2010 Sexually Transmitted Diseases Surveillance

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 poverty, 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 14). After the decline halted for several years, gonorrhea rates decreased further to 98.1 cases in 2009. This is the lowest rate since recording of gonorrhea rates began. The rate increased slightly in 2010 to 100.8 per 100,000 population, with 309,341 cases reported in the United States (Figure 14 and Table 1).

The increase in gonorrhea rates during 2009–2010 was observed among men and women (Figure 15) and among all racial/ethnic groups (Figure 22). During 2009–2010, rates increased in the Northeast, South, and West; gonorrhea rates decreased in the Midwest (Figure 16).

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. Most recently, fluoroquinolone resistance emerged and resulted in the availability of only a single class of antibiotics that meet CDC’s efficacy standards—the cephalosporins.^{4, 5} The 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 2010, a total of 309,341 cases of gonorrhea were reported in the United States, yielding a rate of 100.8 cases per 100,000 population (Table 1). The rate increased 2.8% since 2009; however, the rate decreased 15.8% overall during 2006–2010.

Gonorrhea by Region

In 2010, as in previous years, the South had the highest gonorrhea rate (134.2 cases per 100,000 population) among the four regions of the United States, followed by the Midwest (108.5), Northeast (77.4), and West (58.7) (Table 14). During 2009–2010, rates increased in the Northeast (15.5%), West (11.4%), and South (2.1%), and decreased 6.5% in the Midwest (Figure 16, Table 14).

Gonorrhea by State

In 2010, gonorrhea rates per 100,000 population ranged by state from 7.3 in Wyoming to 209.9 in Mississippi (Figure 17, Table 13). During 2009–2010, 59% (30/51) of states, plus the District of Columbia, reported an increase in gonorrhea rates (Table 14).

Gonorrhea by Metropolitan Statistical Area

The overall gonorrhea rate in the 50 most populous MSAs was 113.9 cases per 100,000 population in 2010 (Table 17), representing a 4.4% rate increase from 2009 (109.1). In 2010, 61.2% of gonorrhea cases were reported by these MSAs (Table 17). The total gonorrhea rate among women in these MSAs in 2010 (113.6) was similar to rates among men (113.7) (Tables 18 and 19).

Gonorrhea by County

In 2010, 50% of reported gonorrhea cases occurred in just 63 counties or independent cities (Table 20).In 2010, 1,408 counties (44.8%) in the United States had a rate less than or equal to 19 cases per 100,000 population (Figure 18). Rates ranged from 19.1 to 100 per 100,000 population in 1,107 counties (35.2%) and more than 100 cases per 100,000 population in 627 counties (19.9%). Most counties with more than 100 cases per 100,000 population were located in the South. Ten counties in Alaska had rates greater than 100 cases per 100,000 population.

Gonorrhea by Sex

Before 1996, gonorrhea rates were higher among men than women (Figure 15). During 1997–2001, rates were similar among women and men. Rates have been higher among women since 2002. In 2010, the gonorrhea rate was 106.5 cases per 100,000 population among women and 94.1 per 100,000 population among men (Tables 15 and 16).

Gonorrhea by Age

In 2010, gonorrhea rates were highest among adolescents and young adults. In 2010, the highest rates were observed among women aged 15–19 years (570.9) and 20–24 years (560.7). Among men, the rate was highest among those aged 20–24 years (421.0) (Figure 19, Table 21).

During 2009–2010, gonorrhea rates increased among most age groups. The largest increases were observed among those aged 20–24 years (4.9%) and 30–34 years (3.2%). Decreases were observed among those aged 35–39 years (1.5%), 55–64 years (1.6%), and 65 years and greater (7.1%) (Table 21).

Among men and women, the largest increases were among those aged 20–24 years (6.2% for men and 3.8% for women) (Figures 20 and 21).

