CDC Laboratory Recommendations for Syphilis Testing, United States, 2024.

This report provides new CDC recommendations for tests that can support a diagnosis of syphilis, including serologic testing and methods for the identification of the causative agent Treponema pallidum. These comprehensive recommendations are the first published by CDC on laboratory testing for syphilis, which has traditionally been based on serologic algorithms to detect a humoral immune response to T. pallidum. These tests can be divided into nontreponemal and treponemal tests depending on whether they detect antibodies that are broadly reactive to lipoidal antigens shared by both host and T. pallidum or antibodies specific to T. pallidum, respectively. Both types of tests must be used in conjunction to help distinguish between an untreated infection or a past infection that has been successfully treated. Newer serologic tests allow for laboratory automation but must be used in an algorithm, which also can involve older manual serologic tests. Direct detection of T. pallidum continues to evolve from microscopic examination of material from lesions for visualization of T. pallidum to molecular detection of the organism. Limited point-of-care tests for syphilis are available in the United States; increased availability of point-of-care tests that are sensitive and specific could facilitate expansion of screening programs and reduce the time from test result to treatment. These recommendations are intended for use by clinical laboratory directors, laboratory staff, clinicians, and disease control personnel who must choose among the multiple available testing methods, establish standard operating procedures for collecting and processing specimens, interpret test results for laboratory reporting, and counsel and treat patients. Future revisions to these recommendations will be based on new research or technologic advancements for syphilis clinical laboratory science.

Incidence and Prevalence of Trichomonas vaginalis Infection Among Persons Aged 15 to 59 Years: United States, 2018.

BACKGROUND: Trichomonas vaginalis (TV) is a sexually transmitted parasite associated with multiple adverse outcomes in women. Estimating TV incidence is challenging because of its largely asymptomatic presentation. METHODS: Per-capita prevalence was estimated using the National Health and Nutrition Examination Survey, 2013 to 2018. Incidence was estimated using ordinary differential equations assuming static incidence at steady state and fit using Bayesian techniques. Model inputs included estimates of proportion of asymptomatic cases, natural clearance, and time to symptomatic treatment seeking. Posterior distributions were drawn, and uncertainty was reported, from 25th (Q1) to 75th (Q3) percentiles. Aggregated measures were estimated by combining component distributions. RESULTS: Among 15- to 59-year-olds in 2018, the number of prevalent TV infections was 2.6 (Q1, 2.4; Q3, 2.7) million overall, 470,000 (Q1, 414,000; Q3, 530,000) among men, and 2.1 (Q1, 2.0; Q3, 2.2) million among women; the numbers of incident infections were 6.9 (Q1, 6.2; Q3, 7.6) million, 3.3 (Q1, 2.8; Q3, 3.8) million, and 3.5 (Q1, 3.1; Q3, 4.0) million among all persons, men, and women, respectively. Persons aged 15 to 24 years comprised 15.6% and 16.3% of all prevalent and incident infections, respectively; prevalence and incidence in both sexes increased with age. Incidences in both sexes were highly dependent on estimates of natural clearance, which were based on few data. CONCLUSIONS: Prevalence and incidence of TV are substantial in the United States, particularly among those 25 years or older. Although estimated prevalence is higher in women, estimated incidence is similar in men and women. Data on key parameters of TV infection are limited; future research should focus on clarifying the natural history of TV.

Prevalence of Urogenital Mycoplasma genitalium Infection, United States, 2017 to 2018.

ABSTRACT: During the 2017-2018 National Health and Nutrition Examination Survey, urine samples from participants aged 14 to 59 years were tested for Mycoplasma genitalium infection. Overall prevalence was 1.7% (95% confidence interval [CI], 1.1%-2.7%). Prevalence was similar between males (1.8% [95% CI, 0.9%-3.1%]) and females (1.7% [95% CI, 0.8%-3.0%]).

Expanding U.S. Laboratory Capacity for Neisseria gonorrhoeae Antimicrobial Susceptibility Testing and Whole-Genome Sequencing through the CDC's Antibiotic Resistance Laboratory Network.

