Ricerca di batteri implicati nella malattia parodontale mediante esame colturale e RT-PCR

Abstract

Objective

Comparison between culture and methodical investigation of commercial real-time polymerase chain reaction (RT-PCR) for the detection of most bacterial species implicated in periodontal disease.

Materials and methods

The study evaluated the microbiological profile of 64 patients with chronic periodontitis. For each patient double samples of subgingival plaque in five sites for more than one dental element were collected using sterile paper points and transferred to a transport medium for the bacterial culture and without a transport medium for RT-PCR.

Results

The bacterial culture versus RT-PCR identified the same percentage of P. intermedia (68.75%), F. nucleatum (87.5%), and T. forsythensis (50%), and a lower percentage of P. gingivalis (56.2% vs 68.75%) and A. actinomycetemcomitans (6.25% vs 31.25%). T. denticola (87.5%) was sought out only by RT-PCR. In particular, P. intermedia (72.7%), P. gingivalis (77.7%), and T. forsythensis (37.5%) showed resistance to amoxicillin and in a lower percentage P. intermedia (40.9%), P. gingivalis (38.8%) and T. forsythensis (37.5%) to metronidazole. Fifty percent of F. nucleatum strains showed resistance to clindamycin and 44.4% of P. gingivalis strains showed resistance to ciprofloxacin.

Conclusions

Our data indicate that RT-PCR was more sensitive and specific than colture examination. Also, it has proven particularly useful in detecting pathogenic species implicated in periodontal disease that cannot be cultivated or are not easily discernible in culture, such as T. denticola. On the other hand, only culture investigation can detect multiple bacterial species simultaneously, highlight the unexpected species and above all allow the evaluation of the antibiotic-resistance. Thanks to these features, this method is still considered the gold standard in the diagnosis and monitoring of periodontal disease.