Gonorrhea

Background

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 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 Together, sexual behavior and community prevalence can increase the risk of acquiring gonorrhea. Social determinants of health, such as socioeconomic status, discrimination, and access to quality health care, may contribute to the burden of gonorrhea in a community.2

N. gonorrhoeae has progressively developed resistance to each of the antimicrobials used for treatment of gonorrhea. Declining susceptibility to cefixime (an oral cephalosporin antibiotic) resulted in a change to the CDC treatment guidelines in 2015 to the current CDC-recommended regimen of ceftriaxone (an injectable cephalosporin) and azithromycin.3 The emerging threat of cephalosporin resistance highlights the need for continued surveillance of N. gonorrhoeae antimicrobial susceptibility.

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

Interpreting Rates of Reported Cases of Gonorrhea

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 or increased screening at extra-genital anatomic sites), the use of diagnostic tests with different test performance (e.g., the broader use of nucleic acid amplification tests [NAATs]), and changes in reporting practices. As with other STDs, the reporting of gonorrhea cases to CDC is incomplete.4 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.

Gonorrhea — United States

In 2018, a total of 583,405 cases of gonorrhea were reported in the United States, yielding a rate of 179.1 cases per 100,000 population (Figure 14, Table 1). During 2017–2018, the rate of reported gonorrhea cases increased 5.0%, and increased 82.6% since the historic low in 2009.

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Gonorrhea by Region

The South had the highest rate of reported gonorrhea cases (194.4 cases per 100,000 population) among the four regions of the United States in 2018, followed by the Midwest (184.5 cases per 100,000 population), the West (179.7 cases per 100,000 population), and the Northeast (138.4 cases per 100,000 population) (Figure 15, Table 14). During 2017–2018, the gonorrhea rate increased in all four regions: 8.5% in the Midwest, 7.4% in the West, 7.3% in the Northeast, and 1.3% in the South (Figure 15, Table 14). During 2014–2018, the rate of gonorrhea in the West increased by 79.9% (99.9 to 179.7 cases per 100,000 population) and the rate in the Midwest increased by 73.7% (106.2 to 184.5 cases per 100,000 population), while the Northeast and South had lower overall increases during this time period (64.0% and 49.7%, respectively).

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Gonorrhea by State

In 2018, rates of reported gonorrhea cases per 100,000 population ranged by state from 43.0 in Vermont to 326.7 in Mississippi; the gonorrhea rate in the District of Columbia was 611.0 cases per 100,000 population (Figure 16, Tables 13 and 14).

During 2017–2018, gonorrhea rates increased in 40 states (78.4%) and decreased in 10 states and the District of Columbia (21.6%) (Table 14).

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Gonorrhea by Metropolitan Statistical Area

The overall rate of reported gonorrhea cases in the 50 most populous metropolitan statistical areas (MSAs) was 194.9 cases per 100,000 population in 2018, representing a 2.9% increase compared with the rate in 2017 (189.4 cases per 100,000 population) (Table 17). In 2018, 60.1% of reported gonorrhea cases were reported by these MSAs. Since 2014, the gonorrhea rate among females in the 50 most populous MSAs has been lower than the rate among males (Tables 18 and 19). In 2018, the rate among females in these MSAs was 139.0 cases per 100,000 females, while the rate among males was 252.5 cases per 100,000 males.

Gonorrhea by County

In 2018, 93.4% of all counties in the United States reported at least one case of gonorrhea; however, 49.0% of reported gonorrhea cases occurred in just 70 counties or independent cities (Figure 17). The rate ranged from 0.0 to 30.0 cases per 100,000 population in 627 counties (20.0%), from 31.0 to 60.0 cases per 100,000 population in 625 counties (20.0%), from 61.0 to 102.0 cases per 100,000 population in 629 counties (20.0%), from 103.0 to 183.0 cases per 100,000 population in 628 counties (20.0%), and was 184.0 cases per 100,000 population or more in 633 counties (20.1%). As in previous years, counties with the highest gonorrhea rates were concentrated in the South.

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Gonorrhea by Sex

As was observed during 2014–2017, the rate of reported gonorrhea cases among males was higher than the rate among females in 2018 (Figure 18, Tables 15 and 16). During 2017–2018, the gonorrhea rate among males increased 6.0% (200.8 to 212.8 cases per 100,000 males) and the rate among females increased 3.6% (140.7 to 145.8 cases per 100,000 females). During 2014–2018, the rate among males increased 78.7% (119.1 to 212.8 cases per 100,000 males) and the rate among females increased 45.2% (100.4 to 145.8 cases per 100,000 females). The magnitude of the increase among males suggests either increased transmission or increased case ascertainment (e.g., through increased extra-genital screening) among gay, bisexual, and other 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 national trends in gonorrhea rates among MSM over time cannot be assessed.

