Selective decontamination of the digestive tract in burn patients: an evidence-based maneuver that reduces mortality

Management and prevention of drug resistant infections in burn patients

Introduction: Despite modern advances, the primary cause of death after burns remains infection and sepsis. A key factor in determining outcomes is colonization with multi-drug resistant (MDR) organisms. Infections secondary to MDR organisms are challenging due to lack of adequate antibiotic treatment, subsequently prolonging hospital stay and increasing risk of adverse outcomes. Areas covered: This review highlights the most frequent organisms colonizing burn wounds as well as the most common MDR bacterial infections. Additionally, we discuss different treatment modalities and MDR infection prevention strategies as their appropriate management would minimize morbidity and mortality in this population. We conducted a search for articles on PubMed, Web of Science, Embase, Cochrane, Scopus and UpToDate with applied search strategies including a combination of: "burns, 'thermal injury,' 'infections,' 'sepsis,' 'drug resistance,' and 'antimicrobials.' Expert opinion: Management and prevention of MDR infections in burns is an ongoing challenge. We highlight the importance of preventative over therapeutic strategies, which are easy to implement and cost-effective. Additionally, targeted, limited use of antimicrobials can be beneficial in burn patients. A promising future area of investigation within this field is post-trauma microbiome profiling. Currently, the best treatment strategy for MDR in burn patients is prevention.

Topical antimicrobial therapy: Current status and challenges

Topically applied antibacterial agents are widely used. Opinions regarding the clinical efficacy of topical antibiotics are conflicting, and for most indications, alternative oral therapies are available. Topical application has many potential advantages over systemic therapy that includes high and sustained concentrations of drug directly at the infected site, low quantity of antibiotic needed, better compliance, fewer systemic side effects and potentially less chance of antimicrobial resistance. Despite these advantages, an important concern has been the difficulty in monitoring antibiotic dosage and duration of therapy. Most topical preparations are applied on sites with pre-existing normal bacterial flora, and the detrimental effect of antibiotic on the 'good' bacteria is difficult to control. Unnecessary exposure of the resident microflora to high drug levels may select drug-resistant phenotypes. The number of antibiotics available and the quality and composition of the formulations recommended for topical drug delivery are improving. Their role in the prevention and treatment of locally invasive infections is established for many clinical conditions. However, there is still a lacuna in the availability of pharmacokinetic (PK) knowledge of these topical preparations and translation of the same to clinical practice. In addition, reporting the clinical outcome following the use of these agents and its analysis considering the recently proposed epidemiological cut-off value-based cut-offs are also areas which merit further research. In this review, we highlight the clinical utility and the PK aspects of topical antimicrobials in various infections. We also discuss the limitations of the current antimicrobial susceptibility testing (AST) protocols and new methods for AMST for topical agents.

Status and Challenges of Predicting and Diagnosing Sepsis in Burn Patients

Burns are a common form of trauma that account for more than 300,000 deaths each year worldwide. Survival rates have improved over the past decades because of improvements in nutritional and fluid support, burn wound care, and infection control practices. Death, however, remains unacceptably high. The primary cause of death has changed over the last decades from anoxic causes to now predominantly infections and sepsis. Sepsis and septic complications are not only major contributors to poor outcomes, but they further result in longer hospital stay and higher healthcare costs. Despite the importance of infections and sepsis, the diagnosis and prediction remain a major challenge. To date, no clear diagnostic criteria or predictive formula exist that can predict reliably the occurrence of sepsis and infections. This review will highlight and discuss current definitions and criteria for diagnosis as well as predictive biomarkers of sepsis in patients with burns. It will also present the diagnostic tools employed, such as procalcitonin, C-reactive protein, and cytokines. We will discuss the benefits and shortcomings of different treatment modalities in the context of sepsis prevention. Last, we identify new therapeutic strategies for sepsis prediction and present future considerations to prevent sepsis in patients with burns. Minimizing and preventing septic complications through early detection would significantly benefit patients and necessitate continued research to unravel new biomarkers and mechanisms. Subsequent studies need to take a fresh perspective and consider the implementation of patient-centered therapeutic strategies.

The pros, cons, and unknowns of search and destroy for carbapenem-resistant enterobacteriaceae

Antibiotic drug discovery has not kept pace with the development of microbial resistance to these agents. There are ever increasing reports where the causative agents of serious infections are multi-drug resistant and in some cases resistant to all known antibiotics. The emergence and spread of carbapenemase-producing Enterobacteriaceae has heightened awareness regarding antibiotic stewardship programs and infection prevention and control measures. There has been much controversy regarding the utility of the "search and destroy" strategy to prevent the spread of carbapenem-resistant Enterobacteriaceae. These controversies center on screening and management of carriers, including decontamination and isolation. It is however clear that a functional infection prevention and control program is fundamental to any strategy that serves to address the spread of microbes within a healthcare facility.

Clinical review: the critical care management of the burn patient

Between 4 and 22% of burn patients presenting to the emergency department are admitted to critical care. Burn injury is characterised by a hypermetabolic response with physiologic, catabolic and immune effects. Burn care has seen renewed interest in colloid resuscitation, a change in transfusion practice and the development of anti-catabolic therapies. A literature search was conducted with priority given to review articles, meta-analyses and well-designed large trials; paediatric studies were included where adult studies were lacking with the aim to review the advances in adult intensive care burn management and place them in the general context of day-to-day practical burn management.

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.