Is a test of cure necessary following treatment for cervical infection with Chlamydia trachomatis?

Variation in clinical practice in genitourinary medicine clinics in the United Kingdom

OBJECTIVES

This study was conducted to examine the variation in clinical practice in genitourinary medicine clinics in the United Kingdom in early 2002.

METHODS

Questionnaires were sent to all 234 consultants in charge of genitourinary medicine clinics in the United Kingdom in March-May 2002. The questions concerned clinical practice in respect of asymptomatic patients presenting for an infection screen, and practice in respect of some specific sexually transmitted and other genitourinary infections.

RESULTS

The test for infection least likely to be offered to heterosexuals is an HIV test (71% and 70% of clinics routinely offer this to male and female heterosexuals respectively). The practice of permitting "low risk" patients to telephone for their HIV results now extends to 24% of clinics. 34% of clinics do not require patients with non-specific urethritis to attend for follow up. 41% of clinics routinely ask patients treated for Chlamydia trachomatis to return for a follow up chlamydia detection test. 25% of clinics routinely offer two tests of cure to all patients with gonorrhoea. 6% of clinics do not routinely offer syphilis serology to heterosexuals. Other significant variations in clinical practice were documented.

CONCLUSIONS

Overall, our findings indicate the need for further evidence to guide clinical practice and a wider knowledge and debate of national guidelines.

Infrequent detection of Chlamydia trachomatis in a longitudinal study of women with treated cervical infection

OBJECTIVE

To determine how often Chlamydia trachomatis cervical infections are detected in women following completion of a currently recommended treatment regimen and the reason for recurrence.

METHODS

A longitudinal follow-up study of 43 initially C trachomatis-positive women for periods of up to two years.

RESULTS

C trachomatis was detected in three women, 19, 16 and about four months, respectively after completion of treatment. All specimens from the other 40 women which were taken during visits two to seven, that is periods of three to 700 days after treatment, were chlamydia-negative.

CONCLUSION

Although C trachomatis is usually eradicated from the genital tract by conventional treatment, occasionally it may be found again. It is difficult to determine whether detection after treatment is due to persistence or reinfection and further studies are required.

Efficacy of single-dose azithromycin versus doxycycline in the treatment of cervical infections caused by Chlamydia trachomatis

The efficacy of single-dose azithromycin therapy in the treatment of cervical Chlamydia trachomatis infections was compared to that of a standard seven-day course of treatment with doxycycline. Cervical samples from 60 patients reacted positively in an enzyme immunoassay for detection of Chlamydia trachomatis. In 31 patients Chlamydia trachomatis was isolated from the sample taken before treatment. Fourteen of the 31 patients were treated with doxycycline and 17 with azithromycin. All cultures of samples taken one and four weeks after the start of therapy were negative. All 31 isolates showed a similar pattern of MICs for the seven antibiotics tested, including azithromycin and doxycycline. No differences were observed between isolates of different serovars. In samples from four patients chlamydial DNA could be detected by PCR one week after the start of the therapy and in two patients also after four weeks. No difference in microbiological parameters could be observed between the two treatment groups. It is concluded that single-dose azithromycin is as effective as a seven-day course of doxycycline in the therapy of cervical Chlamydia trachomatis infections.

Chlamydia trachomatis in sexually active teenage girls. Factors related to genital chlamydial infection: a prospective study

The incidence of new infections with C trachomatis was found to be 19%. Predisposing factors for a subsequent chlamydial infection were multiple partners, smoking and previous infection with C trachomatis. Girls with a spread cervical ectopy were not more likely to contract a chlamydial infection in one year than girls without an ectopy. Oral contraceptive use was not found to predispose for a chlamydial infection.

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.