1435. Time to Positivity of Blood Cultures of Different Candida species Causing Candidemia
Session: Poster Abstract Session: Fungal Infections
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
Background: Time-to-positivity (TTP) is defined as the length of time from the beginning of culture incubation to the detection of pathogen growth by an automated system. The objective of this study was to investigated the TTP for different species of Candida causing bloodstream infection.

Methods: We conducted this study at the Gachon University Gil Hospital, a 1200-bed tertiary care medical centre in Republic of Korea. Data were collected from March 2008 through March 2013. Patients aged 18 years or older patients with one or more blood cultures growing Candida were included. Each patient was included only once at the time of detection of the first bloodstream infection. TTP in each patient was determined using an automated blood culture instrument.  

Results: During the 5-years, a total of 210 patients with blood cultures positive for Candida were enrolled. The mean TTP for all isolates causing candidemia was 27.3±18.5 h. The Candida species isolated from the included patients and their TTP are summarized in Table 1. The TTP for C. glabrata (46.4±31.9 h) was significantly longer (p < 0.001) than the TTP of the other species. In contrast, the TTP of C. tropicalis (17.1±7.9 h) was significantly shorter (p < 0.001). The ROC curve was plotted to evaluate the diagnostic value of TTP for predicting different Candida species. C. glabrata can be predicted by the cut-off value of ≥ 41.5 h. Its AUC was 0.810 [95 % CI 0.705–0.914], with a sensitivity of 78.3 % and a specificity of 63.9 %.  C. tropicalis can be predicted by the cut-off value of ≤ 18.5 h. Its AUC was 0.735 [95 % CI 0.650–0.819], with a sensitivity of 79.6 % and a specificity of 61.6 %.

Conclusion: In conclusion, the different TTP values of different Candida species causing bloodstream infection may be helpful in differentiating C. glabrata and C. tropicalis from other Candida species. But, larger sample size and multi-center prospective study remain necessary in order to verify our results.

Table 1. Time to positivity of different Candida species included in this study

Cnadida species

Number of isolates (%)

Mean TTP ± SD (h)

C. albicans

83 (39.5 %)

23.8±13.4

C. parapsilosis

56 (26.7 %)

29.1±13.8

C. tropicalis

33 (15.7%)

17.1±7.9*

C. glabrata

23 (10.9 %)

46.4±31.9*

*Significantly different from other species, p < 0.001

Song Mi Moon, MD, Su Young Kim, M.D., Kang Lock Lee, M.D., Yoon Soo Park, M.D. and Yong Kyun Cho, M.D., Department of Infectious Disease, Gachon University Gil Hospital, Incheon, South Korea

Disclosures:

S. M. Moon, None

S. Y. Kim, None

K. L. Lee, None

Y. S. Park, None

Y. K. Cho, None

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