Value of papanicolaou smear in detection of Chlamydia trachomatis infection

This study was undertaken to assess the value of Papanicolaou smear for the diagnosis of Chlamydia trachomatis infection. The study was both retrospective (groups I and II) and prospective (group III). Group I consisted of 41 smears with cytomorphological changes proposed by Gupta, Kiviat, or Shiina. Group II was a control group, consisting of 30 cytologically normal smears. All these smears were subjected to specific immunofluorescent (IF) staining under identical conditions to confirm the diagnosis. In group III, 40 consecutive duplicate cervical smears were collected from patients attending the Sexually Transmitted Disease Clinic. One smear was routinely examined, and the specific IF staining was done on the other smear. The results in all the three groups were analysed. It was concluded that Papanicolaou smear is not useful in the detection of Chlamydia trachomatis infection.     

沙眼衣原体诊断技术研究进展

沙眼衣原体（Ct）是一种特殊的病原体,具有与革兰氏阴性细菌相似的细胞壁,含有DNA和RNA两种类型的核酸,严格寄生于宿主细胞内,沙眼衣原体是一种能够通过滤器,以二分裂方式繁殖的原核细胞型微生物.它具有两种形态：在细胞外具有高度传染性的为原体 在细胞内进行复制、无传染性的为始体.它可以引起非淋球菌尿道炎等许多泌尿生殖道相关疾病,近年来其感染率和危害性已超过淋病奈瑟菌而居性传播疾病之首,眼部衣原体侵入人体眼结膜和角膜引起沙眼和包涵体结膜炎,是世界范围致盲的首要病因.约80%的被感染女性无临床症状,感染反复迁移,造成病理改变,可导致复杂的并发症.因此,早期、简便、快速、特异地发现Ct,对临床的诊断,疾病的早期治疗和预防其流行等具有重要的意义.目前,对沙眼衣原体的诊断方法主要有培养法,免疫学法和分子生物学法.     

实时荧光定量PCR检测沙眼衣原体的研究

目的采用TaqMan探针建立检测沙眼衣原体的实时荧光定量PCR（real-time PCR）方法。方法根据沙眼衣原体外膜蛋白A的基因（ompA）序列设计引物和探针,以克隆的ompA部分基因片段作DNA模板,建立实时荧光定量检测方法。结果建立的荧光定量PCR检测方法的最低检出限为5 copies/反应,检测线性范围100～107线性关系良好（r2=0.997）,比巢式PCR敏感100倍;且与鹦鹉热衣原体、淋球菌、解脲脲原体、大肠杆菌等病原菌DNA以及人基因组DNA均无交叉反应,表明该方法具有良好的特异性。以巢式PCR作参比,建立的荧光定量PCR法检测沙眼衣原体的阳性符合率为100.00%,阴性符合率为95.09%,总符合率为96.81%。结论建立的检测沙眼衣原体实时荧光定量PCR具有特异性强和敏感性高的特点,可快速检测样本中微量沙眼衣原体DNA,适用于对沙眼衣原体进行大规模筛选。     

Chlamydia trachomatis antigen detection in pregnancy and its verification by antibody blocking assay

Purpose: To detect the prevalence of genital infection caused by Chlamydia trachomatis in pregnant women and also to confirm the positive results using blocking antibody assay. Methods: Endocervical specimens were collected from 200 symptomatic and asymptomatic pregnant women attending the ANC OPD at M P Shah Medical College, Jamnagar. The samples were tested for presence of Chlamydia trachomatis antigen using the monoclonal antibody. Blocking antibody assay was used to further verify the positive results. Results: Out of 200 pregnant women, 38 (19%) were found positive for Chlamydia trachomatis antigen. Out of the 68 symptomatic patients, C. trachomatis antigen was detected in 26.4%. After verification of the positive samples 13.6% of the asymptomatic pregnant women were found to be harbouring the infection in their genital tract. Two (5.2%) out of the 38 positive samples, on verification with the blocking antibody assay, were found to be false positive by IDEIA,^TM thus the specificity of the IDEIA^TM being 94.8%. In patients with previous history of abortions, 27.7% were tested positive for C. trachomatis infection. Conclusions: Significant number of pregnant women shad C. trachomatis antigen in their endocervical canal, which can be easily diagnosed by this simple enzyme immuno assay having a specificity of 94.8%. Verification of positive results by antibody blocking assay can further improve the specificity of this non-culture test. Asymptomatic patients should also be screened for the infection. History of previous abortions places the patient at a higher risk for C. trachomatis infection thus such patients should be definitely tested for chlamydia infection.     

