Microorganisms isolated from blood cultures in Hacettepe University i̇hsan doǧramacı children's hospital from 2000 to 2011: Evaluation of 12 years

Objective: Identification of microbial agents causing bloodstream infections is necessary to prevent the spread of pathogens and to determine appropriate antimicrobial treatment. The aim of this study was to evaluate microbial growth in blood cultures of children. Material and Methods: Blood cultures submitted to the Hacettepe University İhsan Doǧramaci{dotless} Children's Hospital Microbiology Laboratory during 2000-2011 were investigated. Types of bacteria and changes during the study period were evaluated. In addition, the rates of methicillin resistant Staphylococcus aureus (MRSA) and vancomycin resistant enterococcus (VRE) were determined. Results: A total of 49561 blood cultures were submitted. Microbial growth was detected in 7773 (15.7%) of the cultures. Of all microbial growth, 68.8% was gram positive bacteria, 20.4% was gram negative bacteria and 10.8% was fungi. The most common isolate was coagulase negative staphylococci (48.1%). When possible contaminants (coagulase negative staphylococci, diphtheroids, micrococci and Bacillus spp.) were excluded, and the ratio of gram positive bacteria decreased to 36.7%, the ratio of gram negative bacteria increased to 41.3% and fungi to 22.0%. The most common fungus was Candida albicans (47.3%), followed by Candida parapsilosis (21.7%). S. aureus was detected in 7.1% of the positive cultures and 29.4% of these were methicillin resistant. MRSA rates had a tendency to decrease in time and was 0% in 2011. Enterococci constituted 4.4% of the microbial growth and 6.3% were vancomycin resistant. Conclusion: Information on growth rates of microorganisms in blood cultures helps in determining empiric antimicrobial treatment and might be lifesaving. Differentation between true infection and contamination is significiant, especially for some bacteria such as coagulase negative staphylococci. Additionally, fungal infections should be kept in mind according to the characteristics of the patient population.