Reliability of detecting rRNA sequences of Chlamydia trachomatis with fluorescence in situ hybridization without amplification.
OBJECTIVE
To use fluorescence in situ hybridization (FISH) using ribosomal RNA (rRNA) oligonucleotide probes as the target nucleic acid for the detection of Chlamydia trachomatis.


METHODS
Suitable sequences selected from the rRNA sequence of C trachomatis were labeled with a fluorescent dye and used in FISH for detecting chlamydial inclusion bodies and/ or elementary bodies in paraformaldehyde-fixed urogenital swab samples. The sensitivity and specificity of the FISH assay were compared with those of the polymerase chain reaction (PCR) using plasmid primers. Positive known C trachomatis-infected McCoy cells were used as positive controls. Urogenital swab specimens that were C trachomatis negative on culture and PCR were used as negative controls.


RESULTS
Among the 128 samples included in the study, FISH was positive in 28 (21.8%) and PCR in 33 (25.7%). A significant correlation was found between the 2 detection methods. Results of PCR and FISH were consistent in 115 of the 128 samples (R = 0.89). Thirteen samples showed discordant results. Of these, 9 FISH negative samples were PCR positive and 4 FISH positive samples were PCR negative.


CONCLUSIONS
FISH was a highly specific and fairly sensitive technique for detecting C trachomatis. Signal amplification techniques and use of different fluorophores may further increase the sensitivity of this technique.
Kapur
Sujala
S
Institute of Pathology, Indian Council of Medical Research, Safdarjung Hospital Campus, New Delhi, India.
Abmed
Margoob
M
Singh
Vineeta
V
Krupp
Guido
G
Salhan
Sudha
S
Mittal
Aruna
A
D015373:Bacterial Typing Techniques; D002584:Cervix Uteri / Q000382:microbiology; D002690:Chlamydia Infections / Q000175:diagnosis / Q000382:microbiology*; D002692:Chlamydia trachomatis / Q000235:genetics / Q000302:isolation & purification*; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D016133:Polymerase Chain Reaction; D015347:RNA Probes; D012329:RNA, Bacterial / Q000235:genetics*; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D015203:Reproducibility of Results; D014521:Urethra / Q000382:microbiology
D015347:RNA Probes; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S