The relationship of Chlamydia trachomatis infection and male infertility

Are sexually transmitted infections associated with male infertility? A systematic review and in-depth evaluation of the evidence and mechanisms of action of 11 pathogens

Purpose

To systematically review the evidence on the association between sexually transmitted infections (STIs) and male infertility. We sought to answer two questions: Are STIs significantly associated with detrimental changes in semen parameters?; and, is the prevalence of STIs significantly higher in infertile than fertile men?

Materials and methods

PubMed, Scopus and Google Scholar databases were searched (inceptionMarch 2023) following the PRISMA guidelines. Identified original studies in English on the association between STIs and male infertility were included. Data was tabulated/described by pathogen, mechanisms of action, number of studies and their level of evidence.

Results

Seventy out of 903 originally retrieved articles were included in this review. For the detrimental changes in semen parameters (first question), the evidence seems equivocal based on the nearly equal number of studies and similar levels of evidence. The only exception was for Ureaplasma, where the number of studies and levels of evidence supported an association with male infertility. Pertaining to a significantly higher prevalence of STI among infertile compared to fertile men (second question), evidence was insufficient to support/deny a significant association. The two exceptions were Ureaplasma and Mycoplasma, where the number of studies and evidence levels were in favour of an association with male infertility.

Conclusions

Generally, the relationship between STIs and male infertility remains to be uncovered. Our appraisal of the overall state of this relationship shows that the evidence base leaves much to be desired. The exceptions are Ureaplasma and Mycoplasma, where the evidence convincingly suggests their associations with infertility in men.

AAUS guideline for chlamydial urethritis

Urogenital chlamydial infection is the most common sexually transmitted infection. Many cases of chlamydial infection are reported worldwide every year. Genital chlamydial infection in women can also cause obstetric issues, including infertility and miscarriage. For that purpose, appropriate care should be conducted with the latest knowledge. Only few guidelines come from Asian countries. The Asian Association of Urinary Tract Infection and Sexually Transmitted Infection (AAUS) belonging to the Urological Association of Asia (UAA) had developed the guidelines regarding chlamydial urethritis. We have collected the feedback and updated the guidelines which is now submitted for consideration of publication. In addition to the levels of evidence, the recommendation grades were defined using the modified GRADE methodology. Herein, we present the new edition of the UAA-AAUS guidelines for chlamydial urethritis.

HIV, HPV and Chlamydia trachomatis: impacts on male fertility

Sexually transmitted diseases (STDs) are pathologies that have viruses, bacteria, protozoa and fungi as infectious agents, affecting millions of people worldwide and causing physical and psychological consequences for the carrier. Some of these infections such as HIV, HPV and Chlamydia trachomatis may present an asymptomatic phase, making the diagnosis difficult, which is often only performed when the couple looks for infertility treatment after not achieving spontaneous pregnancy. Infertility affects 15% of couples, 50% of cases are male-related, and it is estimated that STDs, which interfere with the physiology of the male reproductive system and may impair semen in parameters such as motility, concentration, morphology and number, cause 15% of male infertility cases. Since STDs treatments are increasing the expectation and quality of life of infected patients, discussing issues such as sexuality and reproduction is of great importance in clarifying unknown facts. This paper aims to discuss how the infectious processes associated with HIV, HPV and Chlamydia trachomatis can interfere with semen quality causing male infertility without apparent cause.

Bacterial infection of the male reproductive system causing infertility

Bacterial infections play a disruptive and hidden role in male reproductive failure. Different kinds of bacteria are often able to interfere with reproductive function in both sexes and lead to infertility. In this study, to further evaluate the role of bacterial infections in male reproduction we provided an extensive overview of so far researches investigating the effects of bacterial infections on male fertility. We searched Medline, PubMed, Scopus and Google scholar databases to identify the potentially relevant studies on bacterial infections and their implications in male infertility. All the bacteria included in this article have negative effects on the male reproductive function; however, there is ample evidence to blame bacteria such as Escherichia coli, Chlamydia trachomatis, Ureaplasma, Mycoplasma and Staphylococcus aureus for reduced fertility and deterioration of sperm parameters. More studies are needed to clarify the molecular mechanisms by which different bacteria exert their detrimental effects on male reproductive system. Getting more insight into probable mechanisms, would significantly facilitate the production of new, advanced, and effective remedies in the future. In view of all evidence, we strongly suggest increasing awareness among people and considering screening programs for patients seeking fertility both to avoid transmission and to improve fertility outcomes among them.

