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In Situ Detection of Bacteria within Paraffin-embedded Tissues Using a Digoxin-labeled DNA Probe Targeting 16S rRNA
Published on: May 21, 2015
Detection and quantification of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Streptococcus
María José Marin1, Nagore Ambrosio1, Leire Virto1
1Oral Research Laboratory, Faculty of Odontology, University Complutense, Madrid, Spain.
Background:
Culture-based methods (culture broth bottles or lysis methods) have been the standard for detecting bacteremia. More recently, quantitative polymerase chain reaction (qPCR) was proposed as a more sensitive and specific test although none of them has been validated for the identification of periodontal pathogens (fastidious growing bacteria) in blood samples.
Objective:
To compare the ability to detect and quantify Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Streptococcus oralis (alone or in combination) in blood samples with three culture techniques [direct anaerobic culturing (DAC), haemo-culture (BACTEC), and lysis-centrifugation (LC)] and a non-culture dependent approach (qPCR) in an in vitro study.
Material And Methods:
Blood samples from 12 periodontally healthy volunteers were contaminated with three concentrations [104,102 and 101 colony forming units (CFU)/mL] of A. actinomycetemcomitans, P. gingivalis and S. oralis, alone or in combination. Samples were analysed by DAC, BACTEC, LC and qPCR. Sensitivity, specificity, predictive values, kappa index and Lińs correlation coefficients were calculated.
Results:
DAC, LC and qPCR were able to detect the three target species at all concentrations. An excellent concordance (correlation coefficient r: 0.92-1) was observed between DAC and the reference standard (sensitivity raging 93.33-100% and specificity 88.89-100%) values. BACTEC was not able to identify P. gingivalis in any of the performed experiments. qPCR provided false negative results for S.oralis.
Conclusions:
DAC showed the best results for the proper identification and quantification of A. actinomycetemcomitans, P. gingivalis and S. oralis, alone or in combination, in blood samples.
