Upper Respiratory Tract Colonization by Gram-Negative Rods in Patients with Chronic Lymphocytic Leukemia: Analysis of Risk Factors

The aim of the study was to assess the frequency and predisposing factors of colonization of upper respiratory tract by Gram-negative rods (GNRs) in chronic lymphocytic leukemia (CLL) patients. Antimicrobial susceptibility of the isolated strains was determined. A significantly higher frequency of GNR colonization in CLL patients was observed (36.7%) in comparison to healthy volunteers (8.3%). GNR isolates mainly belonged to the Enterobacteriaceae family. Three isolates of GNR demonstrating presence of AmpC β-lactamases and one ESBL-producing strain were obtained from CLL patients. GNR colonization rate was higher among CLL patients with lower level of IgG in serum (P = 0.017), with higher number of neutrophils (P = 0.039) or higher number of lymphocytes in serum (P = 0.053). The longer the time elapsed since diagnosis, the higher the frequency of GNR colonization observed. Multivariate analysis showed importance of the Rai stage, number, and type of infections as independent predictors of GNR colonization in CLL patients.