[Sexually transmitted infections and male fertility]

BACKGROUND

Sexually transmitted infections (STI) are common worldwide and can cause impairment of fertility. In women pelvic inflammatory disease with subsequent tubal sterility is well-documented but the influence of STI on male fertility is still controversely discussed OBJECTIVE: The effects of various bacterial and viral STI on male fertility are discussed.

MATERIAL AND METHODS

An evaluation of the international literature up to 30 April 2018 was carried out including studies on larger collectives from the Asiatic region.

RESULTS

There is still an inconsistent picture of the influence of various bacterial and viral STI on male fertility. Direct or indirect evidence of the impact of a pathogen alone on the quality of ejaculates could not be clearly demonstrated; however, there are indications of a negative effect by Mycoplasma and Ureaplasma species in large Asiatic collectives. The transmission of viral pathogens, such as human papillomavirus (HPV), herpes simplex virus (HSV) and hepatitis B virus (HBV) possible impairs the success of assisted reproductive techniques. In contrast, manifest inflammatory processes of the male genital tract caused by STI (in particular Chlamydia and gonococci) or human immunodeficiency virus (HIV) infections often result in impairment of sperm qualtity.

CONCLUSION

In cases of male fertility disorders a microbiological clarification is recommended. Further studies on the effect of STI on male fertility in larger collectives are necessary, particularly for Caucasian populations. The utilization of existing preventive measures, such as screening for Chlamydia in young women and HPV vaccination also for young males, should be intensively promoted.

Background review for the '2015 European guideline on the management of Chlamydia trachomatis infections'

SummaryChlamydia trachomatis infections are major public health concerns globally. Of particular grave concern is that the majority of persons with anogenital Chlamydia trachomatis infections are asymptomatic and accordingly not aware of their infection, and this silent infection can subsequently result in severe reproductive tract complications and sequelae. The current review paper provides all background, evidence base and discussions for the 2015 European guideline on the management of Chlamydia trachomatis infections (Lanjouw E, et al. Int J STD AIDS 2015). Comprehensive information and recommendations are included regarding the diagnosis, treatment and prevention of anogenital, pharyngeal and conjunctival Chlamydia trachomatis infections in European countries. However, Chlamydia trachomatis also causes the eye infection trachoma, which is not a sexually transmitted infection. The 2015 European Chlamydia trachomatis guideline provides up-to-date guidance regarding broader indications for testing and treatment of Chlamydia trachomatis infections; clearer recommendation of using validated nucleic acid amplification tests only for diagnosis; advice on (repeated) Chlamydia trachomatis testing; recommendation of increased testing to reduce the incidence of pelvic inflammatory disease and prevent exposure to infection and recommendations to identify, verify and report Chlamydia trachomatis variants. Improvement of access to testing, test performance, diagnostics, antimicrobial treatment and follow-up of Chlamydia trachomatis patients are crucial to control its spread.

2015 European guideline on the management of Chlamydia trachomatis infections

Chlamydia trachomatis infections, which most frequently are asymptomatic, are major public health concerns globally. The 2015 European C. trachomatis guideline provides: up-to-date guidance regarding broader indications for testing and treatment of C. trachomatis infections; a clearer recommendation of using exclusively-validated nucleic acid amplification tests for diagnosis; advice on (repeated) C. trachomatis testing; the recommendation of increased testing to reduce the incidence of pelvic inflammatory disease and prevent exposure to infection; and recommendations to identify, verify and report C. trachomatis variants. Improvement of access to testing, test performance, diagnostics, antimicrobial treatment and follow-up of C. trachomatis patients are crucial to control its spread. For detailed background, evidence base and discussions, see the background review for the present 2015 European guideline on the management of Chlamydia trachomatis infections (Lanjouw E, et al. Int J STD AIDS. 2015).

