Diagnosis of external ventricular drainage related infections with real-time 16S PCR and third-generation 16S sequencing.

OBJECTIVE: Investigate the performance of real-time 16S PCR and third-generation 16S sequencing in the diagnosis of external ventricular drain related infections (EVDRI). METHODS: Subjects with suspected EVDRI were prospectively included at Uppsala University Hospital. Subjects were included into three groups: subjects with negative CSF culture with and without antibiotic treatment and subjects with positive CSF culture, respectively. CSF was analysed with real-time 16S PCR and third-generation 16S sequencing. Real-time 16S PCR positivity/negativity and number of 16S sequence reads were compared between groups. For culture positive subjects, species identification in third-generation sequencing and routine culture was compared. RESULTS: 84 subjects were included. There were 18, 44 and 22 subjects in the three groups. Real-time PCR was positive in 17 of 22 subjects in the culture positive group and negative in 61 of the 62 subjects in the two culture negative groups. The sensitivity and specificity for real-time 16S PCR compared to culture was estimated to 77% and 98%, respectively. Species identification in 16S sequencing and culture was concordant in 20 of 22 subjects. The number of 16S sequence reads were significantly higher in the culture positive group than in both culture negative groups (p < 0.001). There was no significant difference in number of 16S sequences between the two culture negative groups. CONCLUSIONS: Real-time 16S PCR predict culture results with sufficient reliability. Third-generation 16S sequencing could enhance sensitivity and species identification in diagnostics of EVD-related infections. False negative culture results appear to be uncommon in patients with suspected EVDRI.

Validation of a web-based self-administered test for cognitive assessment in a Swedish geriatric setting.

Computerized cognitive tests have the potential to cost-effectively detect and monitor cognitive impairments and thereby facilitate treatment for these conditions. However, relatively few of these tests have been validated in a variety of populations. Brain on Track, a self-administered web-based test, has previously been shown to have a good ability to differentiate between healthy individuals and patients with cognitive impairment in Portuguese populations. The objective of this study was to validate the differential ability and evaluate the usability of Brain on Track in a Swedish memory clinic setting. Brain on Track was administered to 30 patients with mild cognitive impairment/mild dementia and 30 healthy controls, all scheduled to perform the test from home after one week and after three months. To evaluate the usability, the patient group was interviewed after completion of the testing phase. Patients scored lower than healthy controls at both the first (median score 42.4 vs 54.1, p<0.001) and the second test (median score 42.3 vs 55.0, p<0.001). The test-retest intra-class correlation was 0.87. A multiple logistic regression model accounting for effects of age, gender and education rendered an ability of Brain on Track to differentiate between the groups with an area under the receiver operation characteristics curve of 0.90 for the first and 0.88 for the second test. In the subjective evaluation, nine patients left positive comments, nine were negative whereas five left mixed comments regarding the test experience. Sixty percent of patients had received help from relatives to log on to the platform. In conclusion, Brain on Track performed well in differentiating healthy controls from patients with cognitive impairment and showed a high test-retest reliability, on par with results from previous studies. However, the substantial proportion of patients needing help to log in could to some extent limit an independent use of the platform.