Time to Positivity of Peripheral Blood Culture in Candidemia

Choi, Seong Ho; Chung, Jin Won; Lee, Mi Kyung

Abstract

BACKGROUND: Recent studies show that the time to positivity (TTP) of peripheral blood culture is a useful marker for some clinical characteristics such as the source of infection and the clinical outcome in bacteremia caused by some virulent bacteria, since TTP has relationship with bacterial blood concentration. One recent study of candidemia also reported the usefulness of TTP in the differentiation between central venous catheter (CVC)-related candidemia and non-CVC-related candidemia.
OBJECTIVE
We investigasted the clinical usefulness of TTP in the patients with candidemia.
METHODS
Fifty-four admitted patients with candidemia were detected between March 2006 and July 2008. After the exclusion, we reviwed the medical records of 45 patients and investigasted the relationship of clinical characteristics of candidemia with TTP, which was recorded by the BACTEC 9240 system.
RESULTS
Most episodes of candidemia developed in non-neutropenic patients, except 4 episodes. Majority of the patients with candidemia had the history of previous antibiotic use (88.6%) and CVCs (62.2%). CVC-related candidemia was observed in more thant a half (24/45, 53.3%) of the patients. However, only in 10 (41.7%) of them, CVCs were removed early. The persistence of candidemia (> or = 3 days) and the fatal outcome (within 30 days) were observed in 14 (31.3%) and 17 (37.8%) patients, respectively. TTP was shorter in CVC-related candidemia (31.3+/-13.2 hours) than that in non-CVCrelated candidemia (52.1+/-37.8 hours) (p=0.032). The patients with the persistence of candidemia had shorter TTP (28.9+/-11.2 hours) than those without the persistence (45.7+/-28.6) (p=0.012). The value of TTP cutoff predicting the CVC-related candidemia and the persistence of candidemia was 38 hours (area under the receiver-operator characteristic curve of 0.70 and 0.75, respectively).
CONCLUSION
TTP may be helpful for the differentiation of the source of candidemia and the prediction of the persistence of candidemia in the patients without neutropenia. The early removal of CVC may prevent the persistence of candidemia in non-neutropenic patients with candidemia of short TTP (< or = 38 hours).