Detection of Chlamydia trachomatis in urine samples by nucleic acid tests: comparison with culture and enzyme immunoassay of genital swab specimens

Schepetiuk, Sonia; Kok, Tuckweng; Martin, Louise; Waddell, Russell; Higgins, G.

doi:10.1128/jcm.35.12.3355-3357.1997

Cited by 37 publications

(13 citation statements)

References 21 publications

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“…While the manuscript was being prepared, two other studies reported similar results for the COBAS AMPLICOR test (14,26). These values are similar to those reported for the nonautomated AMPLICOR C. trachomatis test (2, 6, 25-28, 30, 35) and other amplificationbased C. trachomatis tests (1,6,7,9,14,18,23,25,26,30,33). Virtually identical performance was observed for urine and endocervical swab specimens from women.…”

Section: Discussionsupporting

confidence: 70%

Multicenter Evaluation of the Fully Automated COBAS AMPLICOR PCR Test for Detection of Chlamydia trachomatis in Urogenital Specimens

Vincelette

Schirm²,

Bogard³

et al. 1999

J Clin Microbiol

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The fully automated COBAS AMPLICOR CT/NG test for the detection ofChlamydia trachomatis was evaluated in a multicenter trial. Test performance was evaluated for 2,014 endocervical swab and 1,278 urine specimens obtained from women and for 373 urethral swab and 254 urine specimens obtained from men. Culture served as the reference test. Culture-negative, COBAS AMPLICOR-positive specimens that tested positive in a confirmatory PCR test for an alternative target sequence within the C. trachomatis major outer membrane protein gene were resolved as true positives. The overall prevalence of chlamydia was 4.3% in cervical swabs and 11.0% in urethral swabs from men. When the results for each specimen type were considered separately, the resolved sensitivities were 96.5% (83 of 86) for endocervical swab specimens, 95.1% (39 of 41) for urine specimens from women, 100.0% (41 of 41) for urethral swab specimens from men, and 94.4% (17 of 18) for urine specimens from men; the resolved specificities were 99.4% (1,912 of 1,924) for endocervical swab specimens, 99.8% (1,204 of 1,207) for urine specimens from women, 98.5% (325 of 330) for urethral swab specimens from men, and 100.0% (236 of 236) for urine specimens from men. For the subset of patients from whom both swab and urine specimens were collected, the combined results for both specimen types were used to identify all infected patients. Using these combined reslts as criteria, the resolved sensitivities for the COBAS AMPLICOR test were 82.6% (38 of 46) for endocervical swab specimens, 84.4% (38 of 45) for urine specimens from women, 84.2% (16 of 19) for urethral swab specimens from men, and 89.5% (17 of 19) for urine specimens from men. In comparison, the sensitivity of culture was only 56.5% (26 of 46) for endocervical specimens and 63.2% (12 of 19) for urethral specimens from men. The internal control provided in the COBAS AMPLICOR test revealed that 2.9% of specimens were inhibitory when they were initially tested. Nevertheless, valid results were obtained for 99.1% of specimens because 68.7% of the inhibitory specimens were not inhibitory when a second aliquot of the original sample was tested. Two additional COBAS AMPLICOR-positive specimens were detected by retesting inhibitory specimens. The COBAS AMPLICOR CT/NG test for the detection of C. trachomatis exhibited equally high sensitivities and specificities with both urogenital swab and urine specimens and, thus, is well-suited for use in screening.

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Section: Discussionsupporting

confidence: 70%

Multicenter Evaluation of the Fully Automated COBAS AMPLICOR PCR Test for Detection of Chlamydia trachomatis in Urogenital Specimens

Vincelette

Schirm²,

Bogard³

et al. 1999

J Clin Microbiol

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“…For all samples with discrepant results (no inhibition was observed in these samples, as assessed by the internal control of the Amplicor assay), DNA was isolated from the original urine specimens and positivity for C. trachomatis was determined by an in-house PCR (17). By using serial dilutions of C. trachomatis serovar L2, the in-house test was 10 to 100 times more sensitive than the commercial assays, resulting in a detection limit of 1 inclusion-forming unit for the COBAS Amplicor and the LCx tests (identical sensitivity, as confirmed by others (26,33) and 0.1 to 0.01 inclusion-forming units for the in-house PCR, which is in agreement with sensitivities found previously (17).…”

Section: Resultsmentioning

confidence: 76%

“…Recently, DNA amplification techniques (Amplicor PCR [Roche Diagnostic Systems, Basel, Switzerland] [13,30] and ligase chain reaction [Abbott Laboratories, North Chicago, Ill.] [6,15]) and RNA amplification techniques AMPLIFIED Chlamydia Trachomatis Assay [AMP-CT; Gen-Probe] [5,7] and nucleic acid sequence-based amplification [Organon Teknika] [17,18]) have been successfully introduced for the diagnosis of C. trachomatis infections. They have the advantage of higher sensitivities and specificities compared to those of conventional techniques (3,25,26,29). However, the use of cervical and urethral swabs for screening for C. trachomatis infection in an asymptomatic population will result in low participation rates.…”

