Performance of a multiplex PCR for the determination of Haemophilus influenzae capsular types in the clinical microbiology laboratory

To improve tools for the surveillance of invasive H. influenzae in the cont ext of the drastic decrease of type b infections following the implementati on of vaccination, a two-step PCR technique was developed to detect the cap sule and type specific regions of H. influenzae. The technique of Falla et al (1994) was modified to amplify in a first step the capsule and type b re gions by multiplex PCR. For non-b capsulated strains, the type a, c, d, e, and f loci were afterward detected simultaneously by an optimized touch-dow n PCR technique. An internal control of extraction and amplification (16S r DNA) was included for both PCR techniques. Overall, this technique was show n to perform as efficiently or better than the slide agglutination without risks of interpretation errors. Of the 138 H. influenzae strains tested, se ven that had given doubtful results by the agglutination technique were une quivocally typed by PCR. (C) 2000 Elsevier Science Inc. All rights reserved .