Real-time PCR for determining capsular serotypes of Haemophilus influenzae.
A two-step real-time PCR assay targeting all six capsulation loci of Haemophilus influenzae (i.e., serotypes a to f) was developed and compared with a previously published qualitative PCR assay by using 131 H. influenzae clinical isolates. There was a 98.5% concordance between the two tests. The sensitivity of detection of capsular type-specific reference strains of H. influenzae a to c (10(1) CFU/PCR) was higher than that for type e (10(3) CFU/PCR) and types d and f (10(4) CFU/PCR), and a broader dynamic range was obtained (5 to 8 log(10) units). No cross-reaction was observed with bacteria commonly isolated from the respiratory tract. We showed that both PCR assays are more reliable than slide agglutination serotyping. The real-time PCR-based assay seems to be an alternative of choice for the epidemiological follow-up of H. influenzae invasive infections.
Maaroufi
Younes
Y
Department of Microbiology and Infectious Diseases, Institut Jules Bordet, Rue Héger-Bordet 1, 1000 Brussels, Belgium.
De Bruyne
Jean-Marc
JM
Heymans
Corine
C
Crokaert
Françoise
F
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016667:Bacterial Capsules / Q000235:genetics*; D002675:Child, Preschool; D006193:Haemophilus influenzae / Q000145:classification* / Q000235:genetics*; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D012703:Serotyping / Q000379:methods*