Risk of infection in antimicrobial-resistant Gram-negative bacteria carriers: A systematic review

Abstract

Abstract Background Antimicrobial-resistant Gram-negative bacteria (AMR-GNB) have emerged as important health care-associated pathogens. Infections with AMR-GNB are associated with high patient morbidity and attributable mortality. Colonization is a prerequisite for infection, however the extent to which colonized patients develop infection is unclear. This systematic review explored the risk of developing infection during hospitalisation among AMR-GNB faecal carriers. Also, we investigated the acquisition rate for AMR-GNB colonization among patients not colonized at admission. Methods We searched on PubMed, Scopus and Cochrane databases for studies published from 2010 up to April 2019. We included studies reporting on hospitalised patients ≥18 years old in high-income countries (excluding long-term care facilities). Results Out of 9496 articles, 55 studies fulfilled our inclusion criteria. Forty-two studies reported data from EU/EEA, 6 from USA and 7 from other regions. Almost all studies (n = 45) were conducted in university hospitals. Most studies (n = 41;74.5%) were performed in high-risk wards (ICU, haematology, burn units and transplant units). Out of 55 studies, 8 examined AMR-GNB, 27 Enterobacteriaceae, while the others investigated specific pathogens: Klebsiella spp. (n = 11), E. Coli (n = 2), A. Baumannii (n = 3) and P. Aeruginosa (n = 4). The rate of AMR-GNB carriage acquisition was 10.5% (n = 40 studies; 95% CI:8.2-13.1). The risk of progression to infection among patients colonized at hospital admission was 13.9% (n = 15; 5.4-24.9), while the infection rate in patients who acquired carriage during hospitalization was 23.0% (n = 7; 5.9-45.2). Patients with an undefined time of colonization presented an infection rate of 16.9% (n = 13; 11.2-23.4). Considering these three populations as a whole, the risk of developing infection was 16.0% (11.0-21.0). Conclusions Our results suggest that risk of progression to infection in AMR-GNB colonized patients in hospital setting is high. Key messages The aim of our study was to estimate the risk of progression to infection, during hospital stay, in patients colonized by AMR-GNB at hospital admission in high-income countries. Our results suggest that faecal colonization with AMR-GNB poses a 16.0% risk of subsequent AMR-GNB infection. This risk in higher (23.0%) in patients who acquired colonization during hospitalisation.