The role of intestinal colonization with Gram-negative bacteria as a source for intensive care unit-acquired bacteremia*:

The Relationship between Selective Digestive Decontamination and Nosocomial Infections in Patients Receiving Continuous Renal Replacement Therapy in ICUs: A Multicenter Study

Background: Nosocomial infections are a worldwide healthcare issue, especially in intensive care units (ICUs), and they had a prevalence of 21.1% in 2023 in Spain. Numerous predisposing risk factors have been identified, with the most relevant being invasive techniques, including renal replacement therapies (RRTs). Several outstanding strategies have been published that prevent or reduce their incidence, including the nationwide ZERO in Spain, which consists of structured guidelines to be implemented to tackle this problem. One of these strategies, which is defined as 'highly recommended' in these projects, is selective digestive decontamination (SDD). The main aim of this study is to compare the incidences of ICU-acquired infections, including those due to multidrug-resistant bacteria (MDRB), in two cohorts of RRT with or without SDD. Methods: We conducted a multicenter, prospective, observational study at two tertiary hospitals in Spain. In total, 140 patients treated with RRT were recruited based on their exposure to SDD. Surveillance microbiological samples and nosocomial infection risk factors were obtained. Infection rates per 1000 days of exposure and the MDRB incidence density ratio were determined. Results: SDD statistically significantly reduced RRT-associated nosocomial infections (OR: 0.10, 95% CI: (0.04-0.26)) and the MDRB incidence density ratio (IDR: 0.156, 95% CI = 0.048-0.506). However, mechanical ventilation (OR: 7.91, 95% CI: (2.54-24.66)) and peripheral vascular disease (OR: 3.17, 95% CI: (1.33-7.56)) were significantly associated with increases in infections. Conclusions: Our results favor the use of SDD in ICU patients with renal failure undergoing CRRT as a tool for infection control.

Timing and clinical risk factors for early acquisition of gut pathogen colonization with multidrug resistant organisms in the intensive care unit

BACKGROUND

Microbiome restitution therapies are being developed to prevent gut pathogen colonization among patients in the intensive care unit (ICU) and in other select populations. If preventive therapies are to be effective, they must be administered prior to pathogen acquisition. The timing and risk factors for early acquisition of gut pathogen colonization (within 72 h) are currently unknown and could be helpful to guide ICU trial design.

METHODS

This was a prospective cohort study. Patients in the ICU had deep rectal swabs performed within 4 h of ICU admission and exactly 72 h later. Early gut pathogen colonization was classified as the new presence (based on culture of rectal swabs) of one or more of the following organisms of interest: methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant (VRE), and Gram-negative bacteria that showed multidrug resistance (MDR) or third generation Cephalosporin resistance (Ceph-R). Clinical risk factors for early acquisition of gut pathogen colonization were captured using the Acute Physiology and Chronic Health Evaluation IV (APACHE IV) scoring system.

FINDINGS

Among 131 patients who were swabbed at ICU admission and 72 h later, the rates of gut pathogen colonization at ICU admission were 11.4%, 10.6%, 38.6%, and 8.3% for MRSA, VRE, MDR and Ceph-R Gram-negatives respectively. Among the patients who were negative for a given pathogen at ICU admission, the rates of early acquisition of gut pathogen colonization were 7.8% for MRSA (95% CI 3.6 to 14.2%), 7.7% for VRE (95% CI 3.6 to 14.1%), 11.3% for MDR Gram-negatives (95% CI 4.4 to 18.8%), and 4.2% for Ceph-R Gram-negatives (95% CI 1.4 to 9.5%). There were no clinical risk factors which independently predicted early acquisition of gut pathogen colonization.

INTERPRETATION

Early gut pathogen colonization was common in the ICU, but our single-center study could not identify any clinical risk factors which were significantly associated with acquisition of gut pathogens.

Antimicrobial Resistance in Ventilator-Associated Pneumonia: Predictive Microbiology and Evidence-Based Therapy

Ventilator-associated pneumonia (VAP) is a serious intensive care unit (ICU)-related infection in mechanically ventilated patients that is frequent, as more than half of antibiotics prescriptions in ICU are due to VAP. Various risk factors and diagnostic criteria for VAP have been referred to in different settings. The estimated attributable mortality of VAP can go up to 50%, which is higher in cases of antimicrobial-resistant VAP. When the diagnosis of pneumonia in a mechanically ventilated patient is made, initiation of effective antimicrobial therapy must be prompt. Microbiological diagnosis of VAP is required to optimize timely therapy since effective early treatment is fundamental for better outcomes, with controversy continuing regarding optimal sampling and testing. Understanding the role of antimicrobial resistance in the context of VAP is crucial in the era of continuously evolving antimicrobial-resistant clones that represent an urgent threat to global health. This review is focused on the risk factors for antimicrobial resistance in adult VAP and its novel microbiological tools. It aims to summarize the current evidence-based knowledge about the mechanisms of resistance in VAP caused by multidrug-resistant bacteria in clinical settings with focus on Gram-negative pathogens. It highlights the evidence-based antimicrobial management and prevention of drug-resistant VAP. It also addresses emerging concepts related to predictive microbiology in VAP and sheds lights on VAP in the context of coronavirus disease 2019 (COVID-19).

Surgical Science and the Evolution of Critical Care Medicine

Surgical science has driven innovation and inquiry across adult and pediatric disciplines that provide critical care regardless of location. Surgically originated but broadly applicable knowledge has been globally shared within the pages Critical Care Medicine over the last 50 years.

