Gonorrhea

Background

Gonorrhea is the second most commonly reported notifiable disease in the United States. Infections due to Neisseria gonorrhoeae, like those resulting from C. trachomatis, are a major cause of PID in the United States. PID can lead to serious outcomes in women, such as tubal infertility, ectopic pregnancy, and chronic pelvic pain. In addition, epidemiologic and biologic studies provide strong evidence that gonococcal infections facilitate the transmission of HIV infection.¹ Although an individual’s sexual behavior can increase the risk of acquiring gonorrhea, social determinants of health, such as socioeconomic status, may contribute to the burden of gonorrhea in a community.²

During 1975–1997, the national gonorrhea rate declined 74% after implementation of the national gonorrhea control program in the mid-1970s (Figure 16). After the decline halted for several years, gonorrhea rates decreased further to 98.1 cases per 100,000 population in 2009. This was the lowest rate since recording of gonorrhea rates began. The rate increased slightly in 2010 to 100.2 and increased again in 2011 to 104.2 per 100,000 population, with a total of 321,849 cases reported in the United States in 2011 (Figure 16 and Table 1).

The increase in gonorrhea rates during 2010–2011 was observed among both men and women (Figure 17), among all racial/ethnic groups (Figure 24), and in all regions of the United States (Figure 18).

Although gonorrhea case reporting is useful for monitoring disease trends, the number of gonorrhea cases reported to CDC is affected by many factors in addition to the actual occurrence of the infection within the population. Changes in the burden of gonorrhea may be masked by changes in screening practices (e.g., screening for chlamydia with tests that also detect N. gonorrhoeae infections and broader use of nucleic acid amplification tests [NAATs] at non-genital anatomic sites), the use of diagnostic tests with different test performance, and changes in reporting practices. As with other STDs, the reporting of gonorrhea cases to CDC is incomplete.³ For these reasons, supplemental data on gonorrhea prevalence in persons screened in a variety of settings are useful in assessing the burden of disease in selected populations.

Neisseria gonorrhoeae has progressively developed resistance to each of the antibiotics used for treatment of gonorrhea. In the last decade, the development of fluoroquinolone resistance has resulted in the availability of only a single class of antibiotics that meet CDC’s efficacy standards—the cephalosporins.^4,5 Most recently, declining susceptibility to cefixime resulted in a change in the CDC treatment guidelines, so that dual therapy with ceftriaxone and either azithromycin or doxycycline is now the only CDC-recommended treatment regimen for gonorrhea.⁶ The emerging threat of cephalosporin resistance highlights the need for continued surveillance of N. gonorrhoeae antibiotic susceptibility.

The combination of persistently high gonorrhea morbidity in some populations and threat of cephalosporin-resistant gonorrhea reinforces the need to better understand the epidemiology of gonorrhea.

Gonorrhea—United States

In 2011, a total of 321,849 cases of gonorrhea were reported in the United States, yielding a rate of 104.2 cases per 100,000 population (Table 1). The rate increased 4.0% since 2010; however, the rate decreased 11.7% overall during 2007–2011.

Gonorrhea by Region

In 2011, as in previous years, the South had the highest gonorrhea rate (135.5 cases per 100,000 population) among the four regions of the United States, followed by the Midwest (111.2), Northeast (85.8), and West (62.2) (Table 14). During 2010–2011, rates increased 10.9% in the Northeast, 6.5% in the West, 2.7% in the Midwest, and 2.1% in the South (Figure 18, Table 14).

Gonorrhea by State

In 2011, gonorrhea rates per 100,000 population ranged by state from 7.7 in Vermont to 202.3 in Louisiana (Figure 19, Table 13). During 2010–2011, 61% (31/51) of states, plus the District of Columbia, reported an increase in gonorrhea rates (Table 14).

Gonorrhea by Metropolitan Statistical Area (MSA)

The overall gonorrhea rate in the 50 most populous MSAs was 117.9 cases per 100,000 population in 2011 (Table 17), representing a 3.3% rate increase from 2010 (114.1). In 2011, 60.8% of gonorrhea cases were reported by these MSAs (Table 17). The total gonorrhea rate among women in these MSAs in 2011 (115.6) was similar to rates among men (119.9) (Tables 18 and 19).

