Six of the samples reported as false negatives contained S. agalactiae, S. epidermidis, S. pneumoniae, E. faecalis, E. faecium, and S. aureus as a causative agent. In these cases,
the strict detection rules caused the final outcome to be below the level required for positive identification. These six false negatives learn more were caused by either one completely missing or one low quality duplicated probe, giving results that were insufficient to meet the strict positive CFTRinh-172 identification criteria. Therefore these samples were reported as negative findings by the Prove-it™ Advisor, although other duplicates and probes were detected. We noticed that by using less strict identification rules, these samples were identified correctly. Thus, these samples were considered to be true
positives when calculating the final specificity and sensitivity values of the assay. The other nine samples reported negative by the the Prove-it™ Advisor were: S. pyogenes, S. aureus, S. epidermidis, and six CNS samples. We sequenced the CNS samples using the 16S rRNA gene. Sequencing revealed that these unidentified CNS samples contained Selleck Idasanutlin S. pasteuri, S. capitis and S. hominis (four samples). The mecA gene was identified in two of the CNS samples. The two positive mecA findings were associated with S. capitis and S. hominis. None of the species in the six CNS samples was covered by the CNS probes of the assay panel (Table
2), Cepharanthine thus these samples were considered to be true negatives. The reasons for the remaining three false negative samples (S. pyogenes, S. aureus, S. epidermidis) remained undetermined. The samples were not amplified by the 16s rRNA PCR, suggesting that they could have contained PCR inhibitors or degraded DNA. Two false positive results were observed due to the detection of the mecA gene marker associated with the non-staphylococcus causative agent S. pneumoniae and E faecalis. The causative agent was in line with the corresponding blood culture result. When the results of the assay were compared with the identification provided by HUSLAB, a sensitivity of 82 percent and specificity of 98 percent were achieved. After the alterations presented above were implemented, the sensitivity increased to 96 percent while the specificity remained at 98 percent (Table 5). Table 5 Comparison of the blood culture results with the PCR- and microarray-based analysis.