Chlamydial infection of the cervix in contacts of men with nongonococcal urethritis

Chlamydia trachomatis and oral contraceptive use: a quantitative review

OBJECTIVES

Chlamydia trachomatis is now recognised as a major sexually transmitted disease; oral contraceptive use is rapidly increasing particularly in developing countries. There are thus important public health implications of the many reports that isolation of C trachomatis is more frequent among users of oral contraceptives. The aim of this analysis was to assess the strength and consistency of this association by summarising published studies between 1972 and 1990.

DESIGN

Studies identified were grouped according to whether they were prospective or case-control studies. Data were extracted and pooled estimates of the unadjusted odds ratios were made for all studies, as well as for sub-groups defined by an index of study quality, background prevalence of C trachomatis, and the contraceptive comparison being made.

LOCATION

Studies in the analysis were mainly conducted in Europe and North America; the meta-analysis was done at the Harvard School of Public Health, Boston, MA, USA.

RESULTS

The pooled estimated unadjusted odds ratio for 29 case-control studies examined was 1.93 (95% CI, 1.77-2.11), indicating an almost twofold increased risk of chlamydial infection for oral contraceptive users. Neither study quality nor prevalence of C trachomatis modified this risk. When compared to the use of barrier contraceptives, however, the risk of infection for women using oral contraceptives increased to 2.91 (95% CI, 1.86-4.55). The pooled estimated protective effect of barrier methods in these studies was 0.34 (95% CI, 0.22-0.54).

CONCLUSIONS

Cross-study comparisons of the relationship between oral contraceptive use and chlamydial infection are limited by the design and analysis of many component studies which did not control for confounding factors such as sexual behaviour and age. The almost twofold risk of increased chlamydial infection for oral contraceptive users, supported by the findings of two prospective studies, however, points to the importance of considering the risks and benefits of oral contraceptive use in women who are likely to be exposed to C trachomatis and other STDs. The protective effect of barrier methods emphasizes the continued need for promoting barrier methods of contraception.

Laboratory techniques for the diagnosis of chlamydial infections

Yolk-sac inoculation of embryonated eggs was superseded 25 years ago by the use of cell cultures (often McCoy) for the isolation of Chlamydia trachomatis. Centrifugation of specimens onto the cell monolayers was shown to increase sensitivity, but little of late has further improved sensitivity which is at least ten-fold greater than that of eggs. However, culture is slow and labour intensive so that non-cultural techniques without these drawbacks have come to dominate. Direct fluorescent antibody (DFA) tests are rapid and have sensitivities that range from 70% to 100% for men and 68% to 100% for women, and specificities that range from 87% to 99% for men and 82% to 100% for women; if the tests are read by competent observers the values are at the top end of the ranges. The detection rate may be enhanced even further by relatively low-speed centrifugation of specimens before staining. Skilled reading is not a feature of enzyme immunoassays (EIAs) which according to the literature have sensitivities that range from 62% to 97% for men and 64% to 100% for women, and specificities that range from 92% to 100% for men and 89% to 100% for women. However, comparison against poor reference tests is responsible for most of the higher values and the clinician should not be misled into believing that EIAs have excellent sensitivity; the lower values in the ranges are closer to reality. Furthermore, EIAs that are being designed for use by general practitioners should be regarded with the greatest caution since lack of sensitivity means that chlamydia-positive patients will go undetected. The polymerase chain reaction (PCR) is not bedevilled by insensitivity but it is no more sensitive than the most sensitive cell culture or DFA tests. PCR is unsuitable for routine diagnosis but has a place as a research tool. For men, examination of "first-catch" urine samples by the best of the non-cultural procedures provides an acceptable non-invasive approach to diagnosis; for women, the value of examining urine may be less, but needs to be thoroughly tested. However, there is little doubt that a Cytobrush used to obtain cervical specimens holds no practical advantage over a swab. Serological tests are reliant on the provision of paired sera for making a diagnosis; high antibody titres in single sera may be suggestive of an aetiological association in deep-seated chlamydial infections (epididymitis, arthritis, salpingitis, etc), but unequivocal interpretation is unusual, particularly in an individual case, since the distinction between a current and past infection is problematical.

A new diagnostic index for predicting cervical infection with either Chlamydia trachomatis or Neisseria gonorrhoeae

OBJECTIVE

To develop and test a diagnostic index for estimating the probability of cervical infection with either Chlamydia trachomatis or Neisseria gonorrhoeae.

DESIGN

Prospective, cross-sectional study in two phases: 1) to develop a diagnostic index based on independent predictors of cervical infection; 2) to test the index.

