Reduction of colonization and infection rate during pediatric intensive care by selective decontamination of the digestive tract

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.

Topical antibiotic prophylaxis to reduce respiratory tract infections and mortality in adults receiving mechanical ventilation

BACKGROUND

Patients treated with mechanical ventilation in intensive care units (ICUs) have a high risk of developing respiratory tract infections (RTIs). Ventilator-associated pneumonia (VAP) has been estimated to affect 5% to 40% of patients treated with mechanical ventilation for at least 48 hours. The attributable mortality rate of VAP has been estimated at about 9%. Selective digestive decontamination (SDD), which consists of the topical application of non-absorbable antimicrobial agents to the oropharynx and gastroenteric tract during the whole period of mechanical ventilation, is often used to reduce the risk of VAP. A related treatment is selective oropharyngeal decontamination (SOD), in which topical antibiotics are applied to the oropharynx only. This is an update of a review first published in 1997 and updated in 2002, 2004, and 2009.

OBJECTIVES

To assess the effect of topical antibiotic regimens (SDD and SOD), given alone or in combination with systemic antibiotics, to prevent mortality and respiratory infections in patients receiving mechanical ventilation for at least 48 hours in ICUs.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Acute Respiratory Infections (ARI) Group's Specialised Register, PubMed, and Embase on 5 February 2020. We also searched the WHO ICTRP and ClinicalTrials.gov for ongoing and unpublished studies on 5 February 2020. All searches included non-English language literature. We handsearched references of topic-related systematic reviews and the included studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and cluster-RCTs assessing the efficacy and safety of topical prophylactic antibiotic regimens in adults receiving intensive care and mechanical ventilation. The included studies compared topical plus systemic antibiotics versus placebo or no treatment; topical antibiotics versus no treatment; and topical plus systemic antibiotics versus systemic antibiotics.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included a total of 41 trials involving 11,004 participants (five new studies were added in this update). The minimum duration of mechanical ventilation ranged from 2 (19 studies) to 6 days (one study). Thirteen studies reported the mean length of ICU stay, ranging from 11 to 33 days. The percentage of immunocompromised patients ranged from 0% (10 studies) to 22% (1 study). The reporting quality of the majority of included studies was very poor, so we judged more than 40% of the studies as at unclear risk of selection bias. We judged all studies to be at low risk of performance bias, though 47.6% were open-label, because hospitals usually have standardised infection control programmes, and possible subjective decisions on who should be tested for the presence or absence of RTIs are unlikely in an ICU setting. Regarding detection bias, we judged all included studies as at low risk for the outcome mortality. For the outcome RTIs, we judged all double-blind studies as at low risk of detection bias. We judged five open-label studies as at high risk of detection bias, as the diagnosis of RTI was not based on microbiological exams; we judged the remaining open-label studies as at low risk of detection bias, as a standardised set of diagnostic criteria, including results of microbiological exams, were used. Topical plus systemic antibiotic prophylaxis reduces overall mortality compared with placebo or no treatment (risk ratio (RR) 0.84, 95% confidence interval (CI) 0.73 to 0.96; 18 studies; 5290 participants; high-certainty evidence). Based on an illustrative risk of 303 deaths in 1000 people this equates to 48 (95% CI 15 to 79) fewer deaths with topical plus systemic antibiotic prophylaxis. Topical plus systemic antibiotic prophylaxis probably reduces RTIs (RR 0.43, 95% CI 0.35 to 0.53; 17 studies; 2951 participants; moderate-certainty evidence). Based on an illustrative risk of 417 RTIs in 1000 people this equates to 238 (95% CI 196 to 271) fewer RTIs with topical plus systemic antibiotic prophylaxis. Topical antibiotic prophylaxis probably reduces overall mortality compared with no topical antibiotic prophylaxis (RR 0.96, 95% CI 0.87 to 1.05; 22 studies, 4213 participants; moderate-certainty evidence). Based on an illustrative risk of 290 deaths in 1000 people this equates to 19 (95% CI 37 fewer to 15 more) fewer deaths with topical antibiotic prophylaxis. Topical antibiotic prophylaxis may reduce RTIs (RR 0.57, 95% CI 0.44 to 0.74; 19 studies, 2698 participants; low-certainty evidence). Based on an illustrative risk of 318 RTIs in 1000 people this equates to 137 (95% CI 83 to 178) fewer RTIs with topical antibiotic prophylaxis. Sixteen studies reported adverse events and dropouts due to adverse events, which were poorly reported with sparse data. The certainty of the evidence ranged from low to very low.

AUTHORS' CONCLUSIONS

Treatments based on topical prophylaxis probably reduce respiratory infections, but not mortality, in adult patients receiving mechanical ventilation for at least 48 hours, whereas a combination of topical and systemic prophylactic antibiotics reduces both overall mortality and RTIs. However, we cannot rule out that the systemic component of the combined treatment provides a relevant contribution in the observed reduction of mortality. No conclusion can be drawn about adverse events as they were poorly reported with sparse data.