Association between Chlamydia trachomatis and abnormal uterine bleeding

PROBLEM: The purpose was to identify distinct inflammatory markers in endometrial tissues of women with abnormal uterine bleeding (AUB) and Chlamydia trachomatis infection. METHOD OF STUDY: Archived endometrial specimens from 92 randomly selected premenopausal women with AUB were examined for C. trachomatis using the species-specific monoclonal antibody against major outer membrane protein (MOMP) and for histopathology associated with inflammation. Statistical analyses included single and multiple logistic regression. Diagnostic accuracy was summarized using receiver operating characteristic (ROC) curves. RESULTS: Chlamydia trachomatis was detected in 44 (48%) of 92 AUB specimens. There were statistically significant correlations of positive MOMP with higher counts of plasma cells (P < 0.01), macrophages (P < 0.0001), and lymphocytic foci (P = 0.01). The ROC curve for macrophages was the strongest predictor (area under the curve = 0.82) for C. trachomatis. CONCLUSION: The prevalence of C. trachomatis in women with AUB is under-estimated. Macrophages appear to be a strong marker for the presence of C. trachomatis in the endometrium.     

沙眼衣原体套式（Nested）PCR检测研究

本文报告沙眼衣原体（ＣＴ）的套式（Ｎｅｓｔｅｄ）ＰＣＲ检测方法，本方法ＣＴ隐匿性质粒为靶基因，外套引物采用国外学者所报告灵敏度和特异性较高的序列，内套引物自行设计，经方法学考核表明本法灵敏度和特异性极高。１４６例临检标本套式ＣＴ，ＰＣＲ阳性检出率为３６．３％而市售ＰＣＲ试剂盒（其引物序列与本文外套引物相同）阳性检出率仅为４．１％，前者明显高于后者（Ｐ〈０．０１）。     

Characterization of Apoptotic Activities During Chlamydia trachomatis Infection in Primary Cervical Epithelial Cells

Chlamydiae are obligate intracellular bacteria that infect human epithelial cells. It has been reported that Chlamydia trachomatis, induces apoptosis in epithelial cells, however, the molecular mechanisms responsible for host cell death especially in primary epithelial cells remained largely unknown as most of the studies are in cell line like HeLa. In this study we demonstrated that C. trachomatis induces apoptosis signaling pathway and apoptosis in primary cervical epithelial cells in a time and dose dependent manner. Live cervical epithelial cells were isolated from endocervical cells and induction was done with chlamydial EBs. Our results demonstrated that apoptosis in infected epithelial cells was associated with an increased activity of caspase 8; however, caspase 9 was activated to a lesser extent. Analysis of apoptosis pathway revealed that expression level of McL-1, Bcl-2, CASP8, and TRADD genes were found to be significantly upregulated (P?<?0.01), where as levels of Caspase 1, Caspase 10 and BRIC2 were found to be significantly downregulated (p?<?0.01). Our results showed that Chlamydia induces apoptosis and caspase activation in epithelial cells through caspase 8, with an increased expression of the McL-1, which confers a block at the mitochondrial level.     

Recovery of cytomegalovirus and Chlamydia trachomatis from vaginal tampons

Herpes simplex virus (HSV), cytomegalovirus (CMV), and Chlamydia trachomatis are important agents in venereal and neonatal disease. Vaginal tampon culture for HSV has previously been demonstrated to be a simple and effective technique for quantitative culture of cervical secretions. We have evaluated the tampon culture as a means of performing quantitative cultures for CMV and C trachomatis. Cell-free and cell-associated CMV were quantitatively recovered from vaginal tampons when extraction was performed within one hour of tampon inoculation. However, when tampons were stored, there was a rapid loss of infectivity over time at all storage temperatures except -70 degrees C. C trachomatis was quantitatively recovered from tampons stored at less than or equal to 4 degrees C for four days. When stored at -70 degrees C, C trachomatis was stable on tampons for more than one week. Because HSV, CMV, and C trachomatis are stable in a single transport medium, a tampon stored at 4 degrees C briefly or at -70 degrees C for one week could be utilized for the detection of all three agents.     

Genotyping of Chlamydia trachomatis strains from cultured isolates and nucleic acid amplification test-positive specimens

Urogenital strains of Chlamydia trachomatis are divided into several serogroups (D-K). Since these serovars are represented with differing prevalence in the population a serotyping of strains is necessary, when characterising the epidemiological situation. The aim of this study was the genotyping of C. trachomatis strains, the comparison of the results with those of serotyping, and the genotyping of positive specimens using commercial nucleic acid amplification tests (NAAT). The Chlamydia trachomatis major outer membrane protein gene (omp1) from 55 isolated strains and 36 NAAT-positive specimens was amplified by polymerase chain reaction (PCR). The restriction fragment length polymorphism (RFLP) patterns of these amplicons were compared with those of reference strains. The genotypes E and F were found to be most prevalent. The results are discussed considering other studies, genovariants and epidemiology.     