SETTINGS

A hospital-based clinic and a student health service.

PATIENTS

Development phase: 190 nonpregnant women seen in the gynecology clinic; testing phase: 588 women seen in the gynecology clinic (n = 372) or the student health service (n = 216).

INTERVENTIONS

Experienced clinicians recorded historical, physical, and microscopic findings on standard forms and tested women for chlamydial and gonococcal infections.

RESULTS

Three independent predictors of cervical infection were identified and weighted: age (two points if less than 20 years and one point if 20-29 years); a new sex partner or one suspected of having a genital infection (one point); purulent vaginal discharge (one point). In the testing groups, cervical infection was present in none of 62 women with no points, seven of 269 (3%) with one point, 14 of 188 (7%) with two points, and 19 of 69 (28%) with three or four points (p less than 0.001). The index estimated the probability of infection more accurately (p less than 0.01) than did clinicians, performed well in each site, and remained accurate when C. trachomatis and N. gonorrhoeae were considered separately.

CONCLUSION

The diagnostic index accurately estimates the probability of cervical infection with either C. trachomatis or N. gonorrhoeae and may be useful in selecting women for definitive diagnostic testing.

Evaluation of a seven day course of oxytetracycline in women with chlamydial cervicitis

In an urban clinic for sexually-transmitted diseases, 270 women with cervical swabs culture positive for Chlamydia trachomatis were treated with 250 mg oxytetracycline orally four times daily for 7 days. Chlamydial infection was found again in 17 of 220 (7.3%) women examined one month after treatment, and in 12 of 113 (9.7%) women reexamined three months after treatment. Even in cases where reinfection seemed unlikely, only 177 of 198 (89%) were cured. Most post-treatment infections were not clinically apparent, and laboratory follow-up was essential for evaluation of chemotherapy.

Chlamydial infections of the urethra in women

Cervical and endourethral swabs from 360 untreated women attending a sexually transmitted disease (STD) clinic were cultured for Chlamydia trachomatis and other genitourinary pathogens. The patients included contacts of men with non-gonococcal urethritis, women with gonorrhoea, and those in whom symptoms suggestive of urinary tract infection were the main reasons for their attendance. Chlamydial infection of the urethra was less common than, and seldom occurred in the absence of, cervical chlamydial infection; it was frequently silent, producing no signs or symptoms of urethritis. Only 33/96 women with evidence of urethritis gave chlamydia positive urethral swabs, and 14 of them had other concurrent infections of the genitourinary tract. Chlamydia trachomatis thus does not appear to be a major cause of the signs and symptoms of urethritis commonly found in women attending STD clinics, and there seems to be no indication for taking routine urethral swabs to aid in the diagnosis of chlamydial infection in women.

Prevalence of chlamydial infection in promiscuous women

Chlamydia trachomatis was isolated from the cervix of 18 (33%) of 55 women who admitted to two or more casual sexual contacts to one (3%) of 32 women who admitted to one casual contact in the preceding month. The chlamydial infections did not produce characteristic clinical features. Since promiscuous women are at high risk of acquiring chlamydial infection, they should be regarded as a priority group when resources for chlamydial isolation are limited.

Chlamydial infection: a common sexually transmitted disease

Chlamydia trachomatis infection is more prevalent than gonorrhea and causes a similar clinical picture. It is the prime cause of non-gonococcal urethritis in men and pelvic inflammatory disease in women. Its sequelae in women are ectopic pregnancy and infertility. It can be transmitted from an infected mother to her newborn child, leading to inclusion conjunctivitis and pneumonia. Tetracycline and erythromycin are effective in eradicating chlamydial infections, but the penicillins are not. Screening of high risk groups and special diagnostic facilities would help control this common sexually transmitted disease.

Quantitative study of Chlamydia trachomatis in genital infection

Chlamydia trachomatis inclusion counts on inoculated McCoy cell coverslips were used as an index of the degree of infection of the cervix in women and of the urethra in men with urethritis. High inclusion counts were obtained significantly more often from men than from women, from women with cervical ectopy, and from women who had had recent sexual intercourse. Low inclusion counts were significantly more common in men with a past history of gonococcal urethritis. Higher chlamydial isolation rates in women with gonorrhoea and in women taking the contraceptive pill could not be attributed to a greater degree of infection, since inclusion counts were not raised in these patients. There was evidence that strains of C trachomatis might vary in their ability to establish themselves in the genital tract because high counts in men with NGU were associated with high counts in their female consorts and the levels of counts in men were associated with the frequency of chlamydial isolation from their female consorts. The relatively simple technique of inclusion counts in cultures for chlamydia from the genital tract may yield valuable information about the behaviour of different strains of C trachomatis in causing pathological changes, in the transmission of infection between individuals, and in the response to specific chemotherapy.