The role of bacterial translocation in sepsis: a new target for therapy

Sepsis is a leading cause of death in critically ill patients, primarily due to multiple organ failures. It is associated with a systemic inflammatory response that plays a role in the pathogenesis of the disease. Intestinal barrier dysfunction and bacterial translocation (BT) play pivotal roles in the pathogenesis of sepsis and associated organ failure. In this review, we describe recent advances in understanding the mechanisms by which the gut microbiome and BT contribute to the pathogenesis of sepsis. We also discuss several potential treatment modalities that target the microbiome as therapeutic tools for patients with sepsis.

Structural equation modelling the relationship between anti-fungal prophylaxis and Pseudomonas bacteremia in ICU patients

Purpose

Animal models implicate candida colonization facilitating invasive bacterial infections. The clinical relevance of this microbial interaction remains undefined and difficult to study directly. Observations from studies of anti-septic, antibiotic, anti-fungal, and non-decontamination-based interventions to prevent ICU acquired infection collectively serve as a natural experiment.

Methods

Three candidate generalized structural equation models (GSEM), with Candida and Pseudomonas colonization as latent variables, were confronted with blood culture and respiratory tract isolate data derived from 464 groups from 279 studies including studies of combined antibiotic and antifungal exposures within selective digestive decontamination (SDD) interventions.

Results

Introducing an interaction term between Candida colonization and Pseudomonas colonization substantially improved GSEM model fit. Model derived coefficients for singular exposure to anti-septic agents (− 1.23; − 2.1 to − 0.32), amphotericin (− 1.78; − 2.79 to − 0.78) and topical antibiotic prophylaxis (TAP; + 1.02; + 0.11 to + 1.93) versus Candida colonization were similar in magnitude but contrary in direction. By contrast, the model-derived coefficients for singular exposure to TAP, as with anti-septic agents, versus Pseudomonas colonization were weaker or non-significant. Singular exposure to amphotericin would be predicted to more than halve candidemia and Pseudomonas bacteremia incidences versus literature benchmarks for absolute differences of approximately one percentage point or less.

Conclusion

GSEM modelling of published data supports the postulated interaction between Candida and Pseudomonas colonization towards promoting bacteremia among ICU patients. This would be difficult to detect without GSEM modelling. The model indicates that anti-fungal agents have greater impact in preventing Pseudomonas bacteremia than TAP, which has no impact.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-022-00429-8.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Rescuing the Last-Line Polymyxins: Achievements and Challenges

Antibiotic resistance is a major global health challenge and, worryingly, several key Gram negative pathogens can become resistant to most currently available antibiotics. Polymyxins have been revived as a last-line therapeutic option for the treatment of infections caused by multidrug-resistant Gram negative bacteria, in particular Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacterales. Polymyxins were first discovered in the late 1940s but were abandoned soon after their approval in the late 1950s as a result of toxicities (e.g., nephrotoxicity) and the availability of "safer" antibiotics approved at that time. Therefore, knowledge on polymyxins had been scarce until recently, when enormous efforts have been made by several research teams around the world to elucidate the chemical, microbiological, pharmacokinetic/pharmacodynamic, and toxicological properties of polymyxins. One of the major achievements is the development of the first scientifically based dosage regimens for colistin that are crucial to ensure its safe and effective use in patients. Although the guideline has not been developed for polymyxin B, a large clinical trial is currently being conducted to optimize its clinical use. Importantly, several novel, safer polymyxin-like lipopeptides are developed to overcome the nephrotoxicity, poor efficacy against pulmonary infections, and narrow therapeutic windows of the currently used polymyxin B and colistin. This review discusses the latest achievements on polymyxins and highlights the major challenges ahead in optimizing their clinical use and discovering new-generation polymyxins. To save lives from the deadly infections caused by Gram negative "superbugs," every effort must be made to improve the clinical utility of the last-line polymyxins. SIGNIFICANCE STATEMENT: Antimicrobial resistance poses a significant threat to global health. The increasing prevalence of multidrug-resistant (MDR) bacterial infections has been highlighted by leading global health organizations and authorities. Polymyxins are a last-line defense against difficult-to-treat MDR Gram negative pathogens. Unfortunately, the pharmacological information on polymyxins was very limited until recently. This review provides a comprehensive overview on the major achievements and challenges in polymyxin pharmacology and clinical use and how the recent findings have been employed to improve clinical practice worldwide.

Reducing the dosing frequency of selective digestive tract decontamination to three times daily provides effective decontamination of Gram-negative bacteria

This study evaluated the effectiveness of selective digestive tract decontamination (SDD) application three times daily (t.i.d.) compared to the standard four times daily (q.i.d.). Retrospective equivalence (combined non-inferiority and non-superiority design) study with a before-and-after design on a tertiary ICU in which the SDD frequency was reduced from q.i.d. to t.i.d. All patients with ICU admissions ≥72h and with ≥2 surveillance cultures collected on different dates were included in this study. We compared successful decontamination of Gram-negative bacteria (GNB). Furthermore, time to decontamination, ICU-acquired GNB bacteraemia and 28-day mortality were compared between the two groups. In total 1958 ICU admissions (1236 q.i.d., 722 t.i.d). Decontamination was achieved during the first week of admission in 77% and 76% of patients receiving SDD q.i.d and t.i.d., respectively. Successful decontamination within 14 days (without consecutive acquisition of Gram-negative bacteria) was achieved in 69.3% of the admissions with q.i.d. versus 66.8% in t.i.d. SDD (p-value = 0.2519). The proportions of successful decontamination of GNB were equivalent in both groups (−0.025, 98% CI: −0.087; 0.037). There was no significant difference in time to decontamination between the two regimens (log-rank test p-value = 0.55). Incidence (episodes/1000 days) of ICU-acquired GNB bacteraemia was 0.9 in both groups, and OR for death at day 28 in the t.i.d. group compared to the q.i.d. group was 0.99 (95% confidence interval, 0.80–1.21). This study shows that a t.i.d. application regimen achieves similar outcomes to the standard q.i.d. regime, for both microbiological and clinical outcome measures.