Gastrointestinal complications associated with the surgical treatment of heart disease in children

BACKGROUND/PURPOSE

The gastrointestinal system is prone to complications following heart surgery. We sought to determine the incidence and factors associated with gastrointestinal complication after cardiac surgery in children.

METHODS

A retrospective review of patients aged <16years that underwent cardiac surgery between 2009 and 2013. Primary outcome was occurrence of gastrointestinal complication within 30days. Multivariable logistic regression was performed to identify variables related to occurrence of gastrointestinal complication. Patients with gastrointestinal complication were matched with controls and postoperative lengths of stay compared.

RESULTS

Eight hundred eighty-one children underwent 1120 cardiac surgical procedures. At time of operation, 18% were neonates and 39% were infants. Cardiopulmonary bypass was used in 79%. Of 1120 procedures, 31 (2.8% [95% CI 2.0-3.9%]) had gastrointestinal complication. Necrotizing enterocolitis accounted for 61% of complications. Of patients with gastrointestinal complication, 87% survived to hospital discharge. Gastrointestinal complication was associated with preoperative co-morbidity (OR 2.2 [95% CI 1.02-4.8]) and univentricular disease (OR 2.5 [95% CI 1.1-5.5]). Neonates had the highest risk of gastrointestinal complication. Patients with gastrointestinal complications had longer hospital stays than controls (median difference, 13days [95% CI 3-43]).

CONCLUSIONS

Serious gastrointestinal complications are uncommon but associated with longer hospital stay. Neonates with univentricular disease and preoperative comorbidity are at highest risk.

TYPE OF STUDY

Prognosis study.

LEVEL OF EVIDENCE

II.

Impact of selective digestive decontamination on respiratory tract Candida among patients with suspected ventilator-associated pneumonia. A meta-analysis

The purpose here is to establish the incidence of respiratory tract colonization with Candida (RT Candida) among ICU patients receiving mechanical ventilation within studies in the literature. Also of interest is its relationship with candidemia and the relative importance of topical antibiotic (TA) use as within studies of selective digestive decontamination (SDD) versus other candidate risk factors towards it. The incidence of RT Candida was extracted from component (control and intervention) groups decanted from studies of various TA and non-TA ICU infection prevention methods with summary estimates derived using random effects. A benchmark RT Candida incidence to provide overarching calibration was derived using (observational) groups from studies without any prevention method under study. A multi-level regression model of group level data was undertaken using generalized estimating equation (GEE) methods. RT Candida data were sourced from 113 studies. The benchmark RT Candida incidence is 1.3; 0.9-1.8 % (mean and 95 % confidence intervals). Membership of a concurrent control group of a study of SDD (p = 0.02), the group-wide presence of candidemia risk factors (p < 0.001), and proportion of trauma admissions (p = 0.004), but neither the year of study publication, nor membership of any other component group, nor the mode of respiratory sampling are predictive of the RT Candida incidence. RT Candida and candidemia incidences are correlated. RT Candida incidence can serve as a basis for benchmarking. Several relationships have been identified. The increased incidence among concurrent control groups of SDD studies cannot be appreciated in any single study examined in isolation.

Topical antibiotics as a major contextual hazard toward bacteremia within selective digestive decontamination studies: a meta-analysis

BACKGROUND

Among methods for preventing pneumonia and possibly also bacteremia in intensive care unit (ICU) patients, Selective Digestive Decontamination (SDD) appears most effective within randomized concurrent controlled trials (RCCT's) although more recent trials have been cluster randomized. However, of the SDD components, whether protocolized parenteral antibiotic prophylaxis (PPAP) is required, and whether the topical antibiotic actually presents a contextual hazard, remain unresolved. The objective here is to compare the bacteremia rates and patterns of isolates in SDD-RCCT's versus the broader evidence base.

METHODS

Bacteremia incidence proportion data were extracted from component (control and intervention) groups decanted from studies investigating antibiotic (SDD) or non-antibiotic methods of VAP prevention and summarized using random effects meta-analysis of study and group level data. A reference category of groups derived from purely observational studies without any prevention method under study provided a benchmark incidence.

RESULTS

Within SDD RCCTs, the mean bacteremia incidence among concurrent component groups not exposed to PPAP (27 control; 17.1%; 13.1-22.1% and 12 intervention groups; 16.2%; 9.1-27.3%) is double that of the benchmark bacteremia incidence derived from 39 benchmark groups (8.3; 6.8-10.2%) and also 20 control groups from studies of non-antibiotic methods (7.1%; 4.8 - 10.5). There is a selective increase in coagulase negative staphylococci (CNS) but not in Pseudomonas aeruginosa among bacteremia isolates within control groups of SDD-RCCT's versus benchmark groups with data available.

CONCLUSIONS

The topical antibiotic component of SDD presents a major contextual hazard toward bacteremia against which the PPAP component partially mitigates.

