. Incidence of concurrent infection 27%. There were no superinfections. All S. pneumoniae were sensitive to cefotaxime; one isolate (3.7%) was resistant to penicillin. There were 186 children with meningococcal disease (MD), with a higher PIM (median 0.068, 0.033-0.108), older age (29 months, 10.7-77.9) and shorter length of PICU stay (median 3 days, 2-6). Eight (4.3%) children died from MD. Incidence of concurrent and superinfection was 18% and 6%, respectively in children with MD. All N. meningitidis cases were sensitive to cefotaxime and penicillin. The standardized mortality ratio was considerably higher with IPD (2.0) than with MD (0.52).

CONCLUSIONS

In invasive pneumococcal disease preventative measures including early recognition, immediate antibiotic therapy and vaccination need to be taken in the community, similar to the control of meningococcal disease. Invasive pneumococcal disease should command the same respect as meningococcal disease.

Antibiotic resistance in the intensive care unit: a primer in bacteriology

The clinical use of potent, well-tolerated, broad-spectrum antibiotics has been paralleled by the development of resistance in bacteria, and the prevalence of highly resistant bacteria in some intensive care units is despairingly commonplace. The intensive care community faces the realistic prospect of untreatable nosocomial infections and should be searching for new approaches to diagnose and manage resistant bacteria. In this review, we discuss some of the relevant underlying biology, with a particular focus on genetic transfer vehicles and the relationship of selection pressure to their movements. It is an attempt to demystify the relevant language and concepts for the anaesthetist and intensivist, to explain some of the reasons for the emergence of resistance in bacteria, and to provide a contextual basis for discussion of management approaches such as selective decontamination and antibiotic cycling.

[Selective digestive decontamination: the light as changed from red to green]

OBJECTIVES

To study the efficacy of selective digestive decontamination (SDD) for the prevention of nosocomial infections, particularly pneumonia, as well as its impact on the emergence of multiresistant bacteria.

DATA SOURCES

Data collected from the Pubmed: original articles, review articles and editorial published on SDD. The keywords were: selective digestive decontamination, pneumonia, intensive care unit, infection.

DATA SELECTION

Ten randomized clinical trials performed since 1995 in mechanically ventilated adult patients hospitalized in intensive care unit.

RESULTS

The rationale for the use of SDD consists on the parenteral administration of a short course of antibiotic associated with the topical use of non-absorbable antibiotics directed against Gram negative bacteria. Five randomized studies described a reduction in the incidence of pneumonia associated with SDD. Only one study has showed a decrease in mortality rate. The other five studies, which present some methodological limitations, concluded the lack of efficacy of SDD. Regarding the emergence of multiresistant bacteria, the literature underlines the role of environment. The use of SDD seems to trigger the resistance in endemic areas, while these are softened in the units with a good control of their ecology.

CONCLUSION

The data from the literature provide arguments to use SDD in targeted patient populations like multiple traumas in intensive care units, which have a low rate of multiresistant bacteria.

Effects of selective decontamination of digestive tract on mortality and antibiotic resistance in the intensive-care unit

PURPOSE OF REVIEW

Since its introduction in 1984 several small trials have studied the infection prevention regimen of selective decontamination of the digestive tract (SDD) in intensive care patients. Although meta-analyses of these studies suggested that SDD could reduce mortality, it continued to be a highly controversial strategy. There were not only serious doubts about the methodological quality of the meta-analyses, fear also existed that SDD would lead to increased antibiotic resistance. Recently, two new large randomized trials have been published that studied the effects of SDD on mortality and resistance. In this article, we will review the concept on which SDD is based and the present knowledge of the effects of SDD on mortality and antibiotic resistance.

RECENT FINDINGS

In accordance with earlier meta-analyses of small studies, two recent randomized trials have confirmed that selective decontamination of the digestive tract significantly lowers mortality and decreases the emergence of antibiotic resistance. Limitation of these studies is the fact that they were conducted in intensive-care units (ICUs) with a low prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE).

SUMMARY

There is convincing evidence that selective decontamination of the digestive tract (SDD) lowers mortality as well as resistance in circumstances with low prevalence of methicillin-resistant S. aureus (MRSA) and vancomycin-resistant enterococcus (VRE). SDD should still be considered experimental in area's where MRSA and VRE are endemic. However, given the important potential benefits of SDD, more studies are urgently needed to adapt SDD in a way that proves effective in those settings.

Epidemiology and control of antibiotic resistance in the intensive care unit

PURPOSE OF REVIEW

Resistance to antibiotics is very high in the intensive care units of many countries, although there are several exceptions. Some infections are becoming extremely difficult to treat. The risk of cross-transmission of those strains is very high. This review focuses on recent data (2003 to the present) that may help understanding and dealing with this serious public health problem.