Urethritis associated with Chlamydia trachomatis: comparison of leukocyte esterase dipstick test of first-voided urine and methylene blue-stained urethral smear as predictors of chlamydial infection

The use of nucleic acid amplification tests for the diagnosis of C. trachomatis has made it possible to send urine samples instead of urethral swab specimens to the laboratory. The sensitivity is very high, but not 100%, and we continue to perform a test for urethritis at our STD clinic. The aim of this study was to compare the performance of two alternative tests in the diagnosis of urethritis as predictors of C. trachomatis infection: the leukocyte esterase (LE) dipstick test of first-voided urine and polymorphonuclear leukocyte counts in a methylene blue-stained (MBS) urethral smear. Urine samples from 480 male patients attending an STD clinic were analysed using the LE test and LCR assay for C. trachomatis; urethral samples were analysed with MBS urethral smear and LCR. The majority (75.8%) of the 480 patients examined were asymptomatic. Chlamydial infection was detected in 50 patients. The sensitivity, specificity and positive predictive value of the LE test for predicting C. trachomatis infection were 46.0, 91.6 and 39.0%, respectively, among all patients examined and 25.9, 95.8 and 33.3%, respectively, among the asymptomatic patients. The corresponding values for the MBS urethral smear were 76.0, 82.1 and 33.0% among all patients and 63.0, 89.6 and 32.7% among the asymptomatic patients. At our STD clinic we chose to perform the examination of MBS urethral smears in the diagnosis of urethritis because of its higher sensitivity relative to the LE test for predicting C. trachomatis.     

Multicenter comparative evaluation of two rapid immunoassay methods for the detection of Chlamydia trachomatis antigen in endocervical specimens

Objective: To evaluate two rapid immunoassay methods, QuickVue-Chlamydia (Quidel Corp., San Diego California) and Kodak SureCell (Kodak Corp., Rochester, NY) for the detection of Chlamydia trachomatis antigen in endocervical swabs from high- and low-risk females.
Methods: Seven hundred and twenty-four females attending three clinics were enrolled in the study. The results were compared to McCoy's or BGMK cell culture and discrepancies resolved with polymerase chain reaction and direct fluorescent antibody tests performed on left-over culture specimens.
Results: The sensitivity, specificity, predictive value of a positive and predictive value of a negative of the QuickVue Chlamydia assay were 92.0%, 99.1%, 92.0% and 99.1%, respectively. The sensitivity, specificity, predictive value of a positive and predictive value of a negative of the SureCell assay were 90.0%, 99.8%, 98.6% and 98.8%, respectively.
Conclusions: The performances of the two immunoassay methods were similar, and slight differences in sensitivity and specificity were not statistically significant. Both immunoassay methods performed well in high- and low-risk patient groups, both for symptomatic and for asymptomatic patients.     

Genital Chlamydia trachomatis infections

Chlamydia trachomatis infections affect young, sexually active persons. Risk factors include multiple partners and failure to use condoms. The incidence of infection has increased in the past 10 years. Untreated C .  trachomatis infections are responsible for a large proportion of salpingitis, ectopic pregnancy, infertility and, to a lesser extent, epididymitis. Screening is a possible intervention to control the infection, which is often asymptomatic. The emergence of lymphogranuloma venereum proctitis in men who have sex with men, in Europe, and of a variant with a deletion in the cryptic plasmid, in Sweden, are new features of C .  trachomatis infections in the last years. A diagnosis is best made by using nucleic acid amplification tests, because they perform well and do not require invasive procedures for specimen collection. Single-dose therapy has been a significant development for treatment of an uncomplicated infection of the patient and his or her sexual partner.     

