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 pelvic inflammatory disease (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 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 11). 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. Since 2009, the rate has increased slightly each year, to 100.2 in 2010, 103.3 in 2011, and to 107.5 cases per 100,000 population in 2012, with a total of 334,826 cases reported in the United States in 2012 (Figure 11 and Table 1).

The increase in gonorrhea rates during 2011–2012 was observed among both men and women (Figure 12). Gonorrhea rates increased in the Northeast, Midwest, and West, but decreased in the South (Figure 13). Rates increased among persons aged 20 years or older, but decreased among those aged 15–19 years (Figures 17 and 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 CDCrecommended 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 2012, a total of 334,826 cases of gonorrhea were reported in the United States, yielding a rate of 107.5 cases per 100,000 population (Table 1). The rate increased 4.1% since 2011; however, the rate decreased 2.9% overall during 2008–2012.

Gonorrhea by Region

In 2012, as in previous years, the South had the highest gonorrhea rate (131.9 cases per 100,000 population) among the four regions of the United States, followed by the Midwest (114.6), Northeast (92.6), and West (73.3) (Table 14). During 2011–2012, rates increased 19.4% in the West, 8.4% in the Northeast, and 3.4% in the Midwest; rates decreased 1.4% in the South (Figure 13, Table 14).

Gonorrhea by State

In 2012, gonorrhea rates per 100,000 population ranged by state from 7.7 in Wyoming to 230.8 in Mississippi; the gonorrhea rate in the District of Columbia was 388.7 (Figure 14, Tables 13 and 14). During 2011–2012, gonorrhea rates increased in 70% (35/50) of states and decreased in 30% (15/50) of states and in the District of Columbia (Table 14).

Gonorrhea by Metropolitan Statistical Area (MSA)

The overall gonorrhea rate in the 50 most populous MSAs was 121.5 cases per 100,000 population in 2012 (Table 17), representing a 4.2% rate increase from 2011 (116.6). In 2012, 60.9% of gonorrhea cases were reported by these MSAs. The total gonorrhea rate among women in these MSAs in 2012 (114.3) was lower than rates among men (128.7) (Tables 18 and 19).

Gonorrhea by County

In 2012, 52% of reported gonorrhea cases occurred in just 70 counties or independent cities (Table 20). In 2012, 1,192 counties (37.9%) in the United States had a rate less than or equal to 19 cases per 100,000 population (Figure 15). Rates ranged from 19.1 to 100 per 100,000 population in 1,300 counties (41.4%) and more than 100 cases per 100,000 population in 650 counties (20.7%). 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 slightly higher than those among men since 2001 (Figure 12). During 2011–2012, the gonorrhea rate among women increased 0.6%, to 108.7 cases per 100,000 population, and the rate among men increased 8.3%, to 105.8 per 100,000 population (Tables 15 and 16). The magnitude of the increase among men compared to women is suggestive of either increased transmission or increased case ascertainment (e.g., through increased extra-genital screening) among men who have sex with men (MSM). However, most jurisdictions do not routinely report sex of sex partners or site of infection for gonorrhea cases, so trends in gonorrhea rates among MSM cannot be assessed.

Gonorrhea by Age

In 2012, gonorrhea rates were highest among adolescents and young adults. In 2012, the highest rates were observed among women aged 20–24 years (578.5) and 15–19 years (521.2). Among men, the rate was highest among those aged 20–24 years (462.8) (Figure 16, Table 21).

In 2012, persons aged 15–44 years accounted for 95.0% of reported gonorrhea cases with known age. During 2011–2012, gonorrhea rates increased among most age groups within this age range: the gonorrhea rate increased 3.1% among those aged 20–24 years, 9.8% among those aged 25–29 years, 15.7% among those aged 30–34 years, 14.7% among those aged 35–39 years, and 13.0% among those aged 40–44 years (Table 21). The gonorrhea rate decreased 7.5% among those aged 15–19 years.

