Blood culture findings during neutropenia in adult patients with acute myeloid leukaemia : the influence of the phase of the disease, chemotherapy and the blood culture systems
1University of Oulu, Faculty of Medicine, Institute of Clinical Medicine, Department of Internal Medicine
2Oulu University Hospital, Clinical Microbiology Laboratory
3Oulu University Hospital, Department of Infection Control
4Lapland Central Hospital
|Online Access:||PDF Full Text (PDF, 1 MB)|
|Persistent link:|| http://urn.fi/urn:isbn:9789514263231
Oulu : University of Oulu,
|Publish Date:|| 2010-11-09
|Thesis type:||Doctoral Dissertation
|Defence Note:||Academic dissertation to be presented with the assent of the Faculty of Medicine of the University of Oulu for public defence in Auditorium 7 of Oulu University Hospital, on 19 November 2010, at 12 noon
Docent Pirjo Koistinen
Docent Markku Koskela
Docent Hannu Syrjälä
Docent Olli Meurman
Docent Esa Rintala
In Oulu University Hospital Haematological Ward during the years 1990–1991, a manual blood culture system was able to detect bloodstream infection (BSI) in 23% of febrile episodes of patients with acute myeloid leukaemia (AML), whereas during the years 1992–1993 an automated continuous-monitoring blood culture system (CMBCS) BacT/Alert® detected BSI in 40% of febrile episodes (p = 0.043). During the years 1997–2003, regimens containing high-dose cytarabine predisposed patients to laboratory-confirmed BSI (LCBI) with an odds ratio (OR) of 2.3 (with 95% confidence interval (CI) from 1.2 to 4.2). The LCBI risk was lowest after thioguanine-containing regimens (OR 0.26, 95% CI; 0.12–0.58). In the register data (years 1992–2006) from the prospective multi-centre AML -92 trial, when compared to cycle I, the OR for LCBI was significantly higher (from 4.8 to 5.8) in subsequent cycles (p < 0.001). In all, 67% of mortality due to BSI occurred in patients with active leukaemia.
An inoculum of microorganisms to produce 10 colony-forming units (cfu)/ml of 10 gram-positive coccal strains, 10 gram-negative bacillar strains and 8 Candida yeast strains was cultured in BacT/Alert® blood culture bottles in the presence of several chemotherapeutic drugs. Of the chemotherapeutic drugs tested, the anthracyclines exhibited inhibitory effects on the growth of microorganisms in concentrations corresponding to the therapeutic levels. In the standard bottles, doxorubicin increased the incubation time of gram-positive cocci and idarubicin increased the incubation time of Candida glabrata. However, no increase in the incubation time of any microbes was detected in the antimicrobial-neutralizing FAN bottles.
In conclusion, the use of CMBCSs has resulted in an increased LCBI rate in neutropenic AML patients. In general, chemotherapeutic agents have no significant inhibitory effects on the growth of common microbial pathogens in blood culture. The detection of some difficult-to-culture microbial strains – C. glabrata for example – in blood cultures may be impaired by the presence of chemotherapeutics in blood. The chemotherapeutics may also affect the LCBI rate in other ways. As a predictor of adverse outcome of infection, the presence of active leukaemia is more important than the type of chemotherapy being administered.
Acta Universitatis Ouluensis. D, Medica
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