Occurrence and Antibiotic Resistance of Enterobacteriaceae in Acute Leukemia Patients

Acute leukemia (AL) is a heterogeneous group of malignant hematopoietic diseases and is divided into two basic types: acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Patients with these diseases are highly immunosuppressed and therefore at a high risk of serious infections. This study aimed to perform active surveillance of enterobacteria, which cause these infections, and to determine their antibiotic resistance in patients with AL who were hospitalized at the Hemato-Oncology Center of University Hospital Olomouc.

This study involved 49 patients with AL, of whom 37 had AML (16 women and 21 men) and 12 had ALL (6 women and 6 men). The mean age of the patients was 50.5 years. Samples of clinical material were obtained over 12 months (September 2015 to August 2016) and subjected to standard microbiological examinations. Bacterial strains were identified by MALDI-TOF MS, and their antibiotic susceptibility was established by microdilution method.

A total of 292 samples were obtained from patients with AL. Some of these samples were excluded from analysis to prevent the inclusion of identical strains from the same patient. Consequently, 146 clinical samples obtained from the following nine types of clinical materials were analyzed - throat swabs (n = 47), stools (n = 40), urine (n = 33), hemocultures (n = 11), buccal swabs (n = 5), perianal swabs (n = 4), wound swabs (n = 3), sputum (n = 2), and puncture fluid (n = 1). The most prevalent enterobacteria was Escherichia coli (n = 42), followed by Klebsiella spp. (n = 46), specifically Klebsiella pneumoniae (n = 34) and Klebsiella oxytoca (n = 12), and Enterobacter cloacae (n = 19). The most of enterobacteria were highly resistant to many tested antibiotics.

Antibiotic-resistant enterobacteria colonize patients with hemato-oncological diseases and can cause serious infections. These antibiotic-resistant microorganisms are a serious and frequent problem. These findings together with the high level of immunosuppression mean that patients with hemato-oncological diseases are at a high risk of developing serious infections and consequently active surveillance is crucial.