Reply to “Selective Digestive Tract Decontamination and Spread of Colistin Resistance: Antibiotic Prophylaxis Is Not a Substitute for Hygiene”

Abstract

b W e thank Krueger and colleagues for their critical comments (1). We fully agree that selective digestive tract decontamination (SDD) is not a substitute for good infection control, especially hand hygiene. With respect to their argument that our findings are in sharp contrast to what is known so far about the effect of SDD on the risk of acquisition of colistin-resistant bacteria, we feel differently.Although the emergence of antimicrobial resistance has always been a major concern of SDD use (2, 3), the risk of its occurrence has received insufficient attention in most studies, which have focused on morbidity and mortality as the main outcome measures (4, 5). A recent meta-analysis concluded that there is no clear evidence for the association of SDD or selective oral decontamination (SOD) use and the development of antimicrobial resistance (6). This meta-analysis, however, was almost entirely based on studies in which SDD was classically used as a prophylactic measure in settings with a low baseline prevalence of resistant microorganisms. The reason for this might be that the majority of these studies have been performed in The Netherlands, a country with a low prevalence of multidrug resistance (6), while SDD has not been widely accepted and adopted in countries with high prevalences of resistance, particularly because of fear of encouraging resistance to the antimicrobials used (7,8). In contrast, data on antibiotic resistance, particularly to polymyxins, under SDD used in settings of outbreaks of resistant microorganisms or in settings with high baseline multidrug resistance, such as in our study, are scarce. In some outbreak settings, polymyxin resistance as a consequence of SDD use was not observed (9-11), while in other settings, this did occur (12)(13)(14). Unfortunately, information regarding the occurrence of polymyxin resistance among Enterobacteriaceae or polymyxin susceptibility testing is not provided in numerous studies assessing antimicrobial resistance (including that to polymyxin E) over time under the use of SDD (15)(16)(17)(18)(19).Although concentrations of topical nonabsorbable antibiotics are usually high in the gut (high enough to exceed minimal bactericidal concentrations [15]), colistin might be biologically inactivated by intestinal contents (20) or sucralfate (21), which is often used in ICU patients; therefore, topical antibiotics lack effectiveness, necessitating high oral doses to achieve suitable fecal concentrations (22). In our ICU, sucralfate was avoided, but concentrations of the SDD components in the gut were not measured. Therefore, we cannot exclude the possibility that in some patients, the concentrations of colistin were below the MICs for ESBLproducing Klebsiella pneumoniae strains. This might have contributed to the failure of SDD to eliminate the strain from the carriers and to prevent acquisition of the strain by noncarriers; it may also have contributed to the emergence of resistance among these strains. So, our results are not in sharp contrast to what is known s...

The battle against colistin-resistant E. coli and the need for a one health approach

“…Implementing robust infection control measures in healthcare facilities, livestock production, and food processing industries is vital. Emphasizing hand hygiene, proper sanitation, and responsible waste management can help curtail the spread of resistant bacteria [ [27] , [28] , [29] ].…”