GENOTYPIC CHARACTERIZATION OF 7 STRAINS OF MYCOPLASMA-FERMENTANS ISOLATED FROM SYNOVIAL-FLUIDS OF PATIENTS WITH ARTHRITIS

We performed a genotypic characterization of seven strains of Mycoplas ma fermentans which have been isolated from the synovial fluid of pati ents with rheumatoid arthritis (n = 2), spondyloarthropathy (n = 1), a nd unclassified arthritis (n = 4). We compared them to three reference strains (strains PG18 and K7 and incognitus strain) and to a clinical isolate from the urethra of a patient with nongonococcal urethritis. The characterization methods included electrophoresis of native DNA ar bitrarily primed PCR and restriction fragment length polymorphism anal ysis following conventional and pulsed-field gel electrophoresis. Sout hern blot analysis with a probe internal to an insertion sequence was performed with the restriction products produced by the last two techn iques. No extrachromosomal DNA sequences were detected. The M. ferment ans strains identified by these methods did not present a unique profi le, but they could be separated into two main categories: four articul ar isolates were genetically related to PG18 and the three other isola tes, the urethral isolate, and the incognitus strain were related to K 7. We also looked for the presence of the bacteriophage MAV1 (associat ed with the arthritogenic property of Mycoplasma arthritidis in rodent s) in the M. fermentans strains. MAV1 DNA was not detected in either t he clinical isolates or the reference strains of M. fermentans.