Gonorrhea by Race/Ethnicity

In 2010, gonorrhea rates remained highest among blacks (432.5 cases per 100,000 population) (Figure 22). The rate among blacks was 18.7 times the rate among whites (23.1 per 100,000 population). Gonorrhea rates among American Indians/Alaska Natives (105.7) were 4.6 times those of whites, and rates among Hispanics (49.9) were 2.2 times those of whites (Figure 22, Figure P).

During 2009–2010, gonorrhea rates increased among American Indians/Alaska Natives (21.5%), Asian/Pacific Islanders (13.1%), Hispanics (11.9%), whites (9.0%), and blacks (0.3%) (Figure 22).

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

Gonorrhea by Region and Sex

During 2009–2010, gonorrhea rates among women and men increased in the Northeast, South, and West, and decreased in the Midwest (Tables 15 and 16). In 2010, women (145.2) and men (121.1) in the South had the highest gonorrhea rates.

Gonorrhea by Race/Ethnicity and Sex

Gonorrhea rates were higher in women than men among whites, Hispanics, and American Indians/Alaska Natives in 2010 (Figure Q). Gonorrhea rates were highest among black men (433.6) and black women (430.8) and American Indian/Alaska Native women (133.5) and American Indian/Alaska Native men (77.0).

Among blacks, Hispanics, and Asians/Pacific Islanders aged 15–24 years, rates were higher among women than men (Table 22B). Among blacks, Hispanics, and Asian/Pacific Islanders, aged 25 years and older, rates were higher among men than women. Among whites aged 15–29 years, rates were higher among women than men; men had higher rates than women among those aged 30 years and older. Among American Indians/Alaska Natives, aged 15–39 years, women had higher rates than men.

Gonorrhea by Reporting Source

The number of gonorrhea cases reported by STD clinics declined during 2001–2010 (Figure 23). In 2010, 21.5% of gonorrhea cases were reported by STD clinics (Table A2). This is a decrease from 2009, when 22.6% of gonorrhea cases were reported by STD clinics. In 2010, among women, private physicians or HMOs (29.0%) were the most common reporting source, followed by STD clinics (13.8%), family planning clinics (10.6%), other health department clinics (8.6%), and emergency rooms (5.6%) (Figure 24). Among men, STD clinics were the most common reporting source (30.4%) (Figure 24). Other common reporting sources for males were private physicians/HMOs (22.0%), other health department clinics (9.0%), emergency rooms (5.3%), and family planning clinics (4.6%) (Figure 24).

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 2010, SSuN collaborators interviewed 3,446 gonorrhea cases representing 5% 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 25). San Francisco County, had the highest proportion of estimated MSM cases (83%), while the lowest proportion of morbidity estimated to be attributed to MSM was found in Jefferson County (Birmingham), Alabama at 2.9%. Across all SSuN jurisdictions in 2010, 23.2% of gonorrhea cases were estimated to be among MSM, 28.8% among MSW, and 46.7% among women.

Prevalence Monitoring

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

In 2010, the median state-specific gonorrhea test positivity among women aged 15–24 years screened in selected family planning clinics in 47 states, the District of Columbia, Puerto Rico, and the Virgin Islands was 0.8% (range: 0.0% to 4.1%) (Figure 26).

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 strains of N. gonorrhoeae in the United States.¹⁰ Data are collected from selected STD clinics at 25–30 GISP sentinel sites and from 4–5 regional laboratories (Figure 27).

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 2010 GISP data can be found at http://www.cdc.gov/std/GISP.

Susceptibility to Ceftriaxone

Susceptibility testing for ceftriaxone began in 1987. Figure 28 displays the distribution of minimum inhibitory concentrations (MICs) to ceftriaxone among GISP isolates during 2006–2010. During 2009–2010, the proportion of isolates with MICs of 0.06 µg/ml and 0.125 µg/ml did not change. The proportion of isolates with MICs of 0.25 µg/ml increased slightly from 0% in 2009 to 0.05% (n = 3) in 2010.

