Direct Screening of Blood by PCR and Pyrosequencing for a 16S rRNA Gene Target from Emergency Department and Intensive Care Unit Patients Being Evaluated for Bloodstream Infection.

Here we compared the results of PCR/pyrosequencing to those of culture for detecting bacteria directly from blood. DNA was extracted from 1,130 blood samples from 913 patients suspected of bacteremia (enrollment criteria were physician-ordered blood culture and complete blood count [CBC]), and 102 controls (healthy blood donors). Real-time PCR assays for beta-globin and Universal 16S rRNA gene targets were performed on all 1,232 extracts. Specimens identified by Universal 16S rRNA gene PCR/pyrosequencing as containing staphylococci, streptococci, or enteric Gram-negative rods had target-specific PCR/pyrosequencing performed. Amplifiable beta-globin (melting temperature [Tm], 87.2°C ± 0.2°C) occurred in 99.1% (1,120/1,130) of patient extracts and 100% (102/102) of controls. Concordance between PCR/pyrosequencing and culture was 96.9% (1,085/1,120) for Universal 16S rRNA gene targets, with positivity rates of 9.4% (105/1,120) and 11.3% (126/1,120), respectively. Bacteria cultured included staphylococci (59/126, 46.8%), Gram-negative rods (34/126, 27%), streptococci (32/126, 25.4%), and a Gram-positive rod (1/126, 0.8%). All controls screened negative by PCR/pyrosequencing. Clinical performance characteristics (95% confidence interval [CI]) for Universal 16S rRNA gene PCR/pyrosequencing included sensitivity of 77.8% (69.5 to 84.7), specificity of 99.3% (98.6 to 99.7), positive predictive value (PPV) of 93.3% (86.8 to 97.3), and negative predictive value (NPV) of 97.2% (96.0 to 98.2). Bacteria were accurately identified in 77.8% (98/126) of culture-confirmed sepsis samples with Universal 16S PCR/pyrosequencing and in 76.4% (96/126) with follow-up target-specific PCR/pyrosequencing. The initial PCR/pyrosequencing took ∼5.5 h to complete or ∼7.5 h when including target-specific PCR/pyrosequencing compared to 27.9 ± 13.6 h for Gram stain or 81.6 ± 24.0 h for phenotypic identification. In summary, this molecular approach detected the causative bacteria in over three-quarters of all culture-confirmed cases of bacteremia directly from blood in significantly less time than standard culture but cannot be used to rule out infection.

The representation of self in multidimensional cognitive space.

A number of studies point to the efficiency with which people process self-relevant trait information. The derivative models of self-cognition account for many judgement latency and memory effects. These models tend to limit themselves, however, by neglecting the cognitive representation of the traits themselves. In contrast, research on implicit personality theory has focused on the cognitive representation of trait information, but has not always addressed the relationship between self and the judged traits. These two research domains were linked in an effort to specify the cognitive representation of self. A method for locating individuals and traits within the same spatial representation was developed and validated in two studies. In Study 1, subjects exhibited superior recall for traits located closest to self. In Study 2, subjects rapidly selected which of two traits better or least described self. 'Better' judgements were faster with increasing closeness to self of selected traits whereas 'least' judgements were faster with increasing closeness to self of non-selected traits, supporting the view of self as fixed anchor in self-relevant decision making. Taken as a whole, these two studies provided further evidence for the self as an evaluative organization of knowledge.

Construct accessibility and depression: an examination of cognitive and affective factors.

Two studies in which the parameters of construct accessibility in depression were examined are reported. In Experiment 1, depressed and nondepressed subjects were required to name the colors of tachistiscopically presented depressed-content, neutral-content, and manic-content words. Because of the predicted accessibility and interference effects of the depressed-content words, the depressed subjects were expected to demonstrate longer response latencies to these words than to the non-depressed-content words. This response pattern was found for the depressed subjects; the nondepressed subjects did not demonstrate differential response latencies. In Experiment 2, a mood-induction paradigm was used to investigate whether the interference effects obtained in Experiment 1 were due to temporary mood differences between the depressed and nondepressed subjects, or were a function of more stable depression-associated patterns of information processing. Although predicted group differences were obtained on a mood adjective checklist, no effects were found for task performance. These results suggest that transient mood is not a sufficient explanation for the results obtained in Experiment 1. The implications of the present findings for the understanding of both construct accessibility and depression are discussed, and directions for future research are suggested.