Epidemiology And Prognostic Analysis Of Bloodstream Infection Due To Carbapenem-Resistant Gram-Negative Bacteria In Patients With Hematologic Malignancies

Background: Carbapenem-resistant Gram-negative bacteria(CRGNB)bloodstream infection(BSI)pose a significant threat to the prognosis of patients with hematologic malignancies(HM).Understanding the distribution of pathogenic bacteria,the changes of drug resistance trend,analyzing the risk factors and prognostic correlates of CRGNB bloodstream infection,and exploring the early detection measures will help to reduce the incidence and mortality of CRGNB bloodstream infection.Methods: We collected clinical data from patients with Gram-negative bacteria(GNB)bloodstream infections in the hematology wards of three university-affiliated hospitals in Hunan province,China,from January 2010 to December 2020,and analyzed the changes in carbapenem resistance rates and resistance trends of different Gram-negative bacteria,the impact of CRGNB bloodstream infections on patient prognosis,susceptibility factors and prognosis-related risk factors of carbapenemresistant bacteria bacteremia.We also analyzed the co-infection of other organs and the detection of pathogenic bacteria at the site of infection during the bloodstream infection in patients with HMs.Results: In this study,a total of 902 GNB strains were isolated,15.3%(138/902)were CRGNBs,of which carbapenem-resistant non-fermenting bacteria(CRNFB)accounted for the major proportion(57.2%).The detection rate of CRGNB increased from 6.4% in 2010-2012 to 35.4% in 2019-2020.The 7-day mortality rate was significantly higher in patients with CRGNB BSI than in patients with carbapenem-susceptible Gramnegative bacteria(CSGNB)BSI [31.9%(44/138)vs 9.7%(74/764),P <0.001],and the mortality rate in patients with carbapenem-resistant nonfermenting bacteria(CRNFB)bloodstream infections was generally higher than that of carbapenem-resistant Enterobacteriaceae(CRE).urinary catheter(OR,2.814;CI=1.395-5.680;P=0.004)and prior exposure to carbapenem(OR,4.372;CI=2.881-6.635;P<0.001)were independent risk factors for CRGNB BSI.In contrast,Pitt bacteremia score >3(OR,5.887;CI=1.559-22.232;P=0.009),use of vasopressors(OR,8.671;CI=2.487-30.224;P=0.001),carbapenem-resistant Acinetobacter baumannii bloodstream infection(OR,11.948;CI=2.175-65.640;P=0.004),and HB<60 g/L(OR,11.109;CI=1.181-104.461;P=0.035)were independent risk factors associated with 7-day mortality in patients with CRGNB bloodstream infection.Analysis of co-infections showed that 63.8% of patients with CRGNB bloodstream infections were combined with pulmonary infections,sputum culture results suggested that sputum culture positivity was as high as 57.1%-66.7% in patients with CRAB and Stenotrophomonas maltophilia BSI,and the results of antimicrobial susceptibility testing of sputum cultures were consistent with the blood cultures.Conclusions: Bloodstream infections with carbapenem-resistant Gram-negative bacteria significantly affect the prognosis of patients with hematologic malignancies,especially for the non-fermenting bacteria.patients with pulmonary infections are more likely to develop CRNFB bloodstream infections,and early screening of respiratory specimens for CRNFB in such high-risk patients may help to detect pathogenic bacteria and reduce the incidence and mortality of bloodstream infections.