Evaluation of Abbott RealTime CT/NG assay for detection of Chlamydia trachomatis and Neisseria gonorrhoeae in cervical swabs from female sex workers in China.

BACKGROUND: To evaluate the performance of the Abbott RealTime CT/NG assay for detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) among female sex workers (FSWs) in China. METHODS: Cervical swabs from 997 participants were blindly detected by the Abbott RealTime CT/NG assay on the automated m2000 molecular platform and Roche Cobas Amplicor CT/NG assay. Discrepant analysis were confirmed by the Qiagen care CT PCR assay. The sample was defined as candidate nvCT-positive if it was CT positive in the Abbott m2000 assay, but CT negative in the other two assays. RESULTS: 25 specimens that were discordant for CT and 26 specimens that were discordant for NG between the two assays were resolved by Qiagen care CT & NG PCR assays. The sensitivity and specificity, respectively, for Abbott m2000 assay were 92.59% and 100% for CT and 95.45% and 99.90% for NG. The positive predictive value (PPV) and negative predictive value (NPV) of Abbott m2000 assay were100% and 98.52% for CT and 95.5% and 99.90% for NG, respectively. No candidate new-variant CT(nvCT)specimens were identified. CONCLUSION: Abbott RealTime CT/NG assay were more specify for CT and NG detection, however, its sensitivity for CT and NG were a little bit lower than Roche Cobas Amplicor CT/NG assay. Abbott RealTime CT/NG assay had higher PPV for NG detection than Roche Cobas Amplicor CT/NG assay; it would be more suitable for screening for population with low-prevalence NG. There is currently no evidence that nvCT is present in FSWs in China.

Difference in distribution of Chlamydia trachomatis genotypes among different provinces: a pilot study from four provinces in China.

The objective of this study was to assess the distribution of Chlamydia trachomatis genovars in male sexually transmitted disease (STD) clinic patients from 1 province in eastern China (Jiangsu) and 3 provinces in southern China (Guangdong, Guangxi, and Hainan). Urine specimens (n = 140) were collected from 46 public STD clinics in the 4 provinces. Specimens that tested positive for C. trachomatis by polymerase chain reaction were genotyped for the infecting C. trachomatis strain by amplifying and sequencing the genovar-specific ompA gene, which encodes the chlamydial major outer-membrane protein. Nine C. trachomatis genovars were identified from 129 specimens; they consisted of the F (25.6%), E (17.1%), J (16.3%), D (15.5%), G (11.6%), K (5.4%), H (3.9%), I (1.6%), and B (0.8%) genovars. Nine genovars were found in specimens from Guangxi province, 6 were found in specimens from each of Guangdong and Hainan provinces, but only 5 were found in specimens from Jiangsu province. Genovar G/Ga was shown to be endemic among male patients in southern China.

Epidemiology of sexually transmitted infections, HIV, and related high-risk behaviors among female sex workers in Guangxi Autonomous Region, China.

This study assessed the epidemiology of sexually transmitted infections (STIs), HIV, and associated risk factors among female sex workers (FSWs) in Guangxi autonomous region, China. A cross-sectional study of 488 FSWs was conducted using a structured questionnaire to collect sociodemographic and behavioral information. Biological specimens from subjects were sampled to detect various STIs and HIV infection. Among FSWs, the prevalence rates of syphilis, Neisseria gonorrhoeae, Chlamydia trachomatis, genital herpes, condyloma acuminate, and HIV were 7.2%, 1.8%, 18.2%, 0.4%, 2.3%, and 0.8%, respectively. The prevalence rates of single, double, and triple infections were 22.3%, 3.9%, and 0.20%, respectively. Multivariate analysis indicated that STIs and HIV infection was independently related to low education level (OR = 7.244; 95% CI = 3.031-17.213; P < 0.001), low knowledge of STIs/HIV (OR = 0.191; 95% CI = 0.108-0.337; P < 0.001), low-grade working place (OR = 1.64; 95%CI = 1.016-2.648; P = 0.046), and no condom use during the last sexual intercourse (OR = 0.199; 95% CI = 0.113-0.350; P < 0.001). The prevalence of STIs is high among FSWs in Guangxi, is accompanied by a 0.8% HIV-positive rate, and may be largely related to high-risk sexual behaviors. Future interventions should be focused on the reduction of risk factors, including promotion of condom use and improvement of knowledge of STIs and HIV among FSWs.