U.S. gonorrhea rates are rising, and antibiotic-resistant Neisseria gonorrhoeae (AR-Ng) is an urgent public health threat. Since implementation of nucleic acid amplification tests for N. gonorrhoeae identification, the capacity for culturing N. gonorrhoeae in the United States has declined, along with the ability to perform culture-based antimicrobial susceptibility testing (AST). Yet AST is critical for detecting and monitoring AR-Ng. In 2016, the CDC established the Antibiotic Resistance Laboratory Network (AR Lab Network) to shore up the national capacity for detecting several resistance threats including N. gonorrhoeae AR-Ng testing, a subactivity of the CDC's AR Lab Network, is performed in a tiered network of approximately 35 local laboratories, four regional laboratories (state public health laboratories in Maryland, Tennessee, Texas, and Washington), and the CDC's national reference laboratory. Local laboratories receive specimens from approximately 60 clinics associated with the Gonococcal Isolate Surveillance Project (GISP), enhanced GISP (eGISP), and the program Strengthening the U.S. Response to Resistant Gonorrhea (SURRG). They isolate and ship up to 20,000 isolates to regional laboratories for culture-based agar dilution AST with seven antibiotics and for whole-genome sequencing of up to 5,000 isolates. The CDC further examines concerning isolates and monitors genetic AR markers. During 2017 and 2018, the network tested 8,214 and 8,628 N. gonorrhoeae isolates, respectively, and the CDC received 531 and 646 concerning isolates and 605 and 3,159 sequences, respectively. In summary, the AR Lab Network supported the laboratory capacity for N. gonorrhoeae AST and associated genetic marker detection, expanding preexisting notification and analysis systems for resistance detection. Continued, robust AST and genomic capacity can help inform national public health monitoring and intervention.

Utility of MALDI-TOF MS for differentiation of Neisseria gonorrhoeae isolates with dissimilar azithromycin susceptibility profiles.

BACKGROUND: Antibiotic-resistant gonorrhoea has been a chronic public health burden since the mid-1930s. Recent emergence of isolates resistant to the current recommended antibiotics for gonorrhoea further magnifies the threat of untreatable gonorrhoea. The lack of new, effective antibiotics highlights the need for better understanding of the population structure of Neisseria gonorrhoeae in order to provide greater insight on how to curtail the spread of antimicrobial-resistant N. gonorrhoeae. OBJECTIVES: To explore a potential application of MALDI-TOF MS to differentiate N. gonorrhoeae displaying different levels of susceptibility to the antibiotic azithromycin. METHODS: We conducted MALDI-TOF MS using the Bruker Biotyper on 392 N. gonorrhoeae isolates collected through the Gonococcal Isolate Surveillance Project (GISP) and/or the Strengthening the United States Response to Resistant Gonorrhea (SURRG) project. The MALDI-TOF MS spectra were visually analysed to assess the presence of distinctive peak(s). Statistical analysis was performed to assess the relationship between gonococcal isolates with the distinct protein peak and antibiotic susceptibility. RESULTS: In this study, we were able to differentiate N. gonorrhoeae isolates into two distinct subpopulations using MALDI-TOF MS. Isolates were distinguished by the presence or absence of a spectral peak at 11 300 Da. Notably, these two groups exhibited different levels of susceptibility to azithromycin. CONCLUSIONS: We have shown that in addition to its ability to identify N. gonorrhoeae, MALDI-TOF MS could also be used to differentiate gonococcal isolates with different levels of susceptibility to azithromycin.

Azithromycin Susceptibility Among Neisseria gonorrhoeae Isolates and Seasonal Macrolide Use.

Rising azithromycin nonsusceptibility among Neisseria gonorrhoeae isolates threatens current treatment recommendations, but the cause of this rise is not well understood. We performed an ecological study of seasonal patterns in macrolide use and azithromycin resistance in N. gonorrhoeae, finding that population-wide macrolide use is associated with increased azithromycin nonsusceptibility. These results, indicative of bystander selection, have implications for antibiotic prescribing guidelines.