2015 UK national guideline for the management of infection with Chlamydia trachomatis

This guideline offers recommendations on the diagnostic tests, treatment regimens and health promotion principles needed for the effective management of Chlamydia trachomatis genital infection. It covers the management of the initial presentation, as well the prevention of transmission and future infection. The guideline is aimed at individuals aged 16 years and older presenting to healthcare professionals working in departments offering Level 3 care in sexually transmitted infections management within the UK. However, the principles of the recommendations should be adopted across all levels, using local care pathways where appropriate.

Chlamydia (uncomplicated, genital)

INTRODUCTION

Genital chlamydia is the most commonly reported bacterial sexually transmitted infection in developed countries. The majority of infections affect young adults under the age of 25 years.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of antibiotic treatment for men and non-pregnant women with uncomplicated genital chlamydial infection? What are the effects of antibiotic treatment for pregnant women with uncomplicated genital chlamydial infection? We searched: Medline, Embase, The Cochrane Library, and other important databases up to February 2014 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 26 studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions - for men and non-pregnant women: antibiotics (single-dose) and antibiotics (multiple-dose regimens); for pregnant women: antibiotics (single-dose), erythromycin or amoxicillin (multiple-dose regimens), and clindamycin (multiple-dose regimens).

2010 European guideline for the management of Chlamydia trachomatis infections

This guideline aims to provide comprehensive information regarding the management of infections caused by Chlamydia trachomatis in European countries. The recommendations contain important information for physicians and laboratory staff working with sexually transmitted infections (STIs) and/or STI-related issues. Individual European countries may be required to make minor national adjustments to this guideline as some of the tests or specific local data may not be accessible, or because of specific laws.

Chlamydia, Mycoplasma and Ureaplasma infections in infertile couples and effects of these infections on fertility

OBJECTIVE

In our study, we aimed to determine the prevalence of Chlamydia trachomatis, Mycoplasma hominis and Ureaplasma urealyticum infections among infertile couples and effects of these infections on infertility.

MATERIALS AND METHODS

Prevalence of Chlamydia, Mycoplasma, Ureaplasma antibodies and Chlamydia IgM antibodies and its effect on these agents' sperm parameters, namely, morphology, density, and motility were investigated among a total of 212 patients including fertile and infertile couples. Chlamydia, Mycoplasma, Ureaplasma antigens were evaluated using ELISA in the cervical and urethral samples. Chlamydia IgM antibody was measured using micro-ELISA in blood samples.

RESULTS

No difference was detected among the fertile and infertile groups in the serological investigation of urethral and cervical samples with respect to the prevalence of Chlamydia, Mycoplasma, Ureaplasma antigens and Chlamydia IgM antibody and sperm parameters (p > 0.05).

DISCUSSION

There is no significant difference between fertile and infertile couples in terms of the prevalence of the above mentioned infections. Accordingly, during the infertility assessment, infertile couples should not be routinely screened for these infective agents without any clinically sound evidence.

Medical and surgical management male infertility

Male infertility is the result of a variety of highly treatable conditions. The critical step in treating male infertility is to evaluate properly every male partner of an infertile couple and to generate the proper treatment strategy. There are many medical and surgical options that can help most couples overcome male factor infertility. Male infertility can most easily be broken down into problems of sperm production (testicular dysfunction) and problems of sperm transport (obstruction). When applicable, medical therapies are used as an initial strategy to improve sperm production or as a preliminary therapy to boost production transiently in anticipation of a surgical sperm retrieval attempt. A range of surgical options is available to correct varicoceles, reconstruct the obstructed system, or retrieve sperm for assisted reproduction.

Chlamydial antibodies and risk of prostate cancer

OBJECTIVE

We assessed the risk of prostate cancer by exposure to Chlamydia trachomatis.

METHOD

Seven hundred thirty eight cases of prostate cancer and 2,271 matched controls were identified from three serum sample banks in Finland, Norway, and Sweden by linkage to the population based cancer registries.

RESULTS

A statistically significant inverse association (odds ratio, 0.69; 95% confidence interval, 0.51-0.94) was found. It was consistent by different serotypes and there was a consistent dose-response relationship.

CONCLUSION

C. trachomatis infection is not likely to increase the risk of prostate cancer. Whether the inverse relationship is true or due to difficulties in measuring the true exposure in prostatic tissue by serology, confounders or other sources of error remain open.