Gonorrhea by County

In 2011, 53% of reported gonorrhea cases occurred in just 70 counties or independent cities (Table 20). In 2011, 1,299 counties (41.3%) in the United States had a rate less than or equal to 19 cases per 100,000 population (Figure 20). Rates ranged from 19.1 to 100 per 100,000 population in 1,198 counties (38.1%) and more than 100 cases per 100,000 population in 645 counties (20.5%). Most counties with more than 100 cases per 100,000 population were located in the South.

Gonorrhea by Sex

Gonorrhea rates among women have been higher than those among men since 2002 (Figure 17). During 2010–2011, the gonorrhea rate among women increased 3.1%, to 108.9 cases per 100,000 population, and the rate among men increased 5.1%, to 98.7 per 100,000 population, (Tables 15 and 16).

Gonorrhea by Age

In 2011, gonorrhea rates were highest among adolescents and young adults. In 2011, the highest rates were observed among women aged 20–24 years (584.2) and 15–19 years (556.5). Among men, the rate was highest among those aged 20–24 years (450.6) (Figure 21, Table 21).

In 2011, persons aged 15–44 years accounted for 94.6% of reported gonorrhea cases with known age. During 2010–2011, gonorrhea rates increased among most age groups within this age range: the gonorrhea rate increased 5.8% among those aged 20–24 years, 4.6% among those aged 25–29 years, 6.9% among those aged 30–34 years, 2.5% among those aged 35–39 years, and 4.7% among those aged 40–44 years (Table 21). The gonorrhea rate decreased 0.1% among those aged 15–19 years.

Among women aged 15–44, the largest increase was among those aged 40–44 years (8.4%) (Figure 22). Among men aged 15–44, the largest increase was among those aged 30–34 years (8.4%) (Figure 23).

Gonorrhea by Race/Ethnicity

In 2011, gonorrhea rates remained highest among blacks (427.3 cases per 100,000 population) (Figure 24). The rate among blacks was 17.0 times the rate among whites (25.2 per 100,000 population). The gonorrhea rate among American Indians/Alaska Natives (115.7) was 4.6 times that of whites, and the rate among Hispanics (53.8) was 2.1 times that of whites (Figure 24, Figure P).

During 2010–2011, gonorrhea rates increased among Hispanics (12.3%), whites (7.7%), American Indians/Alaska Natives (7.7%), Asian/Pacific Islanders (4.9%), and blacks (0.3%) (Figure 24).

More information on gonorrhea rates among racial/ethnicity groups can be found in the Special Focus Profiles.

Gonorrhea by Region and Sex

During 2010–2011, gonorrhea rates among women and among men increased in all four regions of the United States: the Northeast, Midwest, South, and West (Tables 15 and 16). In 2011, women (145.4) and men (123.8) in the South had the highest gonorrhea rates.

Gonorrhea by Race/Ethnicity and Sex

Gonorrhea rates were higher in women than men among whites and American Indians/Alaska Natives in 2011 (Figure Q). Gonorrhea rates were highest among black men (428.3) and black women (425.4) and American Indian/Alaska Native women (145.3) and American Indian/Alaska Native men (84.4).

Among blacks, Hispanics, and Asians/Pacific Islanders, rates were higher in women than men among persons aged 15–24, but were higher in men than women among those aged 25 years and older (Table 22B). Among whites, women had higher rates than men among persons aged 15–29 years; men had higher rates than women among those aged 30 years and older. Among American Indians/Alaska Natives, women had higher rates than men among persons aged 15–44 years, but men had higher rates than women among those aged 45 years and older.

Gonorrhea by Reporting Source

The number of gonorrhea cases reported by STD clinics declined during 2002–2011 (Figure 25). In 2011, 18.6% of gonorrhea cases with known reporting source were reported by STD clinics (Table A2). This is a decrease from 2010, when 21.5% of gonorrhea cases were reported by STD clinics. In 2011, among women, private physicians or HMOs (29.7%) were the most common reporting source, followed by STD clinics (11.7%), family planning clinics (10.4%), other health department clinics (8.0%), and emergency rooms (5.4%) (Figure 26). Among men, STD clinics were the most common reporting source (26.4%) (Figure 26). Other common reporting sources for males were private physicians/HMOs (21.5%), other health department clinics (9.3%), emergency rooms (5.4%), and family planning clinics (5.2%) (Figure 26).