Post-gonococcal cervicitis and post-gonococcal urethritis. A study of their epidemiological correlation and the role of Chlamydia trachomatis in their aetiology

In a study of 157 men and 141 women with gonorrhoea post-gonococcal urethritis (PGU) in men was significantly more common among chlamydia-positive (76%) than among chlamydia-negative (22.5%) patients. Clinical investigations of PGU detected 95% of the patients infected with C trachomatis. PGU was, however, asymptomatic in over half of the patients and a careful follow-up for 3-6 weeks was necessary to detect between 80% and over 90% of cases. PGU was not related to age, past history of gonorrhoea or non-gonococcal urethritis, severity of gonococcal infection, or chlamydial inclusion count. Although post-gonococcal cervicitis (PGC) in women was an identifiable entity, it was detected in only one-third of chlamydia-positive patients. PGC was significantly associated with the 20-29 year-old age group but was not related to symptoms or chlamydial inclusion count. In the absence of facilities for culturing chlamydia, selection on an epidemiological basis of all female consorts of men with PGU, together with the remaining women with PGC, would have resulted in some unnecessary treatments and left untreated up to 30% of those harbouring C trachomatis.

Oral contraceptive use and prevalence of infection with Chlamydia trachomatis in women

One thousand eight non-pregnant women aged 16-34 years, presenting for the first time at a clinic for sexually transmitted diseases (STD), were examined and screened for infection with Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and Candida species. The respective prevalence rates were 21.1%, 20.7%, 13.4%, and 27.8%. Isolation rates for C trachomatis, either occurring alone or in association with other genital infections, were significantly greater in women using oral contraceptive agents. This was not because oral contraceptive users were more promiscuous. The findings strengthen the case for providing a routine chlamydial culture service for women attending STD clinics. They also indicate that the likelihood of chlamydial infection in women taking oral contraceptives is increased.

Endometritis caused by Chlamydia trachomatis

Chlamydia trachomatis was found to be the aetiological agent of endometritis in three women with concomitant signs of salpingitis. All patients developed a significant antibody response to the organism. Chlamydia were recovered from aspirated uterine contents of two patients and darkfield examination of histological sections showed chlamydial inclusions in endometrial cells in one patient. Thus, C trachomatis can be recovered from the endometrium of patients in whom the cervical culture result is negative. In one patient curettage showed endometritis with a characteristic plasma-cell infiltration. The occurrence of chlamydial endometritis may explain why irregular bleeding is a common finding in patients with salpingitis. It also suggests a canalicular spread of chlamydia from the cervix to the Fallopian tubes.

Epidemiological and clinical correlates of chlamydial infection of the cervix

Of 474 women studied to identify epidemiological and clinical correlates of chlamydial infection of the cervix, Chlamydia trachomatis was isolated from 158 (33.3%) of all women, from 48.3% of those infected with Neisseria gonorrhoeae, from 43% of the sexual consorts of men with nongonococcal urethritis, and from 74% of those whose consorts were also infected with C trachomatis. C trachomatis was the sole pathogen found in 58 women. Age, marital state, occupation, past history of gonorrhoea, menstrual state, and symptoms had no predictive value. The isolation of C trachomatis was significantly associated with N gonorrhoeae, the use of oral contraceptives, cervical ectopy, cervicitis, and last sexual exposure more than one week previously. Except for three patients, none of the criteria alone or in combination was reliable enough to predict with acceptable accuracy that the 30 chlamydia-positive women among the 191 who were not infected with N gonorrhoeae and whose consorts were not known to have urethritis harboured chlamydia.

Quantitative aspects of chlamydial infection of the cervix

In 580 women with Chlamydia trachonmatis infection of the cervix, the degree of the infection was assessed by counting the number of chlamydial inclusions which developed in McCoy cell monolayers inoculated with cervical swab material under standardised conditions. In 34% of these women inclusion counts were <100 per monolayer whereas in 36% the counts were greater than or equal to 1000. Clinical features in each of these groups were compared to see if certain factors could be identified as the cause, or the result, of high-grade rather than low-grade infection. A significant association was found between high inclusion counts and the presence of cervical mucopus or cervical ectopy. Oral contraceptives acted additively with ectopy but had no significant effect alone. Concurrent gonorrhoea did not affect the degree of chlamydial infection. High inclusion counts were more common in women under 20 years of age than in older women.