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Haemophilus parainfluenzae endocarditis: application of a molecular approach for identification of pathogenic
K A Hamed1, P R Dormitzer, C K Su
1Department of Medicine, Stanford University School of Medicine, California.
Abstract:
Haemophilus parainfluenzae is both a human oropharyngeal commensal bacterium and a cause of serious invasive disease. The fastidious growth characteristics of this organism and the poor specificity of traditional methods for species identification are likely to have led to inaccuracies in the diagnosis of infections caused by H. parainfluenzae and related organisms. We report a case of H. parainfluenzae endocarditis in which confusion related to microbial identification was resolved by the analysis of 16S ribosomal RNA sequences. Rapid identification was facilitated by amplification of 16S ribosomal DNA directly from cultured cells with use of the polymerase chain reaction and by direct DNA sequence determination of the amplified product. This procedure is potentially useful for the identification of fastidious bacterial pathogens by reference laboratories.
Insights
Haemophilus parainfluenzae can cause severe infections, but identifying it is difficult. 16S ribosomal RNA sequencing offers a rapid and accurate method for identifying this fastidious bacterium.
Area of Science:
- Microbiology
- Molecular Biology
- Infectious Diseases
Background:
- Haemophilus parainfluenzae is a common human oropharyngeal commensal.
- This bacterium can also cause serious invasive diseases, complicating diagnosis.
- Traditional identification methods lack specificity, leading to diagnostic inaccuracies.
Observation:
- A case of H. parainfluenzae endocarditis presented diagnostic challenges.
- Confusion arose due to difficulties in microbial identification.
- 16S ribosomal RNA (rRNA) sequence analysis resolved the identification issues.
Findings:
- Polymerase chain reaction (PCR) amplified 16S ribosomal DNA directly from cultured cells.
- Direct DNA sequencing of the amplified product enabled rapid identification.
- This molecular approach accurately identified H. parainfluenzae in the case.
Implications:
- Rapid molecular identification is crucial for diagnosing fastidious bacterial pathogens.
- 16S rRNA sequencing provides a reliable method for identifying H. parainfluenzae.
- This technique can improve the diagnosis of invasive bacterial infections in clinical settings.