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

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

Rationale, Methodological Quality, and Reporting of Cluster-Randomized Controlled Trials in Critical Care Medicine: A Systematic Review

OBJECTIVE

Compared with individual-patient randomized controlled trials, cluster randomized controlled trials have unique methodological and ethical considerations. We evaluated the rationale, methodological quality, and reporting of cluster randomized controlled trials in critical care studies.

DATA SOURCES

Systematic searches of Medline, Embase, and Cochrane Central Register were performed.

STUDY SELECTION

We included all cluster randomized controlled trials conducted in adult, pediatric, or neonatal critical care units from January 2005 to September 2019.

DATA EXTRACTION

Two reviewers independently screened citations, reviewed full texts, protocols, and supplements of potentially eligible studies, abstracted data, and assessed methodology of included studies.

DATA SYNTHESIS

From 1,902 citations, 59 cluster randomized controlled trials met criteria. Most focused on quality improvement (24, 41%), antimicrobial therapy (9, 15%), or infection control (9, 15%) interventions. Designs included parallel-group (25, 42%), crossover (21, 36%), and stepped-wedge (13, 22%). Concealment of allocation was reported in 21 studies (36%). Thirteen studies (22%) reported at least one method of blinding. The median total sample size was 1,660 patients (interquartile range, 813-4,295); the median number of clusters was 12 (interquartile range, 5-24); and the median patients per cluster was 141 (interquartile range, 54-452). Sample size calculations were reported in 90% of trials, but only 54% met Consolidated Standards of Reporting Trials guidance for sample size reporting. Twenty-seven of the studies (46%) identified a fixed number of available clusters prior to trial commencement, and only nine (15%) prespecified both the number of clusters and patients required to detect the expected effect size. Overall, 36 trials (68%) achieved the total prespecified sample size. When analyzing data, 44 studies (75%) appropriately adjusted for clustering when analyzing the primary outcome. Only 12 (20%) reported an intracluster coefficient (median 0.047 [interquartile range, 0.01-0.13]).

CONCLUSIONS

Cluster randomized controlled trials in critical care typically involve a small and fixed number of relatively large clusters. The reporting of key methodological aspects of these trials is often inadequate.

Structural equation modeling the "control of gut overgrowth" in the prevention of ICU-acquired Gram-negative infection

BACKGROUND

Conceptually, the "control of gut overgrowth" (COGO) is key in mediating prevention against infection with Gram-negative bacilli by topical antibiotic prophylaxis, a common constituent of selective digestive decontamination (SDD) regimens. However, the relative importance of the other SDD components, enteral and protocolized parenteral antibiotic prophylaxis, versus other methods of infection prevention and versus other contextual exposures cannot be resolved within individual studies.

METHODS

Seven candidate generalized structural equation models founded on COGO concepts were confronted with Pseudomonas and Acinetobacter bacteremia as well as ventilator-associated pneumonia data derived from > 200 infection prevention studies. The following group-level exposures were included in the models: use and mode of antibiotic prophylaxis, anti-septic and non-decontamination methods of infection prevention; proportion receiving mechanical ventilation; trauma ICU; mean length of ICU stay; and concurrency versus non-concurrency of topical antibiotic prophylaxis study control groups.

RESULTS

In modeling Pseudomonas and Acinetobacter gut overgrowth as latent variables, anti-septic interventions had the strongest negative effect against Pseudomonas gut overgrowth but no intervention was significantly negative against Acinetobacter gut overgrowth. Strikingly, protocolized parenteral antibiotic prophylaxis and concurrency each have positive effects in the model, enteral antibiotic prophylaxis is neutral, and Acinetobacter bacteremia incidences are high within topical antibiotic prophylaxis studies, moreso with protocolized parenteral antibiotic prophylaxis exposure. Paradoxically, topical antibiotic prophylaxis (moreso with protocolized parenteral antibiotic prophylaxis) appears to provide the strongest summary prevention effects against overall bacteremia and overall VAP.

CONCLUSIONS

Structural equation modeling of published Gram-negative bacillus infection data enables a test of the COGO concept. Paradoxically, Acinetobacter and Pseudomonas bacteremia incidences are unusually high among studies of topical antibiotic prophylaxis.

Carbapenemase-producing Enterobacteriaceae - once positive always positive?

PURPOSE OF REVIEW

This review provides an overview of gastrointestinal tract colonization with carbapenemase-producing Enterobacteriaceae (CPE), including risk factors for colonization, determinants for duration of colonization, and whether patients can decolonize, either spontaneously or via targeted interventions.

RECENT FINDINGS

CPE colonization is disseminating globally with increasing numbers of carbapenemases being identified in increasing patient cohorts. Numerous risk factors including repeated healthcare contact, patient co-morbidities and international travel have all been linked to increased rates of colonization. Duration of colonization has been investigated in various healthcare settings and ranges many months or even years. Although new methods for expediting decolonization are being investigated, including faecal microbiota transplantation, high quality evidence of impact is lacking.

