203 - Appropriateness, efficiency and efficacy of some analytical methods to improve blood cultures turnaround time
Autor(s): S. Grosso, A. Camporese
Issue: RIMeL - IJLaM, Vol. 3, N. 3, 2007 (MAF Servizi srl ed.)
Page(s): 203-212
Background. To improve the clinical impact of microbiology results, one of the requirements now emerging is that of reducing the time needed to provide validated results. It is universally recognized that, in order to have a substantial impact on the choice of appropriate antibiotic treatment, reduction of overall hospitalization and diagnostic costs, and, if possible, reduce the levels of mortality, it is necessary to provide antibiotic susceptibility tests in the shortest possible timeframe. This study explores the possibility of improving turnaround time of laboratory diagnosis of septicemic patients using positive blood cultures for direct identification and susceptibility testing. Methods. In order to decrease the time lapse between initial inoculation of blood culture media and the reporting of results of identification and antimicrobial susceptibility tests for microorganism causing bacteriemia, we performed a study in which specially processed fluid from positive blood culture bottles were directly tested with some methods, like Vitek 2, Sensititre YeastOne, CHROMagar Candida, MRSA screen Agar and eTest. A total of 70 strains were investigated, comparing the results with our laboratory reference methods. Results. All 27 bacterial strains with gram negative enteric bacillus-like morphology from positive blood cultures were correctly identified and demonstrated a high percentage of MIC agreements. Among 23 Staphylococci, only 5 were correctly identified, but all demonstrated a good susceptibility testing performance. Sensititre YeastOne for direct antifungal susceptibility testing of yeasts in positive blood cultures demonstrated a high performance and a high percentage of MIC agreements. Conclusions. The use of direct identification and susceptibility testing from positive blood cultures, as well as the reorganization of personnel, thus the workflow itself, can improve in response time and greater efficiency in diagnostic procedures.