PubMed · 14368094
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
W L BRADFORD. 1955. Parapertussis.. https://pubmed.ncbi.nlm.nih.gov/14368094/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
BACKGROUND: Haemophilus influenzae is a common pathogen in adults with chronic obstructive pulmonary disease (COPD). In a prospective study, selected isolates of apparent H. influenzae had an altered phenotype. We tested the hypothesis that these variant strains were genetically different from typical H. influenzae. METHODS: A prospective study of adults with COPD was conducted. Strains of apparent H. influenzae obtained from a range of clinical sources were evaluated by ribosomal DNA sequence analysis, multilocus sequence analysis, DNA-DNA hybridization, and sequencing of the conserved P6 gene. RESULTS: Variant strains were determined to be Haemophilus haemolyticus by means of 4 independent methods. Analysis of 490 apparent H. influenzae strains, identified by standard methods, revealed that 39.5% of sputum isolates and 27.3% of nasopharyngeal isolates were H. haemolyticus. Isolates obtained from normally sterile sites were all H. influenzae. In a prospective study, acquisitions of new strains of H. haemolyticus were not associated with exacerbations of COPD, whereas 45% of acquisitions of new strains of H. influenzae were associated with exacerbations. CONCLUSIONS: Standard methods do not reliably distinguish H. haemolyticus from H. influenzae. H. haemolyticus is a respiratory tract commensal. The recognition that some strains of apparent H. influenzae are H. haemolyticus substantially strengthens the association of true H. influenzae with clinical infection.
The structure of the lipooligosaccharide (LOS) from the commensal Haemophilus somnus strain 1P was elucidated. The structure of the O-deacylated LOS was established by monosaccharide analysis, NMR spectroscopy and mass spectrometry. The following structure for the O-deacylated LOS was determined on the basis of the combined data from these experiments. [chemical structure: see text] In the structure Kdo is 3-deoxy-D-manno-octulosonic acid, Hep is L-glycero-D-manno-heptose and lipid A-OH refers to O-deacylated Lipid A. The elucidation of this structure has increased our understanding of the relationship between the variability in LOS structure and the pathogenic potential of this organism. Specifically, the inability of this commensal strain to sialylate its LOS suggests that LOS sialylation could be a crucial virulence factor for H. somnus.
An indirect hemagglutination test (IHA) and a coagglutination test (CA) were evaluated using saline, boiled, and autoclaved extracts for serotyping Haemophilus parasuis. CA showed several cross-reactions, whereas IHA gave rise to specific reactions, with minor exceptions. IHA was further compared with the immunodiffusion test (the "gold standard") for the serotyping of 67 field isolates. As a conclusion, IHA is recommended as a useful method for sensitive and specific serotyping of H. parasuis.