No isolates with decreased susceptibility to ceftriaxone (MIC ≥ 0.5 µg/ml) were seen in 2010. 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 elevated MICs (≥ 0.25 µg/ml) to cefixime increased during 2006–2010, particularly among isolates from the West and men who have sex with men (MSM).⁸ Figure 29 displays the distribution of MICs to cefixime among GISP isolates in 2006, 2009, and 2010. During 2009–2010, increases were observed in the proportion of isolates with MICs of 0.125 µg/ml (1.4% to 1.6%), 0.25 µg/ml (0.7% to 1.2%), and 0.5 µg/ml (0.1% to 0.2%).

Since 2000, GISP has reported 20 isolates with decreased susceptibility to cefixime (MICs of 0.5 µg/ml). Nine isolates with decreased susceptibility to cefixime were reported in 2010—seven were from the West (Honolulu, Los Angeles, Portland, and San Francisco) and 2 were from the Midwest (Chicago and Cleveland). In 2010, eight (88.9%) isolates with decreased susceptibility to cefixime were from MSM.

Susceptibility to Cefpodoxime

GISP began monitoring cefpodoxime susceptibility in 2009. Of 5,693 GISP isolates tested for cefpodoxime susceptibility in 2010, 58.9% had MICs to cefpodoxime less than or equal to 0.015 µg/ml, 37.9% had MICs of 0.03–0.125 µg/ml, and 1.9% had MICs of 0.250–0.5 µg/ml. There were 70 (1.2%) isolates with decreased susceptibility to cefpodoxime (MICs of 1.0–4.0 µg/ml).

Susceptibility to Azithromycin

GISP began monitoring azithromycin susceptibility in 1992. Figure 30 displays the distribution of MICs to azithromycin among GISP isolates during 2006–2010. The proportion of GISP isolates with MICs of ≥ 2.0 µg/ml to azithromycin decreased from 0.5% in 2007 to 0.2% during 2008–2009, and increased to 0.5% in 2010. In 2010, 9 (0.2%) isolates had MICs to azithromycin of 8.0 µg/ml, and 8 (0.1%) isolates had MICs of 16.0 µg/ml. Of these 17 isolates, 76.5% were from the West and 82.4% were from MSM.

Susceptibility to Spectinomycin

All isolates were susceptible to spectinomycin in 2010. GISP has reported 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% (Figure 31). The proportion decreased to 9.6% by 2009, and increased to 12.5% in 2010.

Quinolone-resistant Neisseria gonorrhoeae by Sex of Sex Partner

The prevalence of QRNG in isolates from MSM peaked at 38.9% in 2006 and then decreased to 20.1% by 2009. In 2010, 23.9% of isolates from MSM and 7.9% of isolates from men who have sex exclusively with women were identified as QRNG.

Other Antimicrobial Susceptibility Testing

Overall in 2010, 27.2% of isolates collected from GISP sites were resistant to penicillin, tetracycline, ciprofloxacin, or some combination of those antibiotics (Figure 32).

Antimicrobial Treatments Given for Gonorrhea

The antimicrobial agents given to GISP patients for gonorrhea therapy are shown in Figure 33. In 2010, 96.5% of GISP patients were treated with cephalosporins, similar to the proportion in 2009 (96.2%). The proportion treated with ceftriaxone 250 mg increased from 21.6% in 2009 to 37.4% in 2010; the proportion treated with ceftriaxone 125 mg decreased from 53.9% in 2009 to 46.9% in 2010. The proportion treated with cefixime decreased from 13.2% in 2008 to 7.8% in 2010. Among patients treated with a cephalosporin, 75.3% were also treated with azithromycin, 23.6% were also treated with doxycycline, 0.1% were also treated with another antibiotic, and 1.1% did not receive a second antibiotic.

During 2010, 0.5% of GISP patients were treated with fluoroquinolones (ciprofloxacin, ofloxacin, or levofloxacin) and 1.7% were treated with azithromycin monotherapy.

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 cases per 100,000 population for 10 years during 1996–2006, decreased during 2006–2009, and increased slightly in 2010. High rates persist in some geographic areas, among adolescents and young adults, and 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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