Surviving Sepsis Campaign Guidelines: selective decontamination of the digestive tract still neglected.

To the Editor: We read with interest the guidelines for the management of severe sepsis and septic shock published in the March 2004 issue of Critical Care Medicine by the Surviving Sepsis Campaign (1). The authors claim to have used evidence-based medicine methodology; however, their major aim was consensus to increase awareness and to improve outcome in severe sepsis. The authors of the Surviving Sepsis Campaign selected 19 interventions, including bicarbonate therapy, deep venous thrombosis prophylaxis, and considerations for limitation of support. Currently, there are five evidence-based medicine maneuvers showing a survival benefit in the intensive care unit (ICU) (Table 1). Only one maneuver is supported by at least two level 1 investigations, providing level 1 evidence with a grade A recommendation, and that is selective decontamination of the digestive tract (SDD) (2, 3). The other four are supported by only one trial, providing a grade B recommendation (4–7). SDD can be administered to all patients at risk of infection, in contrast, the other four only in specific subsets of ICU patients. We were at a loss to explain the omission of the SDD intervention in the Surviving Sepsis Campaign guidelines, despite the availability of 54 randomized, controlled trials with seven meta-analyses showing a significant reduction of infectious morbidity and mortality (8). The rationale behind the maneuver of SDD is the observation that critically ill patients develop infection with their own gut microorganisms and that enteral antimicrobials in combination with early administration of parenteral antibiotics improve survival in critically ill patients (9). A major difference between the only parenteral antibiotic use and SDD is that enteral antibiotics also impact the flora of the oropharynx and gut, whereas systemic agents only treat the lungs, blood, and bladder. Was SDD not considered by the Surviving Sepsis Campaign because some experts assert that it causes antimicrobial resistance, in particular, methicillinresistant Staphylococcus aureus (MRSA)? Two individual trials of SDD (2, 3) showed that there was significantly less carriage and infection resulting from the resistant isolates among the target microorganisms aerobic Gram-negative bacilli in the group receiving SDD. SDD, by design, is not active against MRSA, and six studies suggested a trend toward a higher MRSA infection rate among ICU patients receiving SDD (10–15). SDD requires monitoring using surveillance cultures of the throat and rectum. These cultures also detect carriage of MRSA in an early stage, allowing the addition of enteral vancomycin to the classic SDD protocol. Four studies (16–19), among which two were randomized, controlled trials, support this approach. The concerns of experts that SDD, including enteral vancomycin, promotes vancomycinresistant enterococci and MRSA resistant to vancomycin have been refuted by eight studies (16, 18–24), of which five were randomized (19, 20, 22–24). Systemic broad-spectrum antibiotics are administered to a high proportion of ICU patients, promoting the emergence of antimicrobial resistance. During the interventions of low tidal volume, glucose control, steroids, and activated protein C, the problem of nosocomial infections resulting from resistant microorganisms continued to grow. We believe that SDD may be part of the solution of the resistance problem for two reasons. First, the SDD intervention is underpinned by regular surveillance of gut flora. The chance to detect resistance in gut flora is five times higher than in diagnostic samples of the lower airways, urine, and blood (25). Second, gut overgrowth guarantees the presence of resistant mutants, which are selected by only parenteral antibiotic use through salivary and biliary excretion. The newer, even more potent systemic antimicrobials fail to clear MRSA and Pseudomonas aeruginosa from the gut, because the salivary and fecal concentrations are not lethal. The addition of enteral antimicrobials eliminates the source, controlling resistant mutants in the gut flora. We believe that the assertion that SDD causes resistance is misplaced in this era of evidencebased medicine. In conclusion, the optimal management of severe sepsis and septic shock is complex and will represent a real challenge for the future as long as we are prepared to consider all interventions, including SDD, that contribute to the prevention and treatment of this important clinical syndrome. We are confident that SDD will be incorporated in the dynamic, electronic, Web-based guideline process of the Surviving Sepsis Campaign.