Prevalence of Trichomonas vaginalis Among Civilian, Noninstitutionalized Male and Female Population Aged 14 to 59 Years: United States, 2013 to 2016.

Among the US civilian noninstitutionalized population aged 14 to 59 years in 2013 to 2016, prevalence of Trichomonas vaginalis infection in urine was 1.3% overall. Prevalence was 2.1% among females, 0.5% among males, and highest at 9.6% among non-Hispanic black females. Estimate instability limited analysis of factors beyond sex, age, and race/Hispanic ethnicity.

Extragenital Chlamydia and Gonorrhea Among Community Venue-Attending Men Who Have Sex with Men - Five Cities, United States, 2017.

Sexually transmitted diseases (STDs) disproportionately affect gay, bisexual, and other men who have sex with men (MSM) in the United States (1). Because chlamydia and gonorrhea at extragenital (rectal and pharyngeal) anatomic sites are often asymptomatic, these anatomic sites serve as a reservoir of infection, which might contribute to gonococcal antimicrobial resistance (2) and increased risk for human immunodeficiency virus (HIV) transmission and acquisition (3). To ascertain prevalence of extragenital STDs, MSM attending community venues were recruited in five U.S. cities to provide self-collected swabs for chlamydia and gonorrhea screening as part of National HIV Behavioral Surveillance (NHBS). Overall, 2,075 MSM provided specimens with valid results, and 13.3% of participants were infected with at least one of the two pathogens in at least one of these two extragenital anatomic sites. Approximately one third of participating MSM had not been screened for STDs in the previous 12 months. MSM attending community venues had a high prevalence of asymptomatic extragenital STDs. The findings underscore the importance of sexually active MSM following current recommendations for STD screening at all exposed anatomic sites at least annually (4).

Performance of Chlamydia trachomatis OmcB Enzyme-Linked Immunosorbent Assay in Serodiagnosis of Chlamydia trachomatis Infection in Women.

Chlamydia trachomatis serological assays with improved sensitivity over commercially available assays are needed to evaluate the burden of C. trachomatis infection and the effectiveness of prevention efforts. We evaluated the performance of a C. trachomatis outer membrane complex protein B (OmcB) enzyme-linked immunosorbent assay (ELISA) in the detection of anti-C. trachomatis antibody responses in C. trachomatis-infected women. OmcB ELISA was less sensitive than our C. trachomatis elementary body (EB) ELISA, but it was highly specific. The magnitude of the antibody response was higher in African-Americans and those with prior C. trachomatis infection. Unlike EB ELISA, the IgG1 response to C. trachomatis OmcB was short-lived and was not maintained by repeat C. trachomatis infection.

Susceptibility of Neisseria gonorrhoeae to Gentamicin-Gonococcal Isolate Surveillance Project, 2015-2016.

The gentamicin minimum inhibitory concentrations (MICs) of Neisseria gonorrhoeae isolates were determined. Seventy-three percent of isolates demonstrated an MIC range of 8 to 16 µg/mL, and 27% demonstrated an MIC of 4 µg/mL or less. Significant associations between gentamicin MIC and resistance or reduced susceptibility to other antimicrobials were found.

Preparing for the Chlamydia and Gonorrhea Self-Test.

New technology may soon allow individuals to test themselves for chlamydia and gonorrhea. These new self-tests might help increase screening, but they will also bring new issues for treatment, prevention, and surveillance. Providers will need to decide how to respond to patients who present after a positive screening test and how to approach partner testing and treatment. Research will be needed to identify approaches to increase screening using these tests. Laboratory-based surveillance will not capture infections if testing does not involve a laboratory, so new surveillance techniques will be needed. Self-tests are new tools that will soon be available. We should be prepared to use them.

Improving STD service delivery: Would American patients and providers use self-tests for gonorrhea and chlamydia?

