The use of antimicrobials to reduce levels of aerobic gram-negative bacteria and/or yeast in the intestinal tract and thus prevent infections caused by these organisms is known as selective digestive decontamination (SDD).
SDD has been proposed as a tool for preventing infection in liver transplant patients, who are at high risk of bacterial infection within the first month after transplantation. Such patients are particularly susceptible to gram-negative bacteria, hence the suggestion that SDD may be of particular value in such cases.
However, the true value of SDD has remained controversial. Therefore, Nasia Safdar and colleagues from the University of Wisconsin Medical School, USA, conducted a systematic review and meta-analysis to determine whether SDD is beneficial in patients following liver transplantation.
The researchers examined all studies that evaluated the efficacy of SDD in liver transplant patients, as well as including randomized trials that included liver transplant patients given SDD versus either placebo or no treatment or minimal treatment (e.g. oral nystatin alone) and that provided adequate data to calculate a relative risk ratio.
The researchers found most studies showed SDD to be effective in reducing gram-negative infection.
...the risk of antimicrobial resistance must be considered.
| Nasia Safdar , Liver Transplantation|
They also found the non-randomized and uncontrolled trials showed benefit with SDD in reducing overall infection.
However, the effect on overall infection was limited in the 4 randomized trials evaluated; the pooled relative risk was 0.88, indicating no statistically significant reduction in infection with the use of SDD.
The summary risk ratio for the association between SDD and gram-negative infection was 0.16, indicating an 84% relative risk reduction in the incidence of infection caused by gram-negative bacteria in patients receiving SDD in randomized trials.
The authors conclude that the available literature supports a beneficial effect of SDD on gram-negative infection following liver transplantation.
They caution however, that the risk of antimicrobial resistance must be considered and add, " Larger multicenter randomized trials in this patient population to assess the effect of SDD in reducing infection and mortality, while assessing the risk of antimicrobial resistance, are needed."