Long-term epidemiology of bacterial susceptibility profiles in adults suffering from febrile neutropenia with hematologic malignancy after antibiotic change

J Mebis^1,2, H Jansens³, G Minalu⁴, G Molenberghs⁴, WA Schroyens¹, AP Gadisseur¹, A van de Velde¹, I Vrelust¹, H Goossens³, ZN Berneman<sup>1

1</sup>Division of Hematology, Antwerp University Hospital, Edegem, ²Division of Medical Oncology, Jessa Hospital, Hasselt, ³Division of Microbiology, Antwerp University Hospital, Edegem, ⁴Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Hasselt University, Hasselt, Belgium

Objective: The aim of this study was to investigate the epidemiology and antibiotic ­susceptibility profiles of isolated bacterial organisms in relation to empiric treatment of neutropenic fever over a 15-year period.

Methods: All patients with or at risk febrile neutropenia and treated in the hematology ward of the Antwerp University Hospital during 1994–2008 were prospectively included. Skin, blood, and urine cultures were taken. Oral quinolone prophylaxis was started in patients with neutropenia without fever. Empiric starting therapy consisted of amikacin in combination with cefepime.

Results: A total of 3624 bacteria were isolated. The most common pathogens were coagulase-negative Staphylococci (46%), followed by Escherichia coli (25%), Enterobacteriaceae (15.6%), Staphylococcus aureus (7.2%), and Pseudomonas aeruginosa (3.8%). The balance between Gram-positive and Gram-negative bacteria remained stable, with a majority of Gram-positive bacteria. A shift from oxacillin-sensitive to oxacillin-resistant coagulase-negative Staphylococci was observed. Regarding susceptibility patterns, no vancomycin resistance was detected in coagulase-negative Staphylococci or in S. aureus. The E. coli susceptibility rates remained stable. However, 66% of bloodstream infections were ciprofloxacin-resistant. A reduced susceptibility of P. aeruginosa strains to meropenem was noticed.

Conclusions: Improvement in antibiotic susceptibility of inducible Enterobacteriaceae ­following a switch of empiric antibiotic therapy was maintained 15 years after starting the ­latter treatment. Further improvement in antibiotic susceptibility of these bacteria to ceftazidime was observed, but continuous vigilance is warranted.

Keywords: bacterial susceptibility, febrile neutropenia, antibiotic change