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How has the threat of multi-drug resistant gonorrhea changed chlamydia treatment recommendations?
Nov 28, 2012 by Richard Lester, Medical Head, STI/HIV Services (Clinical Prevention Services), BCCDC
The global threat of multi-drug resistant Neisseria gonorrhea has led to recent changes in treatment recommendations.
Intramuscular ceftriaxone (250mg single dose IM) is now preferred over oral cefixime to treat all proven or suspected gonococcal infections in gay, bisexual and other men who have sex with men (MSM), and for pharyngeal gonorrhea irrespective of the gender of client and partners. In BC, approximately 25% of individuals diagnosed with gonorrhea also test positive for chlamydia within one month. Due to prolonged window periods for tests to become positive for chlamydia compared with gonorrhea, we recommend that all individuals with proven or suspected gonorrhea are empirically treated for chlamydia, regardless of the chlamydia test results.
Doxycycline (100mg PO bid x 7days) and azithromycin (1g PO single dose) are equally effective treatment options for uncomplicated chlamydia infections. Previously in BC, doxycycline has been preferred due to concerns regarding overuse of azithromycin in the community and its potential effect on community-level antimicrobial drug resistance, especially on commensal Streptococcus pneumoniae and other respiratory pathogens. While this is still a concern, the balance has shifted.
Treatment of STI makes up a relatively small proportion of community antibiotic use (compared with respiratory and urinary tract infections), yet there is now a direct threat that gonorrhea may become resistant to cephalosporins - the last reliable class of antibiotics to treat it on an outpatient basis. In order to stave off resistance, an approach familiar to other resistance-prone infections (such as HIV, TB, or resistant gram negative bacteria) is being applied. This includes using multi-drug therapy with at least two different classes of antibiotics (with different mechanisms of action). Since azithromycin has more reliable antimicrobial activity against gonorrhea than doxycycline, US, Canadian, and BC guidelines have updated their recommendations to include azithromycin as the first choice treatment against chlamydia infections unless gonorrhea has been ruled out.
For further information
- Important Notice – Public Health Information Update on the Treatment for Gonococcal Infection. Canadian Guidelines on Sexually Transmitted Infections (December 2011)
- Decreased susceptibility of BC gonorrhea isolates to current treatments
Travis Hottes, Cheryl Prescott, Carolyn Montgomery
Categories: Clinical tips