Summary: A national opportunistic chlamydia screening programme, mainly targeting young sexually active women, is gradually being introduced across the UK and in future will predominantly occur in primary care sites. The relative efficacy of recommended antibiotic treatments for chlamydia has been poorly studied and especially that of single dose azithromycin. In Portsmouth, 1536 patients treated for chlamydia, with four different antibiotic regimens, during the Department of Health pilot study, were asked to return for test of cure. No difference in treatment outcome was found using doxycycline, oxytetracycline, erythromycin or azithromycin. Directly observed therapy with azithromycin may be especially helpful in treating young chlamydia-positive patients.
Keywords: Chlamydia trachomatis, treatment, antibiotics
Introduction
The most active drugs against Chlamydia trachomatis infection, in tissue culture assays, are tetracyclines followed by macrolides, sulphonamides, some quinolones and clindamycin1. In the UK the Association for Genitourinary Medicine (AGUM) and the Medical Society for the Study of Venereal Diseases (MSSVD) have produced clinical effectiveness guidelines for the management of C. tmchomatis genital tract infection2. For uncomplicated infection they recommend the use of either doxycycline or azithromycin. Erythromycin, Deteclo (tetracycline), ofloxacin or tetracycline are mentioned as alternative regimens. In clinical practice resistance to these antibiotics appears to be rare3 and such treatment is safe, cheap and effective4 so that routine test of cure (TOC) is no longer considered necessary. However, randomized controlled studies of chlamydia treatment are few, mostly with small numbers of participants, short follow-up and incomplete details of partner notification4. In 1999 the Department of Health (DH) England set up pilot sites, in Portsmouth and the Wirral, to assess the feasibility, effectiveness and acceptability of opportunistic testing for genital tract C, tmchomatis infection in women aged 16 to 24 years over a period of 12 months. The main findings from this study have now been published5-7. As part of the screening pilot over 1500 participants found to be chlamydia-positive in Portsmouth were treated with either doxycycline, azithromycin, erythromycin or oxytetracyline and all were offered partner notification and TOC. The aim of this study was to compare the cure rates for each of these antibiotics.
Participants and methods
In the DH pilot study all women aged 16-24 years, who had ever been sexually active, were offered opportunistic chlamydia screening when they attended for any reason at a variety of healthcare sites. The majority of 60% were screened in general practice (GP), 20% in family planning (FP) and 5% in genitourinary medicine (GUM) with the remainder attending antenatal, gynaecology, colposcopy, infertility or young people’s clinics. Men in the same age group were offered testing if they attended GUM or young people’s clinics. Men and women under the age of 16 years who attended for a sexual health matter could also participate if deemed Fraser competent. Full details of the study methodology have been published elsewhere8.
First-pass urine samples were tested using a nucleic acid amplification method – the ligase chain reaction (Abbott Laboratories, Maidenhead, UK). Patients found to be chlamydia- positive were contacted by the research nurse and advised to attend GUM for treatment, partner notification and full sexual health screening9. Those unable to attend GUM were treated by the research nurse, usually in a FP clinic, or by their general practitioner. Doxycycline, 100 mg twice daily for seven days, was the standard first line treatment given. Azithromycin as a single l g oral dose, taken under direct observation, was given when compliance with a longer regimen was doubtful. Erythromycin, 500 mg twice daily for 10 days, was prescribed for pregnant women and those known to be allergic to tetracyclines. Although not included in the study protocol some patients, mostly those offered screening while attending GUM, were treated with oxytetracyline 500mg twice daily for 10 days for a suspected infection prior to chlamydia results becoming available. This was the routine therapy for chlamydia infection in use in the GUM department at the time.
All patients treated for chlamydia were asked to return for a TOC, using the same methodology, after 2-4 weeks.
Results
In Portsmouth, 1203 patients diagnosed with chlamydia predominantly in a community setting (GP or FP clinics) were known to have received antibiotic treatment. A further 333 initially diagnosed in GUM were also treated. Details of the medication prescribed, whether patients returned for a TOC and TOC results are shown in Table 1. Overall, of the 1203 community-diagnosed patients 40 (3.3%) were still chlamydia-positive on TOC compared with 1 (0.3%) of the 333 GUM-diagnosed patients.
