Distribution of Bacteria Isolated from Febrile Neutropenic Cases and Their Antibiotic Susceptibilities

Gram-positive bacteria have recently been increasing in frequency as infectious agents of febrile neutropenic patients in our country as in the world. Bacteria isolated from febrile neutropenic patients who were followed between May 1997 and December 2002 and their antibiotic susceptibilities were investigated in order to find out our data. Of 111 isolates, 61 were from blood, 35 from urine, 17 from wound and others from various materials. Gram-negative organisms were responsible for 70 (63%) isolates and the remaining 41 (37%) were gram-positive organisms. The most common isolate was Escherichia coli (n= 37) followed by Staphylococcus aureus (n= 26) and Pseudomonas aeruginosa (n= 12). Antibiotic susceptibilities were investigated by Bauer-Kirby disk diffusion method according to the National Committee for Clinical Laboratory Standards (NCCLS) recommendations. Of the gram-negative isolates, 100% were susceptible to imipenem and meropenem, 90% to amikacin, 89% to cefepime, 84% to piperacillin-tazobactam, 84% to ciprofloxacin, 80% to ceftazidime, 80% to cefoperazone-sulbactam, 80% to gentamicin and 73% to ceftriaxone. Twelve of 26 S. aureus isolates were methicillin-resistant. None of 10 S. pneumoniae isolates were penicillin-resistant. None of the gram-positive isolates were resistant to glycopeptides. Although the frequency of gram-positive isolates has increased over the years (from 20% to 39%), gram-negative organisms are still the most common isolates. However, the frequency of gram-positive bacteremic isolates has also increased (from 41% to 50%) and became the most common bacteremic isolates. As a result; gram-negative organisms, especially E. coli, are still predominant pathogen in our center, but gram-positive isolates, especially S. aureus, became the most common bacteremic pathogen. These new data will be leading us in decision of proper empirical antibiotic policy and the outcome will be success in treatment