HealthDay News — U.S. surveillance data suggests Neisseria gonorrhoeae is developing resistance to cephalosporins, the only remaining class of antimicrobials available to treat gonococcal infections, the CDC reports.
The percentage of N. gonorrhoeae isolates requiring more potent doses of the oral antibiotic cefixime (minimum inhibitory concentrations (MICs) ≥0.25 µg/mL) recently increased from 0.1% in 2006 to 1.4% in 2011, a trend suggesting the drug’s effectiveness is waning.
These findings, published in Morbidity & Mortality Weekly Report, are based on data from the CDC’s Gonococcal Isolate Surveillance System.
The CDC recently updated gonorrhea treatment recommendations based on surveillance trends. Current guidelines state that gonorrhea at any anatomic site be treated with a single 250 mg intramuscular dose of ceftriaxone, plus either 1 g of azithromycin as a single oral dose, or 100 mg of doxycycline taken orally twice daily for 7 day.
Clinicians should only consider a single oral dose of cefixime 400 mg with a single oral dose of azithromycin 1 g and doxycycline 100 mg, as an alternative regimen if ceftriaxone is not available. For patients who are allergic to cephalosporins, clinicans should consider a single 2g oral dose of azithromycin. Patients prescribed either of these two alternative regimens should be advised to return to the office in one week for a test of cure.
“CDC will continue to update treatment recommendations based on surveillance data and clinical research,” the agency wrote in MMWR.
Increases in cefixime MICs were most pronounced in isolates collected from men in the western United States and from men who have sex with men (MSM), the region and population in which fluoroquinolone-resistant gonorrhea strains first emerged during the 1990s and 2000s.
N. gonorrhoeae has been developing antimicrobial resistance to antimicrobials including sulfonamides, penicillin, tetracycline and fluoroquinolones since the 1930s, according to the CDC.
Since 2007, the only remaining antimicrobials recommended to treat gonorrhea in the U.S. are cephalosporins. However, reports of gonorrhea treatment failure with oral cephalosporins began surfacing in Asia and Europe in the past decade, and have now spread to the United States.
Steps to delay the emergence of cephalosporin-resistant gonorrhea strains include:
- Using surveillance data to prioritize populations and areas for enhanced primary prevention, screening and partner services
- Screening sexually active MSM and high-risk sexually active women annually and providing appropriate treatment
- Counseling sexually active adults about ways to reduce gonorrhea transmission.
“Based on past and current data, N. gonorrhoeae will continue to acquire antimicrobial resistance,” the CDC wrote. “However, experience and current data suggest that public health actions outlined in this report provide the best chance of averting the unfavorable outcome of multidrug-resistant gonorrhea, greater disease burden, heightened risk for sequelae, and greater health care costs.”
Clinicians should maintain vigilance for gonorrhea treatment failure, collect isolates for susceptibility testing from such patients, and promptly notify local public health STD programs, the agency recommends.
Working case definitions and more detailed guidance can be found in CDC’s recently released cephalosporin-resistant N. gonorrhoeae public health response plan.