ABSTRACT
Although Sepsis-3 doesn't require evidence of bacteremia to diagnose sepsis, clinicians often want to identify the causative pathogen at autopsy. In principle, if the blood cultures are the same at ante- and postmortem, the cause of death is obvious. However, interpretations of postmortem blood cultures are often difficult due to discordance, negativity, mixed infection, and contamination, of pathogens occupying ≥ 50% of the tests. To increase specificity identifying agonal phase sepsis in the situations where blood cultures are discordant, multiple or negative at postmortem, we established a scoring system using blood cultures, procalcitonin (PCN) showing highest sensitivity and specificity for postmortem serum, and bone marrow polyhemophagocytosis (PHP). Histological sepsis showed significantly higher levels of culture score (2.3 ± 1.5 vs. 0.4 ± 0.5, p < 0.001), PHP score (2.5 ± 0.8 vs. 1.0 ± 1.1, p < 0.001), and PCN score (1.8 ± 0.8 vs. 0.8 ± 0.6, p < 0.01) than non-septic patients. Receiver operating characteristic curve analysis indicated that estimation of three scores was the most reliable indicator for recognizing agonal phase sepsis. These findings suggest that the combination of these three inspections enables to determine the pathological diagnoses of sepsis even it is not obvious by discordant, mixed or negative blood cultures.
Subject(s)
Bacteremia , Sepsis , Humans , Autopsy , Prospective Studies , Sepsis/diagnosis , HospitalsABSTRACT
Early detection of the family Chlamydiaceae as pathogens is essential worldwide for the rapid and sufficient management of atypical pneumonia. GENECUBE (TOYOBO) is a novel fully automated gene analyzer capable of amplifying and detecting target DNAs within 50 min. In this study, we developed a new PCR assay with a specific quenching probe (PCR-QC assay) for rapidly distinguishing between Chlamydia pneumoniae (CPN) and Chlamydia psittaci (CPS). The PCR-QC assay enabled us to precisely and simultaneously detect the 2 different types of DNA fragments even in a mixed sample by identifying unique melting temperatures. Next, we examined a total of 300 frozen samples from patients with respiratory tract infection using the PCR-QC assay and the cell culture method as the gold standard. Kappa index for agreement between the PCR-QC assay and the culture method was 0.43 (95% confidential interval (CI): 0.08-0.78). The sensitivity and specificity of the PCR-QC assay were 36.3% (4/11; 95% CI: 10.9-69.2%)) and 99.0% (286/289; 95% CI: 97.0-99.8%), respectively. The samples positive for CPN (n = 13) or CPS (n = 1) by either method were also examined by a conventional PCR TaqMan assay, which produced the same results as those from the PCR-QC assay. Furthermore, the PCR-QC assay using GENECUBE shortened the full detection time for CPN or CPS (within 50 min vs. more than 2 to 3 h) compared with conventional PCR TaqMan assays. Therefore, the new PCR-QC assay system equipped with GENECUBE is useful for rapidly detecting CPN or CPS pathogens in clinical laboratory, and may improve the management of atypical pneumonia.
Subject(s)
Chlamydophila pneumoniae/isolation & purification , Chlamydophila psittaci/isolation & purification , Polymerase Chain Reaction/methods , Chlamydia Infections/microbiology , Chlamydophila pneumoniae/genetics , Chlamydophila psittaci/genetics , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Discriminant Analysis , Humans , Sensitivity and Specificity , Transition TemperatureABSTRACT
Early detection of tuberculosis (TB) is essential for infection control. The geneCube (Toyobo) is a novel fully automated gene analyzer that can amplify target DNAs within 60 min. In this study, we evaluated the ability of the geneCube to directly detect Mycobacterium tuberculosis complex (MTBC) and Mycobacterium avium complex (MAC) in clinical specimens. The results were then compared with those obtained using conventional culture, microscopy, and the Cobas Amplicor assay (Roche). We examined a total of 516 frozen samples from 69 patients who showed culture-positive infection (73 samples; 39 MTBC, 32 MAC, and 2 mixed infections) and from 354 patients who were culture negative (443 samples). Assays using the geneCube had a sensitivity of 85.4% and a specificity of 99.8% for detection of MTBC and a sensitivity of 85.3% and a specificity of 99.8% for detection of MAC. These results are similar to those obtained using the Amplicor system but were obtained much more rapidly (1 h with the geneCube versus 5.5 h with the Amplicor system). The geneCube thus enables a significant shortening of the assay time with no loss of sensitivity or specificity.
