Probiotics versus antibiotic decontamination of the digestive tract: infection and mortality

Purpose  

Selective decontamination of the digestive tract (SDD) has been shown to decrease the infection rate and mortality in intensive care units (ICUs); Lactobacillus plantarum 299/299v plus fibre (LAB) has been used for infection prevention and does not harbour the potential disadvantages of antibiotics. The objective was to assess whether LAB is not inferior to SDD in infection prevention.     

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.     

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.     

Emergence of multidrug-resistant Gram-negative bacteria during selective decontamination of the digestive tract on an intensive care unit

OBJECTIVES: During treatment with selective decontamination of the digestive tract (SDD), four multidrug-resistant (MDR) strains, three different Escherichia coli and one Klebsiella pneumoniae, were isolated from four patients not known as carriers of such MDR strains before their admission to the intensive care unit (ICU) in the Academic Medical Center (AMC) in Amsterdam. These isolates were extended-spectrum beta-lactamase (ESBL)-positive. We investigated whether this was due to interspecies transfer of resistance genes. METHODS: The MDR strains were typed by amplified fragment length polymorphism (AFLP) analysis. The plasmids from these strains were characterized by restriction fragment length polymorphism and the resistance genes were characterized by PCR and sequence analysis. RESULTS: The strains were genetically unrelated and contained identical plasmids with ESBL genes. CONCLUSIONS: We identified an outbreak of plasmid-mediated ESBL genes during SDD treatment in the ICU. The use of third-generation cephalosporins in SDD is associated with the emergence of ESBLs. We conclude that identification of emerging MDR Gram-negative bacteria and recognition of resistance plasmid transfer during SDD treatment are crucial for optimal application of this regimen in ICUs.     

Long-term use of selective decontamination of the digestive tract does not increase antibiotic resistance: a 5-year prospective cohort study

Purpose  

Despite the evidence, the use of selective decontamination of the digestive tract (SDD) remains controversial, largely because of concerns that it may promote the emergence of antibiotic-resistant strains. The purpose of this study was to evaluate the long-term incidence of carriage of antibiotic-resistant bacteria (ARB), its clinical impact on developing infections and to explore risk factors of acquiring resistance.     

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.     

Infection prevention in intensive care by selective decontamination of the digestive tract

Infection prevention in the ICU by SDD is based on new insights in the pathogenesis of infections. The recognition that the colonization defense of the oropharynx and gastrointestinal tract is severely impaired in critically ill patients plays a crucial role in this concept.Selective decontamination of the digestive tract is a technique aiming at the elimination of aerobic, potentially pathogenic microorganisms from the oropharynx and gastrointestinal tract with topical nonabsorbable antibiotics. It is based on the following observations: the indigenous flora is seldom involved in infections and has important physiologic functions; there are major differences in the intrinsic pathogenic potential of microorganisms; and colonization and infection of the respiratory and urinary tract and wounds are generally preceded by colonization of the oropharynx or gastrointestinal tract.Several studies have shown that SDD is very effective in preventing acquired infections in intensive care. Although in polytrauma patients the outcome seems to improve with SDD, in general surgical patients, the expected reduction of mortality with the prevention of nosocomial infections has not been found. However, none of the studies was designed for that purpose. The most important conclusion is that many patients are admitted in the ICU with potentially preventable infections and that SDD might be more useful in these patients if applied in an earlier stage. Unlike previous attempts with topical antibiotics, emergence of resistance has not been observed. On the contrary, the prevalence of multiresistant strains seems to decrease with the routine application of this regimen. It has been shown that outbreaks with multiresistant gram-negative bacilli can be controlled by SDD.More studies are required to investigate the potential indications and consequences of this technique.     

Selective decontamination of the digestive tract reduces mortality in critically ill patients

Several emotional responses may be invoked in critical care physicians when confronted with selective decontamination of the digestive tract (SDD). Although recent meta-analyses have shown that the use of SDD reduces the occurrence of ventilator-associated pneumonia and improves ICU survival, the effectiveness of SDD has remained controversial. We recently concluded a large randomized, controlled trial on the use of SDD that showed improved survival of ICU patients treated with SDD. A second concern regarding use of SDD has been the fear for the emergence of antimicrobial resistance. Interestingly, a recently published study did not confirm this fear, and our recently finished study even demonstrated a decline in colonization with P. aeruginosa and enterobacteriaceae that were resistant against tobramycin, ceftazidime, imipenem and ciprofloxacin. The hopes are that this study will at long last end the debate about the efficacy and safety of SDD in critically ill patients.     

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.     

Selective digestive tract decontamination and vancomycin-resistant enterococcus isolation in the surgical intensive care unit

Vancomycin-resistant Enterococcus (VRE) has emerged as a significant nosocomial pathogen in the surgical intensive care unit (SICU). We wished to test the hypothesis that the use of selective digestive tract decontamination (SDD) in the SICU affects the frequency of VRE isolation. A retrospective review of hospital records and the SICU database was performed using patients admitted to the SICU service for three or more days from January 1, 1996 to December 31, 1999 at our large tertiary-care teaching hospital. During this time use of SDD in selected patient populations decreased due to physician preference. Information gathered included length of SICU stay, presence of VRE infection or colonization, and use and duration of SDD protocol, vancomycin, and ceftazidime. There were 110 newly diagnosed VRE cases in the SICU during this time period. During the same time period 54 patients received SDD. Eight patients who received SDD had positive VRE cultures and seven had the initial positive culture after receiving SDD. Overall, 9.1% of eligible SICU patients received SDD, 18.5% of patients in the SICU for over 3 days had VRE, 7.3% of VRE patients received SDD, and 13.0% of the SICU patients who received SDD subsequently developed VRE. SDD use was not associated with VRE in univariate analysis. Logistic regression analysis showed higher odds ratios for SDD use in combination with vancomycin than for vancomycin use alone (OR=4.3 vs. 10.9). Odds ratios were over three times higher for SDD plus vancomycin plus ceftazidime use when compared to vancomycin plus ceftazidime use alone (OR=70.5 vs. 19.8). We conclude that administration of SDD alone did not correlate with increased VRE isolation, but that SDD use in conjunction with vancomycin and ceftazidime was associated with VRE isolation.