Assessment of Chlamydia trachomatis infection in asymptomatic male partners of infertile couples

Three specimens from 111 asymptomatic male partners of infertile couples attending the Department of Urology in Amiens, France, were examined by the PCR COBAS AMPLICOR test (Roche Molecular Diagnostics) for the presence of Chlamydia trachomatis. The specimens analysed were: first void urine (FVU), urine obtained after prostatic massage (UPM) and semen specimens. Serum from each patient was also obtained and analysed for the presence of IgG and IgA chlamydial antibodies by in-house microimmunofluorescence (MIF) and pELISA. C. trachomatis was detected by PCR in 5.4% of FVU samples, 2.7% of semen specimens and in 0.9% of UPM samples. Two treatments for processing the samples (storage at -70 degrees C and heating to 95 degrees C) were routinely used before initial testing to reduce the effects of inhibitors of PCR. Despite these precautions, the PCR method revealed the presence of inhibitors in 7.3% of semen specimens and 3.6% of FVU samples. C. trachomatis was detected by PCR COBAS AMPLICOR in seven of 111 patients (6.3%) and by serology in five of 111 patients (4.5%). The detection of C. trachomatis in FVU, UPM and semen specimens can serve as a marker for the presence of this organism in the genital tract, and can be used as a reliable way of detecting asymptomatic carriers of infection.

Update on the impact of Chlamydia trachomatis infection on male fertility

With approximately 90 million cases annually, infection with Chlamydia trachomatis is the most prevalent sexually transmitted bacterial disease in the world. Considering that these infections are often asymptomatic and cause major complications like acute pelvic inflammatory disease, ectopic pregnancy, infertility or infant pneumonia, the estimated costs for diagnosis and treatment in the USA amounts to 2.2 million US dollars for each 500 cases. Therefore, there is a high need for correct, quick and cost-effective diagnosis and treatment of this urogenital tract infection. New innovative therapies provide good results with regard to efficacy and patients' compliance. The success rates of treatments are at least 95%. However, the occurrence of antibiotic resistance should not be ignored and new treatment schemes must be developed. The state-of-the-art of diagnosis and treatment of chlamydial infections as well as the pathophysiology is discussed in this review. In conclusion, infections with C. trachomatis is an important public health problem, especially in third world and developing countries, and more socio-economic studies linking secondary prevention of chlamydial infections, infertility and adverse pregnancy outcome are needed to understand more of its aetiology. In addition, diagnosis and treatment should be improved. Data in men revealed that past infections but not present infections are more related to male infertility. There is still controversial results. In future studies, function of the seminal vesicles and evaluation of the antioxidant capacity should be taken into account when role of C. trachomatis infection on male fertility is assessed.

Male infertility and genital chlamydial infection: victim or perpetrator?

The role of Chlamydia trachomatis in the cause of male infertility is under discussion. This paper attempts to summarize data from the literature, which support the role of C. trachomatis in male infertility or oppose this suggestion. The following observations are based on a survey of the literature: 1) Chlamydia trachomatis is a frequent pathogen in male genital inflammation, the micro-organisms are rarely present in healthy men. 2) Without doubt, C. trachomatis causes inflammations of the male urethra and the epididymis. Prostatitis and glandulitis vesicalis are discussed controversially. 3) Chlamydia trachomatis antigen or DNA is not demonstrable in secretions of the male accessory glands including the semen with sufficient reproducibility. However, it is easily demonstrable in urethral swabs and the urine. 4) Determination of chlamydial antibodies in serum or semen does not conclusively indicate a current infection with C. trachomatis. 5) There are no conclusive studies showing that men infected with C. trachomatis are less fertile than uninfected men. 6) The male genital chlamydial infection is a threat to the female genital organs, because C. trachomatis infection of the female genital organs may be deleterious to female fertility.

Sustained high prevalence of Chlamydia trachomatis infections in female army recruits

BACKGROUND

Chlamydia trachomatis infections are prevalent among young sexually active females, have serious sequelae, and are mostly asymptomatic. Screening and treatment of infected females has been demonstrated to prevent sequelae such as pelvic inflammatory disease.

GOAL

To assess prevalence and risk factors for chlamydia infection in US Army female recruits, whether these changed over time, and to examine variables contributing to any observed patterns.

