Gonorrhea is the second most commonly-reported notifiable disease in the United States. Infections due to Neisseria gonorrhoeae, like those resulting from Chlamydia 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
From 1975 through 1997, the national gonorrhea rate declined 74% following implementation of the national gonorrhea control program in the mid-1970s (Table 1). Gonorrhea rates subsequently appeared to plateau for several years. However, rates increased for the second consecutive year, with 358,366 cases of gonorrhea reported in the United States in 2006 (Figure 11 and Table 1).
Increases in gonorrhea rates in eight western states from 2000 to 2005 have been described among a wide variety of populations in the affected states.2 Increases in quinolone-resistant Neisseria gonorrhoeae (QRNG) in 2006 led to changes in national guidelines that now limit the recommended treatment of gonorrhea to a single class of drug, the cephalosporins.3 The combination of increases in gonorrhea morbidity with increases in resistance and decreased treatment options have increased the need for better understanding of the epidemiology of gonorrhea.
Although gonorrhea case reporting is useful for monitoring trends in gonorrhea, true increases or decreases in disease may be masked by changes in screening practices (affected by concomitant testing for chlamydia and broader use of urine-based testing), use of diagnostic tests with differing test performance, and changes in reporting practices.4
For most areas, the number of gonorrhea cases reported to CDC is affected by many factors, in addition to the occurrence of the infection within the population. As with reporting of other STDs, reporting of gonorrhea cases to CDC is incomplete.5 For these reasons, supplemental data on gonorrhea prevalence in persons screened in a variety of different settings are useful in assessing disease burden in selected populations.
Gonorrhea – United States
In 2006, 358,366 cases of gonorrhea were reported in the United States. The rate of reported gonorrhea in the United States was 120.9 cases per 100,000 population in 2006 (Figure 11 and Table 1), an increase of 5.5% since 2005. Gonorrhea rates increased in 2006 for the second consecutive year.
Gonorrhea by Region
As in previous years, in 2006 the South had the highest gonorrhea rate among the four regions of the country. Although the gonorrhea rate in the South declined for many years, in 2006 it rose by 12.3% from 2005 to a rate of 159.2 cases per 100,000 population. The rate in the West continued to increase, with an increase of 31.8% from 2002 to 2006. In contrast, the rate in the Northeast decreased by 21.2% from 93.6 cases per 100,000 population in 2002 to 73.8 in 2006. The rate in the Midwest (142.2 in 2002 and 136.9 in 2006) has shown minimal change (Figure 13 and Table 13).
An evaluation of increases in gonorrhea in eight western states suggested that increases were likely due to a variety of factors such as changes in testing practices (increased volume and use of more sensitive tests) as well as real increases in disease.2
Gonorrhea by State
In 2006, only four states and Puerto Rico had gonorrhea rates below the HP2010 national target of 19 cases per 100,000 population (Figure 14 and Tables 12 & 13).6 Unfortunately this is two fewer states than met the HP2010 target in 2005.
Gonorrhea by Metropolitan Statistical Area (MSA)
The overall gonorrhea rate in the 50 most populous MSAs was 131.1 cases per 100,000 population in 2006. This is a 3.3% increase from 2005. All of these MSAs had rates higher than the HP2010 target of 19 cases per 100,000 population (Table 17). In 2006, 58.3% of gonorrhea cases were reported by these MSAs. Similar to previous years, in 2006 the total gonorrhea rate among females in these MSAs (130.1) remained similar to that among males (131.6) (Tables 18 and 19).
Gonorrhea by County
In 2006, 1,234 (39.3%) of 3,140 counties in the United States had gonorrhea rates at or below the HP2010 national target of 19 cases per 100,000 population. Rates per 100,000 population were between 19 and 100 in 1,134 counties (36.1%), and greater than 100 in 772 counties (24.6%). The majority of counties with greater than 100 cases per 100,000 population were located in the South (Figure 15).
In 2006, 50% of reported gonorrhea cases occurred in just 68 counties or independent cities (Table 16).
Gonorrhea by Reporting Source
In 2006, 26.8% of gonorrhea cases were reported by STD clinics (Table A2). This is a change from 2002, when 35.2% of gonorrhea cases were reported by STD clinics. In 2006, a higher proportion of male gonorrhea cases were reported from STD clinics than female cases (37.9% and 16.7% respectively) (Figure 16).
