Ontario Researchers Look at Gonorrhea in the Throat

Infection with bacteria called N. gonorrhoeae is a problem among sexually active people, including men who have sex with men (MSM). Moreover, because gonorrhea can cause inflammation in the wet tissues of the genitals, rectum and throat, this inflammation can weaken these tissues and increase the risk of transmitting and getting HIV.

Into the Throat

Researchers in the U.S. have found that gonorrhea-causing bacteria can infect the penis during insertive oral sex. Also, other U.S. researchers have found that gonorrhea of the throat (pharyngeal gonorrhea) can occur because of receptive oral sex.

To study pharyngeal gonorrhea, researchers collaborated at these Canadian institutions:

• Ontario Agency for Health Protection and Promotion
• Public Health Agency of Canada
• McMaster University
• Hassle Free Clinic

The team reviewed medical and laboratory records of men who attended the Hassle Free Clinic -- Toronto's premier clinic for STI (sexually transmitted infection) diagnosis and treatment -- for the management of gonorrhea. The results suggest that gonorrhea is a relatively common STI and that studies assessing effective treatment of throat gonorrhea are needed.

Study Details

Researchers reviewed the clinic's medical records between 1995 and 2008. During this time, clinic staff took swabs from the throat, rectum and urethra of men who entered the study so they could be tested for gonorrhea and Chlamydia. In this report we will focus on gonorrhea.

Results -- Testing

In total, 178 cases of gonorrhea in the throat were detected. However, not all of these people returned to the clinic for further aspects of the study. Other key findings were as follows:

• 40% of 176 men with pharyngeal gonorrhea who underwent gonorrhea testing of their urinary tract (or urine samples) had gonorrhea-causing germs detected in the urinary tract.
• 40% of 89 men who had pharyngeal gonorrhea who also underwent rectal screening for this infection had detectable gonorrhea in their rectum.

These findings suggest that a substantial proportion of men with gonorrhea in their throat can also have this problem in their genitals or rectum.

Results -- Treatment

More than 99% of people who had pharyngeal gonorrhea received antibiotics, usually cefixime (Suprax). Researchers encouraged participants to return to the clinic to undergo further testing to confirm that treatment worked -- their gonorrhea was cured. However, only 122 out of 176 people returned for repeated testing. Among these 122 people, 9% (or 11 people) continued to test positive for gonorrhea of the throat, despite having received a course of antibiotics.

Nine of these 11 men returned for further study. Ten of the men were initially treated with cefixime and the 11th with ofloxacin (Floxcin). The N. gonorrhoeae that could be grown or cultured from these people was still susceptible to cefixime despite its apparent treatment failure. In the case of the 11th man, he had been infected with a strain of ciprofloxacin-resistant gonorrhea.

The nine men were retreated with either cefixime or ofloxacin. Eight were cured. The 9th man received another dose of cefixime and was subsequently cured.

Key Findings

Over the course of this study, N. gonorrhoeae was regularly found from throat swabs of men attending a major STI clinic. Moreover, throat infections would have been missed if urine samples or urethral swabs had been relied upon as the sole sample for analysis.

In about 9% of cases of pharyngeal gonorrhea, repeated bouts of antibiotics were necessary to achieve a cure. Clinic records indicate that the men who needed repeated treatment were abstaining from sex, suggesting that these cases represented apparent failure of treatment and not re-infection from the same partner.

Because of these cases of apparent treatment failure, the study team calls for the development and testing of specific antibiotic treatment regimens for pharyngeal gonorrhea.

References

1. Handsfield HH and Sparling PF. Neisseria gonorrhoeae. In: Mandell, Douglas and Bennett. Principles and Practice of Infectious Diseases. 6th ed. Philadelphia: Elsevier, 2005. P. 2514-2529.
2. PHAC. Gonococcal infections. Canadian Guidelines on Sexually Transmitted Infections. 2008. Available at: www.phac-aspc.gc.ca/std-mts/sti_2006/sti_intro2006-eng.php. [Accessed March 31, 2009].
3. Jakopanec I, Borgen K and Aavitsland P. The epidemiology of gonorrhoea in Norway, 1993-2007: past victories, future challenges. BMC Infectious Diseases. 2009 Mar 19;9(1):33.
4. Ota KV, Jamieson F, Fisman DN, et al. Prevalence of and risk factors for quinolone-resistant Neisseria gonorrhoeae infection in Ontario. Canadian Medical Association Journal. 2009 Feb 3;180(3):287-90.
5. Ota KV, Fisman DN, Tamari IE, et al. Incidence and treatment outcomes of pharyngeal Neisseria gonorrhoeae and Chlamydia trachomatis infections in men who have sex with men: a 13-year retrospective cohort study. Clinical Infectious Diseases. 2009; in press.