Urban density and HIV prevalence linked to rising antibiotic resistance in gonorrhea

By Dr. Sanchari Sinha Dutta, Ph.D.Reviewed by Benedette Cuffari, M.Sc.Feb 7 2025

In a recent study published in The Lancet Regional Health, researchers identify key geographic and health factors that may predict the prevalence of antimicrobial-resistant (AMR) gonorrhea in the United States.

Study: Association between city-level sociodemographic and health factors and the prevalence of antimicrobial-resistant gonorrhea in the US, 2000–2019: a spatial–temporal modeling study. Image Credit: Coronea Borealis Studio / Shutterstock.com

Monitoring the spread of resistant gonorrhea

Neisseria gonorrhoeae is the bacterial pathogen responsible for gonorrhea, a sexually transmitted infection affecting the genitals, rectum, and throat. This pathogen has developed resistance to all antibiotics used to treat the condition, leading to the emergence of AMR gonorrhea.

Significant variations in the prevalence of AMR gonorrhea throughout different geographic regions of the United States have been observed. To better understand the transmission of these strains, the Gonococcal Isolate Surveillance Project (GISP) has been initiated to monitor trends in antimicrobial susceptibilities of gonococcal strains.

Despite these efforts, GISP only provides 25-35 surveillance sites throughout the U.S. every year. Thus, there remains an urgent need to develop robust surveillance strategies that can provide information on the population- and county-level risk of AMR gonorrhea.

About the study

Identifying population-level demographic, socioeconomic, and health factors that are associated with AMR gonorrhea burden could provide important insights needed to clarify the risk of AMR gonorrhea in the absence of local surveillance data. To this end, the researchers of the current study investigated the associations of several spatially- and temporally-varying predictors with the trends and prevalence of AMR gonorrhea between 2000 and 2019 in the U.S.

A mathematical model was developed and trained by data from the GISP. This model was then used to identify multiple population-level factors, including population density, unemployment rate, and prevalence of other sexually transmitted diseases (STDs) that are associated with the prevalence of resistance to ciprofloxacin, penicillin, and tetracycline between 2000 and 2019.

GISP isolates were obtained from the first 25 symptomatic men diagnosed with urethral gonorrhea each month who visited participating STD clinics in one of about 30 select cities.

A total of 112,487 GISP isolates collected from 42 sentinel sites during the study period were included in the analysis. Isolates with resistance to ciprofloxacin, penicillin, and tetracycline were selected, whereas those with resistance to azithromycin, cefixime, and ceftriaxone were excluded from the analysis due to the low proportions of these isolates during the study period.

Regional and demographic trends in AMR gonorrhea

Among all isolates tested for antibiotic susceptibility, about 14%, 12%, and 20% exhibited resistance to ciprofloxacin, penicillin, and tetracycline, respectively.

A higher prevalence of ciprofloxacin- and penicillin-resistant gonorrhea was observed in denser populations. Specifically, a greater prevalence of ciprofloxacin resistance was reported in western regions of the U.S., whereas a higher prevalence of ciprofloxacin and penicillin resistance was observed in the Southeast.

Compared to the Midwest, the Southeast U.S. had a 6.7- and 7.6-fold greater prevalence of gonorrhea with ciprofloxacin and penicillin resistance, respectively. Western regions of the U.S. had a 14-fold higher prevalence of gonorrhea with ciprofloxacin resistance.

Among health factors considered in the study, a positive association was observed between the prevalence of human immunodeficiency virus (HIV) infection and the prevalence of gonorrhea with ciprofloxacin and tetracycline resistance. The percentage of Black American, American Indian, or Alaska Native population, unemployment rates, and those with at least college degree were inversely associated with the prevalence of AMR gonorrhea.

Among selected antibiotics, a higher prevalence of tetracycline resistance was associated with an increased incidence of gonorrhea.

Study limitations

The model utilized in the current study may not be fully specified, as other relevant factors, such as the rate of partner change, rate of reinfection, or trade and migration, were excluded from the analysis. All of these are known to be associated with bacterial resistance.    

Due to the lack of county-level data on antibiotic consumption, the researchers of the current study used state-level data as estimates for the use of antibiotics in catchment areas of GISP surveillance sites. However, this variable was excluded from the main model due to high geographic and ethnic variations.

Future direction

AMR gonorrhea is more likely to arise in cities in the West or Southeast regions of the U.S., cities with high population density, or cities with a high prevalence of HIV. These observations provide important insights into certain factors that may increase the risk of AMR gonorrhea in cities not included in surveillance systems, thereby allowing researchers to identify cities at a greater risk of AMR gonorrhea.

Inconsistent associations were observed between population-level health insurance coverage and the prevalence of ciprofloxacin, penicillin, and tetracycline resistance. Thus, future studies using more recent GISP data are needed to justify these inconsistencies across antibiotics.

The study findings emphasize the importance of continued surveillance efforts to ensure the effective treatment of gonorrhea patients residing in cities with a higher risk of bacterial resistance. GISP might consider monitoring these cities more accurately and revise treatment guidelines in response to any induction in the prevalence of bacterial resistance.