Risk factors for carbapenem-resistant Gram-negative bacterial infections: a systematic review

BACKGROUND: Rapid and widespread increases in carbapenem resistance (CR) necessitate identification of risk factors to guide appropriate interventions.OBJECTIVES: We aimed to identify risk factors for CR Gram-negative infection through a systematic literature review.DATA SOURCES: We searched MEDLINE (via OvidSP and PubMed) and Embase (via OvidSP) databases and the Cochrane Central Register of Controlled Trials.STUDY ELIGIBILITY CRITERIA: Prospective or retrospective cohort and case-control studies reporting quantitative data on risk factors associated with infections due to CR Gram-negative pathogens in hospitalised patients were eligible.PARTICIPANTS: Studies included hospitalised patients with CR infection caused by Gram-negative bacterial pathogens (Enterobacterales and non-fermenters).METHODS: Searches were conducted in January 2018/December 2019 to identify studies published since 2007. Risk factor data were extracted and grouped by factor. The primary metric was proportion of studies reporting a significant association with CR infection for each factor.RESULTS: In total, 92 studies were identified. Risk factors most frequently reported as significantly associated with CR infection (>10 studies) were previous antibiotic use (91.1% [72/79 studies]); previous carbapenem use (82.6% [57/69]); previous colonisation (72.7% [8/11]); mechanical ventilation (66.7% [36/54]); previous intensive care unit stay (64.4% [38/59]); dialysis (61.1% [11/18]); catheter (58.0% [40/69]); length of stay in hospital (54.5% [30/55]); comorbidities (52.7% [39/74]); APACHE II (51.7% [15/29]); and intubation (51.4% [18/35]). Risk factors were mostly consistent across different species and sites of infection.CONCLUSIONS: Several variables, particularly previous antibiotic use, are strong risk factors for CR infection. Interventions to mitigate against CR infection should target these factors.