772. Effect of Selective Digestive Decontamination Using Oral Colistin on HAI Rates and All-Cause Mortality Among Cardiovascular Surgery Patients - A Single Centre Experience from India

Background Hospital acquired infections affect the morbidity and mortality of ICU patients considerably. Selective digestive decontamination (SDD) is defined as the prophylactic application of topical, non-absorbable antimicrobials in the oropharynx and stomach, with the goal of eradicating potentially pathogenic microorganisms but preserving the protective anaerobic microbiota. SDD has been applied in trials among critically ill patients and found to be effective in reducing HAI. Methods This cohort study was conducted in our cardiothoracic vascular surgery ICU of a tertiary care hospital, where patients were given oral colistin syrup (100mg 6th hourly for 5 days) in the immediate post op during the intervention period. We compared the clinical and microbiological outcomes of patients before (5 months, pre-intervention arm) and after (5 months, intervention arm) the implementation of SDD (Oral colistin syrup). Results A total of 78 patients were included in the interventional arm with a mean age of 58.7 years whereas the pre-interventional group consisted of 94 study participants with a median age of 57.5 years. 11 out of 94 had positive respiratory sample culture (11.7%) in the preintervention group which mandated antibiotic therapy for HAP compared to one culture positive in the interventional period (OR 0.0980, 95% CI: 0.0124 to 0.777 and P=0.0279). One patient had blood stream infection in the pre-intervention period compared to none in the intervention phase. All-cause mortality in the pre-interventional group was 7.44% (7 in 94) vs 1.28% (1 in 78) in the interventional group (OR 0.1614, 95% CI: 0.0194 to 1.3416, P= 0.0914). Adverse events (nausea, vomiting & loose stools) were observed in a total of 24 study patients, but necessitated withdrawal of regimen only in nine patients. Conclusion An SDD regimen of Colistin alone in Cardiac Surgery patients resulted in statistically significant reduction in incidence of Hospital Acquired Pneumonia, along with a reduction in all-cause mortality (though not statistically significant). Disclosures All Authors: No reported disclosures

Selective digestive decontamination, a seemingly effective regimen with individual benefit or a flawed concept with population harm?

Selective digestive decontamination (SDD) regimens, variously constituted with topical antibiotic prophylaxis (TAP) and protocolized parenteral antibiotic prophylaxis (PPAP), appear highly effective for preventing ICU-acquired infections but only within randomized concurrent control trials (RCCT’s). Confusingly, SDD is also a concept which, if true, implies population benefit. The SDD concept can finally be reified in humans using the broad accumulated evidence base, including studies of TAP and PPAP that used non-concurrent controls (NCC), as a natural experiment. However, this test implicates overall population harm with higher event rates associated with SDD use within the ICU context.

Selective digestive decontamination solution used as “lock therapy” prevents and eradicates bacterial biofilm in an in vitro bench-top model

Background Most preventing measures for reducing ventilator-associated pneumonia (VAP) are based mainly on the decolonization of the internal surface of the endotracheal tubes (ETTs). However, it has been demonstrated that bacterial biofilm can also be formed on the external surface of ETTs. Our objective was to test in vitro the efficacy of selective digestive decontamination solution (SDDs) onto ETT to prevent biofilm formation and eradicate preformed biofilms of three different microorganisms of VAP. Methods We used an in vitro model in which we applied, at the subglottic space of ETT, biofilms of either P. aeruginosa ATCC 15442, or E. coli ATCC 25922, or S. aureus ATCC 29213, and the SDDs at the same time (prophylaxis) or after 72 h of biofilm forming (treatment). ETT were incubated during 5 days with a regimen of 2 h-locks. ETT fragments were analyzed by sonication and confocal laser scanning microscopy to calculate the percentage reduction of cfu and viable cells, respectively. Results Median (IQR) percentage reduction of live cells and cfu/ml counts after treatment were, respectively, 53.2% (39.4%—64.1%) and 100% (100%–100.0%) for P. aeruginosa, and 67.9% (46.7%–78.7%) and 100% (100%–100.0%) for E. coli. S. aureus presented a complete eradication by both methods. After prophylaxis, there were absence of live cells and cfu/ml counts for all microorganisms. Conclusions SDDs used as “lock therapy” in the subglottic space is a promising prophylactic approach that could be used in combination with the oro-digestive decontamination procedure in the prevention of VAP.