SUMMARY

Current evidence indicates that CPE colonization usually persists throughout the duration of most hospital admissions, although the majority of patients will subsequently spontaneously decolonize. Difficulties remain in determining the point at which patients can be considered decolonized because of the lack acceptable criteria for defining eradication. This has significance implications for infection prevention and control measures during the initial and subsequent hospital admissions. Strategies to reduce the healthcare burden of CPE colonization continue to rely predominantly on preventing acquisition, whereas decolonization efforts remain a focus of research.

Associations Between Enteral Colonization With Gram-Negative Bacteria and Intensive Care Unit-Acquired Infections and Colonization of the Respiratory Tract

Background

Enteral and respiratory tract colonization with gram-negative bacteria may lead to subsequent infections in critically ill patients. We aimed to clarify the interdependence between gut and respiratory tract colonization and their associations with intensive care unit (ICU)-acquired infections in patients receiving selective digestive tract decontamination (SDD).

Methods

Colonization status of the rectum and respiratory tract was determined using twice-weekly microbiological surveillance in mechanically ventilated subjects receiving SDD between May 2011 and June 2015 in a tertiary medical-surgical ICU in the Netherlands. Acquisition of infections was monitored daily by dedicated observers. Marginal structural models were used to determine the associations between gram-negative rectal colonization and respiratory tract colonization, ICU-acquired gram-negative infection, and ICU-acquired gram-negative bacteremia.

Results

Among 2066 ICU admissions, 1157 (56.0%) ever had documented gram-negative carriage in the rectum during ICU stay. Cumulative incidences of ICU-acquired gram-negative infection and bacteremia were 6.0% (n = 124) and 2.1% (n = 44), respectively. Rectal colonization was an independent risk factor for both respiratory tract colonization (cause-specific hazard ratio [CSHR], 2.93 [95% confidence interval {CI}, 2.02-4.23]) and new gram-negative infection in the ICU (CSHR, 3.04 [95% CI, 1.99-4.65]). Both rectal and respiratory tract colonization were associated with bacteremia (CSHR, 7.37 [95% CI, 3.25-16.68] and 2.56 [95% CI, 1.09-6.03], respectively). Similar associations were observed when Enterobacteriaceae and glucose nonfermenting gram-negative bacteria were analyzed separately.

Conclusions

Gram-negative rectal colonization tends to be stronger associated with subsequent ICU-acquired gram-negative infections than gram-negative respiratory tract colonization. Gram-negative rectal colonization seems hardly associated with subsequent ICU-acquired gram-negative respiratory tract colonization.

Appropriateness of empiric antimicrobial therapy with imipenem/colistin in severe septic patients: observational cohort study

BACKGROUND

Empiric antimicrobial therapy (EAMT) using imipenem/colistin is commonly prescribed as a first line therapy in critically ill patients with severe sepsis. We aimed to assess the appropriateness of prescribing imipenem/colistin as EAMT in ICU patients.

METHODS

A 3-year observational prospective study included ICU patients that required imipenem/colistin as EAMT. The EAMT was assessed according to microbiological and clinical outcomes. The outcomes were: delay in apyrexia, delay in the decrease of the biological inflammatory parameters (BIP), the requirement for vasoactive agents, bacteriological eradication, length of stay, ventilator days and 30-day mortality.

RESULTS

79 administrations of EAMT in 70 patients were studied. EAMT was appropriate in 52% of the studied cases. An ICU stay > 6 days was related to inappropriateness, and chronic respiratory failure was associated with appropriateness. In the appropriate EAMT group, we showed: earlier apyrexia, shorter delay in the decrease of the BIP and a reduced significant vasopressors requirement. Furthermore, EAMT improved survival with a median gain of 4 days. Inappropriate EAMT increased the mortality risk by six. The acquisition of NI in ICU was also an independent factor of mortality.

CONCLUSIONS

EAMT using imipenem-colistin was appropriate in half of the cases and inappropriateness was associated with an increased ICU mortality risk.

Collapse of the Microbiome, Emergence of the Pathobiome, and the Immunopathology of Sepsis

The definition of sepsis has been recently modified to accommodate emerging knowledge in the field, while at the same time being recognized as challenging, if not impossible, to define. Here, we seek to clarify the current understanding of sepsis as one that has been typically framed as a disorder of inflammation to one in which the competing interests of the microbiota, pathobiota, and host immune cells lead to loss of resilience and nonresolving organ dysfunction. Here, we challenge the existence of the idea of noninfectious sepsis given that critically ill humans never exist in a germ-free state. Finally, we propose a new vision of the pathophysiology of sepsis that includes the invariable loss of the host's microbiome with the emergence of a pathobiome consisting of both "healthcare-acquired and healthcare-adapted pathobiota." Under this framework, the critically ill patient is viewed as a host colonized by pathobiota dynamically expressing emergent properties which drive, and are driven by, a pathoadaptive immune response.

An Unbalanced Inflammatory Cytokine Response Is Not Associated With Mortality Following Sepsis: A Prospective Cohort Study

OBJECTIVE

The prevailing theory of host response during sepsis states that an excessive production of pro-inflammatory mediators causes early deaths, whereas a predominantly anti-inflammatory response may lead to immunosuppression, secondary infection, and late deaths. We assessed inflammatory (im)balance by measuring pro-inflammatory interleukin-6 and anti-inflammatory interleukin-10 during three distinct time periods after sepsis, and assessed its association with mortality.

DESIGN

Prospective observational cohort.

