Fastidious Gram-Negatives: Identification by the Vitek 2 Neisseria-Haemophilus Card and by Partial 16S rRNA Gene Sequencing Analysis

Taxonomy and identification of fastidious Gram negatives are evolving and challenging. We compared identifications achieved with the Vitek 2 Neisseria-Haemophilus (NH) card and partial 16S rRNA gene sequence (526 bp stretch) analysis with identifications obtained with extensive phenotypic characterization using 100 fastidious Gram negative bacteria. Seventy-five strains represented 21 of the 26 taxa included in the Vitek 2 NH database and 25 strains represented related species not included in the database. Of the 100 strains, 31 were the type strains of the species. Vitek 2 NH identification results: 48 of 75 database strains were correctly identified, 11 strains gave `low discrimination´, seven strains were unidentified, and nine strains were misidentified. Identification of 25 non-database strains resulted in 14 strains incorrectly identified as belonging to species in the database. Partial 16S rRNA gene sequence analysis results: For 76 strains phenotypic and sequencing identifications were identical, for 23 strains the sequencing identifications were either probable or possible, and for one strain only the genus was confirmed. Thus, the Vitek 2 NH system identifies most of the commonly occurring species included in the database. Some strains of rarely occurring species and strains of non-database species closely related to database species cause problems. Partial 16S rRNA gene sequence analysis performs well, but does not always suffice, additional phenotypical characterization being useful for final identification

Multilocus sequence phylogenetic study of the genus Haemophilus with description of Haemophilus pittmaniae sp. nov. Int J Syst Evol Microbiol

The phylogeny of human isolates of Haemophilus species was estimated based on partial sequences of four separate housekeeping genes. The clustering of each set of sequences was in accordance with speciation of the strains with few exceptions: of 108 gene fragments examined, only three appeared to have been subject to recombination events across the species barrier. Housekeeping gene similarity supported previous DNA-DNA hybridization data for the genus rather than the phylogeny inferred from 16S rRNA gene sequence comparison. The similarity of sequences of Haemophilus parainfluenzae with those of Haemophilus influenzae suggested preservation of the former species in the genus Haemophilus. Three strains representing a novel taxon were unique with respect to the four investigated gene loci. 16S rRNA gene sequence analysis suggested that this taxon belonged to the Parainfluenzae cluster. DNA-DNA hybridization data supported this generic placement. Nine strains of the novel taxon were available for analysis. They were distinct from representatives of all current species of the genus Haemophilus by conventional phenotypic characterization. Genotypic and phenotypic data show that the strains merit recognition as a novel species of Haemophilus. The name Haemophilus pittmaniae sp. nov. is proposed, with HK 85 T (=CCUG 48703 T =NCTC 13334 T ) as the type strain

Cerebrospinal Fluid Levels of Interleukin-8 in Delirium, Dementia, and Cognitively Healthy Patients

Background: Delirium is a common and serious complication in geriatric patients. The pathophysiology of delirium is not known. Objective: The objective of the current study was to test the hypothesis that cerebrospinal fluid (CSF) levels of inflammatory markers at the time of spinal anesthesia for hip surgery are associated with delirium. Methods: In total 133 hip fracture patients and 125 cognitively healthy controls undergoing elective surgery, together with 73 Alzheimer’s disease (AD) dementia patients, were recruited at Oslo University Hospital and Diakonhjemmet Hospital, Oslo, Norway. Delirium was evaluated daily in hip fracture patients by the Confusion Assessment Method (CAM). Depression was evaluated by Cornell Scale for Depression in Dementia (CSDD). Tumor necrosis factor alpha (TNF-α), interleukin-1beta (IL-1β), and interleukin-8 (IL-8) levels were measured in CSF using a Mesoscale Discovery (MSD) immunoassay. Results: Hip fracture patients had significantly higher IL-8 levels (p < 0.001) compared to cognitively healthy controls or patients with stable AD dementia. Furthermore, preoperative IL-8 levels were significantly higher (p = 0.013) in hip fracture patients who developed delirium (incident delirium) after surgery as compared to patients with no delirium. However, subgroup analyses showed that IL-8 levels were only significantly higher in delirium patients without dementia (p = 0.006). In contrast, depression subgroup analysis showed that IL-8 concentration was significantly higher (p = 0.002) in delirium patients with depression. Both TNF-α and IL-1β were undetected in most patients. Conclusions: Our study suggests that IL-8 levels are associated with delirium onset and that underlying depression or dementia influences IL-8 levels