Pneumococcal DNA is not detectable in the blood of healthy carrier children by real-time PCR targeting the lytA gene
| Autor: | Laura Becciolini, Maurizio de Martino, Martina Cortimiglia, Maria Moriondo, Francesca Lippi, Massimo Resti, Clementina Canessa, Federica Ghiori, Chiara Azzari |
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| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Microbiology (medical)
DNA Bacterial Adolescent Diagnostics Typing and Identification Urine Biology Microbiology Polymerase Chain Reaction Sensitivity and Specificity Pneumococcal Infections Cerebrospinal fluid Antigen Interquartile range Humans Child Gene Bacteriological Techniques Infant General Medicine Standard Nasal Mucosa Real-time polymerase chain reaction Carriage Blood Child Preschool Immunology Carrier State Asymptomatic carrier |
| Zdroj: | Journal of Medical Microbiology |
| ISSN: | 1473-5644 0022-2615 |
| Popis: | The diagnosis of invasive pneumococcal disease (IPD) is currently based on culture methods, which lack sensitivity, especially after antibiotic therapy. Molecular methods have improved sensitivity and do not require viable bacteria; however, their use is complicated by reports of low specificity with some assays. The present study investigated the specificity of a real-time PCR targeting lytA for the detection of IPD. A group of 147 healthy children, aged 6 months to 16 years (mean 6.4 years, median 4.9 years, interquartile range 6.4 years), who were in hospital for routine examinations, were tested for pneumococcal carrier status and for the presence of detectable pneumococcal DNA in their blood by real-time PCR targeting the pneumococcal lytA gene. In addition, 35 culture-positive biological samples were analysed. Urine was examined for the presence of pneumococcal DNA and C-polysaccharide antigen. Carriage was detected in 77 of the 147 subjects (52.4 %); however, regardless of carrier status, none of the subjects had a positive result from blood. Analysis of the culture-positive biological samples yielded positive results in 100 % (15/15) of cerebrospinal fluid samples and 95 % (19/20) of blood samples. All urine samples from healthy carriers were negative for DNA, whilst antigenuria was detected in 44/77 carriers (57.1 %). In conclusion, real-time PCR is both sensitive and specific and can be a useful tool in the routine diagnosis of IPD. Its sensitivity, which surpasses that of other methods for this purpose, does not come at the cost of reduced specificity. |
| Databáze: | OpenAIRE |
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