Effect of selective decontamination on antimicrobial resistance in intensive care units: a systematic review and meta-analysis

BACKGROUND

Many meta-analyses have shown reductions in infection rates and mortality associated with the use of selective digestive decontamination (SDD) or selective oropharyngeal decontamination (SOD) in intensive care units (ICUs). These interventions have not been widely implemented because of concerns that their use could lead to the development of antimicrobial resistance in pathogens. We aimed to assess the effect of SDD and SOD on antimicrobial resistance rates in patients in ICUs.

METHODS

We did a systematic review of the effect of SDD and SOD on the rates of colonisation or infection with antimicrobial-resistant pathogens in patients who were critically ill. We searched for studies using Medline, Embase, and Cochrane databases, with no limits by language, date of publication, study design, or study quality. We included all studies of selective decontamination that involved prophylactic application of topical non-absorbable antimicrobials to the stomach or oropharynx of patients in ICUs, with or without additional systemic antimicrobials. We excluded studies of interventions that used only antiseptic or biocide agents such as chlorhexidine, unless antimicrobials were also included in the regimen. We used the Mantel-Haenszel model with random effects to calculate pooled odds ratios.

FINDINGS

We analysed 64 unique studies of SDD and SOD in ICUs, of which 47 were randomised controlled trials and 35 included data for the detection of antimicrobial resistance. When comparing data for patients in intervention groups (those who received SDD or SOD) versus data for those in control groups (who received no intervention), we identified no difference in the prevalence of colonisation or infection with Gram-positive antimicrobial-resistant pathogens of interest, including meticillin-resistant Staphylococcus aureus (odds ratio 1·46, 95% CI 0·90-2·37) and vancomycin-resistant enterococci (0·63, 0·39-1·02). Among Gram-negative bacilli, we detected no difference in aminoglycoside-resistance (0·73, 0·51-1·05) or fluoroquinolone-resistance (0·52, 0·16-1·68), but we did detect a reduction in polymyxin-resistant Gram-negative bacilli (0·58, 0·46-0·72) and third-generation cephalosporin-resistant Gram-negative bacilli (0·33, 0·20-0·52) in recipients of selective decontamination compared with those who received no intervention.

INTERPRETATION

We detected no relation between the use of SDD or SOD and the development of antimicrobial-resistance in pathogens in patients in the ICU, suggesting that the perceived risk of long-term harm related to selective decontamination cannot be justified by available data. However, our study indicates that the effect of decontamination on ICU-level antimicrobial resistance rates is understudied. We recommend that future research includes a non-crossover, cluster randomised controlled trial to assess long-term ICU-level changes in resistance rates.

FUNDING

None.

Selective decontamination of the digestive tract in critically ill children: systematic review and meta-analysis

OBJECTIVE

We examined the impact of selective decontamination of the digestive tract on morbidity and mortality in critically ill children.

DATA SOURCES

We searched MEDLINE, EMBASE, the Cochrane Register of Controlled Trials, and previous meta-analyses.

STUDY SELECTION

We included all randomized controlled trials comparing administration of enteral antimicrobials in selective decontamination of the digestive tract with or without a parenteral component with placebo or standard therapy used in the controls.

DATA EXTRACTION

The primary end point was the number of acquired pneumonias. Secondary end points were number of infections and overall mortality. Odds ratios were pooled with the random effect model.

DATA SYNTHESIS

Four randomized controlled trials including 335 patients were identified. Pneumonia was diagnosed in five of 170 patients (2.9%) for selective decontamination of the digestive tract and 16 of 165 patients (9.7%) for controls (odds ratio 0.31; 95% confidence interval 0.11-0.87; p = .027). Overall mortality for selective decontamination of the digestive tract was 13 of 170 (7.6%) vs. control, 11 of 165 (6.7%) (odds ratio 1.18; 95% confidence interval 0.50-2.76; p = .70). In three studies (n = 109), infection occurred in ten of 54 (18.5%) patients on selective decontamination of the digestive tract and 24 of 55 (43.6%) in the controls (odds ratio 0.34; 95% confidence interval 0.05-2.18; p = .25).

CONCLUSIONS

In the four available pediatric randomized controlled trials, selective decontamination of the digestive tract significantly reduced the number of children who developed pneumonia.

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.

Impact of selective decontamination of the digestive tract on multiple organ dysfunction syndrome: systematic review of randomized controlled trials

OBJECTIVE

We examined the impact of selective decontamination of the digestive tract on multiple organ dysfunction syndrome.

DATA SOURCES

We searched MEDLINE, EMBASE, the Cochrane Register of Controlled Trials, previous meta-analyses, and meetings proceedings.

STUDY SELECTION

We included all randomized trials comparing both oropharyngeal and intestinal administration of antibiotics in selective decontamination of the digestive tract with or without a parenteral component, with placebo or standard therapy used in the controls.