Table 1. Details of antibiotic therapy in patients diagnosed Chlamydia trachomatis-positive in community and CUM settings
Table 2. Community and genitourinary medicine treated patients analysed together
Table 2 shows cure rates, as indicated by a chlamydia-negative TOC, obtained with each of the four antibiotic regimens when community and GUM patient results were analysed together. Of those who attended for TOC no difference in positivity rate was found (P = 0.4333). Partner notification details for those patients with a chlamydia-positive TOC are included.
Discussion
In this study no difference in efficacy, as determined by the number of patients with a chlamydiapositive TOC, was found between doxycycline, azithromycin, erythromycin or oxytetracycline
With the availability of effective antibiotic treatments, as well as staffing and cost pressures, TOC for chlamydia is no longer recommended. Not unexpectedly, of the 1536 treated patients described in this paper 300 (19.5%) failed to attend for TOC with little difference across the treatment arms. The number of patients with chlamydiapositive TOC was small in all groups and the majority of their partners are known to have been seen and treated. All patients with a chlamydiapositive TOC reported only one partner in the previous three months with the exception of five patients who reported two. Partner notification was considered unsuccessfully completed unless all traceable partners named by the patient were known to have been seen. Inevitably the accuracy of contacts’ details cannot be guaranteed but the treatment results obtained in this study may reflect a true failure rate of the antibiotics used.
Patients diagnosed with chlamydia in the community had a TOC chlamydia-positivity rate of 3.3% compared with 0.3% in those initially diagnosed in GUM. This marked difference may be accounted for by the fact that those attending GUM had chosen to present for a sexual health screen possibly suspecting that they may have been at risk of acquiring a sexually transmitted infection. Those tested in the community were offered screening while attending for any health reason. In GUM, patients found to have evidence of infection on examination or microscopy, even if asymptomatic, were treated and contact tracing initiated ahead of a positive chlamydia result being obtained. Often a partner would accompany a patient to the clinic and if necessary would be offered a check at the same time. It is likely that in these circumstances motivation to complete medication and to ensure treatment of partners would be higher than in those offered opportunistic screening elsewhere who might wait several weeks before receiving their results and obtaining treatment.
In conclusion, the main finding of this study was that, in a large opportunistic screening programme for chlamydia in young people attending predominantly primary care settings, there was no difference in treatment outcome using doxycycline, azithromycin, erythromycin or oxytetracycline in those found to be chlamydia- positive.
Acknowledgements: The authors wish to thank all doctors, nurses and receptionists in the Portsmouth GUM department who worked with them on the pilot study. The Chlamydia Pilot Study was funded by the DH (England).
References
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2 UK Clinical Effectiveness Guidelines, [www.agum.org.uk]
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5 Pimenta JM, Catchpole M, Rogers PA, et al. Opportunistic screening for genital chlamydial infection. 1: Acceptability of urine testing in primary and secondary healthcare settings. Sex Transm Infect 2003;79:16-21
6 Pimenta JM, Catchpole M, Rogers PA, et al. Opportunistic screening for genital chlamydial infection. 2: Prevalence among healthcare attenders, outcome, and evaluation of positive cases. Sex Transm Infect 2003;79:22-7
7 Underhill G, Hewitt G, McLean L, et al. Who has chlamydia? The prevalence of genital tract Chlamydia trachomatis within Portsmouth and South East Hampshire, UK. J Fam Plann 2003;29:17-21
8 Catchpole M, Gr\ay M, Hopwood J, et al. Chlamydia trachomatis screening pilot: Project initiation document. London: Department of Health, 2000
9 Harindra V, Tobin JM, Underhill G. Opportunistic chlamydia screening; should positive patients be screened for co-infections? M J STD AIDS 2002;13:821-5
(Accepted 5 August 2003)
J M Tobin FRCOG MFFP1, V Harindra FRCP1 and R Mani MRCP2
1 Department CU Medicine, St Mary’s Hospital, Portsmouth PO3 6AD; 2 Department CU Medicine, Royal South Hants Hospital, Southampton, UK
Correspondence to: Dr J M Tobin
E-mail: [email protected]
Copyright Royal Society of Medicine Press Ltd. Nov 2004
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