mentioning

confidence: 99%

“…Therefore, the reliable detection of C. trachomatis in urine specimens from both men and women by amplification methods (5,10,29) is a major breakthrough. The sensitivities of these assays with urine specimens are higher than those of enzyme immunoassay, direct immunofluorescence assay, and cell culture performed with urethral swabs for men (3,10,26,34). In addition, amplification methods had comparable sensitivities with urine specimens and the corresponding cervical scrapes and urethral swabs from a pop-ulation with sexually transmitted diseases, making the use of urine specimens a valuable tool for the early detection of C. trachomatis infections (23,34).…”

mentioning

confidence: 99%

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Determination of Chlamydia trachomatis Prevalence in an Asymptomatic Screening Population: Performances of the LCx and COBAS Amplicor Tests with Urine Specimens

Morré

Valkengoed²,

Moes³

et al. 1999

J Clin Microbiol

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This study determined the performances of the LCx (Abbott) and COBAS Amplicor (Roche) tests with urine specimens for the detection ofChlamydia trachomatis in an asymptomatic screening population. Randomly selected women and men (age range, 15 to 40 years) registered in 20 general practices in Amsterdam, The Netherlands, were invited to participate in this study. Urine specimens (n = 2,906; 1,138 specimens from men and 1,717 specimens from women) were tested for C. trachomatis by the COBAS Amplicor (Roche) and LCx (Abbott) tests. Samples which were positive by only one assay were subjected to discrepant analyses by a third assay (in-house plasmid PCR). By the LCx assay C. trachomatis DNA was detected in urine specimens from 46 of 1,717 women and 29 of 1,138 men, while the COBAS Amplicor detected C. trachomatis DNA in 52 and 35 specimens, respectively. When comparing the LCx and COBAS Amplicor tests, 32 test results (20 for women and 12 for men) were discrepant. After discrepant analyses the following sensitivities, specificities, and positive predictive values were found for the LCx and COBAS Amplicor tests: 78.6 versus 98.8%, 99.7 versus 99.9%, and 88.0 versus 95.4%, respectively. No prominent differences were found between men and women with regard to the test performances. After discrepant analyses the overall prevalences ofC. trachomatis in women and men were 3.0 and 2.8%, respectively. For both women and men the prevalence in the younger age groups was higher than that in the older age groups. In conclusion, the COBAS Amplicor tests shows better diagnostic characteristics than the LCx assay for the detection of C. trachomatis in urine specimens from an asymptomatic screening population. In this asymptomatic population the overall prevalence of C. trachomatis was 2.9%.

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“…The target nucleic acid sequences are amplified by polymerase chain reaction (PCR) and the products (amplicons) detected in ethidium bromide-stained gels, or by colorimetric enzyme immunoassay. In order to amplify nucleic acids (DNA or RNA), these molecules need to be extracted and separated from other components of microorganisms or cellular materials that could inhibit amplification reactions [1][2]. Traditionally, guanidine isothiocyanate, followed by ethanol precipitation, has been used to obtain RNA from cells and microorganisms [3].…”

mentioning

confidence: 99%

Comparison of four extraction methods to detect hepatitis A virus RNA in serum and stool samples

Paula¹,

Villar²,

Gaspar³

2003

Braz J Infect Dis

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The efficiency of extraction methods for hepatitis A virus (HAV) RNA in clinical samples is of great importance for molecular diagnosis, especially in regions endemic for HAV, such as Brazil. We compared the efficiency of four different extraction techniques in serum and stool samples for the detection of hepatitis A virus by reverse transcription PCR (RT-PCR). We used PCR to analyse serum and stool samples of 12 patients who were referred to the Brazilian Reference Center for Viral Hepatitis (BRCVH) in Rio de Janeiro. The methods tested were Proteinase K, Silica, TRIzol and Guanidine isothiocyanate. Proteinase K extraction was the best method for serum samples; it detected the HAV-RNA in 11 of the 12 samples. The guanidine isothiocyanate method was the most effective for stool samples, detecting HAV-RNAs in 9 of the samples. The TRIzol® method worked best with serum samples, and the silica method was unsatisfactory with both serum and stool samples. The RNA extraction method affected the outcome. The use of appropriate RNA extraction methods is a critical step for successful and valid PCR studies on clinical samples. We recommend that RNA extraction techniques be carefully selected for their efficiency with each type of specimen

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Detection of Chlamydia trachomatis in urine samples by nucleic acid tests: comparison with culture and enzyme immunoassay of genital swab specimens

Cited by 37 publications

References 21 publications

Multicenter Evaluation of the Fully Automated COBAS AMPLICOR PCR Test for Detection of Chlamydia trachomatis in Urogenital Specimens

Multicenter Evaluation of the Fully Automated COBAS AMPLICOR PCR Test for Detection of Chlamydia trachomatis in Urogenital Specimens

Determination of Chlamydia trachomatis Prevalence in an Asymptomatic Screening Population: Performances of the LCx and COBAS Amplicor Tests with Urine Specimens

Comparison of four extraction methods to detect hepatitis A virus RNA in serum and stool samples

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