Gonorrhea by Race/Ethnicity
Changes in gonorrhea rates between 2002 and 2006 differed by race/ethnic group. Gonorrhea rates decreased by 7.7% during this time period for African Americans from 713.7 to 658.4 cases per 100,000 population. However, the gonorrhea rate among African Americans increased by 6.3% between 2005 and 2006, the first increase for this population since 1998.
Other racial and ethnic groups have also seen increases in gonorrhea rates. Since 2002, the gonorrhea rate among American Indian/Alaska Natives increased 22.8%, whites increased 17.7%, and Hispanics increased 11.8%. The gonorrhea rate among Asian/Pacific Islanders decreased 1.4% between 2002 and 2006 (Figure 17 and Table 21B).
In 2006, the gonorrhea rate among African Americans was 18 times greater than the rate for whites. This is a decrease from 2002 when there was a 23-fold difference in rates. Gonorrhea rates were 3.8 times greater among American Indian/Alaska Natives, and 2.1 times greater among Hispanics than among whites in 2006. Rates among Asian/Pacific Islanders were 1.7 times lower than among whites in 2006.
Gonorrhea by Sex
Prior to 1996, rates of gonorrhea among men were higher than rates among women. For the sixth consecutive year, however, gonorrhea rates among women are slightly higher than among men (Figure 12). In 2006, the gonorrhea rate among women was 124.3 and the rate among men was 116.8 cases per 100,000 population (Tables 14 and 15).
Gonorrhea by Region and Sex
Between 2002 and 2006, gonorrhea rates among women increased 39.3% in the West and 1.3% in the South. Gonorrhea rates among women decreased 22.0% in the Northeast and were unchanged in the Midwest during the same time period.
Gonorrhea by Age and Sex
In 2006, gonorrhea rates continued to be highest among adolescents and young adults. The overall gonorrhea rate was highest for the 20- to 24-year-old age group (527.5), which is over four times higher than the national gonorrhea rate. Among females in 2006, 15- to 19- and 20- to 24-year-old women had the highest rates of gonorrhea (647.9 and 605.7, respectively); 20- to 24-year-old males had the highest rate (454.1) (Figure 18 and Table 20).
Although the gonorrhea rate among those 15 to 19 years of age decreased in recent years, in 2006 this rate increased 6.3%. Similar slight increases were seen among other younger age groups (4.4% among those 20 to 24 years of age and 8.1% among those 25 to 29 years of age) (Table 20). Similar increases were seen among both males and females in all age groups 29 years of age and younger (8.4% for males and 5.3% for females ages 15 to 19 years of age; 4.5% and 4.4% for males and females aged 20 to 24 years of age, respectively; and 7.6% for males and 8.8% for females aged 25 to 29 years of age) (Figures 19 and 20, and Table 20).
Gonorrhea by Race/Ethnicity and Sex
From 2002 to 2006 the overall rate in African-American men decreased 8.8% from 770.7 per 100,000 population to 702.7 despite an increase of 6.8% between 2005 and 2006. Increases were seen in this time period for African-American men in most age groups. The overall rate in American Indian/Alaska Native men increased 8.5% between 2005 and 2006, 7.4% among Hispanic men, and 2.5% among white men. Gonorrhea rates among Asian/Pacific Islander men decreased 24.0% between 2005 and 2006 (Table 21B).
Between 2002 and 2006 the overall rate among African-American women decreased 6.6% from 662.1 per 100,000 population to 618.1. However, increases of 5.8% were seen between 2005 and 2006 overall for African-American women and in most age groups. Currently, 15- to 19-year-old African-American women still have the highest gonorrhea rate of any group (2,898.1 per 100,000 population).
Rates among Hispanic women increased 6.5% between 2005 and 2006, 4.7% among white women, and 3.5% among American Indian/Alaska Native women. A decrease of 8.1% was seen among Asian/Pacific Island women (Table 21B).
Gonorrhea Prevalence Monitoring Projects
Gonorrhea test positivity data are available from a variety of settings. Screening criteria and practices may vary by state and over time.
Family Planning Clinics
In 2006, the median state-specific gonorrhea test positivity among 15- to 24-year-old women screened in selected family planning clinics in 43 states, Puerto Rico, the District of Columbia, and the Virgin Islands was 1.1% (range 0.0% to 4.8%) (Figure 21). Median gonorrhea positivity in family planning clinics has shown minimal change in recent years (0.9% in 2002).
