Objective: To establish a gap ligase chain reaction (G-LCR) assay for the detection of Chlamydia trachomatis (Ct) in neonates with pneumonia.
Methods: A G-LCR DNA amplification assay that targeted the outer major membrane protein gene (omp1) of Ct was developed to detect Ct. The sensitivity and specificity of the G-LCR test was examined by the use of highly purified elementary bodies (EBs). Nasopharyngeal swabs taken from 328 neonates with pneumonia were analyzed by Gap-LCR and cell culture.
Results: The detection limit of G-LCR was 2 EBs. G-LCR could detect five species of Ct and was not cross-reacted with C psittaci and other bacteria. The prevalence of Ct in 328 neonates with pneumonia, using an expanded gold standard of a positive cell culture or two confirmed positive non-culture tests, was 21% (69/328). After analysis of discrepant results, the sensitivity, specificity, and positive and negative predictive values for the G-LCR were 98.6%, 100%, 100% and 99.6%, respectively; whereas those for culture were 86.9%, 100%, 100% and 96.6%, respectively.
Conclusion: This study demonstrated that the G-LCR was a highly sensitive nonculture technique and good alternative test for the detection of chlamydial infections.