SETTING

Two tertiary mixed ICUs in The Netherlands.

PATIENTS

Consecutive patients presenting with severe sepsis or septic shock from 2011 to 2013.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We repeatedly measured plasma interleukin-6 and interleukin-10 concentrations using cytometric bead array. Poisson regression was used to analyze the relation between inflammatory markers measured on 1) ICU admission and day 4 mortality, 2) day 4 and day 28 mortality, and 3) ICU discharge and 1-year mortality. Secondary outcome was development of ICU-acquired infections. Among 708 patients, 86 (12%) died within 4 days, 140 (20%) died between days 4 and 28, and an additional 155 (22%) died before 1 year. Interleukin-6 and interleukin-10 levels were both independently associated with mortality, but the balance of this response as modelled by an interleukin-6 and interleukin-10 interaction term was not (relative risk, 0.99; 95% CI, 0.95-1.04 on admission; relative risk, 1.02; 95% CI, 0.98-1.06 on day 4; and relative risk, 1.12; 95% CI, 0.98-1.29 at ICU discharge). However, inflammatory imbalance on day 4 was associated with development of ICU-acquired infections (subdistribution hazard ratio, 0.87; 95% CI, 0.77-0.98).

CONCLUSIONS

Although both interleukin-6 and interleukin-10 productions are associated with death, the balance of these inflammatory mediators does not seem to impact either early, intermediate, or late mortality in patients presenting to the ICU with sepsis.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

What's new in multidrug-resistant pathogens in the ICU?

Over the last several decades, antibacterial drug use has become widespread with their misuse being an ever-increasing phenomenon. Consequently, antibacterial drugs have become less effective or even ineffective, resulting in a global health security emergency. The prevalence of multidrug-resistant organisms (MDROs) varies widely among regions and countries. The primary aim of antibiotic stewardship programs is to supervise the three most influential factors contributing to the development and transmission of MDROs, namely: (1) appropriate antibiotic prescribing; (2) early detection and prevention of cross-colonization of MDROs; and (3) elimination of reservoirs. In the future, it is expected that a number of countries will experience a rise in MDROs. These infections will be associated with a high consumption of healthcare resources manifested by a prolonged hospital stay and high mortality. As a counteractive strategy, minimization of broad-spectrum antibiotic use and prompt antibiotic administration will aid in reduction of antibiotic resistance. Innovative management approaches include development and implementation of rapid diagnostic tests that will help in both shortening the duration of therapy and allowing early targeted therapy. The institution of more accessible therapeutic drug monitoring will help to optimize drug administration and support a patient-specific approach. Areas where further research is required are investigation into the heterogeneity of critically ill patients and the need for new antibacterial drug development.

Carbapenem-resistant Enterobacteriaceae colonization and infection in critically ill patients: a retrospective matched cohort comparison with non-carriers

OBJECTIVES

To examine whether carbapenem-resistant Enterobacteriaceae (CRE) carriage is associated with incidence of clinical infection as a means of assessing whether the morbidity and mortality associated with these bacteria are mediated by underlying conditions or intrinsic properties of CRE.

METHODS

This retrospective matched cohort study compared the incidence of invasive infections in CRE-colonized patients and matched non-carriers in the intensive care unit (ICU). The primary outcome was infection caused by CRE of the same species as the colonizing strain among CRE carriers, and infections caused by carbapenem-sensitive strains of the same organism in non-carriers. Hospital discharge and death were considered as competing events. Competing-risks hazard analysis was performed for the entire cohort and for a nested cohort matched by Acute Physiology and Chronic Health Evaluation (APACHE) II scores, stratified by matching.

RESULTS

In total, 146 CRE carriers were compared with 292 non-carriers. Patients were well matched for most risk factors for Enterobacteriaceae infection, including age, renal failure, previous invasive infection, previous hospitalization, APACHE II score, length of mechanical ventilation, length of hospitalization and CRE carriage. On regression analysis, colonization with CRE was independently associated with Enterobacteriaceae infection {cause-specific hazard ratio (CSHR) 2.06 [95% confidence interval (CI) 1.03-4.09]}. On regression analysis of the APACHE-II-matched cohort (N=284), colonization with CRE remained significantly associated with Enterobacteriaceae infection [CSHR 3.32 (95% CI 1.31-8.43)].

CONCLUSIONS

Colonization with CRE was associated with at least a two-fold increased risk of infection by the colonizing strain amongst ICU patients.

Central line-associated bloodstream infections among critically-ill patients in the era of bundle care

BACKGROUND/PURPOSE

Patients admitted to intensive care units (ICUs) are at high risk for central line-associated bloodstream infections (CLABSIs). Bundle care has been documented to reduce CLABSI rates in Western countries, however, few reports were from Asian countries and the differences in the epidemiology or outcomes of critically-ill patients with CLABSIs after implementation of bundle care remain unknown. We aimed to evaluate the incidence, microbiological characteristics, and factors associated with mortality in critically-ill patients after implementation of bundle care.

METHODS

Prospective surveillance was performed on patients admitted to ICUs at the National Taiwan University Hospital, Taipei, Taiwan from January 2012 to June 2013. The demographic, microbiological, and clinical data of patients who developed CLABSI according to the National Healthcare Safety Network definition were reviewed. A total of 181 episodes of CLABSI were assessed in 156 patients over 46,020 central-catheter days.

