Ciprofloxacin-resistant gonorrhea on the rise
Recent increases in the number of gonorrhea cases resistant to fluoroquinolone antibiotics, which include ciprofloxacin, ofloxacin, and levofloxacin, are spurring fears that these antibiotics eventually may lose their effectiveness as a frontline treatment for the sexually transmitted disease (STD).
According to the Atlanta-based Centers for Disease Control and Prevention (CDC), each year approximately 650,000 people in the United States are infected with Neisseria gonorrhoeae, a gram-negative diplococcus. Ciprofloxacin has been an inexpensive treatment option for treatment of the STD; however, recent information presented at the 2002 STD Prevention Conference in San Diego shows that ciprofloxacin-resistant gonorrhea is becoming more common in the United States.1
Gonorrhea, considered a "smart" bacteria, long ago developed mechanisms to resist other antibiotics, including penicillin. Ciprofloxacin and other fluoroquinolones have been top-line treatments since the 1980s, when gonorrhea grew resistant to tetracycline.2
Ciprofloxacin-resistant gonorrhea, which is resistant to all fluoroquinolone antibiotics, already constitutes a substantial proportion of total gonorrhea cases in Hawaii and Southeast Asia. So far, 14% of gonorrhea cases in Hawaii are ciprofloxacin-resistant, and West Coast rates, although lower, rose to 0.4% in 2000 from 0.1% in 1998.2 The emergence of resistant strains on the West Coast may have resulted from contracting gonorrhea while traveling in the Pacific region, public health officials believe.
Look to the soon-to-be-released Guidelines for Treatment of Sexually Transmitted Diseases from the CDC for updated information on treatment of gonorrhea, says Susan Wang, MD, MPH, medical epidemiologist in the CDC’s division of STD prevention. Wang coordinates the CDC’s Gonococcal Isolate Surveillance Project, the national sentinel surveillance system designed to monitor gonorrhea cases.
"If a patient could have acquired gonorrhea in Asia, Hawaii, or the Pacific Islands, even if they’re now in New York City or New Orleans or wherever, then they should be treated with something other than fluoroquinolones," says Wang. "We are recommending that clinicians ask about travel history for any patient they think has gonorrhea so they can select the right antibiotic."
Examine the data
According to the March 2002 report, a total of 41 ciprofloxacin-resistant cases were identified from 1991 through 2000.1 The proportion of gonorrhea cases that were ciproflaxin-resistant, while still small, doubled from 0.1% to 0.2% between 1998 and 1999 and remained constant in 2000.
Nearly two-thirds of the cases were concentrated in four areas on the West Coast: Seattle (10 cases), Orange County, CA (seven), San Francisco (five), and San Diego (five). Among 22 patients who were asked about their travel histories, researchers note half had traveled recently in a foreign country or had a sexual partner with recent foreign exposure.
The San Francisco Department of Public Health performs routine surveillance to measure the proportion of gonococcal isolates with intermediate susceptibility and resistance to ciprofloxacin, says Jeffrey Klausner, MD, MPH, director of the department’s STD prevention and control services. In 2001, about 22% of men at the city STD clinic had gonococcal isolates with intermediate susceptibility, and 2% had resistant gonococcal isolates. These figures reflect an increase from 10% and 0.3% in 2000, respectively, he notes.
What are the options?
The CDC treatment recommendations include three drugs for treatment of gonorrhea: cefixime, ceftriaxone, or one of the three fluoroquinolones (ciprofloxacin, ofloxacin, or levofloxacin), says Wang. If clinicians have any concern that a patient may have ciprofloxacin-resistant gonorrhea, then they should use only cefixime or ceftriaxone, she advises. If the patient is treated, then returns with the same symptoms, the CDC recommends that a culture test and susceptibility test be performed to determine the drug resistance, she says.
In addition, the CDC is working with STD programs in selected areas of the country to perform additional testing of gonococcal specimens, says Wang. By performing more susceptibility testing, these areas can gain a broader idea of what is going on in their population, she notes.
The San Francisco Department of Public Health issued a 2001 medical advisory stating that fluoroquinolones were no longer recommended treatment for gonorrhea, and that cefixime and ceftriaxone, both cephalosporin antibiotics, were recommended options, says Klausner.
"For patients with a possible allergy to cephalo-sporin antibiotics, we recommended fluoroquino-lone treatment with patient education about potential treatment failure and follow-up, particularly in those patients with risk factors for fluoroquinolone-resistant gonococcal infection such as recent sexual contact outside of the United States," says Klausner. "We also reminded physicians that persons with gonorrhea should be co-treated for chlamydia, unless chlamydia has been ruled out."
References
1. Conner S, Wang S. Characteristics of patients infected with ciprofloxacin-resistant Neisseria gonorrhoeae in the continental United States, 1994-2000. Presented at the 2002 National STD Prevention Conference. San Diego; March 2002.
2. Chase M. Some strains of gonorrhea resist Cipro. The Wall Street Journal, March 5, 2002:B5.
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