DATA EXTRACTION

Two reviewers independently applied selection criteria, performed quality assessment, and extracted the data. The primary end point was the number of patients with multiple organ dysfunction syndrome developing during intensive care unit stay. Secondary end points were overall mortality and multiple organ dysfunction syndrome-related mortality. Odds ratios were pooled with the random effect model.

DATA SYNTHESIS

We identified seven randomized trials including 1270 patients. Multiple organ dysfunction syndrome was found in 132 of 637 patients (20.7%) in the selective decontamination of the digestive tract group and in 219 of 633 patients (34.6%) in the control group (odds ratio, 0.50; 95% confidence interval, 0.34-0.74; p < .001). Overall mortality for selective decontamination of the digestive tract vs. control patients was 119 of 637 (18.7%) and 145 of 633 (22.9%), respectively, demonstrating a nonsignificant reduction in the odds of death (odds ratio, 0.82; 95% confidence interval, 0.51-1.32; p = .41). In five studies including 472 patients, multiple organ dysfunction syndrome-related mortality was demonstrated in 31 of 239 (13%) patients in selective decontamination of the digestive tract group and 37 of 233 (15.9%) in the controls (odds ratio, 0.84; 95% confidence interval, 0.48-1.41; p = .54).

CONCLUSIONS

Selective decontamination of the digestive tract reduces the number of patients with multiple organ dysfunction syndrome. Mortality was not significantly reduced, probably because of the small sample size.

Antibiotic prophylaxis to reduce respiratory tract infections and mortality in adults receiving intensive care

BACKGROUND

Pneumonia is an important cause of mortality in intensive care units (ICUs). The incidence of pneumonia in ICU patients ranges between 7% and 40%, and the crude mortality from ventilator-associated pneumonia may exceed 50%. Although not all deaths in patients with this form of pneumonia are directly attributable to pneumonia, it has been shown to contribute to mortality in ICUs independently of other factors that are also strongly associated with such deaths.

OBJECTIVES

To assess the effects of prophylactic antibiotic regimens, such as selective decontamination of the digestive tract (SDD) for the prevention of respiratory tract infections (RTIs) and overall mortality in adults receiving intensive care.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, issue 1), which contains the Cochrane Acute Respiratory Infections (ARI) Group's Specialised Register; MEDLINE (January 1966 to March 2009); and EMBASE (January 1990 to March 2009).

SELECTION CRITERIA

Randomised controlled trials (RCTs) of antibiotic prophylaxis for RTIs and deaths among adult ICU patients.

DATA COLLECTION AND ANALYSIS

At least two review authors independently extracted data and assessed trial quality.

MAIN RESULTS

We included 36 trials involving 6914 people. There was variation in the antibiotics used, patient characteristics and risk of RTIs and mortality in the control groups. In trials comparing a combination of topical and systemic antibiotics, there was a significant reduction in both RTIs (number of studies = 16, odds ratio (OR) 0.28, 95% confidence interval (CI) 0.20 to 0.38) and total mortality (number of studies = 17, OR 0.75, 95% CI 0.65 to 0.87) in the treated group. In trials comparing topical antimicrobials alone (or comparing topical plus systemic versus systemic alone) there was a significant reduction in RTIs (number of studies = 17, OR 0.44, 95% CI 0.31 to 0.63) but not in total mortality (number of studies = 19, OR 0.97, 95% CI 0.82 to 1.16) in the treated group.

AUTHORS' CONCLUSIONS

A combination of topical and systemic prophylactic antibiotics reduces RTIs and overall mortality in adult patients receiving intensive care. Treatment based on the use of topical prophylaxis alone reduces respiratory infections but not mortality. The risk of resistance occurring as a negative consequence of antibiotic use was appropriately explored only in one trial which did not show any such effect.

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.

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.

[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.

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.

The use of topical nonabsorbable gastrointestinal antifungal prophylaxis to prevent fungal infections in critically ill immunocompetent patients: A meta-analysis

OBJECTIVE

To investigate the preventive effect of topical nonabsorbable gastrointestinal antifungal prophylaxis on the incidence of fungal infection in critically ill immunocompetent patients.

DATA SOURCE

Randomized controlled studies involving critically ill pediatric and adult patients in different languages from the Cochrane Controlled Trial Register (2004, issue 1), EMBASE, and MEDLINE databases (1966 to 30 April 2004) were included. Studies evaluating absorbable antifungal prophylaxis were excluded. Two reviewers assessed the quality of the studies and performed data extraction independently.

