Chlamydia trachomatis infection during pregnancy associated with preterm delivery: A population-based prospective cohort study

Chlamydia trachomatis infection is the most prevalent bacterial sexually transmitted infection and may influence pregnancy outcome. This study was conducted to assess the effect of chlamydial infection during pregnancy on premature delivery and birthweight. Pregnant women attending a participating midwifery practice or antenatal clinic between February 2003 and January 2005 were eligible for the study. From 4,055 women self-administered questionnaires and urine samples, tested by PCR, were analysed for C. trachomatis infection. Pregnancy outcomes were obtained from midwives and hospital registries. Gestational ages and birthweights were analysed for 3,913 newborns. The C. trachomatis prevalence was 3.9%, but varied by age and socio-economic background. Chlamydial infection was, after adjustment for potential confounders, associated with preterm delivery before 32 weeks (OR 4.35 [95% CI 1.3, 15.2]) and 35 weeks gestation (OR 2.66 [95% CI 1.1, 6.5]), but not with low birthweight. Of all deliveries before 32 weeks and 35 weeks gestation 14.9% [95% CI 4.5, 39.5] and 7.4% [95% CI 2.5, 20.1] was attributable to C. trachomatis infection. Chlamydia trachomatis infection contributes significantly to early premature delivery and should be considered a public health problem, especially in young women and others at increased risk of C. trachomatis infection

Chlamydia trachomatis infection during pregnancy associated with preterm delivery: a population-based prospective cohort study

Chlamydia trachomatis infection is the most prevalent bacterial sexually transmitted infection and may influence pregnancy outcome. This study was conducted to assess the effect of chlamydial infection during pregnancy on premature delivery and birthweight. Pregnant women attending a participating midwifery practice or antenatal clinic between February 2003 and January 2005 were eligible for the study. From 4,055 women self-administered questionnaires and urine samples, tested by PCR, were analysed for C. trachomatis infection. Pregnancy outcomes were obtained from midwives and hospital registries. Gestational ages and birthweights were analysed for 3,913 newborns. The C. trachomatis prevalence was 3.9%, but varied by age and socio-economic background. Chlamydial infection was, after adjustment for potential confounders, associated with preterm delivery before 32 weeks (OR 4.35 [95% CI 1.3, 15.2]) and 35 weeks gestation (OR 2.66 [95% CI 1.1, 6.5]), but not with low birthweight. Of all deliveries before 32 weeks and 35 weeks gestation 14.9% [95% CI 4.5, 39.5] and 7.4% [95% CI 2.5, 20.1] was attributable to C. trachomatis infection. Chlamydia trachomatis infection contributes significantly to early premature delivery and should be considered a public health problem, especially in young women and others at increased risk of C. trachomatis infection

Standardization of SARS-CoV-2 Nucleic Acid Amplification Techniques by Calibration and Quantification to the First WHO International Standard for SARS-CoV-2 RNA

Clinical decision-making regarding isolation of SARS-CoV-2 patients is usually based on semiquantitative cycle-threshold (Ct) values without standardization. However, not all molecular assays produce Ct values, and there is ongoing discussion about whether Ct values can be safely used for decision-making. In this study, we standardized two molecular assays which use different nucleic acid amplification techniques (NAAT): the Hologic Aptima SARS-CoV-2/Flu (TMA) and Roche Cobas 6800 SARS-CoV-2 assays. We calibrated these assays against the first WHO international standard for SARS-CoV-2 RNA by using linear regression of log10 dilution series. These calibration curves were used to calculate viral loads for clinical samples. Clinical performance was assessed retrospectively using samples collected between January 2020 and November 2021, including known positives of the wild-type SARS-CoV-2 virus, the VOCs (alpha, beta, gamma, delta, and omicron) and quality control panels. Linear regression and Bland-Altman analysis showed good correlations for SARS-CoV-2 between Panther TMA and Cobas 6800 when standardized viral loads were used. These standardized quantitative results can benefit clinical decision-making and standardization of infection control guidelines