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Gonorrhea by Region and Sex

In most regions, the rate of gonorrhea increased among both males and females during 2017–2018 and during 2014–2018 (Tables 15 and 16). The rate of reported gonorrhea cases among females increased the most in the West (8.7% during 2017–2018 and 71.0% during 2014–2018) and Midwest (7.1% during 2017–2018 and 57.5% during 2014–2018) with smaller increases in the Northeast (3.1% during 2017–2018 and 30.8% during 2014–2018) and South (33.2% during 2014–2018) (Table 15). The rate of reported gonorrhea cases among males increased the most in the Midwest (10.1% during 2017–2018 and 90.8% during 2014–2018) and Northeast (9.3% during 2017–2018 and 86.2% during 2014–2018); however, increases were all also reported in the West (6.6% during 2017–2018 and 85.0% during 2014–2018) and South (2.4% during 2017–2018 and 66.3% during 2014–2018) (Table 16).

Gonorrhea by Age

In 2018, rates of reported gonorrhea cases continued to be highest among adolescents and young adults (Figure 19, Table 21). In 2018, the highest rates among females were observed among those aged 20–24 years (702.6 cases per 100,000 females) and 15–19 years (548.1 cases per 100,000 females). Among males, the rate was highest among those aged 20–24 years (720.9 cases per 100,000 males) and 25–29 years (674.0 cases per 100,000 males).

In 2018, persons aged 15–44 years accounted for 91.6% of reported gonorrhea cases with known age (Table 21). Among 15–19 year olds, rates decreased 1.3% during 2017–2018. However, the gonorrhea rate increased among the following age groups during 2017–2018: 1.2% among those aged 20–24 years, 6.2% among those aged 25–29 years, 12.4% among those aged 30–34 years, 10.5% among those aged 35–39 years, and 11.8% among those aged 40–44 years (Table 21). Increases in rates were observed in most age groups for both males and females during 2017–2018. However, rates decreased 1.7% among females aged 15–19 years (557.3 to 548.1 cases per 100,000 females) and 0.9% among males aged 15–19 years (323.3 to 320.5 cases per 100,000 males) (Figures 20 and 21).

Figure 19 - Bar graph showing rates of reported cases of gonorrhea in the United States by age group and sex. In 2018, rates of reported gonorrhea cases continued to be highest among adolescents and young adults. In 2018, the highest rates among females were observed among those aged 20–24 years (702.6 cases per 100,000 females) and 15–19 years (548.1 cases per 100,000 females). Among males, the rate was highest among those aged 20–24 years (720.9 cases per 100,000 males) and 25–29 years (674.0 cases per 100,000 males).

Figure 20 - Line graph showing rates of reported cases of gonorrhea in the United States among females aged 15–44 years by age group from 2009–2018. Increases in rates of reported gonorrhea cases were observed in most age groups for females during 2017–2018. However, rates decreased 1.7% among females aged 15–19 years (from 557.3 to 548.1 cases per 100,000 females).

Figure 21 - Line graph showing rates of reported cases of gonorrhea in the United States among males aged 15–44 years by age group from 2009–2018. Increases in rates of reported gonorrhea cases were observed in most age groups for males during 2017–2018. However, rates decreased 0.9% among males aged 15–19 years (from 323.3 to 320.5 cases per 100,000 males).

Gonorrhea by Race/Hispanic Ethnicity

In 2018, the rate of reported gonorrhea cases remained highest among Blacks (548.9 cases per 100,000 population) (Table 22B). The rate among Blacks was 7.7 times the rate among Whites (71.1 cases per 100,000 population). The gonorrhea rate among American Indians/Alaska Natives (AI/AN) (329.5 cases per 100,000 population) was 4.6 times that of Whites, the rate among Native Hawaiians/Other Pacific Islanders (NHOPI) (181.4 cases per 100,000 population) was 2.6 times that of Whites, the rate among Hispanics (115.9 cases per 100,000 population) was 1.6 times that of Whites, the rate among Multirace persons (94.4 cases per 100,000 population) was 1.3 times that of Whites, and the rate among Asians (35.1 cases per 100,000 population) was half the rate of Whites (Table 22B).

