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


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Hospital for Children and Adolescents, Helsinki University Central Hospital, Helsinki, Finland. heikki.peltola@hus.fi.
Heikki
H
Peltola
Irmeli
I
Roine
Maija
M
Leinonen
Leena
L
Kuisma
Antonio González
AG
Mata
Antonio
A
Arbo
José
J
Goyo
Annika
A
Saukkoriipi
D000293:Adolescent; D001431:Bacteriological Techniques / Q000379:methods; D002555:Cerebrospinal Fluid / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification*; D003890:Desiccation; D019741:Haemophilus influenzae type b / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007223:Infant; D008583:Meningitis, Haemophilus / Q000175:diagnosis* / Q000382:microbiology; D008586:Meningitis, Pneumococcal / Q000175:diagnosis* / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000379:methods; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods*; D013296:Streptococcus pneumoniae / Q000235:genetics / Q000302:isolation & purification*
D004269:DNA, Bacterial