DATA

Amphotericin B and nystatin were used as the nonabsorbable antifungal prophylaxis in the 15 studies included in this meta-analysis. Ten studies used a concomitant systemic antibiotic and four more studies used concomitant topical nonabsorbable antibiotics in the treatment group. Only one study compared topical nonabsorbable antifungal prophylaxis alone with placebo. The total incidence of fungal infections (relative risk [RR], 0.30; 95% confidence interval [CI], 0.18-0.48; p < .00001; extent of inconsistency [I(2)] = 0%) and proportion of patients with fungal infection (RR, 0.50; 95% CI, 0.28-0.87; p = .02; I(2) = 0%) were significantly reduced with topical nonabsorbable antifungal prophylaxis. The incidence of fungal urinary tract infection was significantly reduced (RR, 0.27; 95% CI, 0.10-0.74; p = .01; I(2)= 0%) but not fungal pneumonia (RR, 0.57; 95% CI, 0.28-1.16; p = .12; I(2)= 0%). Fungemia and catheter-related fungal sepsis were rare and not significantly reduced with nonabsorbable antifungal prophylaxis. The results remained unchanged in the sensitivity analyses after exclusion of studies with unclear study quality or exclusion of the contribution of fungal urinary tract infections to the total incidence of fungal infections.

CONCLUSIONS

In critically ill immunocompetent patients who are at high risk of fungal infection, topical nonabsorbable gastrointestinal antifungal prophylaxis was associated with a reduced incidence of urinary fungal infections and a trend toward reduction in respiratory fungal infections and fungemia. Limitations in study data are such that many of these infections may have represented superficial infections of uncertain clinical importance; a large, randomized, controlled trial is needed to assess the cost-effectiveness and safety of topical nonabsorbable antifungal prophylaxis in critically ill patients.

A prospective study of septicaemia on a paediatric oncology unit: A three-year experience at The Royal Liverpool Children’s Hospital, Alder Hey, UK

Septicaemia in neutropaenic patients is predominantly due to gut translocation [endogenous septicaemia] and contamination of the central venous catheter by microorganisms not carried by the patient [exogenous septicaemia]. To control both types of infection, a protocol was implemented based on pre 1990's parenteral and enteral antimicrobials together with strict hygiene. Surveillance cultures of throat/rectum were taken to distinguish exogenous from endogenous septicaemia and enteral non-absorbable antibiotics are administered as part of selective decontamination of the digestive tract (SDD). This protocol was evaluated in a 14-bedded paediatric oncology unit over a period of 3 years. 313 Septicaemia episodes were recorded in 131 children. 28.4% of the septicaemias were caused by microorganisms associated with the unit, equivalent to 0.82 episodes per 100 patient days. Low-level pathogens such as coagulase-negative staphylococci caused more than 70% of infections. Amongst the potential pathogens, Pseudomonas species (7.8%) and Staphylococcus aureus (5.5%) were predominant. Antibiotic resistance was rare with no superinfections or outbreaks. Four patients (3%) died, two due to Candida species and two due to Pseudomonas aeruginosa. We believe that the addition of enteral non-absorbable antibiotics to systemic antibiotics maintained a low level of resistance and mortality but a randomised controlled trial is indicated to confirm these observations.

Impact of selective decontamination of the digestive tract on fungal carriage and infection: systematic review of randomized controlled trials

OBJECTIVE

To determine the impact of the antifungal component of selective decontamination of the digestive tract on fungal carriage, infection and fungaemia.

DESIGN

Meta-analysis of randomized controlled trials of selective decontamination of the digestive tract.

STUDY SELECTION

Data sources included Medline, Embase, Cochrane Register of Controlled Trials, previous meta-analyses, personal communications and conference proceedings, without restriction of language or publication status. All randomized trials were selected that compared oropharyngeal and/or intestinal administration of antifungals amphotericin B or nystatin, as part of selective decontamination protocol, with no treatment in the controls. There were 42 randomized controlled trials with a total of 6,075 critically ill patients.

METHODS

Three reviewers independently applied selection criteria, performed quality assessment and extracted the data. The main outcome measures were patients with fungal carriage, patients with fungal infections and patients with fungaemia. Odds ratios were pooled with the random effect model.

MEASUREMENTS AND RESULTS

Enteral antifungals significantly reduced fungal carriage (odds ratio 0.32, 95% confidence interval 0.19-0.53) and overall fungal infections (0.30, 0.17-0.53). Fungaemia was not significantly reduced in the treatment group (0.89, 0.16-4.95).

CONCLUSIONS

Antifungals, as part of selective decontamination of the digestive tract, reduce fungal carriage and infection but not fungaemia in critically ill patients and may justify the inclusion of an antifungal component in the decontamination protocol.

Sepsis in pediatric burn patients

OBJECTIVE

To review the specific infections common in pediatric burns, including their categorization, diagnosis, and treatment.

DESIGN

Review of the literature and expert opinion.

RESULTS

Children with serious burns are prone to a host of septic complications. This proclivity to infection is secondary to the immunosuppressive effect of burn injury, the loss of the skin and mucosal physical barriers, and the requirement for invasive support devices.

CONCLUSION

Sepsis is common in the pediatric burn patient and can markedly increase morbidity and mortality. Anticipation, prompt diagnosis of infection, and effective therapy can result in successful outcomes for many of these children.

Once-daily netilmicin for neutropenic pyrexia in paediatric oncology

AIM

To establish the safety and efficacy of single daily intravenous netilmicin 6 mg/kg with piperacillin 100 mg/kg every 8 h for empirical, first-line management of children with neutropenic pyrexia following cytotoxic chemotherapy.

