Presence of muramic acid, a bacterial cell wall component, was analyse
d by gas chromatography-mass spectrometry in synovial fluid (SF) of 40
patients with acute inflammatory arthritis. SF muramic acid was obser
ved in 4/14 patients with acute, culture negative inflammatory arthrit
is of unclear origin. Each of these four patients had a history of a r
ecent bacterial disease (pansinuitis, purulent leg ulcer, erysipelas,
unexplained fever with suspicion of cholecystitis and urinary tract in
fection). In the bacterial arthritis, SF muramic acid was detected in
6/12 patients (in 2/6 culture negative cases). In the reactive arthrit
is due to Salmonella or Yersinia, the rate of positivity was 2/14. Nin
eteen samples of traumatic SF effusion were muramic acid negative. The
se findings indicate that several cases of undefined acute inflammator
y arthritis are of bacterial origin.