Identification of isolated aerob bacreria by bactec blood culture system and evaluation of their antibiotic susceptibility results

The purpose of this study was to evaluate the results of blood cultures which were incubated in BACTEC 9050 (Becton Dickinson ,Sparks, MD, USA) system in the Central Laboratory ,Dicle University Hospital ,between May 2003 and April 2004. Antibiotic susceptibility and identification of isolated aerob bacteria were made by Sceptor (Becton Dickinson ,Sparks, MD, USA) microdilution system. While no growth occured in 958 (70.14%) of total 1366 blood cultures ,408 (29.86%) were growth positive. Of the positive growth cultures;75.00 % of them were gram-positive bacteria, 17.40% were gram-negative bacteria ,4.65 % were Candida spp. and 2.95 % of them were accepted as contamination. Among all the gram-positive bacteria coagulase-negative staphylococci (74.50 %) and S.aureus (17.64 %) were mostly isolated. 42 % of S.aureus and 72 % of coagulase-negative staphylococci were found methicillin resistant. Vankomycin (100%) and teicoplanin (100%) were the most effective antibiotics for them. The most common isolated gram-negative bacteria were E.coli (25.35%) ,Klebsiella spp. (23.94%) and Acinetobacter spp. (14.08%) .Gram-negative bacteria were highly resistant to ampicillin but amikacin and imipenem were most effective antibiotics for them.