The value and limitations of the Gram stain examination in the diagnosis of intraamniotic infection

Roberto Romero, Mohamed Emamian, Ruben Quintero, Macor Wan, John C. Hobbins, Moshe Mazor, Stephen Edberg

Research output: Contribution to journalArticlepeer-review

156 Scopus citations

Abstract

Gram stain examination of amniotic fluid is a method used for the rapid diagnosis of intraamniotic infection in patients with preterm premature rupture of membranes and preterm labor. The management of these patients relies heavily on the Gram stain results. Therefore, it is critical that the diagnostic value and limitations, optimal technique, and outcome correlates be precisely established. Most studies have focused on culture results rather than on Gram stain results to describe neonatal and maternal outcome. However, management is based on the Gram stain because culture results are not immediately available. One hundred eighty-seven amniocenteses were performed in 131 patients with preterm premature rupture of the membranes (n = 90) and preterm labor (n = 41). Spun and unspun Gram stains were performed. Centrifugation of the sample did not improve the sensitivity of the technique significantly. The agreement between the two methods was substantial (kappa index 0.89, p < 0.001). The sensitivity of the Gram stain was 44.8% and the specificity was 97.6%. The sensitivity of the Gram stain was directly proportional to the number of bacteria present in amniotic fluid. In the presence of >105 colony forming units per milliliter, 80% of the Gram stains were positive. The absence of both bacteria and white blood cells in a smear was associated with a negative culture of amniotic fluid in 95% of the cases. Clinical chorioamnionitis was associated with a positive Gram stain of amniotic fluid (p < 0.001). There was a trend toward a higher incidence of endometritis in patients with a positive Gram stain compared with those with a negative Gram stain (p = 0.07). There was no neonatal infectious morbidity in patients with a true negative Gram stain. Patients with a false negative Gram stain had a 25% incidence of neonatal infectious complications (proved and suspected sepsis).

Original languageEnglish (US)
Pages (from-to)114-119
Number of pages6
JournalAmerican journal of obstetrics and gynecology
Volume159
Issue number1
DOIs
StatePublished - Jul 1988

Keywords

  • Gram stain
  • intraamniotic infection
  • preterm labor
  • preterm premature rupture of the membranes

ASJC Scopus subject areas

  • Medicine(all)
  • Obstetrics and Gynecology

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