Chlamydia trachomatis (CT) and Neisseria gonorrhea (GC) are the most frequently reported notifiable diseases in the United States and costs for diagnosis and treatment of these two infections are approximately $700 million per year. A proposed new method for screening for these two infections is self-tests; similar to at-home pregnancy and HIV tests which do not include sending collected specimens to a laboratory for diagnosis. However, no such self-tests for sexually transmitted diseases (STD) have been approved by the Food and Drug Administration (FDA). To determine the acceptability of such a test, we used three surveys, conducted in 2017, including the American Men's Internet Survey, the SummerStyles survey, and the DocStyles survey to ask potential users about their interest in this type of test and how they might use it. Among our sampled population of men who have sex with men, 79.5% said they would prefer to take this type of test at home and 73.9% said they would be willing to pay at least $20 for the test. Among young adults (18-29 years), 54.1% indicated that they would like to take this test at home and 64.5% were willing to pay more than $10 for such a test. Among sampled physicians, 85.1% were "likely" or "very likely" to use an FDA-approved STD self-test in their office to screen for CT or GC. Self-tests for STDs are on our horizon and we need to be prepared to integrate these tests into our healthcare systems.

Immunoglobulin-Based Investigation of Spontaneous Resolution of Chlamydia trachomatis Infection.

Chlamydia trachomatis elementary body enzyme-linked immunosorbent assay (ELISA) was used to investigate serum anti-CT immunoglobulin G1 (IgG1; long-lived response) and immunoglobulin G3 (IgG3; short-lived response indicating more recent infection) from treatment (enrollment) and 6-month follow-up visits in 77 women previously classified as having spontaneous resolution of chlamydia. Of these women, 71.4% were IgG1+IgG3+, consistent with more recent chlamydia resolution. 15.6% were IgG3- at both visits, suggesting absence of recent chlamydia. Using elementary body ELISA, we demonstrated approximately 1 in 6 women classified as having spontaneous resolution of chlamydia might have been exposed to C. trachomatis but not infected. Further, we classified their possible infection stage.

Cluster of Neisseria gonorrhoeae Isolates With High-level Azithromycin Resistance and Decreased Ceftriaxone Susceptibility, Hawaii, 2016.

BACKGROUND: The Centers for Disease Control and Prevention (CDC) currently recommends dual therapy with ceftriaxone and azithromycin for gonorrhea to ensure effective treatment and slow emergence of antimicrobial resistance. Since 2013, the prevalence of reduced azithromycin susceptibility increased in the United States; however, these strains were highly susceptible to cephalosporins. We identified a cluster of Neisseria gonorrhoeae isolates with high-level azithromycin resistance, several of which also demonstrated decreased ceftriaxone susceptibility. METHODS: Eight N. gonorrhoeae isolates collected from 7 patients on Oahu, Hawaii, seen 21 April 2016 through 10 May 2016 underwent routine Etest antimicrobial susceptibility testing by the Hawaii Department of Health. All demonstrated elevated azithromycin minimum inhibitory concentrations (MICs) >256 µg/mL and elevated ceftriaxone MICs (≥0.125 µg/mL). Isolates were sent to the University of Washington and CDC for confirmatory agar dilution testing; sequence data were sent to CDC for analysis. All patients were interviewed and treated, and when possible, partners were interviewed, tested, and treated. RESULTS: All isolates had azithromycin MICs >16 µg/mL and 5 had ceftriaxone MICs = 0.125 µg/mL by agar dilution. All isolates were ß-lactamase positive and were resistant to penicillin, tetracycline, and ciprofloxacin. Genomic analysis revealed genetic relatedness. No patients reported recent travel or antibiotic use, and no male patients reported male sex partners. All patients were successfully treated. CONCLUSIONS: This cluster of genetically related gonococcal isolates with decreased ceftriaxone susceptibility and high-level azithromycin resistance may bring the threat of treatment failure in the United States with the current recommended dual therapy one step closer.