A high-resolution melting analysis for genotyping urogenital Chlamydia trachomatis.

We have developed a high-resolution melting analysis (HRMA) for the genotyping of Chlamydia trachomatis and applied it specifically to the 11 sexually transmitted infection-related genotypes: D through K and L1 through L3. The variable segment 2 (VS2) was selected as the target for HRMA genotype identification. Eleven C. trachomatis genotypes were amplified by a nested real-time polymerase chain reaction (PCR) in the presence of the LCGreen saturating dye and showed no cross-reaction with 10 pathogenic bacteria or commensals from urogenital tract. The detection limit of HRMA method was 100 elementary bodies (EB)/mL. All of the 11 genotypes can be distinguished from each other by following an HRMA workflow. Genotype F, G, H, I, J, K, L2, and L3 could be directly identified from each other, whereas D, E, and L1 could be distinguished from each other by a second analysis with fewer curves or by heteroduplex formation with a known reference strain. In the validation panel of 36 C. trachomatis-positive urogenital samples genotyped by VS1-VS2 sequencing, nested real-time VS2 PCR followed by HRMA was able to discriminate between all samples correctly. This assay requires no fluorescence-labeled probes or separate post-PCR analysis and provides a simple and rapid approach for genotyping the C. trachomatis strains that are the most commonly sexually transmitted.

[Comparative proteome analysis of human papillomavirus-infected cervical specimens and the difference between the high- and low-risk genotypes of human papillomavirus].

OBJECTIVE: To perform an comparative proteome analysis of human papillomavirus-infected cervical specimens and to investigate different expressions between high- and low-risk genotypes. METHODS: The cervical specimens were divided into two groups (cervical intraepithelial neoplasia group and condyloma acuminatum group) according to their genotypes. Using comparative proteome technology, high-risk human papillomavirus-infected cervical intraepithelial neoplasia, low-risk human papillomavirus-infected condyloma acuminatum, and normal cervical intraepithelial tissue were compared. The differential expression protein spots were identified by mass spectrometry. RESULTS: Totally 26 differential spots were selected and analyzed, and 22 peptide mass fingerprints (PMF) maps were obtained by MALDI-TOF-MS. Eighteen proteins were preliminarily identified after searching the NCBInr database. The function information of these 18 proteins mainly involved cell metabolism, signal transduction, cell secretion, cell cytoskeleton construction, cell proliferation, and apoptosis. CONCLUSION: The proteomic expressions after the cervical infection of high- or low-risk genotype of human papillomavirus are obviously different.

Distribution study of Chlamydia trachomatis serovars among high-risk women in China performed using PCR-restriction fragment length polymorphism genotyping.

This was one of the first epidemiological studies in China focused on genital Chlamydia trachomatis serotype distribution in high-risk female populations using omp1 gene-based restriction fragment length polymorphism analysis. One thousand seven hundred seventy cervical swab samples from women attending sexually transmitted disease clinics and female sex workers in six cities in China (Shenzhen and Guangzhou in southern China, Nanjing and Shanghai in eastern China, and Nanning and Chengdu in southwestern China) were subjected to serovar genotyping. The proportion of omp1 genes successfully amplified in 240 C. trachomatis plasmid-positive samples was 94.2% (226/240). Serotypes E (n = 63; 27.9%), F (n = 53; 23.5%), G (n = 28; 12.4%), and D (n = 25; 11.1%) were most prevalent. Though there was no significant difference in the geographic distribution of C. trachomatis, serotype E was predominant in the South (32.1%) and East (27.1%), while serotype F was predominant in the Southwest (28.3%). Serotype F infection was associated with young age and single status. Serovar G was associated with lower abdominal pain; 47.5% of asymptomatic patients were infected with serovar E. These results provide information on distribution of genital C. trachomatis serotypes among high-risk women in China and indicate that high-risk women, including those who are asymptomatic, can be infected with multiple serovars of C. trachomatis, revealing exposure to multiple sources of infection. Although the scope for generalizations is limited by our small sample size, our results showing clinical correlations with genotypes are informative.