STD Surveillance Network

The STD Surveillance Network (SSuN) is a network of 12 states and independently funded cities collecting enhanced information on a representative sample of gonorrhea cases reported to the state or city health department from all reporting sources. This project provides more complete estimates of case characteristics often missing on routine case reports—such as gender of sex partners—which is essential for better targeting of gonorrhea control efforts. In 2011, SSuN collaborators interviewed 4,540 gonorrhea cases representing 6.7% of total morbidity across participating jurisdictions. Additional information about SSuN methodology can be found in the STD Surveillance Network section of the Appendix, Interpreting STD Surveillance Data.

Based on these enhanced interviews, the burden of disease represented by MSM, MSW, and women varied substantially across collaborating sites (Figure 27). San Francisco County had the highest proportion of estimated MSM cases (83.0%), while the lowest proportion of morbidity estimated to be attributed to MSM was found in Jefferson County (Birmingham), Alabama at 4.8%. Across all SSuN jurisdictions in 2011, 21.6% of gonorrhea cases were estimated to be among MSM, 31.0% among MSW, and 47.4% among women.

Positivity in Selected Populations

Positivity data from gonorrhea tests are primarily available from family planning clinics. Screening criteria and practices vary by state and over time.

In 2011, the median state-specific gonorrhea test positivity among women aged 15–24 years screened in selected family planning clinics in 48 states, Puerto Rico, and the Virgin Islands was 0.7% (range: 0.0% to 3.5%) (Figure 28).

Gonococcal Isolate Surveillance Project

Antimicrobial resistance remains an important consideration in the treatment of gonorrhea.^4–9 In 1986, the Gonococcal Isolate Surveillance Project (GISP), a national sentinel surveillance system, was established to monitor trends in antimicrobial susceptibilities of N. gonorrhoeae strains in the United States.¹⁰ Data are collected from selected STD clinic sentinel sites and from regional laboratories (Figure 29).

With the renewed availability of cefixime, susceptibility testing for this oral cephalosporin antibiotic was restarted in 2009. Susceptibility testing for an additional oral cephalosporin, cefpodoxime, was started in 2009.

Information on the GISP antimicrobial susceptibility criteria used can be found in the Gonococcal Isolate Surveillance Project section of the Appendix, Interpreting STD Surveillance Data. More information about 2011 GISP data can be found at http://www.cdc.gov/std/GISP.

Susceptibility to Ceftriaxone

Susceptibility testing for ceftriaxone began in 1987. Figure 30 displays the distribution of ceftriaxone minimum inhibitory concentrations (MICs) among GISP isolates during 2007–2011. During 2010–2011, the proportion of isolates with MICs of 0.125 µg/ml increased slightly from 0.3% in 2010 to 0.4% in 2011. The proportion of isolates with MICs of 0.25 µg/ml decreased slightly from 0.05% in 2010 to 0.02% (n = 1) in 2011.

No isolates with decreased susceptibility to ceftriaxone (MIC ≥ 0.5 µg/ml) were seen in 2011. GISP has reported four isolates with decreased susceptibility to ceftriaxone (MIC of 0.5 µg/ml). The locations and years of these isolates were San Diego, 1987; Cincinnati, 1992 and 1993; and Philadelphia, 1997.

Susceptibility to Cefixime

Susceptibility testing for cefixime began in 1992, was discontinued in 2007, and was restarted in 2009. The percentage of isolates with cefixime MICs of 0.125 µg/ml increased each year, from 1.4% in 2009 to 1.7% in 2011 (Figure 31). The percentage of isolates with cefixime MICs of 0.25 µg/ml increased from 0.7% in 2009 to 1.3% in 2011.The proportion with decreased susceptibility to cefixime (MIC=0.5 µg/ml) decreased from 0.2% in 2010 to 0.05% in 2011.

Since 2000, GISP has reported 23 isolates with decreased susceptibility to cefixime (MICs of 0.5 µg/ml). Three isolates with decreased susceptibility to cefixime were reported in 2011 and were collected in the South (Baltimore, Maryland), Midwest (Minneapolis, Minnesota) and West (Phoenix, Arizona). Unlike 2010, during which 89% of isolates with decreased susceptibility to cefixime were collected from MSM, two of the three isolates with decreased susceptibility to cefixime collected in 2011 were from men who have sex exclusively with women (MSW).

