Gram-Negative Bacteria Bloodstream Infections in Patients with Hematological Malignancies - The Impact of Pathogen Type and Patterns of Antibiotic Resistance: A Retrospective Cohort Study

Background: Enterobacteriaceae (EB) and non-fermentative bacteria (NFB) are the main pathogens responsible for gram-negative bloodstream infections (GN-BSI) in patients with hematological malignancies (HMs). These two pathogen types have heterogeneous resistance mechanisms to antibiotics. However, the impact of pathogen species and pattern of antibiotic resistance on the outcomes of patients with HMs remains unclear. Methods: We retrospectively collected clinical data of patients with HMs at three comprehensive hospitals in Hunan Province, China, between January 2010 and May 2018. The data analyzed the impact that different species and patterns of antibiotic resistance had on the outcome of patients with HMs. Results: The majority of the 835 monomicrobial isolates collected from patients with HMs and GN-BSIs were Enterobacteriaceae (75.7%). While detections of MDR pathogens in BSIs as a whole are decreasing, sub-analysis shows that detections of extended spectrum beta-lactamase-producing (ESBL) Enterobacteriaceae and carbapenem-resistant pathogens in BISs are rising. Comparing different species, the early mortality rate associated with infections caused by NFB was significantly higher than infections caused by Enterobacteriaceae (22.6% vs 9.7%, p < 0.001). Across different multidrug-resistant (MDR) patterns, ESBL bacteria did not have a significant impact on health outcomes. Carbapenem-resistant bacteria, on the other hand, were observed to significantly affect early mortality rate, such as carbapenem-resistant Klebsiella pneumoniae (36.0% vs 7.6%, P < 0.001) and carbapenem-resistant non-fermentative bacteria (44.7% vs 16.5%, P < 0.001). Conclusion: Our findings suggest that both species and patterns of antibiotic resistance can affect the early mortality of patients with HMs during BSI.

Automated summary

The study found that Enterobacteriaceae were the most common pathogen type in GN-BSIs of patients with hematological malignancies, while infections caused by non-fermentative bacteria were associated with significantly higher early mortality rate. Although the detection rates of multidrug-resistant pathogens are decreasing, ESBL-producing Enterobacteriaceae and carbapenem-resistant pathogens are on the rise.