During 2014–2018, for all five years during that period, the gonorrhea rate increased among all race/Hispanic ethnicity groups: 119.5% among Multirace persons, 99.4% among Asians, 90.3% among NHOPI, 89.1% among Whites, 84.2% among AI/AN, 66.0% among Hispanics, and 38.8% among Blacks (Figure 22).

More information on gonorrhea rates among race/Hispanic ethnicity groups can be found in the Special Focus Profiles, STDs in Racial and Ethnic Minorities.

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Gonorrhea by Reporting Source

In 2018, 8.4% of gonorrhea cases were reported from STD clinics, 77.7% were reported from venues outside of STD clinics, and 13.9% had an unknown reporting source (Table A2).

During 2009–2018, the percent of gonorrhea cases reported by STD clinics declined 42.6% among females and 19.8% among males; however, the percent of gonorrhea cases with missing/unknown reporting source increased 80.4% among females and 277.3% among males (Figures 23 and 24). During 2017–2018, the percent of gonorrhea cases reported by STD clinics decreased 7.5% among females and 4.9% among males.

In 2018, the largest proportion of cases among females were reported by private physicians/health maintenance organizations (HMOs) (24.1%), followed by other hospital clinics/facilities (13.6%), laboratories (9.0%), emergency rooms (6.0%), and STD clinics (5.8%) (Figure 23). Among males, private physicians/HMOs (20.7%) were the most common reporting source, followed by other hospital clinics/facilities (12.3%), STD clinics (10.3%), emergency rooms (7.1%), and laboratories (6.9%) (Figure 24).

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STD Surveillance Network

The STD Surveillance Network (SSuN) is an ongoing collaboration of state, county, and city health departments conducting sentinel and enhanced surveillance activities. These include collecting enhanced clinical and behavioral information among all patients attending selected STD clinics, among women aged 15–44 years in selected reproductive health clinics, and conducting enhanced patient and provider investigations on a representative sample of gonorrhea cases diagnosed and reported from all reporting sources in their jurisdiction.

Enhanced gonorrhea case report data for 2018 were obtained from Cycle 3 of SSuN, which includes 10 jurisdictions randomly sampling all cases reported in their jurisdictions. In 2018, SSuN collaborators interviewed 6,842 gonorrhea cases, representing 4.3% of all cases reported from participating jurisdictions. The estimated burden of disease represented by men who have sex with men (MSM; including men who have sex with both men and women), men who have sex with women only (MSW), and women varied substantially across collaborating sites based on weighted analysis (Figure 25). San Francisco had the highest proportion of cases estimated to be MSM (86.4%), while Baltimore had the lowest proportion of MSM cases (20.1%). In total, across all SSuN sites, 42.5% of gonorrhea cases were estimated to be among MSM, 25.1% among MSW, and 32.4% among women.

Among six jurisdictions participating in SSuN continuously from 2010 to 2018, estimated rates of gonorrhea among MSM, MSW, and women were calculated by extending published estimates of the MSM population and are presented in Figure 26.5,6 The estimated gonorrhea case rate among MSM increased 375.5% during 2010–2018 from 1,368.6 cases per 100,000 MSM in 2010 to 6,508.0 cases per 100,000 MSM in 2018. Over the same time period, case rates among MSW and women also increased by 69.3% and 95.2%, respectively.

Collaborating SSuN jurisdictions also conduct sentinel surveillance on all patients seeking care in selected STD clinics. In 2018, the proportion of STD clinic patients who tested positive for gonorrhea varied by sex and sex of sex partners, as well as age group (Figure 27). The overall prevalence, represented by the average of the mean value by nine of the 10 SSuN jurisdictions, where data was available, was 20.5% for MSM, 9.1% for MSW, and 5.4% for women. Among those attending these clinics, MSM disproportionately had higher positivity rates when compared to MSW and women in all age groups. Although overall gonorrhea positivity rates declined with increasing age for women, MSM, and MSW, a slower decline by age was observed in MSM <40 years of age.

Additional information about the SSuN methodology can be found in Section A2.2 of the Appendix.

Figure 25 - The estimated burden of disease represented by men who have sex with men (MSM; including men who have sex with both men and women), men who have sex with women only (MSW), and women varied substantially across collaborating sites based on weighted analysis. San Francisco had the highest proportion of cases estimated to be MSM (86.4%), while Baltimore had the lowest proportion of MSM cases (20.1 %). In total, across all SSuN sites, 42.5% of gonorrhea cases were estimated to be among MSM, 25.1% among MSW, and 32.4% among women.

