Typing of Chlamydia trachomatis strains from urine samples by amplification and sequencing the major outer membrane protein gene (omp1).

OBJECTIVES: To develop a novel protocol for the extraction, amplification, and sequencing of Chlamydia trachomatis MOMP gene (omp1) from urine, a non-invasive source, and apply it to an epidemiological study on the distribution of C trachomatis strains in a population of pregnant women in Thailand. METHODS: The C trachomatis DNA was extracted from culture stocks and urine using a slightly modified commercially available kit, the High Pure PCR Template Preparation Kit (Roche Molecular Biochemicals, IN, USA). The PCR and sequencing primers used for the amplification and sequencing of the omp1 were designed based on the nucleotide sequence of multiple C trachomatis strains found in GenBank. The protocol for the extraction, amplification, and sequencing was tested on laboratory culture stocks of reference strains of all C trachomatis serovars and on urine samples collected in a cross sectional study designed to assess the prevalence of C trachomatis infections in the cities of Bangkok and Chiang Rai, Thailand. RESULTS: The omp1 gene was successfully amplified and sequenced from 18 laboratory C trachomatis reference strains and from 45 C trachomatis positive urine clinical samples collected from asymptomatic pregnant women. Among clinical samples, we found nine different C trachomatis genotypes: F (11, 25%), D (10, 22.6%), H (5, 11.7%), K (5, 11.7%), E (4, 9.3%), Ia (3, 7%), B (3, 7%), Ja (2, 4.5%), and G (1, 2.3%). One specimen generated an omp1 DNA sequence pattern indicating the presence of a mixed infection with at least two different serovars. CONCLUSIONS: Urine is a convenient and reliable source for genotyping C trachomatis strains. A clear advantage of urine over traditional samples, such as cervical swabs, is that urine is a non-invasive source which makes collection easier and thus facilitates the enrolment of patients in clinical and epidemiological studies. In addition to typing, urine is increasingly used for diagnosis of C trachomatis infection by several commercially available nucleic acid amplification assays which represents a distinct advantage for collecting, transport, storage, and laboratory handling of samples.

HIV-1 seroprevalence, risk factors, and preventive behaviors among women in northern Thailand.

To study HIV-1 seroprevalence, risk factors, and preventive behaviors among reproductive-age women in northern Thailand, 804 consenting women who were identified postpartum or who were visiting family planning clinics were interviewed and tested during 1998 to 1999. Almost all women were currently married and had been pregnant more than once. Their median age was 27 years. HIV-1 seroprevalence was 3.1% overall and was higher in women aged between 25 and 29 years (5.9%), having had > or =2 lifetime sex partners (6.5%), or whose current marriage had lasted for < or =1 year (7.0%). No woman reported HIV risk factors other than heterosexual sex. Most (76%) HIV-infected women reported no casual sex partners and, therefore, had likely acquired the infection from their husbands. HIV testing and partner communications were common, but only 2% of couples used condoms consistently in the prior 6 months. Nearly half of these women perceived themselves at no or low risk for HIV infection; these women were less likely to have taken preventive actions. To prevent HIV transmission in stable partnerships in this population, additional efforts are needed to increase HIV testing and condom use, to improve women's negotiation skills, and to develop new methods that do not require partner cooperation such as vaginal microbicides or vaccines.

HIV-1 seroprevalence among childbearing women in northern Thailand: monitoring a rapidly evolving epidemic.

OBJECTIVES: To describe trends in prevalence of HIV-1 infection among women giving birth at Chiang Rai Hospital (CRH) and to assess risk factors associated with HIV infection in this population. DESIGN: Analysis of hospital registry data for all deliveries at CRH from 1990 to mid-1997. METHODS: From 1990 to mid-1997, women giving birth at CRH were tested for HIV-1 infection using enzyme immunoassay (EIA); positive sera were confirmed using a different manufacturer's EIA. Demographic and clinical data were abstracted from delivery-ward log books. RESULTS: Data from 40723 deliveries indicated that overall HIV-1 seroprevalence increased sharply, from 1.3% in 1990 to a peak of 6.4% in 1994, and then declined to 4.6% in the first 6 months of 1997. Prevalence was highest, at 7.0%, among young (age < or = 24 years) primigravidas, compared with 2.4% among older (age > or = 25 years) multigravidas. When we controlled for age, prevalence declined 40% from 1994 to 1997 among young primigravidas (95% confidence interval for percentage reduction, 16-57). Amongst older multigravid women, prevalence was consistently lower but increased steadily from 2.7% in 1994 to 3.4% in 1997. CONCLUSIONS: A rapid rise in HIV prevalence in childbearing women was followed by a sharp decline among young primigravidas. In each year, the prevalence was highest among young primigravidas. They may be the best subgroup of pregnant women for monitoring HIV epidemic trends, but they also represent a challenging prevention priority that will require its own targeted interventions.

Rapid assessment of sexually transmitted diseases in a sentinel population in Thailand: prevalence of chlamydial infection, gonorrhoea, and syphilis among pregnant women--1996.

OBJECTIVE: To determine the prevalence of sexually transmitted diseases (STDs) among pregnant women in Thailand, where case reporting suggests a marked decrease in STDs following a campaign promoting condom use during commercial sex. DESIGN: Cross sectional study of women at their first visit to the study hospitals' antenatal clinics in Chiang Rai (n = 500) and Bangkok (n = 521). METHODS: First catch urine specimens were tested for Chlamydia trachomatis and Neisseria gonorrhoeae using the Amplicor CT/NG polymerase chain reaction assay. Syphilis and HIV serological testing were performed in the study hospitals' laboratories. RESULTS: The prevalence of chlamydial infection was 5.7%, gonorrhoea 0.2%, and syphilis 0.5% (all VDRL or RPR titres were < or = 1:4). The prevalence of HIV infection was 7.1% in Chiang Rai and 2.9% in Bangkok. In a multivariate logistic regression analysis, chlamydial infection was associated with younger age and with higher gestational age at first antenatal clinic visit, but was not associated with marital status, gravidity, city of enrollment, or HIV infection status. CONCLUSIONS: There was a low prevalence of gonorrhoea and syphilis among these pregnant women in Thailand. Chlamydial infection was detected at a higher prevalence, especially among younger women and women registering later for antenatal care. Testing of pregnant women using easily collected urine specimens and a sensitive nucleic acid amplification assay is a feasible method of rapidly assessing chlamydial and gonococcal prevalence.