Antibiotic consumption and chlamydia prevalence in international studies

To determine whether there is an ecological association between antibiotic use and chlamydia prevalence.

A systematic review was undertaken of international studies on chlamydia prevalence among women aged 15-25 years published between 2000 and 2005. Preference was given to studies using nucleic acid testing and representative population-based sampling methods. Data were obtained on per capita antibiotic consumption according to the defined daily dose.

For the 12 countries for which both antibiotic consumption and relevant prevalence data for chlamydia were available, a non-significant negative correlation was found between total antibiotic consumption per capita and chlamydia prevalence among younger women according to country (r(s) = -0.242, P = 0.449). When an outlier (from the Netherlands) was excluded, the correlation was significant (r(s) = -0.615, P = 0.044). Combined use of tetracyclines and macrolides was also associated with lower chlamydia prevalence (r(s) = -0.697, P = 0.017).

It is possible that antibiotics used for other reasons may have unexpectedly reduced the prevalence of chlamydia.