Clinical Implications of Multi-Drug Resistant Organisms’ Gastrointestinal Colonization in an Internal Medicine Ward: The Pandora’s Box

Background: Multi-drug resistant organisms (MDRO) are an emerging health problem with an important impact on clinical outcome in Intensive Care Units (ICUs) and immunocompromised patients. Conversely, the role of MDRO colonization in Internal Medicine is less clear. The objective of our study is to evaluate the clinical impact (namely sepsis development, in-hospital and 30-days mortality, and re-hospitalization) of MDRO colonization in Internal Medicine. Methods: Patients admitted to our Internal Medicine Unit between January 2019 and March 2020 were potentially includible. Outcomes in patients with a positive rectal swab for MDRO (RS+) and in patients without a RS+ were compared. Results of the multivariate analyses were expressed as Odds Ratios (ORs) and the corresponding 95% Confidence Interval (CI). Results: In a cohort of 2147 patients, 77 patients with RS+ were consecutively identified; 377 patients with a rectal swab negative for MDRO were randomly selected from the same cohort (five for each patient with RS+). At the multivariate analysis, RS+ was associated with an increased risk of sepsis development during hospitalization (OR 4.18; 95% CI, 1.99–8.78) and with death or re-hospitalization at 30 days (OR 4.79; 95% CI, 2.79–8.23), whereas RS+ did not appear to be associated with death during hospitalization or need for ICU transfer. Conclusions: Our results suggest for the first time a prognostic role for RS+ in Internal Medicine. Thus, assessment of rectal swab at hospital admission appears useful even in this setting. However, larger prospective studies and a cost–benefit analysis are needed to confirm our preliminary findings.