STUDY DESIGN

Prevalence study of 23,010 non-healthcare-seeking female Army recruits enrolled in a chlamydia screening program at Fort Jackson, SC, from January 1996 through June 1999. Each of the 4-year cohorts was examined separately for prevalence and risk factors.

MAIN OUTCOME MEASURES

Urine-based testing for C trachomatis by ligase chain reaction was used to determine prevalence, and questionnaires were used to collect demographic and risk information. State home of record for each recruit was transformed into Public Health reporting region: West, Midwest, South, Northeast, and Territories.

RESULTS

Prevalence for all years was 9.51%, but a progressive increase from 8.51% to 9.92% occurred over the course of study (P=0.018). The proportion of individuals reporting specific risk factors during the 90 days preceding the study generally decreased over time. In a regression model, significant risk factors for infection included black race, age 25 years or younger, home-of-record from the South, being screened during years 3 and 4 of the study, more than one sex partner, a new sex partner, and history of any sexually transmitted disease. Condom use was protective. In another model controlling for age and home-of-record from the South, being screened in years 2, 3, and 4 of the study were significantly predictive for being chlamydia positive.

CONCLUSION

A high and slightly increasing prevalence of C trachomatis infection was observed among young females entering the military over 4 consecutive years. Young age, black race, home-of-record from the South, more than one sex partner, a new sex partner, condom use, and a history of having a sexually transmitted disease were correlates of chlamydia infection. Sustained high rates of C trachomatis infection in this population provide clear justification for a chlamydia control program for young women entering the Army consisting of screening at entry on the basis of age and possibly home-of-record together with continued periodic rescreening.

SUMMARY

A study of 23,010 female Army recruits demonstrated that a high prevalence of C trachomatis was sustained during 4 years of observation. Year of study, young age, and being from the South were significant predictors of infection.

Effect of an STD/HIV behavioral intervention on women's use of the female condom

OBJECTIVES

This study assessed the effectiveness of a sexually transmitted disease (STD)/HIV behavior change intervention in increasing women's use of the female condom.

METHODS

A total of 604 women at high risk for STDs and HIV in New York City, Baltimore, Md, and Seattle, Wash, enrolled in a randomized controlled trial of a small-group, skills-training intervention that included information and skills training in the use of the female condom.

RESULTS

In a logistic regression, the strongest predictors of use were exposure to the intervention (odds ratio [OR] = 5.5; 95% confidence interval [CI] = 2.8, 10.7), intention to use the female condom in the future (OR = 4.5; 95% CI = 2.4, 8.5), having asked a partner to use a condom in the past 30 days (OR = 2.3; 95% CI = 1.3, 3.9), and confidence in asking a partner to use a condom (OR = 1.9; 95% CI = 1.1, 3.5).

CONCLUSIONS

Clinicians counseling women in the use of the female condom need to provide information, demonstrate its correct use with their clients, and provide an opportunity for their clients to practice skills themselves.

Chlamydia trachomatis genes whose products are related to energy metabolism are expressed differentially in active vs. persistent infection

The Chlamydia trachomatis genome encodes glycolysis and pentose phosphate pathway enzymes, two ATP/ADP exchange proteins, and other energy transduction-related components. We asked if and when chlamydial genes specifying products related to energy transduction are expressed during active vs. persistent infection in in vitro models and in synovia from Chlamydia-associated arthritis patients. Hep-2 cells infected with K serovar were harvested from 0-48 h post-infection (active infection). Human monocytes identically infected were harvested at 1, 2, 3, 5 days post-infection (persistent). RNA from each preparation and from synovial samples PCR-positive/-negative for Chlamydia DNA was subjected to RT-PCR targeting (a) chlamydial primary rRNA transcripts and adt1 mRNA, (b) chlamydial mRNA encoding enzymes of the glycolysis (pyk, gap, pgk) and pentose phosphate (gnd, tal) pathways, the TCA cycle (mdhC, fumC), electron transport system (cydA, cydB), and sigma factors (rpoD, rpsD, rpoN). Primary rRNA transcripts and adt1 mRNA were present in each infected preparation and patient sample; controls were negative for chlamydial RNA. In infected Hep-2 cells, all energy transduction-related genes were expressed by approximately 11 h post-infection. In monocytes, pyk, gap, pgk, gnd, tal, cydA mRNA were present in 1-2-day-infected cells but absent at 3 days and after; cydB, mdhC, fumC were expressed through 5 days post-infection. RT-PCR targeting mRNA from sigma factor genes indicated that lack of these gene products cannot explain selective transcriptional down-regulation during persistence. Analyses of RNA from synovial tissues mirrored those from the monocyte system. These data suggest that in the first phase of active chlamydial infection, ADP/ATP exchange provides energy required for metabolism; in active growth, glycolysis supplements host ATP. In persistence host, rather than bacterially produced, ATP is the primary energy source. Metabolic rate in persistent C. trachomatis is lower than in actively growing cells, as judged from assays for relative chlamydial primary rRNA transcript levels in persistent vs. actively growing cells.

