Is it time to switch to doxycycline from azithromycin for treating genital chlamydial infections in women? Modelling the impact of autoinoculation from the gastrointestinal tract to the genital tract.
BACKGROUND
Single-dose azithromycin is recommended over multi-dose doxycycline as treatment for chlamydial infection. However, even with imperfect adherence, doxycycline is more effective in treating genital and rectal infection. Recently, it has been suggested that autoinoculation from the rectum to the genitals may be a source of persistent chlamydial infection in women. We estimated the impact autoinoculation may have on azithromycin and doxycycline effectiveness.


METHODS
We estimate treatment effectiveness using a simple mathematical model, incorporating data on azithromycin and doxycycline efficacy from recent meta-analyses, and data on prevalence of rectal infection in women with genital chlamydial infection.


RESULTS
When the possibility of autoinoculation is taken into account, we calculate that doxycycline effectiveness may be 97% compared to just 82% for azithromycin.


CONCLUSIONS
Consideration should be given to re-evaluating azithromycin as the standard treatment for genital chlamydia in women.
The Kirby Institute, UNSW Australia, Sydney, NSW, 2052, Australia. acraig@kirby.unsw.edu.au.
Andrew P
AP
Craig
Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, 3004, Australia. kongf@unimelb.edu.au.
Fabian Y S
FY
Kong
University of Arkansas for Medical Sciences & Arkansas Children's Hospital Research Institute, Little Rock, AR, 72202, USA. VLYeruva@uams.edu.
Laxmi
L
Yeruva
Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, 3004, Australia. j.hocking@unimelb.edu.au.
Jane S
JS
Hocking
University of Arkansas for Medical Sciences & Arkansas Children's Hospital Research Institute, Little Rock, AR, 72202, USA. RankRogerG@uams.edu.
Roger G
RG
Rank
The Kirby Institute, UNSW Australia, Sydney, NSW, 2052, Australia. dwilson@unsw.edu.au.
David P
DP
Wilson
The Kirby Institute, UNSW Australia, Sydney, NSW, 2052, Australia. bdonovan@kirby.unsw.edu.au.|Sydney Sexual Health Centre, Sydney Hospital, Sydney, NSW, 2000, Australia. bdonovan@kirby.unsw.edu.au.
Basil
B
Donovan
D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D017963:Azithromycin / Q000494:pharmacology / Q000627:therapeutic use*; D002690:Chlamydia Infections / Q000188:drug therapy*; D002692:Chlamydia trachomatis; D004318:Doxycycline / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D041981:Gastrointestinal Tract / Q000187:drug effects; D005831:Genital Diseases, Female / Q000188:drug therapy*; D006801:Humans; D008962:Models, Theoretical; D016896:Treatment Outcome; D014566:Urogenital System / Q000187:drug effects
D000900:Anti-Bacterial Agents; D017963:Azithromycin; D004318:Doxycycline