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Analysis of bacterial DNA in synovial tissue of Tunisian patients with reactive and undifferentiated arthritis by broad-range PCR, cloning and sequencing

Mariam Siala1, Benoit Jaulhac2, Radhouane Gdoura1, Jean Sibilia2, Hela Fourati3, Mohamed Younes4, Sofien Baklouti3, Naceur Bargaoui4, Slaheddine Sellami5, Abir Znazen1, Cathy Barthel2, Elody Collin2, Adnane Hammami1* and Abdelghani Sghir67

Author Affiliations

1 Laboratoire de Recherche 'Micro-organismes et Pathologie Humaine', EPS Habib Bourguiba, Rue El Ferdaous, 3029 Sfax, Tunisie

2 Laboratoire de Physiopathologie des Interactions Hôte-bactérie, UPRES-EA 3432, Faculté de Médecine, Université Louis-Pasteur, rue Koeberlé, 67000 Strasbourg, France

3 Service de Rhumatologie Hôpital Hedi Chaker, Avenue Majida Boulila, 3029 Sfax, Tunisie

4 Service de Rhumatologie, EPS Fattouma Bourguiba, Rue 1er Juin, 5019 Monastir, Tunisie

5 Service de Rhumatologie, EPS La Rabta, rue 7051 Centre Urbain Nord, 1082 Tunis, Tunisie

6 CNRS-UMR 8030, CEA-Genoscope, rue Gaston Crémieux, 91000 Évry, France

7 University of Evry Val d'Essonne, Boulevard François Mitterrand, 91025 Évry Cedex, 91000 Évry, France

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Arthritis Research & Therapy 2008, 10:R40  doi:10.1186/ar2398

Published: 14 April 2008



Bacteria and/or their antigens have been implicated in the pathogenesis of reactive arthritis (ReA). Several studies have reported the presence of bacterial antigens and nucleic acids of bacteria other than those specified by diagnostic criteria for ReA in joint specimens from patients with ReA and various arthritides. The present study was conducted to detect any bacterial DNA and identify bacterial species that are present in the synovial tissue of Tunisian patients with reactive arthritis and undifferentiated arthritis (UA) using PCR, cloning and sequencing.


We examined synovial tissue samples from 28 patients: six patients with ReA and nine with UA, and a control group consisting of seven patients with rheumatoid arthritis and six with osteoarthritis (OA). Using broad-range bacterial PCR producing a 1,400-base-pair fragment from the 16S rRNA gene, at least 24 clones were sequenced for each synovial tissue sample. To identify the corresponding bacteria, DNA sequences were compared with sequences from the EMBL (European Molecular Biology Laboratory) database.


Bacterial DNA was detected in 75% of the 28 synovial tissue samples. DNA from 68 various bacterial species were found in ReA and UA samples, whereas DNA from 12 bacteria were detected in control group samples. Most of the bacterial DNAs detected were from skin or intestinal bacteria. DNA from bacteria known to trigger ReA, such as Shigella flexneri and Shigella sonnei, were detected in ReA and UA samples of synovial tissue and not in control samples. DNA from various bacterial species detected in this study have not previously been found in synovial samples.


This study is the first to use broad-range PCR targeting the full 16S rRNA gene for detection of bacterial DNA in synovial tissue. We detected DNA from a wide spectrum of bacterial species, including those known to be involved in ReA and others not previously associated with ReA or related arthritis. The pathogenic significance of some of these intrasynovial bacterial DNAs remains unclear.