Kk. Asbill et al., Detection of Neisseria gonorrhoeae and Chlamydia trachomatis colonization of the gravid cervix, AM J OBST G, 183(2), 2000, pp. 340-344
OBJECTIVES: The aims of the study were to determine whether a Gram stain of
cervical mucus can accurately rule out infection with Neisseria gonorrhoea
e or Chlamydia trachomatis and to compare a diagnostic test that is based o
n the polymerase chain reaction with a deoxyribonucleic acid probe in the d
etection of these organisms.
STUDY DESIGN: Gravid patients were screened for N gonorrhoeae and C trachom
atis with a deoxyribonucleic acid probe, Gram stain, and analysis with the
polymerase chain reaction. A normal, noninfected sample was defined by <10
polymorphonuclear leukocytes per high-power field on the Gram stain. Standa
rd statistical methods were used to compare results of the Gram stain and t
he deoxyribonucleic acid probe, as well as to compare results of deoxyribon
ucleic acid probe hybridization and polymerase chain reaction analysis. A P
value of < .05 was considered statistically significant.
RESULTS: Patient enrollment totaled 519. The prevalence of infection as det
ermined by deoxyribonucleic acid probe hybridization was 1.4% for N gonorrh
oeae (7/518) and 6.8% for C trachomatis (35/518). The cervical Gram stain p
redicted the absence of infection in 17% (90/518) of patients, with a negat
ive predictive value of 99% for N gonorrhoeae and 97% for C trachomatis. Af
rican American race, age <20 years, and unmarried status were all predictor
s of the presence of C trachomatis or N gonorrhoeae cervicitis. For the pat
ients who lacked these risk factors (n = 74), the Gram stain had 100% negat
ive predictive value. Analysis with the polymerase chain reaction detected
8 additional patients with C trachomatis and 105 additional patients with N
gonorrhoeae, in comparison with deoxyribonucleic acid probe hybridization.
CONCLUSION: The cervical Gram stain can accurately predict the absence of N
gonorrhoeae and C trachomatis in gravid women. Analysis with the polymeras
e chain reaction indicates that N gonorrhoeae and C trachomatis are signifi
cantly more prevalent in this population than previously reported.