ObjectiveTo understand isolation of carbapenemresistant Serratia marcescens(CRSM), analyze risk factors for infection and colonization with CRSM.MethodsPatients whose specimens were isolated Serratia marcescens(S. marcescens) in a hospital between January 2014 and December 2016 were recruited in the study. Patients who isolated CRSM were as case group, and those who isolated carbapenemsensitive Serratia marcescens(CSSM) were as control group. Patients’ medical records were surveyed retrospectively, univariate and logistic regression analysis of related factors were performed.ResultsA total of 120 patients were isolated S. marcescens, 38 were in case group, and 82 in control group. 32(84.2%) strains of CRSM and 61(74.4%) strains of CSSM were isolated from sputum respectively. Univariate analysis showed that risk factors for CRSM infection and colonization were patients with hypoproteinemia, respiratory failure, tracheal intubation or tracheotomy, vascular catheterization, history of carbapenem and fluoroquinolone use within two weeks, and history of staying in intensive care unit(all P<0.05). Multivariate analysis showed that hypoproteinemia and carbapenem use within two weeks were independent risk factors for CRSM infection and colonization(P<0.05).ConclusionInfection and colonization with CRSM is related to multiple factors, hypoproteinemia and carbapenem use within two weeks are independent risk factors.