RESULTS

The incidence of CLABSI was 3.93 per 1000 central-catheter days. The predominant causative microorganisms isolated from CLABSI episodes were Gram-negative bacteria (39.2%), followed by Gram-positive bacteria (33.2%) and Candida spp. (27.6%). Median time from insertion of a central catheter to occurrence of CLABSI was 8 days. In multivariate analysis, the independent factors associated with mortality were higher Pitt bacteremia score [odds ratio (OR) 1.41; 95% confidence interval (CI) 1.18-1.68] and longer interval between onset of CLABSIs and catheter removal (OR 1.10; 95% CI 1.02-1.20), respectively.

CONCLUSION

In institutions with a high proportion of CLABSI caused by Gram-negative bacteria, severity of bacteremia and delay in catheter removal were significant factors associated with mortality.

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.

A multicentre cohort study on colonization and infection with ESBL-producing Enterobacteriaceae in high-risk patients with haematological malignancies

BACKGROUND

Bloodstream infections (BSIs) caused by enterobacteria remain a leading cause of mortality in patients with chemotherapy-induced neutropenia. The rate and type of colonization and infection with ESBL-producing Enterobacteriaceae (ESBL-E) and their mode of transmission in German cancer centres is largely unknown.

METHODS

We performed a prospective, observational study at five German university-based haematology departments. Participating sites screened for intestinal ESBL-E colonization within 72 h of admission, every 10 ± 2 days thereafter and before discharge. Three of the five centres performed contact isolation for patients colonized or infected with ESBL-E. Molecular characterization of resistance mechanisms and epidemiological typing of isolates by repetitive extragenic palindromic PCR (rep-PCR) and PFGE was performed to assess strain transmission between patients.

RESULTS

Between October 2011 and December 2012, 719 hospitalizations of 497 haematological high-risk patients comprising 20,143 patient-days were analysed. Mean duration of in-hospital stay was 36.6 days (range: 2-159 days). ESBL-E were identified from screening samples (82.8% Escherichia coli and 14.6% Klebsiella pneumoniae) in 55/497 patients (11.1%; range by centre: 5.8%-23.1%). PFGE and rep-PCR revealed only a single case of potential cross-transmission among two patients colonized with K. pneumoniae. Six episodes of BSI with ESBL-E were observed. Multivariate analysis revealed previous colonization with ESBL-E as the most important risk factor for BSI with ESBL-E (OR 52.00; 95% CI 5.71-473.89).

CONCLUSIONS

Even though BSI with ESBL-E is still rare in this high-risk population, colonization rates are substantial and vary considerably between centres. In-hospital transmission of ESBL-E as assessed by molecular typing was the exception.

The evolving landscape of healthcare-associated infections: recent advances in prevention and a road map for research

This white paper identifies knowledge gaps and new challenges in healthcare epidemiology research, assesses the progress made toward addressing research priorities, provides the Society for Healthcare Epidemiology of America (SHEA) Research Committee's recommendations for high-priority research topics, and proposes a road map for making progress toward these goals. It updates the 2010 SHEA Research Committee document, "Charting the Course for the Future of Science in Healthcare Epidemiology: Results of a Survey of the Membership of SHEA," which called for a national approach to healthcare-associated infections (HAIs) and a prioritized research agenda. This paper highlights recent studies that have advanced our understanding of HAIs, the establishment of the SHEA Research Network as a collaborative infrastructure to address research questions, prevention initiatives at state and national levels, changes in reporting and payment requirements, and new patterns in antimicrobial resistance.

Carbapenem-Resistant Enterobacteriaceae: Laboratory Detection and Infection Control Practices

Over the past decade, carbapenem-resistant Enterobacteriaceae (CRE) have become one of the most challenging problems in infectious diseases. Fast and accurate detection of carbapenem resistance is crucial for guiding the treatment of the individual patient as well as for instituting proper infection control measures to limit the spread of the organism. Currently there are no consensus recommendations for screening, detection and confirmation of CRE either on the clinical or the laboratory side. In infection control, data from controlled intervention studies is largely missing and most recommendations have been deduced from outbreak situations. From the available limited evidence, infection control guidelines have been developed in most countries at national, regional and hospital levels. The aim of this review is to summarize the currently available laboratory methods and infection control options.

Gastro-intestinal vascular emergencies

Gastro-Intestinal Vascular Emergencies include all digestive ischaemic injuries related to acute or chronic vascular and/or haemodynamic diseases. Gastro-intestinal ischaemic injuries can be occlusive or non-occlusive, arterial or venous, localized or generalized, superficial or transmural and share the risks of infarction, organ failure and death. The diagnosis must be suspected, at the initial presentation of any sudden, continuous and unusual abdominal pain, contrasting with normal physical examination. Risk factors are often unknown at presentation and no biomarker is currently available. The diagnosis is confirmed by abdominal computed tomography angiography identifying intestinal ischaemic injury, either with vascular occlusion or in a context of low flow. Recent knowledge in the pathophysiology of acute mesenteric ischaemia, clinical experience and existing recommendations have generated a multimodal and multidisciplinary management strategy. Based on the gastro-intestinal viability around a simple algorithm, and coordinated by gastroenterologists, the dual aim is to avoid large intestinal resections and death.

