title: Detection and quantification of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Streptococcus oralis in blood samples with different microbiological identification methods: An in vitro study.
abstract: 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.
  
  
  METHODS
  Blood samples from 12 periodontally healthy volunteers were contaminated with three concentrations [104,102and 101colony 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.
authors.affiliation: Oral Research Laboratory, Faculty of Odontology, University Complutense, Madrid, Spain.
authors.forename: María José
authors.initials: MJ
authors.lastname: Marin
authors.affiliation: Oral Research Laboratory, Faculty of Odontology, University Complutense, Madrid, Spain.
authors.forename: Nagore
authors.initials: N
authors.lastname: Ambrosio
authors.affiliation: Oral Research Laboratory, Faculty of Odontology, University Complutense, Madrid, Spain.
authors.forename: Leire
authors.initials: L
authors.lastname: Virto
authors.affiliation: Department of Special Needs, School of Medicine and Dentistry, Santiago de Compostela University, Santiago de Compostela, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: Diz
authors.affiliation: Research Laboratory, Department of Clinical Microbiology, Xeral-Cíes Hospital, Vigo, Spain.
authors.forename: Maximiliano
authors.initials: M
authors.lastname: Álvarez
authors.affiliation: Etiology and Therapy of Periodontal Diseases (ETEP) Research Group, University Complutense, Madrid, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Herrera
authors.affiliation: Etiology and Therapy of Periodontal Diseases (ETEP) Research Group, University Complutense, Madrid, Spain.
authors.forename: Mariano
authors.initials: M
authors.lastname: Sanz
authors.affiliation: Oral Research Laboratory, Faculty of Odontology, University Complutense, Madrid, Spain; Etiology and Therapy of Periodontal Diseases (ETEP) Research Group, University Complutense, Madrid, Spain. Electronic address: elfiguer@ucm.es.
authors.forename: Elena
authors.initials: E
authors.lastname: Figuero
mesh_terms: D016976:Aggregatibacter actinomycetemcomitans / Q000235:genetics / Q000302:isolation & purification*; D016470:Bacteremia / Q000175:diagnosis / Q000382:microbiology; D058491:Bacterial Load; D001431:Bacteriological Techniques / Q000295:instrumentation / Q000379:methods*; D001769:Blood / Q000382:microbiology*; D015169:Colony Count, Microbial; D046508:Culture Techniques / Q000379:methods; D004269:DNA, Bacterial / Q000032:analysis / Q000302:isolation & purification; D005798:Genes, Bacterial / Q000235:genetics; D006801:Humans; D010510:Periodontal Diseases / Q000175:diagnosis / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000379:methods; D016966:Porphyromonas gingivalis / Q000235:genetics / Q000302:isolation & purification*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019533:Streptococcus oralis / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D004269:DNA, Bacterial
keywords: Aggregatibacter actinomycetemitans; Bacteremia; Culture; Periodontal; Porphyromonas gingivalis; Quantitative PCR