METHODS

Observational study of children admitted to a regional oncology unit from October 1999-April 2002. Primary outcome measure was temperature 72 h after commencing antibiotic therapy; secondary measures were mortality, nephrotoxicity, symptomatic ototoxicity and serum netilmicin levels.

RESULTS

280 episodes for 128 patients (median age 7.1 y) were documented, and 248 episodes were evaluated and compared with a previous cohort of 100 episodes for which the only difference was administration of netilmicin three times daily. Twenty-seven per cent of single-dose netilmicin episodes remained febrile at 72 h compared to 32% in the comparator group (difference -4.7%; 95 % CI: -6.8% to 16.2%; p = 0.41). No patients died and we were unable to find evidence of nephrotoxicity or ototoxicity. Eighty-nine per cent of "peak" serum netilmicin levels measured 30 min after infusion were 10 mg/l or greater, and 94% and 86% measured 12-16 h after the first and third dose, respectively, were 1 mg/l or less. Peak serum netilmicin level measurements and 12-16-h measurements after the first dose were abandoned after the first 180 episodes.

CONCLUSIONS

Netilmicin can safely be given as a single daily dose to children with febrile neutropenia who do not have biochemical evidence of nephrotoxicity. Monitoring peak serum levels of netilmicin is unnecessary. Levels taken 12-16 h after the third dose are adequate to monitor therapy if used in conjunction with a therapeutic guideline detailing the response to abnormal serum creatinine and netilmicin levels.

Infection in prolonged pediatric critical illness: A prospective four-year study based on knowledge of the carrier state

OBJECTIVE

This study was performed to determine the rate, timing, and incidence density of infections occurring in a subgroup of patients requiring a prolonged stay in a regional pediatric intensive care unit.

DESIGN

Prospective, observational cohort study over 4 yrs.

SETTING

This epidemiologic descriptive study was performed in a university hospital 20-bed pediatric intensive care unit.

PATIENTS

Critically ill children requiring > or = 4 days of intensive care.

INTERVENTIONS

The microbial carrier state of the children was monitored by surveillance cultures of throat and rectum, obtained on admission and twice weekly afterward.

MEASUREMENTS AND MAIN RESULTS

Data are presented on a total of 1,241 children, accounting for 1,443 admissions to the unit, corresponding to 18,203 patient days. The median pediatric index of mortality was 0.063 (interquartile range, 0.025-0.131), and the mortality rate in this subset of children was 9.6%. Five hundred twenty children had infections, an overall infection rate of 41.9% (520 of 1,241); 14.5% (180 of 1,241) of the children developed viral and 33.0% (410 of 1,241) developed bacterial/yeast infections. The incidence of bloodstream infection was 20.1 and lower airway infection 9.1 episodes per 1,000 patient days. We found that 13.3% of the children were infected with a bacterial/yeast microorganism acquired on the pediatric intensive care unit; 4.0% (50 of 1,241) of children developed infections due to resistant microorganisms. There were a total of 803 bacterial/yeast infectious episodes, of which 59.8% (480) were due to microorganisms imported in the patients' admission flora. These primary endogenous infections predominantly occurred within the first week of pediatric intensive care unit stay. The other 38.9% (312) were caused by microorganisms acquired on the pediatric intensive care unit. A total of 38 viral infections (24.5%) were acquired during pediatric intensive care unit stay.

CONCLUSIONS

Two thirds of all infections diagnosed in children with prolonged illness on pediatric intensive care unit were due to microorganisms present in the patients' admission flora.

Selective decontamination of the digestive tract

Ventilator-associated pneumonia usually originates from the patient's oropharyngeal microflora. In selective digestive decontamination, topical antibiotics are applied to the oropharynx and stomach for prevention of pneumonia and other infections, possibly reducing infection-related mortality. Selective digestive decontamination is also used for the prevention of gut-derived infections in acute necrotizing pancreatitis and liver transplantation. Despite numerous clinical trials, selective digestive decontamination remains controversial. Reduction of the incidence of pneumonia is accepted, but the extent of reduction is debated. Mortality was not reduced in most individual trials, but this finding was calculated in meta-analyses, especially for combined use of topical and systemic antibiotics in surgical ICU patients. Some investigators reported increased resistance and a shift to Gram-positive pathogens. Today, it appears that selective means not only selective suppression of pathogenic bacteria but also selection of appropriate groups of patients for underlying diseases and severity of illness, and selection of ICUs, where the endemic resistance patterns might allow the use of selective digestive decontamination at a relatively low risk for increased selection pressure.

Gastrointestinal problems in the chronically critically ill patient

In summary, a variety of gastrointestinal processes may occur in the chronically critically ill patient population, usually as consequence of the primary systemic process. The clinical presentation is frequently nonclassic and there often is a substantial delay in diagnosis, resulting in increased morbidity and mortality.