Rapid emergence of secondary resistance to gentamicin and colistin following selective digestive decontamination in patients with KPC-2-producing Klebsiella pneumoniae: a single-centre experience

After a single patient was transferred to Leipzig University Hospital from a hospital in Rhodes, Greece, the hospital experienced the largest outbreak due to a KPC-2-producing Klebsiella pneumoniae (KPC-2-KP) strain thus far observed in Germany. Ninety patients hospitalised between July 2010 and October 2012 were affected. In an attempt to eliminate KPC-2-KP from their digestive tracts, 14 consecutive patients (16%) were treated with a short course (7 days) of selective digestive decontamination (SDD), employing colistin (1 million units q.i.d.) and gentamicin (80 mg q.i.d.) as oral solutions, and applying colistin/gentamicin gel (0.5 g) to the oral cavity. In a retrospective analysis, these 14 SDD patients were compared with the remaining 76 patients harbouring KPC-2-KP. KPC-2-KP carrier status was followed in all 14 SDD patients by submitting stool samples to KPC-specific PCR. The mean follow-up period was 48 days (range 12-103 days). Successful elimination of KPC-2-KP was defined as a minimum of three consecutive negative PCR test results separated by ≥48 h each. Decolonisation of KPC-2-KP was achieved in 6/14 patients (43%) after a mean of 21 days (range 12-40 days), but was also observed in 23/76 (30%) of the non-SDD controls (P = 0.102). SDD treatment resulted in the development of secondary resistance to colistin (19% increase in resistance rate) and gentamicin (45% increase) in post-treatment isolates. In the control group, no secondary resistance occurred. We conclude that the SDD protocol applied in this study was not sufficiently effective for decolonisation and was associated with resistance development.

Causes, consequences, and perspectives in the variations of intestinal density of colonization of multidrug-resistant enterobacteria

The intestinal microbiota is a complex environment that hosts 10¹³ to 10¹⁴ bacteria. Among these bacteria stand multidrug-resistant enterobacteria (MDRE), which intestinal densities can substantially vary, especially according to antibiotic exposure. The intestinal density of MDRE and their relative abundance (i.e., the proportion between the density of MDRE and the density of total enterobacteria) could play a major role in the infection process or patient-to-patient transmission. This review discusses the recent advances in understanding (i) what causes variations in the density or relative abundance of intestinal colonization, (ii) what are the clinical consequences of these variations, and (iii) what are the perspectives for maintaining these markers at low levels.

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.

Transfer from high-acuity long-term care facilities is associated with carriage of Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae: a multihospital study

OBJECTIVE

To determine whether transfer from a long-term care facility (LTCF) is a risk factor for colonization with Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae upon acute care hospital admission.

DESIGN

Microbiologic survey and nested case-control study.

SETTING

Four hospitals in a metropolitan area (Chicago) with an early KPC epidemic.

PATIENTS

Hospitalized adults.

METHODS

Patients transferred from LTCFs were matched 1∶1 to patients admitted from the community by age (± 10 years), admitting clinical service, and admission date (± 2 weeks). Rectal swab specimens were collected within 3 days after admission and tested for KPC-producing Enterobacteriaceae. Demographic and clinical information was extracted from medical records.

RESULTS

One hundred eighty patients from LTCFs were matched to 180 community patients. KPC-producing Enterobacteriaceae colonization was detected in 15 (8.3%) of the LTCF patients and 0 (0%) of the community patients ([Formula: see text]). Prevalence of carriage differed by LTCF subtype: 2 of 135 (1.5%) patients from skilled nursing facilities without ventilator care (SNFs) were colonized upon admission, compared to 9 of 33 (27.3%) patients from skilled nursing facilities with ventilator care (VSNFs) and 4 of 12 (33.3%) patients from long-term acute care hospitals (LTACHs; [Formula: see text]). In a multivariable logistic regression model adjusted for a propensity score that predicted LTCF subtype, patients admitted from VSNFs or LTACHs had 7.0-fold greater odds of colonization (ie, odds ratio; 95% confidence interval, 1.3-42; [Formula: see text]) with KPC-producing Enterobacteriaceae than patients from an SNF.

CONCLUSIONS

Patients admitted to acute care hospitals from high-acuity LTCFs (ie, VSNFs and LTACHs) were more likely to be colonized with KPC-producing Enterobacteriaceae than were patients admitted from the community. Identification of healthcare facilities with a high prevalence of colonized patients presents an opportunity for focused interventions that may aid regional control efforts.

Adhesion GPCRs are widely expressed throughout the subsections of the gastrointestinal tract

Background

G protein-coupled receptors (GPCRs) represent one of the largest families of transmembrane receptors and the most common drug target. The Adhesion subfamily is the second largest one of GPCRs and its several members are known to mediate neural development and immune system functioning through cell-cell and cell-matrix interactions. The distribution of these receptors has not been characterized in detail in the gastrointestinal (GI) tract. Here we present the first comprehensive anatomical profiling of mRNA expression of all 30 Adhesion GPCRs in the rat GI tract divided into twelve subsegments.

Methods

Using RT-qPCR, we studied the expression of Adhesion GPCRs in the esophagus, the corpus and antrum of the stomach, the proximal and distal parts of the duodenum, ileum, jejunum and colon, and the cecum.

Results

We found that twenty-one Adhesion GPCRs (70%) had a widespread (expressed in five or more segments) or ubiquitous (expressed in eleven or more segments) distribution, seven (23%) were restricted to a few segments of the GI tract and two were not expressed in any segment. Most notably, almost all Group III members were ubiquitously expressed, while the restricted expression was characteristic for the majority of group VII members, hinting at more specific/localized roles for some of these receptors.

Conclusions

Overall, the distribution of Adhesion GPCRs points to their important role in GI tract functioning and defines them as a potentially crucial target for pharmacological interventions.

