Alpha Hemolytic Streptococcal Infection During Intensive Treatment for Acute Myeloid Leukemia: A Report From the Children’s Cancer Group Study CCG-2891

Abstract

PURPOSE: Past reports indicate that alpha hemolytic streptococcal (AHS) organisms are a common cause of infection among acute myeloid leukemia (AML) patients. This study was intended to ascertain the population incidence and rate (infections per 100 patient-days of treatment) of AHS and to identify associated risk factors. PATIENTS AND METHODS: Patients (n = 874 with 151,350 days of risk) enrolled on the Children’s Cancer Group (CCG) protocol for newly diagnosed AML, CCG-2891, which randomly assigned intensity of induction and intensification, were prospectively evaluated for infectious complications. RESULTS: AHS occurred in 21% of patients, was primarily blood borne (86%), made up 21% of bacteremic infections, and had a recurrent incidence of 31% during subsequent therapy. AHS was more often life-threatening (59%) than other infections (41%) (P = .001). AHS rates increased with age less than 10 years (odds ratio [OR], 2.0; P = .007), intensively timed induction (OR, 1.8 to 1.9; P = .02), and high-dose cytarabine intensification (OR, 3.7; P < .0001). Among all courses, the greatest incidence (19%) and rate (0.41) were associated with the use of high-dose cytarabine. Gastrointestinal toxicity correlated significantly with AHS bacteremia (P < .01). Infection with AHS resulted in increased hospital days (P = .0001). Only among bone marrow transplant patients were overall survival (OR, 2.8; P = .0001) and disease-free survival (OR, 2.1; P = .008) decreased after AHS bacteremia. CONCLUSION: This study, the first to prospectively examine AHS incidence among uniformly treated patients in multiple institutions, established that as the intensity of AML therapy has increased, so has the rate of AHS. Young children, those with previous AHS bacteremias, and those receiving high-dose cytarabine are at particularly high risk of AHS bacteremia.