Distribution of Mycoplasma pneumoniae and Mycoplasma salivarium in the synovial fluid of arthritis patients

Abstract

By use of a very sensitive nested PCR method targeting part of the strongly conserved mycoplasmal 16S RNA genes, Mycoplasma pneumoniae was found in the synovial fluid of 19/24 (79%) of rheumatoid arthritis patients, 6/6 (100%) of patients with nonrheumatoid inflammatory arthritis, and 8/10 (80%) of osteoarthritis patients attending the rheumatology clinic for drainage of joint effusions. It was not found in the synovial exudates of 13 people attending the orthopedic clinic with traumatic knee injuries or undergoing surgery for knee replacement. However, M. pneumoniae was detected in 2/4 synovial biopsy specimens from orthopedic patients with traumatic knee injuries. M. pneumoniae was associated with the increased synovial fluids found in arthritic flares but was not found in the synovial fluids of trauma patients. Mycoplasma salivarium occurred sporadically. Mycoplasma fermentans had previously been isolated from patients with inflammatory cellular infiltrates, such as rheumatoid arthritis, but it was not detected for osteoarthritic patients from either clinic. It is possible that these organisms may contribute to chronic inflammation within the joints.

FIG. 1.

Comparison of the part of the 16S rRNA genes for M. pneumoniae and M. salivarium used to identify the organisms in synovial fluid. MS is M. salivarium, edited part of sequence MSRRNAS. MP is M. pneumoniae, part of sequence MPRRNAPN. Positions of the outer and inner primers are marked with dotted lines and arrows, and sequencing primers are underlined. Base 304 is underlined and in bold type as it was identified by the sequencer. It is described as N in sequence MSRRNAS and is identical to the corresponding base in M. pneumoniae.