Gut mucosal injury in neonates is marked by macrophage infiltration in contrast to pleomorphic infiltrates in adult: evidence from an animal model

Necrotizing enterocolitis (NEC) is an inflammatory bowel necrosis of premature infants. In tissue samples of NEC, we identified numerous macrophages and a few neutrophils but not many lymphocytes. We hypothesized that these pathoanatomic characteristics of NEC represent a common tissue injury response of the gastrointestinal tract to a variety of insults at a specific stage of gut development. To evaluate developmental changes in mucosal inflammatory response, we used trinitrobenzene sulfonic acid (TNBS)-induced inflammation as a nonspecific insult and compared mucosal injury in newborn vs. adult mice. Enterocolitis was induced in 10-day-old pups and adult mice (n = 25 animals per group) by administering TNBS by gavage and enema. Leukocyte populations were enumerated in human NEC and in murine TNBS-enterocolitis using quantitative immunofluorescence. Chemokine expression was measured using quantitative polymerase chain reaction, immunoblots, and immunohistochemistry. Macrophage recruitment was investigated ex vivo using intestinal tissue-conditioned media and bone marrow-derived macrophages in a microchemotaxis assay. Similar to human NEC, TNBS enterocolitis in pups was marked by a macrophage-rich leukocyte infiltrate in affected tissue. In contrast, TNBS-enterocolitis in adult mice was associated with pleomorphic leukocyte infiltrates. Macrophage precursors were recruited to murine neonatal gastrointestinal tract by the chemokine CXCL5, a known chemoattractant for myeloid cells. We also demonstrated increased expression of CXCL5 in surgically resected tissue samples of human NEC, indicating that a similar pathway was active in NEC. We concluded that gut mucosal injury in the murine neonate is marked by a macrophage-rich leukocyte infiltrate, which contrasts with the pleomorphic leukocyte infiltrates in adult mice. In murine neonatal enterocolitis, macrophages were recruited to the inflamed gut mucosa by the chemokine CXCL5, indicating that CXCL5 and its cognate receptor CXCR2 merit further investigation as potential therapeutic targets in NEC.

For whom should we use selective decontamination of the digestive tract?

PURPOSE OF REVIEW

This review discusses the relevant studies on selective decontamination of the digestive tract (SDD) published between 2009 and mid-2011.

RECENT FINDINGS

In a multicenter cluster-randomized cross-over study in the Netherlands, SDD and selective oropharyngeal decontamination (SOD) were associated with higher survival at day 28, with a lower incidence of ICU-acquired bacteremia and with less acquisition of respiratory tract colonization with antibiotic resistant pathogens, compared to standard care. A post-hoc analysis of this study suggests that SDD might be more effective in surgical patients and SOD in nonsurgical patients. In a randomized study perioperative use of SDD in patients undergoing gastrointestinal surgery was associated with lower incidences of anastomotic leakages. A Cochrane meta-analysis, not including any of the before mentioned studies, reported a reduction of respiratory tract infections in studies by using topical antibiotics only and higher survival rates when topical antibiotics were combined with parenteral antibiotics.

SUMMARY

Recent studies show that in ICUs with low levels of antibiotic resistance, SDD and SOD improved patient outcome and reduced infections and carriage with antibiotic-resistant pathogens. The effect in settings with higher levels of antibiotic resistance remains to be determined as well as the efficacy of SDD and SOD in specific patient groups.

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.

A randomized, double-blind, placebo-controlled trial of selective digestive decontamination using oral gentamicin and oral polymyxin E for eradication of carbapenem-resistant Klebsiella pneumoniae carriage

OBJECTIVE

To assess the effectiveness of selective digestive decontamination (SDD) for eradicating carbapenem-resistant Klebsiella pneumoniae (CRKP) oropharyngeal and gastrointestinal carriage.

DESIGN

A randomized, double-blind, placebo-controlled trial with 7 weeks of follow-up per patient.

SETTING

A 1,000-bed tertiary-care university hospital.

PATIENTS

Adults with CRKP-positive rectal swab cultures.

METHODS

Patients were blindly randomized (1 :1) over a 20-month period. The SDD arm received oral gentamicin and polymyxin E gel (0.5 g 4 times per day) and oral solutions of gentamicin (80 mg 4 times per day) and polymyxin E (1 x 10(6) units 4 times per day for 7 days). The placebo arm received oral placebo gel 4 times per day and 2 placebo oral solutions 4 times per day for 7 days. Strict contact precautions were applied. Samples obtained from the throat, groin, and urine were also cultured.

RESULTS

Forty patients (mean age ± standard deviation, 71 ± 16 years; 65% male) were included. At screening, greater than or equal to 30% of oropharyngeal, greater than or equal to 60% of skin, and greater than or equal to 35% of urine cultures yielded CRKP isolates. All throat cultures became negative in the SDD arm after 3 days (P < .0001). The percentages of rectal cultures that were positive for CRKP were significantly reduced at 2 weeks. At that time, 16.1% of rectal cultures in the placebo arm and 61.1% in the SDD arm were negative (odds ratio, 0.13; 95% confidence interval, 0.02-0.74; P < .0016). A difference between the percentages in the 2 arms was still maintained at 6 weeks (33.3% vs 58.5%). Groin colonization prevalence did not change in either arm, and the prevalence of urine colonization increased in the placebo arm.

CONCLUSIONS

This SDD regimen could be a suitable decolonization therapy for selected patients colonized with CRKP, such as transplant recipients or immunocompromised patients pending chemotherapy and patients who require major intestinal or oropharyngeal surgery. Moreover, in outbreaks caused by CRKP infections that are uncontrolled by routine infection control measures, SDD could provide additional infection containment.