Screening for Chlamydia trachomatis in subfertile women

Chlamydia trachomatis is the most common sexually transmitted disease in the UK and Europe. The majority of female infections are asymptomatic and recognized sequelae include pelvic inflammatory disease, infertility, and ectopic pregnancy. Women with chlamydial infection who undergo uterine instrumentation are recognized to be at risk of ascending infection. Most patients attending for infertility investigations and treatment will undergo some form of uterine instrumentation. Published data regarding the prevalence of chlamydial infection in the subfertile are few and conflicting. In this study, more than 400 consecutive women presenting for infertility investigation and treatment at a single regional fertility centre were screened for Chlamydia: Half were screened using enzyme immunoassay (EIA) and half by ligase chain reaction (LCR). Prevalence by diagnostic test was 0% with EIA and 1.9% with LCR. Overall, the low prevalence was at least partly explained by older age. Until more evidence comes from studies testing consecutive subfertile patients both with EIA and a DNA amplification method such as LCR, centres using EIA should consider using prophylactic antibiotics prior to uterine instrumentation.     

Chlamydia trachomatis causing neonatal conjunctivitis in a tertiary care center

Chlamydia trachomatis is considered a major aetiological agent of conjunctivitis in newborns. The objective of the present study was to determine the aetiology of neonatal conjunctivitis and clinico-epidemiological correlates of chlamydial ophthalmia neonatorum. Fifty-eight newborns with signs and symptoms of conjunctivitis were studied. Conjunctival specimens were subjected to Gram staining, routine bacteriological culture, culture for Neisseria gonorrhoeae and direct fluorescent antibody (DFA) staining for diagnosis of C. trachomatis infection. C. trachomatis was detected in 18 (31%) neonates. Findings suggest that since C. trachomatis is the most common cause of neonatal conjunctivitis, routine screening and treatment of genital C. trachomatis infection in pregnant women and early diagnosis and treatment of neonatal Chlamydial conjunctivitis may be considered for its prevention and control.     

Use of the ligase chain reaction on urine of men and their female sexual partners for detection of genital Chlamydia trachomatis infection

Objective: The purpose of the present study was to evaluate an in vitro DNA amplification assay named the ligase chain reaction (LCR) for the detection of Chlamydia trachomatis cryptic plasmid DNA in urine from men and women, in comparison with urethral swab culture in men and cervical swab culture in women.
Methods: 591 patients (394 men with urethritis and 197 female sex partners) attending a center for sexually transmitted diseases in northern Italy between January 1994 and January 1995 were enrolled in this study. A cervical swab was collected from women and a urethral swab from men for standard tissue cell culture. From each patient 20 mL of the first stream of the urine (FVU), taken at least 2 h after the last urination, were collected for LCR analysis. Discrepant results were further analyzed by direct fluorescence and a LCR with alternative primers.
Results: In men the prevalence of C. trachomatis infection by urethral culture was 13.45% and, after resolution of discordant results, the LCR method performed on FVU showed a sensitivity, specificity, positive predictive value and negative predictive value of 89.4%, 100%, 100% and 98.2%, respectively; the sensitivity of tissue cell culture was 92.8%. In female sex partners, the prevalence of C. trachomatis infection by cervical culture was 3.04%; LCR detected eight true positive samples, two more than tissue cell culture, and no false-negative results.
Conclusion: LCR analysis of FVU is a rapid, non-invasive technique and represents a good alternative to tissue cell culture. Further study is needed to investigate possible LCR inhibitors present in urine samples.     

Detection of Chlamydia trachomatis and herpes simplex virus type 1 or 2 in cervical samples in human papilloma virus (HPV)-positive and HPV-negative women

This study investigated whether the prevalence of human papilloma virus (HPV) in association with Chlamydia trachomatis, herpes simplex virus (HSV)-1 and/or HSV-2 was greater in high-grade than in low-grade or control cervical biopsy specimens. HPV-positive (n = 86) and HPV-negative (n = 213) women were screened for HPV, HSV and C. trachomatis by PCR. The most common HPV genotypes were HPV-16, HPV-6 and HPV-33; mixed HPV infection (n = 12) was also seen. A higher prevalence of C. trachomatis, HSV-1 and HSV-2 was found in HPV-positive samples. High-risk HPV genotypes and combined HPV + C. trachomatis or HPV + HSV-1, but not HSV-2, infections were associated with a greater risk of developing cervical carcinoma.     

不孕不育者生殖道淋球菌、沙眼衣原体和解脲支原体的检测结果分析

目的了解在不孕不育患者中生殖道淋球菌（NC）、沙眼衣原体（CT）、解脲支原体（UU）感染的情况。方法应用实时荧光定量PCR方法对465例不孕不育患者生殖道3种病原体基因进行定量测定。结果阳性检出268例，总阳性率为57．64％，其中UU的阳性检出率最高，占43．87％；重叠感染中以UU＋CT的阳性检出率最高，占3．44％。结论不孕不育患者生殖道中3种病原体感染率不尽相同，尤以UU感染率最高，是造成不孕不育的重要原因。