Figure 26 - The estimated gonorrhea case rate among MSM increased 375.5% during 2010–2018 from 1,368.6 cases per 100,000 MSM in 2010 to 6,508.0 cases per 100,000 MSM in 2018. Over the same time period, case rates among MSW and women also increased by 69.3% and 95.2%, respectively.

Figure 27 - In 2018, the proportion of STD clinic patients who tested positive for gonorrhea varied by sex and sex of sex partners, as well as age group. The overall prevalence, represented by the average of the mean value by nine of the 10 SSuN jurisdictions, where data was available, was 20.5% for MSM, 9.1% for MSW, and 5.4% for women. Among those attending these clinics, MSM disproportionately had higher positivity rates when compared to MSW and women in all age groups. Although overall gonorrhea positivity rates declined with increasing age for women, MSM, and MSW, a slower decline by age was observed in MSM <40 years of age.

Gonococcal Isolate Surveillance Project

Antimicrobial resistance remains an important consideration in the treatment of gonorrhea.3, 7-9 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.7 Data are collected from selected STD clinic sentinel sites and from regional laboratories (Figure 28).

Antimicrobial susceptibility is measured by the minimum inhibitory concentration (MIC), the lowest antimicrobial concentration that inhibits bacterial growth in the laboratory. Increases in MICs demonstrate that the bacteria can survive at higher antimicrobial concentrations in the laboratory. Monitoring of MIC trends is useful because increasing MICs can oftentimes be an early indicator of the emergence of antimicrobial resistance.

Information on the antimicrobial susceptibility criteria used in GISP can be found in Section A2.3 in the Appendix. More information about GISP and additional data can be found at: https://www.cdc.gov/std/GISP.

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Ceftriaxone Susceptibility

Susceptibility testing for ceftriaxone began in 1987. During 2009–2018, the percentage of GISP isolates that exhibited elevated ceftriaxone MICs, defined as ≥0.125 µg/mL, fluctuated between 0.1% and 0.4% (Figure 29). In 2018, 0.2% of isolates had elevated ceftriaxone MICs. Five isolates with decreased ceftriaxone susceptibility (MIC = 0.5 µg/mL) have been previously identified in GISP: one from San Diego, California (1987), two from Cincinnati, Ohio (1992 and 1993), one from Philadelphia, Pennsylvania (1997), and one from Oklahoma City, Oklahoma (2012).

Cefixime Susceptibility

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) declined from 1.4% in 2011 to 0.3% in 2018 (Figure 29).

Azithromycin Susceptibility

Susceptibility testing for azithromycin began in 1992. Figure 29 displays the distribution of azithromycin MICs among GISP isolates collected during 2009–2018. Most isolates had MICs of 0.125–0.5 µg/mL. During 2012–2014, the percentage of isolates with elevated azithromycin MICs (≥2 µg/mL) ranged from 0.3% to 2.5% with a sharp increase during 2013–2014 (from 0.6% to 2.5%); during 2014–2018, the percentage increased from 2.5% to 4.6%.

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Susceptibility to Other Antimicrobials

Susceptibility testing for gentamicin began in 2015. Between 2015 and 2017, 66.7–75.3% of all tested isolates had an MIC value of 8 µg/mL (Figure 30). Starting in 2018, the range of MIC values tested in GISP was expanded to include MICs as low as 0.25 µg/mL and as high as 64 µg/mL. In 2018, 0.02% of all tested isolates had an MIC above 16 µg/mL.

In 2018, 31.2% of isolates collected from GISP sites were resistant to ciprofloxacin, 25.6% to tetracycline, and 13.7% to penicillin (Figure 31). Although these antimicrobials are no longer recommended for treatment of gonorrhea, the resistance phenotypes remain common. The different susceptibility patterns seen in GISP in 2018 are shown in Figure 32. Panel A demonstrates the percentage of isolates with resistance or elevated MICs to various numbers of antimicrobials. Panel B further highlights the specific combinations of resistance or elevated MICs across antimicrobials (vertical bars). The overall percentage of reduced susceptibility for each antimicrobial (horizontal bars) are the same percentages seen for 2018 in Figure 31. Of all the isolates collected in GISP in 2018, 4.5% demonstrated resistance or elevated MICs to at least three antibiotics tested with the majority of the combinations including tetracycline, penicillin and ciprofloxacin; no isolates with elevated azithromycin MICs had elevated ceftriaxone MICs (Figure 32). In 2018, 48.7% of all tested isolates were susceptible to all antibiotics tested.

