Chlamydia trachomatis detection and the menstrual cycle

The complexity of interactions between female sex hormones and Chlamydia trachomatis infections

PURPOSE OF REVIEW

This review focuses specifically on the mechanisms by which female sex hormones, estrogen and progesterone, affect Chlamydia trachomatis infections in vivo and in vitro.

RECENT FINDINGS

Recent data support previous work indicating that estrogen enhances chlamydial development via multiple mechanisms. Progesterone negatively impacts Chlamydia infections also through multiple mechanisms, particularly by altering the immune response. Conflicting data exist regarding the effect of synthetic hormones, such as those found in hormonal contraceptives, on chlamydial infections.

SUMMARY

Numerous studies over the years have indicated that female sex hormones affect C. trachomatis infection. However, we still do not have a clear understanding of how these hormones alter Chlamydia disease transmission and progression. The studies reviewed here indicate that there are many variables that determine the outcome of Chlamydia/hormone interactions, including: 1) the specific hormone, 2) hormone concentration, 3) cell type or area of the genital tract, 4) hormone responsiveness of cell lines, and 5) animal models.

Chlamydia detection during the menstrual cycle: a cross-sectional study of women attending a sexual health service

Background

We investigated the detection of chlamydia at different stages of the menstrual cycle.

Methods

Electronic medical records for women attending Melbourne Sexual Health Centre between March 2011 and 31^st December 2012, who were tested for chlamydia by nucleic acid amplification of high vaginal, cervical, or urinary samples, and who recorded a date of last normal menstrual period (LNMP) between 0–28 days were included in the analysis. Logistic regression was used to calculate adjusted odds ratio (aOR) and 95% confidence intervals (CI) for the association of chlamydia with menstrual cycle adjusted by demographics and behavioural variables. Chlamydia and beta globin load were determined on those with stored samples.

Results

Of the 10,017 consultations that included a test for chlamydia and a valid LNMP, there were 417 in which chlamydia was detected. The proportion of samples with chlamydia was greater in the luteal phase (4.8%, 184/3831) than in the follicular phase (3.4%, 233/6816) both in the crude (OR 1.29 95%CI 1.1–1.6, p = 0.01) and adjusted odds ratio (aOR) 1.4 (95%CI 1.1–1.8, p = 0.004). Among women using hormonal contraception, there was no significant association with the luteal phase of the menstrual cycle (aOR 1.3, 95%CI 0.9, 1.8, p = 0.18). Among women not using hormonal contraception, there was a significant association with the luteal phase (aOR 1.6, (95% CI 1.1–2.3, p = 0.007). The chlamydia load was not significantly different in the 329 positive stored samples in weeks 3 and 4 vs weeks 1 and 2 for any site (P>0.12).

Conclusions

The higher detection of chlamydia detection in the luteal phase of the menstrual cycle in only those not taking hormonal contraception suggest that hormonal factors influence chlamydia detection. The absence of a significantly highly chlamydia load in women during the luteal phase raises questions about the mechanism.

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.

Virulence blockers as alternatives to antibiotics: type III secretion inhibitors against Gram-negative bacteria

In recent years mounting problems related to antibiotic-resistant bacteria have resulted in the prediction that we are entering the preantibiotic era. A way of preventing such a development would be to introduce novel antibacterial medicines with modes of action distinct from conventional antibiotics. Recent studies of bacterial virulence factors and toxins have resulted in increased understanding of the way in which pathogenic bacteria manipulate host cellular processes. This knowledge may now be used to develop novel antibacterial medicines that disarm pathogenic bacteria. The type III secretion system (T3SS) is known to be a potent virulence mechanism shared by a broad spectrum of pathogenic Gram-negative bacteria that interact with human, animal and plant hosts by injecting effector proteins into the cytosol of host cells. Diseases, such as bubonic plague, shigellosis, salmonellosis, typhoid fever, pulmonary infections, sexually transmitted chlamydia and diarrhoea largely depend on the bacterial proteins injected by the T3SS machinery. Recently a number of T3SS inhibitors have been identified using screening-based approaches. One class of inhibitors, the salicylidene acylhydrazides, has been subjected to chemical optimization and evaluation in several in vitro and ex vivo assays in multiple bacterial species including Yersinia spp., Chlamydia spp., Salmonella spp. and Pseudotuberculosis aeruginosa. Reports published up to date indicate that T3SS inhibitors have the potential to be developed into novel antibacterial therapeutics.