Among women aged 15–44, the largest increase was among those aged 40–44 years (14.1%) (Figure 17). Among men aged 15–44, the largest increase was among those aged 30–34 years (18.1%) (Figure 18).

Gonorrhea by Race/Ethnicity

In 2012, among the 48 jurisdictions (47 states and the District of Columbia) that submitted data in the new race and ethnic categories according to the revised Office of Management and Budget (OMB) standards, gonorrhea rates remained highest among blacks (462.0 cases per 100,000 population) (Table 22B). The rate among blacks was 14.9 times the rate among whites (31.0 per 100,000 population). The gonorrhea rate among American Indians/Alaska Natives (124.9) was 4.0 times that of whites, the rate among Native Hawaiians/Other Pacific Islanders (87.8) was 2.8 times that of whites, the rate among Hispanics (60.4) was 1.9 times that of whites, and the rate among Asians (16.9) was 0.5 times that of whites (Table 22B).

During 2008–2012, among the 39 jurisdictions (38 states and the District of Columbia) that submitted data in the new race and ethnic categories for all five years during that period, gonorrhea rates increased among American Indians/Alaska Natives (61.8%), Native Hawaiians/Pacific Islanders (33.5%), whites (22.9%), and Asians (14.5%). During this same time period, the gonorrhea rate decreased among blacks (15.5%) (Figure 19).

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

Gonorrhea by Region and Sex

During 2011–2012, gonorrhea rates among women and among men increased in the Northeast, Midwest, and West (Tables 15 and 16). In the South, the gonorrhea rate among men increased, but the gonorrhea rate among women decreased. In 2012, women in the South (138.5), women in the Midwest (127.1) and men in the South (124.5) had the highest gonorrhea rates.

Gonorrhea by Race/Ethnicity and Sex

Among the 48 jurisdictions (47 states and the District of Columbia) that submitted data in the new race and ethnic categories according to the revised OMB standards, gonorrhea rates were higher in women than men among American Indians/Alaska Natives, Native Hawaiians/Other Pacific Islanders, and whites in 2012 (Figure N, Table 22B). Gonorrhea rates were higher in men than women among Asians, blacks, and Hispanics. Overall, gonorrhea rates were highest among black men (467.7) and black women (456.3).

Gonorrhea by Reporting Source

The number of gonorrhea cases reported by STD clinics declined during 2003–2012 (Figure 20). In 2012, 17.3% of gonorrhea cases with known reporting source were reported by STD clinics (Table A2). This is a decrease from 2011, when 18.6% of gonorrhea cases were reported by STD clinics. In 2012, among women, private physicians or health maintenance organizations (HMOs) (30.2%) were the most common reporting source, followed by family planning clinics (11.3%), STD clinics (10.6%), other health department clinics (6.8%), and emergency rooms (5.7%) (Figure 21). Among men, STD clinics were the most common reporting source (24.5%) (Figure 21). Other common reporting sources for males were private physicians/HMOs (22.9%), other health department clinics (8.8%), emergency rooms (5.8%), and family planning clinics (5.8%).

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 2012, SSuN collaborators interviewed 6,228 gonorrhea cases representing 8.2% 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, men who have sex with women only (MSW), and women varied substantially across collaborating sites (Figure 22). San Francisco County had the highest proportion of estimated MSM cases (87.8%), while the lowest proportion of morbidity estimated to be attributed to MSM was found in Jefferson County (Birmingham), Alabama at 10.9%. Across all SSuN jurisdictions in 2012, 26.6% of gonorrhea cases were estimated to be among MSM, 29.4% among MSW, and 44.1% among women.

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 urethral N. gonorrhoeae strains in the United States.¹⁰ Data are collected from selected STD clinic sentinel sites and from regional laboratories (Figure 23).

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

Susceptibility to Ceftriaxone

Susceptibility testing for ceftriaxone began in 1987. The percentage of GISP isolates that exhibited elevated ceftriaxone minimum inhibitory concentrations (MICs), defined as ≥0.125 μg/ml, increased from 0.1% in 2008 to 0.4% in 2011, and decreased slightly to 0.3% in 2012 (Figure 24).