Chlamydia during pregnancy: implications and impact on perinatal and neonatal outcomes

Chlamydia is the most prevalent sexually transmitted disease in the United States, with an estimated 3 million cases occurring annually. Untreated Chlamydia can cause severe, costly reproductive and other health problems with both short- and long-term consequences. When Chlamydia coexists with pregnancy, it can have negative consequences for the woman, the pregnancy, and the newborn. Nurses are in important positions to ensure safe health care practices for all pregnant women. Awareness of the perinatal implications and routine screening for Chlamydia in pregnant women will provide safer health care for the mother and her baby.

IgA antibodies to Chlamydia trachomatis and seminal parameters in asymptomatic infertile males

Prevalence of IgA antibodies to Chlamydia trachomatis in semen samples from infertile men was estimated and its clinical meaning is discussed. The ejaculate of 102 infertile men without any symptom of genital infection was studied, and seminal alterations were classified according to WHO criteria. Antichlamydial IgA antibodies were detected using a solid-phase, enzyme-linked immunoassay (ImmunoComb II Chlamydia trachomatis monovalent IgA) and related to sperm count, motility and membrane integrity, seminal leucocyte count, and past history of sexually transmitted disease (STD). Prevalence of IgA antibodies to C. trachomatis was 23%. There was no relationship between IgA antibodies and the sperm variables or leucocyte count in semen. However, a strong association between antichlamydial IgA antibodies and the antecedent of STD was found (p < .005; OR = 6). IgA antibodies to C. trachomatis did not cause alterations in sperm function and they were not associated with inflammatory response. However, these antibodies in semen of asymptomatic infertile men would indicate a risk of C. trachomatis infection for the couples of those patients.

Chlamydial infections and male infertility

Chlamydial infections may be difficult to diagnose due to the silent symptoms and difficulty in culturing. An infectious process may impair fertility by adversely affecting sperm functions, resulting in testicular damage or causing obstruction of the genital tract. In our study, we tried to find Chlamydial antigen by using EIA (Enzyme Immune Assay) and to compare the Ag(+) and Ag(-) groups according to semen parameters. Except for semen volume, we found significant differences in density, morphology, motility and viability (intervolume p > 0.05, interdensity p < 0.01, intermorphology p < 0.001, intermotility p < 0.001 and interviability p < 0.001).

Do men become infertile after having sexually transmitted urethritis? An epidemiologic examination

OBJECTIVE

To critically assess the possibility that gonorrhea or chlamydia causes male infertility.

DESIGN

Comprehensive literature review structured to evaluate the epidemiologic tenets for causality, including biologic plausibility, strength of association, dose response, consistency, temporality, and treatment effect.

RESULT(S)

It is biologically plausible that gonorrhea and/or chlamydia could cause male infertility. There is clinical and pathologic evidence linking these pathogens to urethritis, linking urethritis to epididymo-orchitis, and linking epididymo-orchitis to infertility. Retrospective epidemiologic results also support an association between chlamydia serologies and male infertility, which in most of these small studies does not reach the level of statistical significance. However, there is no consistent epidemiologic evidence that these pathogens alter sperm characteristics. We discuss the methodologic limitations of previous epidemiologic studies and suggest strategies for future research.

CONCLUSION(S)

Whether gonorrhea and/or chlamydia cause male infertility is currently unclear. Sound methodologic research strategies must be applied to future studies.