Impact of patient characteristics on performance of nucleic acid amplification tests and DNA probe for detection of Chlamydia trachomatis in women with genital infections

The performance of nucleic acid amplified tests (NAAT) for Chlamydia trachomatis at the cervix and in urine was examined in 3,551 women, and the impacts of clinical findings (age, endocervical and urethral inflammation, menses, and gonococcal coinfection) were assessed. Ligase chain reaction (LCR) and first-generation uniplex PCR were studied relative to an unamplified DNA probe (PACE2) and to an expanded, independent diagnostic reference standard. Relative to the expanded standard, cervical or urine LCR was generally the most sensitive test in most subgroups. Increased detection by NAAT of cervical C. trachomatis over PACE2 was highest among women without mucopurulent endocervical discharge versus those with (relative increase in positivity with cervical LCR, 46%) and among women > or =20 years old versus younger women (relative increase in positivity with cervical LCR, 45%). The sensitivity of cervical PCR was highest when mucopurulent endocervical discharge was present (84%) and highest for cervical LCR when cervical gonococcal coinfection was detected (91%). Urethral inflammation was associated with higher sensitivities of urine LCR (86 compared to 70% when inflammation was absent) and PCR (82 compared to 62% when inflammation was absent). Menses had no effect on test performance. The effects of patient characteristics on test specificities were less pronounced and were closely related to observed sensitivities. These findings support expanded use of NAAT for screening and diagnosis of C. trachomatis in diverse clinical populations of women.

Parallel observation of four methods for screening women under 25 years of age for genital infection with Chlamydia trachomatis

OBJECTIVES

To compare four methods of screening women for Chlamydia trachomatis in an obstetrics and gynaecology department.

STUDY DESIGN

A total of 303 healthy women under 25 years were recruited from antenatal, induced abortion, and family planning clinics. Each underwent parallel testing of endocervical specimens by enzyme immunoassay (EIA) and ligase chain reaction (LCR), vulval swabs by LCR, and urine by LCR. Outcome measures included sensitivity, specificity, acceptability of each method, and the influence of pregnancy.

RESULTS

Overall prevalence (95% CI) was 9.9% (6.8-14%). All methods had a high rate of detection (75-100%), not affected by pregnancy. Urine was most acceptable, followed by vulval swabbing.

CONCLUSIONS

Opportunistic screening of women under 25 years attending obstetric and gynaecology affiliated clinics found high rates of C. trachomatis infection. Both urine and vulval swab methods were highly sensitive, acceptable, and not affected by pregnancy status. Due to pragmatic issues surrounding the urine method, screening by vulval swabs deserves wider recognition.

Chlamydia trachomatis infection: incidence, health costs and prospects for vaccine development

Chlamydia trachomatis infection is now the most common sexually transmitted disease worldwide. World Health Organisation figures estimated that 89 million new cases of genital Chlamydia infections occurred in 1995, highlighting the worldwide prevalence of infections and the economic burden on healthcare delivery. A number of methods have been developed for detection of chlamydial infection, which vary in sensitivity and specificity. No single method has yet gained general acceptance and in many countries Chlamydia infections are not reported, suggesting that the above figures may be an underestimate of the problem. As yet there is no consensus as to what constitutes a protective immune response against genital Chlamydia infection. Studies in animal models have shown that cell-mediated immunity, both Th1-driven macrophage activation and cytotoxic T cell responses, as well as antibody can mediate protection at different stages of the chlamydial life cycle. A successful vaccine would probably need to elicit both a systemic cell-mediated immune response to limit/resolve established infections and a mucosal IgA response to reduce bacterial shedding and the resulting spread of infection to partners of infected individuals. The immune response to Chlamydia, either through natural infection or following immunisation, also has the potential to enhance inflammation and to act as a driving force for constant mutation in the variable regions of the major outer membrane protein. As a result a constant prevalence of infection is maintained even in an immune population through the emergence of new allelic variants. Immune responses against antigens such as the 60 kDa heat shock protein can exacerbate inflammation through molecular mimicry and must not be elicited as a result of vaccination. Thus there are many challenges for the development of a successful vaccine which must elicit immunity against multiple serovars while at the same time minimising damaging pro-inflammatory immune responses.

Impact of menstrual cycle on the diagnostic performance of LCR, TMA, and PCE for detection of Chlamydia trachomatis in home obtained and mailed vaginal flush and urine samples

OBJECTIVES

To assess the impact of the menstrual cycle on the diagnostic performance of various assays for detection of Chlamydia trachomatis in home obtained and mailed vaginal flush and urine specimens.

METHODS

A ligase chain reaction assay (LCR; Abbott Laboratories), a transcription mediated amplification assay (TMA; Gen-Probe), and an enzyme amplified immunoassay (PCE; Dako Diagnostics) were evaluated for their validity in detecting C trachomatis in vaginal flush, first void urine, and midstream urine specimens obtained by female high school students at home and mailed directly to the diagnostic laboratory.

RESULTS

C trachomatis was detected in 45 of 889 females (5.1%). The vaginal flush material was positive by TMA and LCR in 84% and 82% of the chlamydia positive females, respectively. First void urine was positive by TMA in 73% and by LCR in 49% of the cases. Midstream urine was positive by TMA and LCR in 69% and 42% of the females, respectively. On a pool of first void and midstream urine, PCE detected 49% of the chlamydia positive females. The overall prevalence of C trachomatis increased with increasing time after the last menstrual bleeding. In urine samples, but not vaginal flush specimens, obtained 3 weeks after the last menstrual bleeding, the sensitivities of TMA, LCR, and PCE decreased markedly suggesting that inhibitors to the assays are excreted in the urine but not in vaginal secretions at this time.

CONCLUSION

Vaginal flush samples are superior to urines for detection of chlamydia infections in females. In screening of young asymptomatic females, samples should be obtained in the latter part of the menstrual cycle.