Background: Carbapenem-resistant Gram-negative bacteria (CRGNB) bloodstream infection (BSI) pose a significant threat to the prognosis of hematologic malignancies (HM) patients. Understanding the distribution of pathogenic bacteria, changes in carbapenem-resistant trends, risk factors for CRGNB infections, and exploring the early detection measures can help reduce mortality.
Methods: We conducted a multicenter retrospective study of Gram-negative bacteria (GNB) BSI in patients with HM in three university-affiliated hospitals in Hunan Province, China, from January 2010 to December 2020. Demographic and clinical data were collected from the hospital electronic medical records system.
Results: CRGNB caused 138 (15.3%) of 902 GNB BSI. 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 Gram-negative bacteria (CSGNB) BSI [31.9% (44/138) vs 9.7% (74/764), P < 0.001], and the mortality rate in patients with carbapenem-resistant non-fermenting 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. Analysis of co-infections showed that 50%– 85% of patients with CRGNB BSI had pulmonary infections, sputum culture results suggested that sputum culture positivity rate was as high as 57.1%– 66.7% in patients with carbapenem-resistant Acinetobacter baumannii (CRAB) and Stenotrophomonas maltophilia BSI, and the results of antimicrobial susceptibility testing of sputum cultures were consistent with the blood cultures.
Conclusion: Carbapenem resistance has dramatically increased in HM patients with GNB BSI in recent years and is associated with a worse outcome, especially for non-fermenting bacteria. In high-risk patients, early screening of the respiratory tract specimens may help to detect CRNFB colonization and protect patients from breakthrough BSI.
Keywords: hematological malignancies, carbapenem-resistant, gram-negative bacteria, bloodstream infections, non-fermentative bacteria