For women attending selected prenatal clinics in 20 states, Puerto Rico, and the Virgin Islands, the median positivity was 1.0% (range 0.0% to 3.2%) (Figure F). Median gonorrhea positivity in prenatal clinics has shown minimal change in recent years (0.9% in 2002).
National Job Training Program
For 16- to 24-year-old women entering the National Job Training Program in 36 states, Puerto Rico, and the District of Columbia in 2006, the median state-specific gonorrhea prevalence was 2.4% (range 0.0% to 7.1%) in 2006 (Figure M). Among men entering the program from 20 states in 2006, the median state-specific gonorrhea positivity was 3.6% (range 0.0% to 6.2%) (Figure N).
In 2006, the median positivity for gonorrhea in women entering 37 juvenile corrections facilities was 3.8% (range 0.0% to 12.2%), and in men entering 62 juvenile corrections facilities was 0.9% (range 0.0% to 4.5%) (Table CC).
Gonococcal Isolate Surveillance Project (GISP)
Antimicrobial resistance remains an important consideration in the treatment of gonorrhea.3,7-14 In 1986, the Gonococcal Isolate Surveillance Project (GISP), a national sentinel surveillance system, was established to monitor trends in antimicrobial susceptibilities of strains of Neisseria gonorrhoeae in the United States among selected STD clinics or sites14 (Figure 22).
Overall, 25.6% of isolates collected in 2006 in 28 GISP sites were resistant to penicillin, tetracycline, ciprofloxacin, or some combination of those antibiotics (Figure 23).
Quinolone-resistant N. gonorrhoeae (QRNG)
Resistance to ciprofloxacin (a fluoroquinolone in the quinolone family of antimicrobials) was first identified in GISP sites in 1991. From 1991 through 1998, fewer than nine quinolone-resistant N. gonorrhoeae (QRNG) isolates were identified each year, and such isolates were identified in only a few GISP clinics. However since 1999 QRNG prevalence has steadily increased, first in Hawaii and in the Pacific Islands, then in the Western states, and then among MSM.8-11,13,15 In 2006, 843 (13.8% of the total) GISP isolates were identified as QRNG, an increase from 2005, when 581 (9.4% of the total) isolates were identified as QRNG. QRNG isolates were submitted from 27 of 28 GISP clinics in 2006 (Figures 22 and 24).
QRNG by Region
In 2006, 34 (35.8%) of 95 isolates submitted from Honolulu demonstrated ciprofloxacin-resistance, up from 17 (19.3%) of 88 isolates in 2005.
In California, increases in the number of isolates resistant to ciprofloxacin were identified in all GISP sites. In Los Angeles, 22.7% of isolates in 2006 were ciprofloxacin-resistant compared with 14.5% in 2005; in Long Beach, 28.4% were resistant in 2006 compared with 23.5% in 2005; in Orange County, 34.6% were resistant in 2006 compared with 27.5% in 2005; in San Diego, 35.1% were resistant in 2006 compared to 26.2% in 2005; and in San Francisco, 44.5% were resistant in 2006 compared with 31.3% in 2005.
Similarly in other West Coast sites, Denver, Las Vegas, Phoenix, Portland, and Seattle the prevalence of QRNG remains high. Between 2005 and 2006, in Denver, the prevalence increased to 15.7% from 10.9%; in Las Vegas, increased to 8.7% from 5.4%; in Phoenix, to 11.9% from 7.1%; in Portland, to 27.2% from 23.1%; and in Seattle the prevalence almost tripled to 31.8% from 11.6%.
In the South, increases in the prevalence of QRNG continued to be observed in Atlanta, Dallas, Greensboro, Miami, New Orleans, and Oklahoma City. Between 2005 and 2006 in Atlanta, QRNG resistance increased to 5.7% from 3.8%; in Dallas, the prevalence doubled to 6.1% from 3.2%; in Greensboro it increased to 1.7% from 0.6%; in Miami it doubled to 19.8% from 9.1%; in New Orleans, the prevalence of QRNG increased to 10.2% from 6.3%; and in Oklahoma City, it increased to 4.3% from 2.3%. In Baltimore, the prevalence was slightly down to 1.4% in 2006 from 3% in 2005. In Birmingham, the prevalence remained the same at 1.1%.
