Identification of selected respiratory pathogens in endodontic infections

To determine whether endodontic infections could harbor common etiologic agents of respiratory infections such as Streptococcus pneumoniae and Chlamydia pneumoniae.

Specimens were aseptically obtained from 40 patients with endodontic infections. For the detection of C. pneumoniae, single-step 16S rRNA-based polymerase chain reaction (PCR) and nested PCR targeting aromatic amino acid hydroxylase were used. For the identification of S. pneumoniae, primers targeting 16S rRNA gene and autolysin (lytA) were used.

Of 21 patient samples tested with the 16S rRNA-based PCR for S. pneumoniae, positive amplification was observed in all except 3 specimens. However, sequencing and phylogenetic analysis revealed that the product belonged to other bacterial phylotypes. The lytA-based PCR for S. pneumoniae and both PCR assays for C. pneumoniae failed to detect these organisms in all of the specimens tested.

Streptococcus pneumoniae and C. pneumoniae were not present in endodontic infections. PCR primers with less stringent specificity will inaccurately identify respiratory pathogens.