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Ask Dr. Grennan! Answers to health provider questions about STIs

“My patient had a positive Neisseria gonorrhoeae urine nucleic acid amplification test (NAAT), but a negative Chlamydia trachomatis NAAT.  Why do I have to treat for both?”

The treatment of choice for gonorrhea is a third-generation cephalosporin (either cefixime 800mg PO once, or ceftriaxone 250mg IM once). 

Concomitant treatment with either azithromycin or doxycycline is also recommended for two reasons: 

  1. The co-infection rate with organisms like chlamydia and Mycoplasma genitalium is high in some populations (up to 50% for chlamydia), and the incubation period for chlamydia can be significantly longer than that of gonorrhea. 
  2. Given the emerging resistance we have seen globally in gonorrhea strains, some experts believe there to be a theoretical ‘antimicrobial resistance benefit’ in treating gonorrhea with two agents with different molecular targets.

“A patient came to me stating that they were exposed to syphilis and they needed treatment. What should I do?”

Partner care of syphilis (and any STI) is an important component in the overall management of STIs. The treatment of sexual contacts is critical, particularly with syphilis, where the incubation period can be as long as 90 days, and the infectivity is very high in early infection (upwards of 30%). 

Any sexual contacts to syphilis within the past 90 days should be both treated empirically and tested. Those partners dating back > 90 days should be tested. 

We recognize that clinicians may have concerns about treating someone without a confirmed diagnosis. However, it is our strong belief that the benefits here – both for the individual and the community – greatly outweigh the risks, and we therefore strongly recommend that all sexual partners of syphilis cases within 90 days be treated with benzathine penicillin.

“My patient reports an allergy to penicillin, but needs treatment for gonorrhea. Can I safely use cefixime or ceftriaxone?”

Most likely, yes. There is a widespread misconception that the cross-reactivity between penicillin and cephalosporins for allergy is in the 10-20% range. If you have a true allergy to penicillin (i.e. proven via skin test), the likelihood of a reaction to a cephalosporin is less than 2%. However, of all individuals reporting an allergy to penicillin (without confirmation), the likelihood of cross-allergy is closer to 0.1%.

The other thing to keep in mind is that a vast majority of individuals reporting a penicillin allergy – close to 90% of them – will be negative on skin testing. Those who have proven negative skin testing for penicillin allergy can receive cephalosporins without an elevated risk of allergic reaction over the general population.

“My 18-year-old male patient is concerned about human papillomavirus (HPV), because his girlfriend was recently diagnosed. How can he get the HPV vaccine?”

In BC, quadrivalent HPV vaccination (Gardasil®) is provided free to males who are between the ages of 9-26 years of age AND who fall into any of the following risk categories: 

  • HIV-positive
  • men who have sex with men or questioning their sexuality
  • street-involved 

Additionally, males aged 9-18 years in the care of the Ministry of Child and Family Development, as well as males aged 12-17 years in youth custody service centres are also eligible for free vaccine. All others must either pay out-of-pocket (roughly $150-190 per dose) or rely on a third-party payer (e.g. private insurance).

“I need help figuring out what to do with a patient. Who can I call?”

If you have any questions about the testing or treatment of STIs, or other clinically-related questions, please call the BCCDC STI Physician at 604-707-5610

If you have questions about, or need help with partner notification or management, need information on a patient’s previous results or treatments, or would like to order STI treatment, call the BCCDC Nursing Team at 604-707-5603.