RECENT FINDINGS

Intensive care units can be considered as 'factories' for creating, disseminating and amplifying resistance to antibiotics, for many reasons: importation of resistant microorganisms at admission, selection of resistant strains with an extensive use of broad-spectrum antibiotics, cross-transmission of resistant strains via the hands or the environment. Some national programs can be considered as failures, as in the UK and the USA. Other countries have been able to maintain a low level of resistance (Scandinavian countries, Netherlands, Switzerland, Germany, Canada). There is clearly an 'inoculum effect' above which preventive measures become poorly efficient. Several preventive measures have been proposed including preventive isolation, systematic screening at admission, local, national or international antibiotic guidelines, antibiotic prescriptions advice by infectious-disease teams, antibiotic prevention with selective digestive decontamination, antibiotic strategies such as 'cycling', or rather, for some authors, the use of an 'à la carte' antibiotic strategy which could be considered as a 'patient-to-patient antibiotic rotation'.

SUMMARY

There is obviously an international concern regarding the level of resistance to antibiotics in the intensive-care-unit setting. A strong program including prevention of cross-transmission and better usage of antibiotics seems to be needed in order to be successful. We do not know if this kind of program will enable countries with a very high endemic level of resistance to decrease the level in future years.

The role of selective digestive decontamination for reducing infection in patients undergoing liver transplantation: a systematic review and meta-analysis

Selective digestive decontamination (SDD) refers to the use of antimicrobials to reduce the burden of aerobic gram-negative bacteria and/or yeast in the intestinal tract to prevent infections caused by these organisms. Liver transplant patients are highly vulnerable to bacterial infection particularly with gram-negative organisms within the first month after transplantation, and SDD has been proposed as a potential measure to prevent these infections. However, the benefit of this procedure remains controversial. We undertook a systematic review and meta-analysis to determine whether SDD is beneficial in reducing infections overall and those caused by gram-negative bacteria in patients following liver transplantation. All studies that evaluated the efficacy of SDD in liver transplant patients were included. Randomized trials that included liver transplant patients given SDD versus either placebo or no treatment or minimal treatment (e.g., oral nystatin alone), and that provided adequate data to calculate a relative risk ratio, were included in the meta-analysis. Our review shows that most studies found SDD to be effective in reducing gram-negative infection. The nonrandomized and uncontrolled trials also showed benefit with SDD in reducing overall infection; however, the effect on overall infection was limited in the 4 randomized trials, in which the pooled relative risk was 0.88 (95% CI, 0.7-1.1), indicating no statistically significant reduction in infection with the use of SDD. The summary risk ratio for the association between SDD and gram-negative infection was 0.16 (95% CI, 0.07-0.37), indicating an 84% relative risk reduction in the incidence of infection caused by gram-negative bacteria in patients receiving SDD in randomized trials. In conclusion, the available literature supports a beneficial effect of SDD on gram-negative infection following liver transplantation; however, the risk of antimicrobial resistance must be considered. Larger multicenter randomized trials in this patient population to assess the effect of SDD in reducing infection and mortality, while assessing the risk of antimicrobial resistance, are needed.

Trauma and critical care II: abdominal trauma

The Intensivist is involved in the management of patients with abdominal trauma from their original presentation in the Emergency Department, where assessment of haemodynamic stability will influence the decision to opt for surgical, as opposed to conservative, treatment. Subsequently a large percentage of these patients, particularly those with blunt abdominal injuries, may require level 2 (HDU) or level 3 (ITU) care to monitor progress, correct any coagulopathy, maintain organ support and allow for early recognition of the major sequelae of such injuries. These include severe sepsis, trauma-related pancreatitis and the abdominal compartment syndrome. All are associated with significant morbidity and mortality, usually many days or weeks after admission. This article, in addition to reviewing some of the contributory factors involved in trauma-related coagulopathy, will discuss these sequelae and some of the concepts and strategies currently used in their management. It also includes an overview of therapies used in a critical care setting to maintain nutrition and renal homeostasis in the event of sequential organ failure.

Antibiotic prophylaxis strategies in the prevention of ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) is defined as a nosocomial pneumonia occurring > 48 h after endotracheal intubation. VAP may occur very early after intubation and it is usually defined as early-onset pneumonia, which occurs during the first 4 days. The occurrence of VAP is associated with an increase in morbidity and mortality. The pathogenesis of VAP often results from aspiration of colonised secretions in injured patients and this colonisation of the upper airway acts as a main risk factor in the development of pneumonia. It has been hypothesised that the bacterial inoculum may be decreased through the administration of systemic antibiotic prophylaxis. Antibiotic prophylaxis strategies to prevent VAP can be administered over an extended period to cover all microorganisms using selective digestive decontamination regimens, or in a short-term course of no more than 24 h. Probably, the second strategy is the most useful in the prevention of VAP because it has a lower impact on the emergence of bacterial resistance. This manuscript aims to review current opinions regarding antibiotic prophylaxis strategies in the prevention of VAP.