ABSTRACT
The rapid diagnosis of intra-amniotic infection in patients with premature rupture
of the membranes (PROM) and preterm labor is of utmost importance. The Gram's stain
examination of amniotic fluid can only detect half of these infections. The acridine
orange (AO) stain has been claimed to be superior to the Gram's stain in the detection
of bacteria in biologic fluids. Therefore, we undertook the present study to examine
the value of AO in the detection of bacteria in amniotic fluid. One hundred and thirty-eight
patients with a culture-documented prevalence of intra-amniotic infection of 23.2%
were studied. The diagnostic indices of the AO were: sensitivity, 43.8%, specificity,
97.2%, positive predictive value, 82.8%, and negative predictive value, 85.1%; the
diagnostic indices for the Gram's stain were: sensitivity, 46.8%, specificity, 98.1%,
positive predictive value, 88.2%, and negative predictive value, 85.9%. There was
no difference in the diagnostic values of the tests. The agreement between the two
techniques was substantial, as indicated by a kappa index of 0.72 (SE = 0.17, p <
0.001). The AO offered no significant advantage over the Gram's stain examination
of amniotic fluid in the detection of intra-amniotic infection. However, the AO stain
was able to identify mycoplasma infections that escaped detection by the Gram's stain.
Therefore, the AO is presently the only microscopic technique capable of detecting
mycoplasma in amniotic fluid.
