Sensitivity evaluation of the Gen-Probe AMP-CT assay by pooling urine samples for the screening of Chlamydia trachomatis urogenital infection.

The sensitivity of two urine pool sizes versus individual testing, to detect Chlamydia trachomatis urogenital infection, was evaluated using the Gen-Probe AMP-CT assay. Thirty-three (33) known polymerase chain reaction (PCR) positive urine specimens were combined with 231 fresh first-catch urine (FCU) samples in 33 groups of four and 33 groups of eight, to make up 4X and 8X pooled samples, respectively. Gen-Probe AMP-CT assay was performed on pools as well as on individual samples at the same time. For the discrepant cases, the known positive samples were diluted 1:4 and 1:8 using the manufacturer's dilution buffer and were retested. Additional positive specimens found among fresh FCU samples were also tested by the Amplicor-PCR assay to confirm their positivity. The sensitivities of 8X pooling, 4X pooling and individual testing were 86.5%, 94.3% and 91.9%, respectively. The Gen-Probe AMP-CT assay applied to a 4X urine pooling model was highly sensitive and may be useful for a population based screening programme.

Neisseria gonorrhoeae and Chlamydia trachomatis infections in patients attending STD and family planning clinics in Bissau, Guinea-Bissau.

Accurate clinical and laboratory data about sexually transmitted diseases (STD) prevalence in Guinea-Bissau are not available. These data are important, since HIV2 is prevalent in this country, rates of HIV1 are increasing and STDs facilitate HIV transmission. Since DNA amplification methods have demonstrated to accurately diagnose chlamydial infections and gonorrhoea, the Amplicor CT/NG PCR Assay with Internal Control of Amplification (Roche Diagnostic System, Branchburg, NJ, USA) was used to estimate the prevalence of Neisseria gonorrhoeae and Chlamydia trachomatis genital infections in STDs and Family Planning Clinic attenders in Bissau, from March to July 1997. Two hundred and two cervical swabs and 31 urethral swabs were examined. Two women were excluded from this study because their cervical swabs contained inhibitory substances. N. gonorrhoeae was identified in 34/200 (17%) women and in 12/31 (38.7%) men. C. trachomatis was detected in 8/200 (4%) women there were no positive C. trachomatis results among the 31 men with urethritis. One woman presented a mixed infection with both organisms. The prevalence difference between men and women was not statistically significant (P=0.6) for C. trachomatis infection, but it was significant for N. gonorrhoeae infection (P=0.01). The prevalence rates of these infections found in this study, support the need for an urgent strategy to control STD in the region.

High-level tetracycline resistant Neisseria gonorrhoeae isolated in Portugal.

The first high-level tetracycline resistance (MIC > or = 16 mg/l) isolates of Neisseria gonorrhoeae (TRNG) were reported in 1990 from patients attending a Sexual Transmitted Disease (STD) Center in Lisbon. The TRNG prevalence was 4% in 1991, 5.3% in 1992 and 10,8% in 1994, exploding to 52.2% in 1995. The tet M determinant was evaluated by PCR. The digests of PCRP using HpaII produced the restriction pattern 2 for all the strains, except one (pattern 3). 78.3% of the TRNG strains were beta-lactamase producers and the 4.5 MDa penicillinase plasmid was the dominant (83%), 90% and 93.3% of the TRNG strains belonged to the auxotype NR and to the serogroup IA, respectively. The IA-8/NR class represented 58.3% of the TRNG isolates, suggesting a clonal spreading.

Genotyping of Portuguese Chlamydia trachomatis urogenital isolates.

OBJECTIVE: To determine the prevalence of the different Chlamydia trachomatis genotypes in Portuguese patients. METHODS: Urogenital isolates (n = 240) derived from attenders of various clinics in the Lisbon area were differentiated into genovars by genotyping with restriction fragment length polymorphism (RFLP) analysis of the PCR amplified omp1 gene. RESULTS: Genotype E was the most common for both men (47.9%) and women (43.8%). Genotypes D and F were the second most prevalent for men (11.3%) and genotype H was the second most prevalent for women (19.5%). Genotypes F, G, D, in women and H, G, I, in men, were found in a lower percentage of cases. Genotypes B, Ba, J, K, L1 and L2 were very rarely detected. CONCLUSIONS: With one exception, the overall distribution of Chlamydia trachomatis genotypes in our study is similar to what has been observed in other western countries. The only exception is the unusual prevalence of genotype H among women. The clinical manifestations associated with this and other genotypes were similar.

[Genotype of C. trachomatis strains isolated in a region of Guinea-Bissau: Farim]. / Génotypage de souches de C. trachomatis isolées dans une région de Guinée-Bissau: farim.

In order to diagnose the trachoma we observed the eyes of 506 students aged between 6 and 14 years. 14,03% of these children presented follicular or intense trachomatous inflammation of the eye. The use of molecular biology methods (PCR + RFLP) over the conjonctival samples we had collected, led us to the identification of 21 C. trachomatis strains: 11 of the A genotype and 10 of the B genotype.

Comparison of the Amplicor Chlamydia trachomatis test and cell culture for the detection of urogenital chlamydial infections.

OBJECTIVE: To compare the polymerase chain reaction (PCR) Amplicor Chlamydia trachomatis test with the cell culture method, in diagnosing urogenital chlamydial infections. SUBJECTS: 439 patients (327 women and 112 men) attending one STD clinic and Family Planning and Gynaecological Clinics in Lisbon, Portugal, between November 1993 and March 1994. METHODS: In women, two endocervical swab samples were collected: one for PCR Amplicor and one for standard culture technique. Men were asked to submit 20 ml of urine (first pass urine) for PCR Amplicor and one urethral specimen was taken for culture. The order of collection of the specimens was rotated every 50 patients. Discrepant results were further analysed by a second PCR with primers directed against the C trachomatis major outer membrane protein (MOMP) and by direct fluorescent antibody (DFA). RESULTS: After analysis of discrepancies, the adjusted sensitivity and specificity of PCR on endocervical specimens were 92.9% and 100% and the positive and negative predictive values were 100% and 99.7% respectively; on the urine samples these values were 100%, 99.1%, 100% and 99.1%, respectively. CONCLUSION: These results indicate that the PCR Amplicor test is a rapid sensitive and specific assay for the detection of C trachomatis in urogenital infections and provides a non-invasive technique for screening chlamydia infection in men.