Studies of selective digestive decontamination as a natural experiment to evaluate topical antibiotic prophylaxis and cephalosporin use as population-level risk factors for enterococcal bacteraemia among ICU patients

BackgroundSelective digestive decontamination (SDD) and selective oropharyngeal decontamination (SOD) regimens appear protective against ICU-acquired overall bacteraemia. These regimens can be factorized as topical antibiotic prophylaxis (TAP) with (SDD) or without (SOD) protocolized parenteral antibiotic prophylaxis (PPAP) using cephalosporins. Both TAP and cephalosporins are risk factors for enterococcal colonization although their impact on enterococcal bacteraemia within studies of SDD/SOD remains unclear.ObjectivesTo benchmark the enterococcal bacteraemia incidence within component (control and intervention) groups of SDD/SOD studies among ICU patients versus studies without intervention (observational groups).MethodsThe literature was searched for SDD/SOD studies reporting enterococcal bacteraemia incidence data. In addition, component groups of studies of various non-antibiotic interventions served to provide additional points of reference.ResultsThe mean incidence per 100 patients (and 95% CI) for enterococcal bacteraemia among 19 SDD/SOD studies was equally increased among concurrent control (2.1; 1.0%–4.7%) and intervention (2.3; 2.0%–2.7%) groups versus the benchmark incidence (0.8; 0.6%–1.2%) derived from 16 observational study groups and also versus 9 component groups from non-antibiotic studies. These higher incidences remained apparent (P < 0.02) in a meta-regression model adjusting for groupwide factors such as PPAP use, mechanical ventilation proportion, group mean length of stay >7 days and publication year.ConclusionsThe incidences of enterococcal bacteraemia within both concurrent control and intervention groups of SDD/SOD studies are unusually high compared with the literature-derived benchmark. The impact of parenteral cephalosporin used as PPAP additional to TAP on enterococcal bacteraemia incidence was indeterminate in this analysis.

Antibiotic susceptibility trend before and after long-term use of selective digestive decontamination: a 16 year ecological study

Objectives The aim of this study was to compare antimicrobial susceptibility rates in a Spanish ICU before and after the introduction of selective digestive decontamination (SDD) and also to compare these with susceptibility data from other Spanish ICUs without SDD. Methods We performed a retrospective study in the ICU of the University Hospital of Alava, where SDD was implemented in 2002. The SDD protocol consisted of a 2% mixture of gentamicin, colistin and amphotericin B applied on the buccal mucosa and a suspension of the same drugs in the gastrointestinal tract; additionally, for the first 3 days, systemic ceftriaxone was administered. From 1998 to 2013 we analysed the susceptibility rates for 48 antimicrobial/organism combinations. Interrupted time series using a linear dynamic model with SDD as an intervention was used. Data from other ICUs were obtained from the ENVIN-HELICS national registry. Results Only amoxicillin/clavulanic acid against Escherichia coli and Proteus mirabilis, and a high concentration of gentamicin against Enterococcus faecalis, resulted in a significant decrease in the susceptibility rate after the implementation of SDD, with a drop of 20%, 27% and 32%, respectively. Compared with other Spanish ICUs without SDD, the susceptibility rate was higher in the ICU of our hospital in most cases. When it was lower, differences were <10%, except for a high concentration of streptomycin against Enterococcus faecium, for which the difference was 19%. Conclusions No relevant changes in the overall susceptibility rate after the implementation of SDD were detected. Susceptibility rates were not lower than those in the Spanish ICUs without SDD.