In the Midwest and Northeast, increases in prevalence of QRNG were seen in Cleveland and Philadelphia. In Cleveland, the prevalence of isolates that were resistant to ciprofloxacin increased to 3.1% in 2006 from 2.8% in 2005 and in Philadelphia, the prevalence more than doubled to 30.3% in 2006 from 14.3% in 2005. There was a slight decrease in QRNG prevalence in Chicago to 4.1% in 2006 from 4.7% in 2005; in Cincinnati to 0.7% from 1%; and in Minneapolis to 5.7% from 8%. The prevalence remained the same for Detroit at 0.3%.
Sites that identified ciprofloxacin-resistant isolates for the first time in GISP in 2006 included Albuquerque and New York City (which joined GISP in 2006). Tripler Army Medical Center did not identify any QRNG isolates in 2006 (Figure 22).
QRNG by Sexual Behavior
The number of QRNG isolates from MSM has continued to increase in 2006 to 499 (39% of all specimens from MSM) from 387 (29%) isolates in 2005. During the same time period, the number of these isolates from heterosexuals almost doubled from 183 (3.8%) to 328 (7%) (Figure 25).
As a result of this continued high prevalence of QRNG among MSM and more recently among heterosexuals, in April 2007, CDC revised the 2006 CDC STD Treatment Guidelines.
Fluoroquinolones are no longer recommended for use in the treatment of gonorrhea and associated conditions such as pelvic inflammatory disease.12
Other Antimicrobial Susceptibility Testing
To date, cephalosporin resistance has not been identified in GISP, and the proportion of GISP isolates demonstrating decreased susceptibility to ceftriaxone or cefixime has remained very low over time. In 2001, three GISP isolates with decreased susceptibility to cefixime were also found to be resistant to penicillin, tetracycline, and ciprofloxacin; such multi-drug resistance in combination with decreased susceptibility to cefixime had not previously been identified in the United States.13 In 2004, two GISP isolates had decreased susceptibility to cefixime; one of those isolates demonstrated the same resistance pattern as the 2001 isolates described above. In 2005, there were no GISP isolates that had decreased susceptibility to ceftriaxone or cefixime; in 2006, one GISP isolate had decreased susceptibility to cefixime only.
The proportion of GISP isolates demonstrating elevated minimum inhibitory concentrations (MICs) to azithromycin has been increasing since GISP began monitoring azithromycin susceptibility in 1992. In 2005, there was a change in the media used for antimicrobial susceptibility testing which resulted in an observational shift of the MIC curve for azithromycin. Thus, the azithromycin MIC for decreased susceptibility was changed from ≥ 1.0 µg/ml to ≥ 2.0 µg/ml from 2005 and thereafter. In 2006, ≥ 0.2% (14/6,089) isolates had azithromycin MIC ≥ 2.0 µg/ml which is a slight decrease from 0.6% (35/6,199) isolates from 2005.
Gonorrhea Among Special Populations
Additional information about gonorrhea in racial and ethnic minority populations, adolescents, MSM, and other at risk populations can be found in the Special Focus Profiles.
In summary, the national gonorrhea rate increased in 2006 for the second consecutive year. Gonorrhea rates increased in all regions of the country except the Northeast, among most age groups, and among all race/ethnic groups except Asian/Pacific Islanders.
Of particular concern are increases noted for the first time since 1998 among African Americans, the population with the greatest burden of disease and experiencing the greatest disparity as compared to other race/ethnic groups.
Rates among adolescent and young adults had been decreasing in recent years, but 2006 data demonstrate increases in these populations as well.
In addition, 2006 GISP data shows notable increases in QRNG prevalence, especially in the Midwest and Northeast; regions where previously it had been lower. As a response, modifications were made to the 2006 CDC STD Treatment Guidelines. 3
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13 Wang SA, Lee MV, Iverson CJ, Ohye RG, Whiticar PM, Hale JA, Trees DL, Knapp JS, Effler PV, Weinstock HS. Multi-drug resistant Neisseria gonorrhoeae with decreased susceptibility to cefixime, Hawaii, 2001. CID 2003;37:849-52.
15 Wang SA, Harvey AB, Conner SM, et al. Antimicrobial Resistance for Neisseria gonorrhoeae in the United States, 1988 to 2003: The Spread of Fluoroquinolone Resistance. Annals of Internal Medicine 2007;147:81-89.