Investigation of Chlamydia pneumonite and Mycoplasma spp. In clinical specimens from patients with arhritis

Objectives: Chlamydia-induced arthritis is the most frequent form of reactive arthritis in Western countries. Recent advances in the standardization of polymerase chain reaction techniques has accounted for considerable progress in identification of Chlamydia. Although C. pneumoniae is often detected by molecular assays, it is rarely investigated with a panel of multiple genes in different human fluids. We mainly focused in the amplification and detection of DNA and or mRNAs fragments from Chlamydia and Mycoplasma genome. Methods: PCR and RT-PCR were used to assess bacterial DNA and mRNA transcripts on 40 specimens from 12 patients with undefined arthritis. Specimens including sinovial fluid, PBMC and serun samples, were analysed by either nested polymerase chain reaction (n-PCR) or touchdown PCR for Mycoplasma and C. pneumoniae with primer sets targeting the 16S-rRNA and urease gene of Mycoplasma Spp and U. urealyticum and the major outer membrane protein (MOMP), the 16S rRNA and the Heat shock Protein 60-70 (Hsp-60-70) of C. pneumoniae. A molecular study to evaluate genetic diversity among isolates of both pathogens and to compare bacterial sequences was done. Results: Five out 12 (41.6%) patients (10/33 specimens) were found n-PCR positive for C. pneumoniae Momp (21.2%) or 16s rRNA (24.4%); two patients (16.6%) did also show HsP-60 gene. One C. pneumoniae negative specimen was found positive for Mycoplasma hominis. Four specimen (including those HsP+) were also positive by rt-PCR. Chart analysis revealed that C. pneumoniae positive specimens were from patients with psoriatic arthropaty, atipic arthritis, rheumathic polymialgy and reactive arthritis. The Mycoplasma hominis positive specimen was from a patient with psoriatic artrhopaty. Previous serological analyses provided no evidence of recent exposure to both pathogens. Conclusion: Molecular biology not only has improved the ability to detect Chlamydia in the joint for diagnostic purposes but also has extended the current understanding of whether the organism triggers or perpetuates disease. In two patients, the detection of MOMP and 16s rRNA C. pneumoniae gene in either blood or sinovial fluid was together with the metabolic active HsP-60 transcripts. This finding together with the genetic background of the patients, may indicate an alternate state used by Chlamydia to escape the immune system of the host and cause worsening of disease.