Antibiotics for preventing respiratory tract infections in adults receiving intensive care

OBJECTIVES

Pneumonia is an important cause of mortality in intensive care units. The objective of this review was to assess the effects of antibiotics for preventing respiratory tract infections and overall mortality in adults receiving intensive care.

SEARCH STRATEGY

We searched MEDLINE, proceedings of scientific meetings and reference lists of articles from January 1984 to September 1997. We also contacted investigators in the field.

SELECTION CRITERIA

Randomised trials of antibiotic prophylaxis for respiratory tract infections and deaths among adult intensive care unit patients.

DATA COLLECTION AND ANALYSIS

Trials were assessed for quality and investigators contacted for additional information.

MAIN RESULTS

Overall 33 trials involving 5727 people were included. There was variation in the antibiotics used, patient characteristics and the risk of respiratory tract infections and mortality in the control groups. In 16 trials (involving 3493 patients) of a topical and systemic antibiotic combination, the average rates of respiratory tract infections and deaths in the control group were 33% and 28% respectively. There was a significant reduction of both respiratory tract infections (odds ratio 0.36, 95% confidence interval 0.30 to 0. 43) and total mortality (odds ratio 0.80, 95% confidence interval 0. 68 to 0.93). On average five patients needed to be treated to prevent one infection and 23 treated to prevent one death. In 17 trials (involving 2366 patients) of topical antimicrobials the rates of respiratory tract infections and deaths in the control groups were 30% and 24% respectively. There was a significant reduction of respiratory tract infections (odds ratio 0.57, 95% confidence interval 0.46 to 0.69) but not in total mortality (odds ratio 1.01, 95% confidence interval 0.84 to 1.22).

REVIEWER'S CONCLUSIONS

A combination of topical and systemic prophylactic antibiotics can reduce respiratory tract infections and overall mortality in adult patients receiving intensive care. [This abstract has been prepared centrally.]

Prevention of nosocomial infection in a pediatric intensive care unit (PICU) through the use of selective digestive decontamination

OBJECTIVE

To assess the effectiveness of selective digestive decontamination (SDD) on the control of nosocomial infection (NI) in critically ill pediatric patients.

DESIGN

A prospective, randomized, non-blinded and controlled clinical microbiology study.

SETTING

The pediatric intensive care unit (PICU) of a tertiary level pediatric university hospital. CRITERIA FOR INCLUSION: Patients 1 month to 14 years old, who underwent some kind of manipulation or instrumentation (mechanical ventilation, vascular cannulation, monitoring of intracranial pressure, thoracic or abdominal drainage, bladder catheterization, peritoneal dialysis, etc.) and/or presented a neurological coma requiring a stay in the PICU of 3 or more days.

PATIENTS

Over a period of 2 years, 244 patients met the inclusion criteria; 18 patients were withdrawn because of protocol violation. The treatment group comprised 116 patients and the control group, 110 patients.

INTERVENTION

The treatment group received a triple therapy of colimycin, tobramycin and nystatin administered orally or via nasogastric tube every 6 hours. All patients with mechanical ventilation or immune-depression received decontamination treatment of the oropharyngeal cavity with hexitidine (Oraldine 0.5 mg/ml) every 6-8 hours in accordance with the PICU's conventional protocol.

METHOD

Up to 10 types of nosocomial infection were diagnosed following criteria of the Centers for Disease Control (CDC). The severity and manipulation of the patients on admission was assessed using the therapeutic intervention scoring system (TISS) and multi-organ system failure scores (MOSF).

MEASUREMENTS AND MAIN RESULTS

UNIVARIANT ANALYSIS: SDD did not significantly reduce the incidence of NI, antibiotic use, the length of stay, or mortality; although a small percentage of respiratory and urinary tract infections was detected, catheter-related bacteremia was the most common infection. MULTIVARIANT ANALYSIS: Controlling the risk factors for each child through log regression showed that SDD acted as a protective factor for more than 90% of the sample with respect to the appearance of respiratory and urinary tract infections, reducing the risk of such infections to 1/5 and 1/3, respectively.

CONCLUSIONS

SDD was effective in controlling respiratory and urinary tract infections in children admitted to the PICU, but it did not reduce the incidence of other types of nosocomial infection.

Effectiveness and cost of selective decontamination of the digestive tract in critically ill intubated patients. A randomized, double-blind, placebo-controlled, multicenter trial