Comparison of synovial tissue and synovial fluid as the source of nucleic acids for detection of Chlamydia trachomatis by polymerase chain reaction

OBJECTIVE

Difficulties in detecting Chlamydia trachomatis in human joints by polymerase chain reaction (PCR) may be related to whether synovial tissue or synovial fluid (SF) is used as the source of DNA in PCR amplification. In this study, a new PCR assay was developed and used to compare chlamydial DNA in paired samples of SF and synovial tissue from patients with arthritis.

METHODS

The PCR assay targeted the ribosomal RNA operons, which are present in 2 copies on the C trachomatis chromosome. DNA from several relevant bacteria and chlamydial serovars was used for testing this screening system. The detection of chlamydial DNA in nucleic acid preparations from matched samples of SF and synovial tissue was compared by PCR assay. Samples were obtained from 55 patients, including patients with reactive arthritis, Reiter's syndrome, and other arthropathies.

RESULTS

Testing of the PCR screening system confirmed it to be highly specific and sensitive. Use of this assay to screen DNA from SF and synovial tissue samples showed that 29 (53%) of 55 synovial tissue preparations were positive for chlamydial DNA, but only 16 (29%) of the matched SF samples from these 29 patients were similarly positive. Five (9%) of 55 SF samples, but not their tissue counterparts, were positive for chlamydial DNA by PCR.

CONCLUSION

Detection of chlamydial DNA in the joints of patients by PCR gives positive results more often when synovial tissue rather than SF is the source of target nucleic acids. Although synovial tissue is the source of choice for the most reliable determination of chlamydia in the joint, both synovial tissue and SF should be assayed if possible.

The immunobiology and immunopathology of chlamydial infections

Chlamydiae are obligate intracellular bacterial pathogens of eukaryotic cells responsible for a wide variety of important human and animal infections. In humans, chlamydial infections are generally localised to superficial epithelial or mucosal surfaces, are frequently asymptomatic and may persist for long periods of time if untreated, inducing little protective immunity. Nevertheless, neutralising antibodies of limited efficacy are produced against the main chlamydial outer envelope protein, while gamma interferon (IFN gamma) is chlamydiastatic and paradoxically may play a role both in chlamydial persistence and in protective immunity. Delayed hypersensitivity responses to chlamydiae caused by repeated or persistent infection are thought to be important in the development of the severe scarring sequelae characteristic of cicatricial trachoma and of chronic salpingitis. Chlamydial heat shock proteins bearing close homology with their human equivalents may be major targets for immunopathological responses and their expression is upregulated in IFN gamma induced persistent infection. C. pneumoniae, a common cause of acute respiratory infection in humans, may persist in coronary arteries and is strongly implicated as a risk factor in atherosclerosis and in acute myocardial infarction. This paper reviews the immunology and immunopathology of chlamydial infections in the context of the unique biology of this fascinating but challenging group of organisms.

Case report: in situ hybridization for detection of inapparent infection with Chlamydia trachomatis in synovial tissue of a patient with Reiter's syndrome

The authors have shown that protein antigens, RNA, and DNA from Chlamydia trachomatis are present in synovial tissues of patients with Reiter's syndrome (RS). However, those studies gave no insight into the host cell type involved or the precise tissue location of the bacteria. To address such issues, the authors developed an in situ hybridization system to detect chlamydia, and they used that system to examine synovial biopsies from a patient with RS and a patient without RS. The in situ system uses a previously described digoxigenin-labeled DNA probe that hybridizes with chlamydial 16S rRNA sequences in paraformaldehyde-fixed samples. Control studies with chlamydia-infected and uninfected HeLa cells confirmed that the in situ system is as sensitive as is direct fluorescence cytology for detection of the organism. Morphology of host and chlamydia cells is preserved after hybridization. Studies using synovial tissue from an osteoarthritis patient produced no in situ hybridization signal, but similar hybridization to tissue from a culture-/direct fluorescence cytology- negative RS patient had a strong intracellular signal for chlamydia within a subsynovial cell layer. These in situ hybridization results confirm the extensive presence of chlamydia in synovia and extend the authors' earlier observation that chlamydia RNA is present in the synovia of patients with RS. The data also confirm their electron microscopy studies, indicating that chlamydia are intracellular in synovial tissue, and they further show that infected host cells are located beneath the synovial lining.