Enhanced Outcomes in Bacteremia Through Rapid Phenotype Identification of Carbapenemase-Producing Organisms

Objective: The treatment of carbapenemase-producing organisms (CPOs) causing bacteremia in patients with intra-abdominal infections remains challenging. The early detection of CPOs from blood specimens is critical for guaranteeing the timely selection of appropriate antibiotics and achieving favorable outcomes. Our aim was to evaluate whether the rapid identification of CPOs can improve clinical outcomes.Patients and Methods: Between January 2019 and January 2024, we conducted a retrospective study of all bacteremia patients admitted to the Intestinal Fistulae and Intra-abdominal Infection Center at Jinling Hospital. A subset of patients underwent screening for CPOs using lateral flow immunoassays (LFIA) method.Results: A total of 163 patients were enrolled, with 96 in the 30-day survivors group and 67 in the 30-day non-survivors group. LFIA was performed in 76 patients, revealing the identification of 64 carbapenemases in four classes: bla Klebsiella pneumoniae carbapenemases (KPC) (45/76, 59.2%), bla NDM (11/76, 14.5%), bla oxacillinase (OXA)-48 (6/76, 7.9%), and bla imipenemase (IMP) (2/45, 2.2%). The most prevalent CPOs cultured were carbapenem-resistant Klebsiella pneumoniae (104/163, 63.8%), followed by carbapenem-resistant Acinetobacter baumannii (36/163, 22.1%), carbapenem-resistant Pseudomonas aeruginosa (32/163, 19.6%), carbapenem-resistant Escherichia coli (19/163, 11.7%), and others (28/163, 17.2%). Univariable analysis revealed that risk factors related to mortality included outbreaks in the intensive care unit or community, sources from the respiratory tract, mechanical ventilation, Pitt score of ≥4, and active therapy before blood culture collection. Multivariable logistic regression analysis indicated that outbreaks in the intensive care unit or community, sources from the respiratory tract, and mechanical ventilation were independent predictors of clinical failure. In addition, LFIA test was associated with decreased 30-day mortality.Conclusions: The LFIA method can rapidly detect the presence of CPOs in patients with bacteremia, thereby improving clinical outcomes. Future multicenter randomized controlled trial (RCT) studies are warranted to investigate the benefits of LFIA detection in bacteremia.