We evaluated the effect of selective decontamination of the digestive tract (SDD) on the incidence of ventilator-associated pneumonia (VAP) and its associated morbidity and cost in a mixed population of intubated patients. Two hundred seventy-one consecutive patients admitted to the intensive care units (ICUs) of five teaching hospitals and who had an expected need for intubation exceeding 48 h were enrolled and received topical antibiotics or placebo. Uninfected patients additionally received ceftriaxone or placebo for 3 d. VAP occurred in 11.4% of SDD-treated and 29.3% of control-group patients (p < 0.001; 95% confidence interval [CI]: 7.8 to 27.9). The incidence of nonrespiratory infections in the two groups was 19.1% and 30.7%, respectively (p = 0.04; 95% CI: 0.7 to 22.7). Among survivors, the median length of ICU stay was 11 d (interquartile range: 7 to 21.5 d) for the SDD-treated group and 16. 5 d (10 to 30 d) for the control group (p = 0.006). Mean cost per survivor was $11,926 for treated and $16,296 for control-group patients. Mortality was 38.9% and 47.1%, respectively (p = 0.57). In decontaminated patients, the prevalence of gram-negative bacilli fell within 7 d from 47.4% to 13.0% (p < 0.001), whereas colonization with resistant gram-positive strains was higher (p < 0. 05) than in the placebo group. In a mixed population of intubated patients, SDD was associated with a significant reduction of morbidity at a reduced cost. Our findings support the use of SDD in this high-risk group.

Treatment and Control of Colonization in the Prevention of Nosocomial Infections

Patients frequently develop nosocomial infections that are caused by normal flora colonizing the patient at the time of admission, or by exogenous pathogens that are acquired and subsequently colonize the patient after admission to the hospital. To prevent nosocomial infections, a variety of strategies have been used either to prevent colonization from occurring, to eradicate colonizing organisms, or to prevent the progression from colonization to infection. These strategies include implementation of infection control measures designed to prevent acquisition of exogenous pathogens, eradication of exogenous pathogens from patients or personnel who have become colonized, suppression of normal flora, prevention of colonizing flora from entering sterile body sites during invasive procedures, microbial interference therapy, immunization of high-risk patients, and modification of antibiotic utilization practices. Because strategies that require widespread use of antimicrobial agents to suppress or eradicate colonizing organisms tend to promote emergence of multidrug-resistant pathogens, greater emphasis should be given to those strategies that prevent colonization from occurring or employ techniques other than administration of prophylactic antibiotics to eradicate colonization. Restricting inappropriate use of antibiotics should reduce the frequency with which patients become colonized and infected with multidrug-resistant organisms.

Prophylaxis with enteral antibiotics in ventilated patients: selective decontamination or selective cross-infection?

Selective decontamination of the digestive tract (SDD) has been evaluated as a method to prevent colonization and infection in ventilated patients in 40 trials. On the basis of an assumption that cross-infection would be reduced as a consequence of SDD and that this would distort the results of SDD studies that used concurrent controls, 14 studies used historic controls. To test this assumption, three observations from the two types of studies were compared. (i) The differences between observed and expected event rates for each study were used to perform a meta-analysis. This revealed that the summary odds ratios for bacteremia and respiratory infection were marked by significant heterogeneity (P > 0.95) and inconsistencies between those derived from studies with concurrent versus studies with historic controls. (ii) Where the data were available, the rates of acquisition of colonization in control groups were higher in studies with concurrent controls than in studies with historic controls. (iii) At least four studies with concurrent controls have shown a pattern of pathogenic isolates consistent with cross-infection between groups. These results are contrary to the initial assumption and suggest the possibility that SDD represents a major cross-infection hazard.

Pathogen and host differences in bacterial adherence to human buccal epithelial cells in a northeast Brazilian community

The adherence of several strains of Escherichia coli to human buccal epithelial cells was studied, using cells obtained from five groups: healthy adults, healthy children, children with acute diarrhea, children with persistent diarrhea associated with cryptosporidial parasites, and children with noncryptosporidial persistent diarrhea. All groups lived or worked in an urban slum in northeastern Brazil. Samples of buccal epithelial cells from subjects in each of these groups were incubated with wild-type E. coli K-12 (strain C600), the enteroaggregative E. coli strains 17-2 and PDAS 30-5, CFA/II-positive E. coli 1392+ and its plasmid-cured derivative 1392-, and hydrophobic E. coli 132-3. Samples were evaluated microscopically to determine background contamination and the percentage of cells with more than 15% of their surface area obscured by adherent bacteria after incubation and washing. The assay was tested under field conditions and was shown to produce reliable and consistent results. Both enteroaggregative strains of E. coli were shown to adhere to a significantly higher percentage of all groups of human buccal epithelial cells than any of the other tested strains. In addition, buccal epithelial cells from children with nonparasitic persistent diarrhea showed substantially more bacterial adherence in both the native state and with all tested strains of E. coli than did cells from children with persistent cryptosporidial diarrhea or acute diarrhea or from healthy controls. This study provides evidence that enteroaggregative strains of E. coli demonstrate increased adherence to human buccal epithelial cells (as well as to cultured HEp-2 cells) and that buccal epithelial cells from children with noncryptosporidial persistent diarrhea appear to be more susceptible to bacterial adherence and colonization than buccal epithelial cells from control groups. These findings suggest that host differences as well as pathogen differences are important in the pathogenesis of persistent diarrhea and have implications for a potential role for buccal epithelial cell analysis in the diagnosis or risk stratification of children susceptible to noncryptosporidial persistent diarrhea.