Figure 30 - Between 2015 and 2017, 66.7–75.3% of all tested isolates had an MIC value of 8 µg/mL. In 2018, 0.02% of all tested isolates had an MIC above 16 µg/mL.

Figure 31 - In 2018, 31.2% of isolates collected from GISP sites were resistant to ciprofloxacin, 25.6% to tetracycline, and 13.7% to penicillin.

Figure 32 - Two-panel figure showing resistance or elevated minimum inhibitory concentration patterns of Neisseria gonorrhoeae isolates to antimicrobials during 2018. The different susceptibility patterns seen in GISP in 2018 are shown. Panel A, a pie graph, demonstrates the percentage of Neisseria gonorrhoeae isolates with resistance or elevated minimum inhibitory concentrations to azithromycin, cefixime, ceftriaxone, fluoroquinolone, tetracycline, and penicillin. Panel B, an UpSet graph, further highlights the specific combinations of resistance or elevated minimum inhibitory concentrations across antimicrobials (vertical bars). The overall percentage of reduced susceptibility for each antimicrobial (horizontal bars) are the same percentages seen for 2018 in Figure 31. Of all the Neisseria gonorrhoeae isolates collected in GISP in 2018, 4.5% demonstrated resistance or elevated minimum inhibitory concentrations to at least three antibiotics tested with the majority of the combinations including tetracycline, penicillin and ciprofloxacin; no isolates with elevated azithromycin minimum inhibitory concentrations had elevated ceftriaxone minimum inhibitory concentrations. In 2018, 48.7% of all tested isolates were susceptible to all antibiotics tested.

Antimicrobial Treatments Given for Gonorrhea

The antimicrobial agents given to GISP patients for gonorrhea therapy are shown in Figure 33. The proportion of patients treated with ceftriaxone 250 mg increased from 84.0% in 2011 to 98.1% in 2017 but decreased slightly to 96.5% in 2018. Patients treated with gentamicin 240 mg increased from 0.2% in 2015 to 1.4% in 2018 and patients treated with cefixime 400mg decreased from 0.3% in 2015 to 0.1% in 2018.

In 2018, based on weighted analysis of SSuN jurisdictions with documented treatment information (i.e., antimicrobials and dosages) for ≥80% of cases, 85.8% (95% CI: 84.1–87.5) of reported patients with gonorrhea in SSuN jurisdictions received the recommended treatment for uncomplicated gonorrhea (Figure 34). The proportion of reported patients that received the recommended dual treatment ranged from 83.8% (95% CI: 81.9–85.6) in Florida to 95.5% (95% CI: 92.9–98.1) in San Francisco, California.

Figure 33 - Area graph showing the distribution of primary antimicrobial drug used to treat gonorrhea among GISP participants from 1988 to 2018. The proportion of GISP participants treated for gonorrhea with ceftriaxone 250 mg increased from 84.0% in 2011 to 98.1% in 2017 but decreased slightly to 96.5% in 2018. Participants treated with gentamicin 240 mg increased from 0.2% in 2015 to 1.4% in 2018 and participants treated with cefixime 400 mg decreased from 0.3% in 2015 to 0.1% in 2018.

Figure 34 - In 2018, based on weighted analysis of SSuN jurisdictions with documented treatment information (i.e., antimicrobials and dosages) for ≥80% of cases, 85.8% (95% CI = 84.1–87.5) of reported patients with gonorrhea in SSuN jurisdictions received the recommended treatment for uncomplicated gonorrhea. The proportion of reported patients that received the recommended dual treatment ranged from 83.8% (95% CI = 81.9–85.6) in Florida to 95.5% (95% CI = 92.9–98.1) in San Francisco, California.

Gonorrhea Among Special Populations

More information about gonorrhea in race/Hispanic ethnicity groups, females of reproductive age, adolescents, young adults, and MSM can be found in the Special Focus Profiles.

Gonorrhea Summary

The national rate of reported gonorrhea cases reached a historic low in 2009, but increased each year during 2009–2012. After a temporary decrease in 2013, the gonorrhea rate increased again during 2014–2018. This increase was largely attributable to increases among men. Enhanced surveillance data suggest the largest increases are among MSM. However, high gonorrhea rates persist in certain geographic areas, among adolescents and young adults, and in some racial/Hispanic ethnicity groups. Continued surveillance for antimicrobial resistant gonorrhea is critical to monitor for the emergence of reduced susceptibility and resistance to cephalosporins and azithromycin.

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