Susceptibility to Cefpodoxime

GISP began monitoring cefpodoxime susceptibility in 2009. Of 5,467 GISP isolates tested for cefpodoxime susceptibility in 2011, 1.1% had MICs of 0.5 µg/ml, 1.3% had MICs of 1 µg/ml, and 0.2% had MICs of 2 µg/ml.

Susceptibility to Azithromycin

Susceptibility testing for azithromycin began in 1992. Figure 32 displays the distribution of azithromycin MICs among GISP isolates during 2007–2011. The proportion of GISP isolates with azithromycin MICs of ≥ 2.0 µg/ml decreased from 0.5% in 2010 to 0.3% in 2011. In 2011, 5 (0.1%) isolates had azithromycin MICs of 8.0 µg/ml, and 1 (0.02%) isolate had an MIC of 16.0 µg/ml. Of these 6 isolates with MICs 8–16 µg/ml, 5 (83.3%) were from the West and 5 were from MSM.

Susceptibility to Spectinomycin

All isolates were susceptible to spectinomycin in 2011. GISP has identified five spectinomycin-resistant isolates—from St. Louis in 1988, Honolulu in 1989, San Francisco in 1989, Long Beach in 1990, and West Palm Beach in 1994.

Susceptibility to Ciprofloxacin

Resistance to ciprofloxacin (a fluoroquinolone antimicrobial) was first identified at GISP sites in 1991. Since 1999, fluoroquinolone-resistant Neisseria gonorrhoeae (QRNG) prevalence steadily increased, first in Hawaii and the Pacific Islands, then in the Western states, then among MSM,^11,12 and eventually among all populations in all regions of the United States.⁴

The proportion of GISP isolates identified as QRNG peaked in 2007 at 14.8%. The overall proportion decreased to 9.6% by 2009, and increased to 13.3% in 2011.

The prevalence of QRNG in isolates from MSM peaked at 38.9% in 2006 and then decreased to 20.1% by 2009 (Figure 33). In 2011, 26.0% of isolates from MSM were identified as QRNG. The prevalence of QRNG in isolates from MSW peaked at 8.7% in 2007, decreased to 6.0% in 2009, and increased to 8.0% in 2011.

Other Antimicrobial Susceptibility Testing

In 2011, 30.4% of isolates collected from GISP sites were resistant to penicillin, tetracycline, ciprofloxacin, or some combination of those antimicrobials (Figure 34). Although these antimicrobials are no longer recommended for treatment of gonorrhea, the resistance phenotypes remain common.

Antimicrobial Treatments Given for Gonorrhea

The antimicrobial agents given to GISP patients for gonorrhea therapy are shown in Figure 35. The proportion of GISP patients treated with ceftriaxone 250 mg increased from 37.4% in 2010 to 84.0% in 2011. The proportion treated with ceftriaxone 125 mg decreased from 46.9% in 2010 to 4.8% in 2011, and the proportion treated with cefixime decreased from 7.8% in 2010 to 5.3% in 2011.

In 2011, 0.3% of GISP patients were treated with fluoroquinolones (ciprofloxacin, ofloxacin, or levofloxacin) and 2.3% were treated with azithromycin 2 gram monotherapy.

Among patients treated with ceftriaxone 250 mg or cefixime 400 mg, 84.6% were also treated with azithromycin, 14.9% were also treated with doxycycline, 0.04% were treated with another antimicrobial, and 0.5% did not receive a second antimicrobial.

Gonorrhea Among Special Populations

More information about gonorrhea in racial/ethnic groups, women of reproductive age, adolescents, MSM, and other populations at higher risk can be found in the Special Focus Profiles.

Gonorrhea Summary

The national gonorrhea rate fluctuated at about 115–120 cases per 100,000 population for 10 years during 1996–2006, decreased during 2006–2009, and increased during 2009–2011. High rates persist in some geographic areas, among adolescents and young adults, and in some racial/ethnic groups.

The GISP continues to monitor for the emergence of decreased susceptibility and resistance to cephalosporins and azithromycin.

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