Chlamydia trachomatis infection is stabilised but not eradicated by repeated antibiotic treatment
Rates of ocular chlamydia among children living in hyper-endemic areas of Africa can be stabilised with mass, annual or biannual azithromycin administrations, however according to the results of research published in PLoS Medicine, this approach fails to achieve the goal of complete eradication of the disease.
What is ocular chlamydia
The ocular chlamydia o trachoma is a bacterial infection of the conjunctiva and cornea, caused by Chlamydia trachomatisa gram-negative, intracellular obligate bacterium. Transmission of theinfection can come from the eyes or nose of an infected person either through direct or indirect contact, through clothes or insects that have been in contact with the eyes or nose of the sick person.
Trachoma constitutes the main cause of blindness in areas where the infection is hyper-endemic, concentrated in Africa and especially in northern Ethiopia.
The WHO (World Health Organisation) recommends annual mass administrations of azithromycin communities with prevalence rates >5% of trachoma follicular inflammation (TF) in children, followed by treatment re-treatment at 1, 3 and 5 years. Doubts arose, however, about the actual efficacy of these multiple rounds of antibiotic therapy, later confirmed by the results of the study by the University of California, San Francisco team, led by Prof. Jeremy D. Keenan.
The Chlamydia Therapy Study
The 7-year study observed 48 communities with a total of 3,938 children, aged between 0 and 9 years, and included 4 annual cycles of azithromycin treatment followed by randomisation for continuation or discontinuation of treatment.
In a selected sample of children, at 36 months after baseline, it appeared that in communities that had continued to receive treatment, despite 7 years of annual treatment, the infection was not eradicated, but had a prevalence of 6.6%. This figure was, however, significantly lower than in the communities where azithromycin had been discontinued, which reached a prevalence of 14.7%. In neither branch of the study was the threshold <5% TF, established as the withdrawal level, reached.
Prof. Keenan then drew the conclusion that 'Communities in which annual or biannual mass azithromycin administrations were continued had the stabilisation of the infection and clinical disease, suggesting that antibiotics alone are not sufficient for total eradication of infection in hyper-endemic areas. However, continuing with mass distribution of azithromycin after three to five years is far better to maintain low levels of ocular chlamydiarather than discontinuing the treatment'.
Source
Keenan JD, Tadesse Z, Gebresillasie S et al. Mass azithromycin distribution for hyperendemic trachoma following a cluster-randomised trial: A continuation study of randomly reassigned subclusters (TANA II). PLoS Med. 2018 Aug 14;15(8):e1002633. doi: 10.1371/journal.pmed.1002633. eCollection 2018 Aug.
To help little brothers Sililo, 6 years old, and Maimbolwa, only 3 years old (pictured) see https://www.sightsavers.it/appelli-speciali/2018/01/tu-fai-la-differenza-contro-il-tracoma/
Dr. Carmelo Chines
Direttore responsabile
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