Incidence of fecal Enterobacteriaceae producing broad-spectrum beta-lactamases in patients with hematological malignancies.

ABSTRACT

AIM: Given the steadily increasing numbers of resistant bacteria, the frequency and severity of infections are on the rise. In patients with hematological malignancies, the treatment itself increases the risk of complicating bacterial infections. One important mechanisms of resistance is production of broad-spectrum beta-lactamases, increasingly detected not only in bacterial pathogens but also in bacteria contained in the normal microflora of the human body. The objectives of this study were determination and analysis of the prevalence of multiresistant ESBL- and AmpC-positive Enterobacteriaceae in the gastrointestinal tract (GIT) of patients with hematological malignancies. METHODS: For 3 months, rectal swabs were taken from patients with hematological malignancies and analyzed using chromogenic screening plates to isolate ESBL- and AmpC-producing Enterobacteriaceae. Beta-lactamase production was determined by phenotype tests and confirmed by detecting genes encoding ESBL and AmpC types. At the same time, ESBL- and AmpC-positive Enterobacteriaceae were isolated from clinical samples collected from patients with bacterial infection. RESULTS: Over the study period, fifteen patients (21%) of all patients treated at the Department of Hemato-Oncology were shown to have ESBL- or AmpC-positive Enterobacteriaceae in their GIT. Most frequently identified were ESBL-positive strains of Klebsiella pneumoniae and AmpC-positive strains of Citrobacter freundii. The ESBL enzymes were mainly of the CTX-M type. Isolates producing AmpC were found to contain genes for enzymes mainly from the CIT and DHA groups. CONCLUSION: The study identified patients diagnosed with urinary tract and bloodstream infections caused by ESBL-positive strain of Klebsiella pneumoniae and AmpC-positive strain of Enterobacter cloacae contained in the GIT microflora.