In vitro effects of spectinomycin and ceftriaxone alone or in combination with other antibiotics against Chlamydia trachomatis.

The in vitro effects of spectinomycin and ceftriaxone, alone or in combination with erythromycin, ofloxacin, and doxycycline, against Chlamydia trachomatis were investigated by the checkerboard method and compared by Ridit (reference identical unit) analysis. A combination of spectinomycin with erythromycin or doxycycline was found to be more effective than that of ceftriaxone.

Validation of diagnostic algorithms for syndromic management of sexually transmitted diseases.

OBJECTIVES: To validate our revised syndromic algorithms of the management of sexually transmitted diseases and determine their sensitivity, specificity, positive predictive value and cost-effectiveness. METHODS: Patients with either urethral discharge, vaginal discharge or genital ulcer, were selected during their first visits to three urban sexually transmitted disease clinics in Fujian Province, China. They were managed syndromically according to our revised flowcharts. The etiology of the syndromes was detected by laboratory testing. The data were analyzed using EPI INFO V6.0 software. RESULTS: A total of 736 patients were enrolled into the study. In male patients with urethral discharge, the sensitivities for gonococcal and chlamydial infections were 96.7% and 100%, respectively, using the syndromic approach. The total positive predictive value was 73%. In female patients with vaginal discharge, the sensitivity was 90.8%, specificity 46.9%, positive predictive value 50.9%, and negative predictive value 89.3% for the diagnosis of gonorrhea and/or chlamydial infection by syndromic approach. In patients with genital ulcer, the sensitivities were 78.3% and 75.8%, specificities of 83.6% and 42.9%, and positive predictive values of 60.0% and 41.0% for the diagnosis of syphilis and genital herpes, respectively, using the syndromic approach. Cost-effectiveness analysis indicated that the average cost of treatment for a patient with urethral discharge was RMB 46.03 yuan using syndromic management, in comparison with RMB 149.19 yuan by etiological management. CONCLUSIONS: The syndromic management of urethral discharge was relatively effective and suited clinical application. The specificity and positive predictive value for syndromic management of vaginal discharge are not satisfactory. The revised flowchart of genital ulcer syndrome could be suitable for use in clinical settings. Further validation and revision are needed for syndromic approaches of vaginal discharge and genital ulcer.

Validation of syndromic algorithm for the management of genital ulcer diseases in China.

OBJECTIVES: 1. To determine the aetiologies of genital ulcers in China. 2. To evaluate a modified WHO syndromic management algorithm for genital ulcer disease (GUD). METHODS: Patients with genital ulcers were enrolled at their first visit to STD clinics in the cities of Shanghai and Chengdu. They were managed according to a modified WHO algorithm for GUD, in which no treatment was given for chancroid. A multiplex polymerase chain reaction was used to detect Treponema pallidum, Herpes simplex and Haemophilus ducreyi. Dark field examination and serology (rapid plasma reagin and Treponema pallidum particle agglutination assay (TPPA) were also used to diagnose syphilis. RESULTS: A total of 227 male and female patients were enrolled. Syphilis alone was diagnosed in 78 (35%), genital herpes alone in 43 (19%), and both infections were present in 28 (12%). No diagnosis was made in 76 (34%). No case of chancroid was identified. The sensitivity of the algorithm for syphilis and herpes was 88.7% and 69.0% respectively, the specificity 95.0% and 50.0%. 12/106 cases of syphilis were incorrectly classified as herpes (11%), and did not receive treatment. More than 97% of patients followed up responded clinically to treatment. CONCLUSION: Further validation and revision of the WHO flowchart for GUD are needed.