Re: Q-koorts nieuws - 2013
Q-koorts kan zeer hardnekkig zijn
Q-koorts patienten met een hartklepontsteking die genezen zijn verklaard, kunnen toch nog de bacterie bij zich dragen.
Onderzoekers gebruikten een testmethode die gevoeliger was de gebruikelijke methode.
Bij een aantal genezen verklaarde patienten vonden ze DNA van de Coxiella Burnetii, ofwel de Q-koorts bacterie.
Bij 1 patient zelfs 16 jaar na genezen te zijn verklaard.
De onderzoekers adviseren om de testprotocollen aan te passen.
Q-koorts kan zeer hardnekkig zijn
Q-koorts patienten met een hartklepontsteking die genezen zijn verklaard, kunnen toch nog de bacterie bij zich dragen.
Onderzoekers gebruikten een testmethode die gevoeliger was de gebruikelijke methode.
Bij een aantal genezen verklaarde patienten vonden ze DNA van de Coxiella Burnetii, ofwel de Q-koorts bacterie.
Bij 1 patient zelfs 16 jaar na genezen te zijn verklaard.
De onderzoekers adviseren om de testprotocollen aan te passen.
J. Clin. Microbiol. September 2013 vol. 51 no. 9 3012-3017
Persistence of DNA in a Cured Patient and Positive Culture in Cases with Low Antibody Levels Bring into Question Diagnosis of Q Fever Endocarditis
Sophie Edouarda, Matthieu Milliona, Hubert Lepidia, Jean-Marc Rolaina, Pierre-Edouard Fourniera, Bernard La Scolaa, Dominique Grisolib and Didier Raoulta
+ Author Affiliations
Aix Marseille Universit?, URMITE, UM63, CNRS 7278, IRD 198, Inserm 1095, Marseille, Francea
Service de Chirurgie Cardiaque, H?pital de la Timone, Marseille, Franceb
ABSTRACT
We evaluated the performance of tools for diagnosing Q fever cardiovascular infection. We retrospectively analyzed 162 cardiovascular samples from 125 patients who were tested serologically by immunofluorescence, quantitative PCR (qPCR), 16S rRNA gene amplification, culture, and immunohistochemistry, and we assessed the viability of Coxiella burnetii by measuring the transcription of the 16S rRNA gene. The qPCR technique was significantly more sensitive than 16S rRNA gene amplification (P < 0.0001), cell culture (P = 0.0002), and immunohistochemistry (P < 0.0001). The sensitivity of these techniques was reduced when applied to patients who had been previously treated. The severity of infection appears to be correlated with phase I IgG levels.
We report for the first time 4 cases of endocarditis with positive qPCR and/or culture assay result from patients with a low phase I IgG (IgG I) titer (<800), and we have identified the longest (16 years) persistence of DNA described in a heart valve from a patient cured after being previously treated for endocarditis. The active transcription of the 16S rRNA gene was found in 19/59 tested samples, with a positive predictive value of 100% for a positive culture.
In conclusion, the diagnosis of Q fever cardiovascular infection should not be excluded in patients with low titers of phase I IgG when they present with valvulopathy. We recommend testing cardiovascular samples using 3 or 4 different biopsy sections by qPCR evaluation for patients with IgG I titers of ≥200.
JCM
Persistence of DNA in a Cured Patient and Positive Culture in Cases with Low Antibody Levels Bring into Question Diagnosis of Q Fever Endocarditis
Sophie Edouarda, Matthieu Milliona, Hubert Lepidia, Jean-Marc Rolaina, Pierre-Edouard Fourniera, Bernard La Scolaa, Dominique Grisolib and Didier Raoulta
+ Author Affiliations
Aix Marseille Universit?, URMITE, UM63, CNRS 7278, IRD 198, Inserm 1095, Marseille, Francea
Service de Chirurgie Cardiaque, H?pital de la Timone, Marseille, Franceb
ABSTRACT
We evaluated the performance of tools for diagnosing Q fever cardiovascular infection. We retrospectively analyzed 162 cardiovascular samples from 125 patients who were tested serologically by immunofluorescence, quantitative PCR (qPCR), 16S rRNA gene amplification, culture, and immunohistochemistry, and we assessed the viability of Coxiella burnetii by measuring the transcription of the 16S rRNA gene. The qPCR technique was significantly more sensitive than 16S rRNA gene amplification (P < 0.0001), cell culture (P = 0.0002), and immunohistochemistry (P < 0.0001). The sensitivity of these techniques was reduced when applied to patients who had been previously treated. The severity of infection appears to be correlated with phase I IgG levels.
We report for the first time 4 cases of endocarditis with positive qPCR and/or culture assay result from patients with a low phase I IgG (IgG I) titer (<800), and we have identified the longest (16 years) persistence of DNA described in a heart valve from a patient cured after being previously treated for endocarditis. The active transcription of the 16S rRNA gene was found in 19/59 tested samples, with a positive predictive value of 100% for a positive culture.
In conclusion, the diagnosis of Q fever cardiovascular infection should not be excluded in patients with low titers of phase I IgG when they present with valvulopathy. We recommend testing cardiovascular samples using 3 or 4 different biopsy sections by qPCR evaluation for patients with IgG I titers of ≥200.
JCM
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