Infection of a prosthetic knee joint with Peptostreptococcus magnus.

Abstract

SUMMARY Infection of a prosthetic knee joint with Peptostreptococcus magnus in an immunosuppressed patient with rheumatoid arthritis is described. The organism is a skin commensal, generally thought to be of low pathogenicity; the difficulty in making the diagnosis is emphasised.Key words: rheumatoid arthritis, pyrexia of unknown origin, immunosuppression.Case report A 54 year old man with erosive seropositive rheumatoid arthritis, unresponsive to gold, penicillamine, sulphasalazine and a course of intensive immunosuppression,1 underwent bilateral total knee replacement (TKR) under antibiotic cover, 10 years from onset. A right Stanmore TKR was performed in February 1985; the only complication was a small wound haematoma with sterile serosanguinous discharge, treated with flucloxacillin for 10 days. A kinematic TKR was inserted in the left knee the following June.Two months later, while taking 150 mg azathioprine and 7-5 mg of prednisolone daily, he developed fatigue and rigors. He was pyrexial; lymphadenopathy and splenomegaly, previously noted before intensive immunosuppression, persisted; and an ejection systolic murmur was heard. The knee joints were not painful and there were no clinical signs of septic arthritis. Eight sets of blood cultures were negative. An x ray of the prostheses was unremarkable; a bone scan showed increased activity in relation to the femoral component of the right TKR (Fig. 1), but this was difficult to interpret only nine months postoperatively. Lymph node and liver biopsy were performed: histology of each was

Anaerobic prosthetic joint infection

“…Pain around the site of the prosthesis has been noted in some cases [37,38,45]. Two cases were associated with both underlying rheumatoid arthritis and the use of immunosuppressive therapies [37,38], and two were associated with a recent dental procedure [38,45]. A separate study also involved one case of Peptostreptococcus PJI of the hip following recent periodontal surgery [90].…”

“…The clinical presentations amongst the various cases differ, with some infections being reported as subclinical in nature with no distinct signs of joint infection including warmth or swelling [37,45], while others do present with these signs [38]. Pain around the site of the prosthesis has been noted in some cases [37,38,45]. Two cases were associated with both underlying rheumatoid arthritis and the use of immunosuppressive therapies [37,38], and two were associated with a recent dental procedure [38,45].…”

“…Culture of synovial fluid in anaerobic blood culture bottles, and of tissue samples in liquid (e.g., thioglycolate broth) and, to a lesser extent, on solid (e.g., CDC anaerobic sheep blood agar) anaerobic media, are generally reliable methods for detecting anaerobic bacteria, including Clostridium species [11,13e15,19,32e36], Peptostreptococcus and Finegoldia species [37,38], Actinomyces species [24,39e41] and Bacteroides species [20]. Of note, the diagnosis of P. acnes PJI can be particularly challenging, as periprosthetic tissue cultures may be falsely-negative due to the indolent nature of this organism, although when properly performed, cultures can accurately identify this organism.…”

“…Peptostreptococcus species and F. magna have been reported to cause PJI in a limited number of cases. The clinical presentations amongst the various cases differ, with some infections being reported as subclinical in nature with no distinct signs of joint infection including warmth or swelling [37,45], while others do present with these signs [38]. Pain around the site of the prosthesis has been noted in some cases [37,38,45].…”

“…A separate study also involved one case of Peptostreptococcus PJI of the hip following recent periodontal surgery [90]. Given that these organisms can produce acute inflammation, the presence of elevated inflammatory markers, along with radiographic periprosthetic lucency and histopathology showing acute inflammation and even purulence are often present [37,38,45]. F. magna PJI may occur as a nosocomial infection or infection following a traumatic event [46].…”