Article

Diagnosis of Streptococcus pneumoniae and Haemophilus influenzae type b meningitis by identifying DNA from cerebrospinal fluid-impregnated filter paper strips.

Hospital for Children and Adolescents, Helsinki University Central Hospital, Helsinki, Finland. .
The Pediatric Infectious Disease Journal (Impact Factor: 3.57). 02/2010; 29(2):111-4. DOI: 10.1097/INF.0b013e3181b4f041
Source: PubMed

ABSTRACT Bacterial meningitis remains often etiologically unconfirmed, especially in resource-poor settings. We tested the potential of real-time polymerase chain reaction to identify Streptococcus pneumoniae (Pnc) and Haemophilus influenzae type b (Hib) from cerebrospinal fluid impregnated on filter paper strips.
Pnc and Hib genome equivalents were blindly quantified by polymerase chain reaction from 129 liquid cerebrospinal fluid (CSF) samples-the standard-and strips stored at room temperature for months. Genome counts were compared by simple regression.
The strips showed a sensitivity and specificity of 92% and 99% for Pnc, and of 70% and 100% for Hib, respectively. The positive and negative predictive values were 94% and 97% for Pnc, and 100% and 89% for Hib, respectively. For Pnc, the positive and negative likelihood ratio was 92 and 0.08, and the overall accuracy 98%, whereas for Hib they were 70 and 0.30, and 91%, respectively. Genome counting showed good correlation between the filter paper and liquid CSF samples, r(2) being 0.87 for Pnc and 0.68 for Hib (P < 0.0001 for both).
Although not replacing bacterial culture, filter paper strips offer an easy way to collect and store CSF samples for later bacteriology. They can also be transported in standard envelops by regular mail.

0 Bookmarks
 · 
113 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: In recent decades the treatment of childhood acute bone and joint infections has shifted towards shorter antibiotic courses and rapid transition to oral therapy. We prospectively collected 265 culture-positive cases of non-neonatal bone and joint infections in Finnish children during 1983-2005. The duration of antimicrobial treatment and the extent of surgery were defined in the study protocol, but for ethical reasons, the liaison clinician determined the time of discharge using normalization of the serum C-reactive protein (CRP) level as a yardstick. We examined changes during the study in the distribution of causative organisms, severity of disease, and length of hospital stay. Staphylococcus aureus was overwhelmingly the most common causative agent throughout the study, whereas Haemophilus influenzae type b was eliminated soon after the introduction of vaccination. The mean time from initial symptoms to presentation remained the same at 4 days, and no significant change was observed in the severity of disease, CRP, or the rate of sequelae. The mean duration of intravenous antibiotic administration was only 4 days. The average hospital stay shortened significantly from 13 days to 9 days (p = 0.0001). The shortened hospital stay was not due to a change in the anatomical site of these infections, but to simplified treatment. Considerable savings in hospital stay, and thus costs, are feasible in osteoarticular infections of childhood by using CRP in monitoring the disease and shortening intravenous treatment by a swift move to per oral administration.
    Scandinavian Journal of Infectious Diseases 05/2012; 44(9):683-8. · 1.71 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We investigated whether dried cerebrospinal fluid (CSF) conserved on filter paper can be used as a substrate for accurate PCR diagnosis of important causes of bacterial meningitis in the Lao PDR. Using mock CSF, we investigated and optimized filter paper varieties, paper punch sizes, elution volumes and quantities of DNA template to achieve sensitive and reliable detection of bacterial DNA from filter paper specimens. FTA Elute Micro Card™ (Whatman, Maidstone, UK) was the most sensitive, consistent and practical variety of filter paper. Following optimization, the lower limit of detection for Streptococcus pneumoniae from dried mock CSF spots was 14 genomic equivalents (GE)/μL (interquartile range 5.5 GE/μL) or 230 (IQR 65) colony forming units/mL. A prospective clinical evaluation for S. pneumoniae, S. suis and Neisseria meningitidis was performed. Culture and PCR performed on fresh liquid CSF from patients admitted with a clinical diagnosis of meningitis (n = 73) were compared with results derived from dried CSF spots. Four of five fresh PCR-positive CSF samples also tested PCR positive from dried CSF spots, with one patient under the limit of detection. In a retrospective study of S. pneumoniae samples (n = 20), the median (IQR; range) CSF S. pneumoniae bacterial load was 1.1 × 10(4) GE/μL (1.2 × 10(5) ; 1 to 6.1 × 10(6) DNA GE/μL). Utilizing the optimized methodology, we estimate an extrapolated sensitivity of 90%, based on the range of CSF genome counts found in Laos. Dried CSF filter paper spots could potentially help us to better understand the epidemiology of bacterial meningitis in resource-poor settings and guide empirical treatments and vaccination policies.
    Clinical Microbiology and Infection 05/2013; · 4.58 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Tropical infectious diseases diagnosis and surveillance are often hampered by difficulties of sample collection and transportation. Filter paper potentially provides a useful medium to help overcome such problems. We reviewed the literature on the use of filter paper, focusing on the evaluation of nucleic acid and serological assays for diagnosis of infectious diseases using dried blood spots (DBSs) compared with recognized gold standards. We reviewed 296 eligible studies: 101 studies evaluating DBSs and 192 studies on other aspects of filter paper use. We also discuss the use of filter paper with other body fluids and for tropical veterinary medicine. In general, DBSs perform with sensitivities and specificities similar or only slightly inferior to gold standard sample types. However, important problems were revealed with the uncritical use of DBS, inappropriate statistical analysis, and lack of standardized methodology. DBSs have great potential to empower healthcare workers by making laboratory-based diagnostic tests more readily accessible, but additional and more rigorous research is needed.
    The American journal of tropical medicine and hygiene 12/2013; · 2.53 Impact Factor

Full-text

View
0 Downloads
Available from