One isolate with decreased susceptibility to ceftriaxone (MIC = 0.5 μg/ml) was identified in 2012. The isolate was collected in Oklahoma City, Oklahoma from a heterosexual man; the isolate exhibited penicillin resistance (MIC = 2.0 μg/ml), intermediate susceptibility to tetracycline (MIC = 1.0 μg/ml), and decreased susceptibility to cefixime (MIC = 1.0 μg/ ml). Four isolates with decreased susceptibility to ceftriaxone (MIC = 0.5 μg/ml) have been previously identified in GISP: one from San Diego, California (1987), two from Cincinnati, Ohio (1992 and 1993), and one from Philadelphia, Pennsylvania (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 elevated cefixime MICs (≥0.25 μg/ml) increased from 0.1% in 2006 to 1.4% in 2010 and 2011, and declined to 1.0% in 2012 (Figure 25).

In 2012, two isolates had cefixime MICs of 0.5 μg/ ml (from Chicago, Illinois and Orange County, California), and one had an MIC of 1.0 μg/ml (from Oklahoma City, Oklahoma).

Susceptibility to Cefpodoxime

Monitoring of cefpodoxime susceptibility in GISP began in 2009. Of 5,495 GISP isolates tested for cefpodoxime susceptibility in 2012, 0.8% had MICs of 0.5 μg/ml, 1.3% had MICs of 1.0 μg/ml, and 0.4% had MICs of 2.0 μg/ml.

Susceptibility to Azithromycin

Susceptibility testing for azithromycin began in 1992. The proportion of GISP isolates with azithromycin MICs of ≥2.0 μg/ml decreased from 0.5% in 2010 to 0.3% in 2012 (Figure 26). In 2012, two (0.04%) isolates had azithromycin MICs of 8.0 μg/ml, four (0.1%) isolates had MICs of 16.0 μg/ml, and one isolate, collected from a heterosexual man in Honolulu, Hawaii had an MIC ≥256 μg/ml.

Susceptibility to Spectinomycin

All isolates were susceptible to spectinomycin in 2012. A spectinomycin-resistant isolate was last identified in GISP in 1994 (West Palm Beach, Florida).

Susceptibility to Ciprofloxacin

The proportion of GISP isolates with ciprofloxacin resistance (MIC ≥1 μg/ml) peaked in 2007 at 14.8%. Following a decline in 2008 and 2009, the proportion increased from 9.6% in 2009 to 14.7% in 2012. In 2012, 27.1% of isolates from MSM and 8.7% of isolates from MSW exhibited ciprofloxacin resistance.

Other Antimicrobial Susceptibility Testing

In 2012, 33.4% of isolates collected from GISP sites were resistant to penicillin, tetracycline, ciprofloxacin, or some combination of those antimicrobials (Figure 27). Although these antimicrobials are no longer recommended for treatment of gonorrhea, the resistance phenotypes remain common. Conversely, 66.6% of isolates were susceptible to all three of these antimicrobials.

Antimicrobial Treatments Given for Gonorrhea

The antimicrobial agents given to GISP patients for gonorrhea therapy are shown in Figure 28. The proportion of patients treated with ceftriaxone 250 mg increased from 84.0% in 2011 to 93.9% in 2012. The proportion treated with cefixime decreased from 5.3% in 2011 to 1.6% in 2012.

In 2012, 3.2% of patients were treated with azithromycin 2 grams as monotherapy, and 0.1% of patients were treated with a fluoroquinolone (ciprofloxacin or ofloxacin).

Among patients treated with ceftriaxone 250 mg or cefixime 400 mg, 83.1% were also treated with azithromycin one gram, 16.7% were also treated with doxycycline, and 0.2% 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 declined dramatically during 1975–1997. After 1997, the gonorrhea rate fluctuated but generally trended downwards until it reached an all-time low in 2009. However, during 2009–2012 the gonorrhea rate has increased each year. 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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