Bloodstream infections in patients with solid tumors: epidemiology, antibiotic therapy, and outcomes in 528 episodes in a single cancer center

Abstract

Current information regarding bloodstream infection (BSI) in patients with solid tumors is scarce. We assessed the epidemiology, antibiotic therapy, and outcomes of BSI in these patients. We also compared patients who died with those who survived to identify risk factors associated with mortality. From January 2006 to July 2012 all episodes of BSI in patients with solid tumors at a cancer center were prospectively recorded and analyzed. A total of 528 episodes of BSI were documented in 489 patients. The most frequent neoplasms were hepatobiliary tumors (19%), followed by lung cancer (18%) and lower gastrointestinal malignancies (16%). Many patients had received corticosteroid therapy (41%), and 15% had neutropenia (<500 neutrophils/μL) at the time of BSI. The most common source of BSI was cholangitis (21%), followed by other abdominal (19.5%) and urinary tract infections (17%). Gram-negative BSI occurred in 55% of cases, mainly due to Escherichia coli (55%), Pseudomonas aeruginosa (18%), and Klebsiella pneumoniae (16%). Among gram-positive BSI (35%), viridans group streptococci were the most frequent causative organisms (22%), followed by Staphylococcus aureus (21%) and Enterococcus species (18%). We identified 61 multidrug-resistant (MDR) organisms (13%), mainly extended-spectrum β-lactamase-producing Enterobacteriaceae (n = 20) and AmpC-producing Enterobacteriaceae (n = 13). The majority of patients with BSI caused by MDR organisms had received antibiotics (70%), and they had been previously hospitalized (61.4%) more frequently than patients with BSI caused by susceptible strains. Inadequate empirical antibiotic therapy was given to 23% of patients, with a higher proportion in those with BSI due to a MDR strain (69%). Early (<48 h) and overall (30 d) case-fatality rates were 7% and 32%, respectively. The overall case-fatality rate was higher among cases caused by MDR organisms (39.3%). The only independent risk factors for the early case-fatality rate were the endogenous source of BSI (odds ratio [OR], 3.57; 95% confidence interval [CI], 1.06-12.02), shock at presentation (OR, 3.63; 95% CI, 1.63-8.09), and corticosteroid therapy (OR, 3.245; 95% CI, 1.43-7.32). The independent risk factors for overall case-fatality rate were the presence of a chronic advanced cancer (OR, 35.39; 95% CI, 2.48-504.91), shock at presentation (OR, 25.84; 95% CI, 3.73-179.0), and corticosteroid therapy (OR, 6.98; 95% CI, 1.61-30.21).BSI in patients with solid tumors occurred mainly among those with hepatobiliary cancer, and cholangitis was the most frequent source; gram-negative bacilli were the most frequent causative agents. MDR organisms were relatively common, particularly in patients who had previously received antibiotics and had been hospitalized; these patients were frequently treated with inadequate empirical antibiotic therapy and had a poorer outcome. The case-fatality rate of patients with solid tumors and BSI was high and was associated with chronic advanced cancer, corticosteroid therapy, and shock at presentation.