• Katsunori Yanagihara, Yuko Kitagawa, Masao Tomonaga, Kunihiro Tsukasaki, Shigeru Kohno, Masafumi Seki, Hisashi Sugimoto, Takeshi Shimazu, Osamu Tasaki, Asako Matsushima, Yasuo Ikeda, Shinichiro Okamoto, Naoki Aikawa, Shingo Hori, Hideaki Obara, Akitoshi Ishizaka, Naoki Hasegawa, Junzo Takeda, Shimeru Kamihira, Kazuyuki Sugahara, Seishi Asari, Mitsuru Murata, Yoshio Kobayashi, Hiroyuki Ginba, Yoshinobu Sumiyama, and Masaki Kitajima.
• Department of Laboratory Medicine, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki City, Nagasaki 852-8501, Japan. kyana-ngs@umin.ac.jp
• Crit Care. 2010 Jan 1;14(4):R159.

IntroductionSepsis is a serious medical condition that requires rapidly administered, appropriate antibiotic treatment. Conventional methods take three or more days for final pathogen identification and antimicrobial susceptibility testing. We organized a prospective observational multicenter study in three study sites to evaluate the diagnostic accuracy and potential clinical utility of the SeptiFast system, a multiplex pathogen detection system used in the clinical setting to support early diagnosis of bloodstream infections.MethodsA total of 212 patients, suspected of having systemic inflammatory response syndrome (SIRS) caused by bacterial or fungal infection, were enrolled in the study. From these patients, 407 blood samples were taken and blood culture analysis was performed to identify pathogens. Whole blood was also collected for DNA Detection Kit analysis immediately after its collection for blood culture. The results of the DNA Detection Kit, blood culture and other culture tests were compared. The chosen antimicrobial treatment in patients whose samples tested positive in the DNA Detection Kit and/or blood culture analysis was examined to evaluate the effect of concomitant antibiotic exposure on the results of these analyses.ResultsSeptiFast analysis gave a positive result for 55 samples, while 43 samples were positive in blood culture analysis. The DNA Detection Kit identified a pathogen in 11.3% (45/400) of the samples, compared to 8.0% (32/400) by blood culture analysis. Twenty-three pathogens were detected by SeptiFast only; conversely, this system missed five episodes of clinically significant bacteremia (Methicillin-resistant Staphylococcus aureus (MRSA), 2; Pseudomonas aeruginosa, 1; Klebsiella spp, 1; Enterococcus faecium, 1). The number of samples that tested positive was significantly increased by combining the result of the blood culture analysis with those of the DNA Detection Kit analysis (P = 0.01). Among antibiotic pre-treated patients (prevalence, 72%), SeptiFast analysis detected more bacteria/fungi, and was less influenced by antibiotic exposure, compared with blood culture analysis (P = 0.02).ConclusionsThis rapid multiplex pathogen detection system complemented traditional culture-based methods and offered some added diagnostic value for the timely detection of causative pathogens, particularly in antibiotic pre-treated patients. Adequately designed intervention studies are needed to prove its clinical effectiveness in improving appropriate antibiotic selection and patient outcomes.

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