Strengthening Global Surveillance for Antimicrobial Drug-Resistant Neisseria gonorrhoeae through the Enhanced Gonococcal Antimicrobial Surveillance Program.

Monitoring trends in antimicrobial drug-resistant Neisseria gonorrhoeae is a critical public health and global health security activity because the number of antimicrobial drugs available to treat gonorrhea effectively is rapidly diminishing. Current global surveillance methods for antimicrobial drug-resistant N. gonorrhoeae have many limitations, especially in countries with the greatest burden of disease. The Enhanced Gonococcal Antimicrobial Surveillance Program is a collaboration between the World Health Organization and the Centers for Disease Control and Prevention. The program aims to monitor trends in antimicrobial drug susceptibilities in N. gonorrhoeae by using standardized sampling and laboratory protocols; to improve the quality, comparability, and timeliness of gonococcal antimicrobial drug resistance data across multiple countries; and to assess resistance patterns in key populations at highest risk for antimicrobial drug-resistant gonorrhea so country-specific treatment guidelines can be informed.

Antimicrobial Drug Prescription and Neisseria gonorrhoeae Susceptibility, United States, 2005-2013.

We investigated whether outpatient antimicrobial drug prescribing is associated with Neisseria gonorrhoeae antimicrobial drug susceptibility in the United States. Using susceptibility data from the Gonococcal Isolate Surveillance Project during 2005-2013 and QuintilesIMS data on outpatient cephalosporin, macrolide, and fluoroquinolone prescribing, we constructed multivariable linear mixed models for each antimicrobial agent with 1-year lagged annual prescribing per 1,000 persons as the exposure and geometric mean MIC as the outcome of interest. Multivariable models did not demonstrate associations between antimicrobial drug prescribing and N. gonorrhoeae susceptibility for any of the studied antimicrobial drugs during 2005-2013. Elucidation of epidemiologic factors contributing to resistance, including further investigation of the potential role of antimicrobial drug use, is needed.

Azithromycin Resistance and Decreased Ceftriaxone Susceptibility in Neisseria gonorrhoeae, Hawaii, USA.

During 2016, eight Neisseria gonorrhoeae isolates from 7 patients in Hawaii were resistant to azithromycin; 5 had decreased in vitro susceptibility to ceftriaxone. Genomic analysis demonstrated a distinct phylogenetic clade when compared with local contemporary strains. Continued evolution and widespread transmission of these strains might challenge the effectiveness of current therapeutic options.

Prevalence and risk factors associated with STIs among women initiating contraceptive implants in Kingston, Jamaica.

BACKGROUND: There is limited information on rates of STIs in Jamaica due to syndromic management and limited aetiological surveillance. We examined the prevalence of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and Trichomonas vaginalis (TV) and characteristics associated with STIs among sexually active women who participated in a randomised trial of a progestin implant initiation in Jamaica (the Sino-Implant Study (SIS)). METHODS: SIS was a randomised trial conducted in Kingston, Jamaica, from 2012 to 2014 to evaluate whether initiation of the Sino-Implant (II) led to more unprotected sex among women ages 18-44 years. Data collected included self-reported demographic, sexual behaviour information; and vaginal swabs collected at baseline, 1-month and 3-month follow-up visits for a biomarker of recent semen exposure (prostate-specific antigen (PSA)) and for STIs. We examined associations between STIs and PSA, demographics, sexual behaviour and insertion of an implant, with a repeated-measures analysis using generalised estimating equations (SAS Institute, V.9.3). RESULTS: Remnant vaginal swabs from 254 of 414 study participants were tested for STIs. At baseline, 29% of participants tested for STIs (n=247) had laboratory-confirmed CT, 5% NG, 23% TV and 45% any STI. In a repeated-measures analysis adjusted for study arm (immediate vs delayed implant insertion), those with PSA detected did not have an increased prevalence of any STI (prevalence ratio (PR)=1.04 (95% CI 0.89 to 1.21)), whereas prevalence decreased for each 1-year increase in age (PR=0.98 (95% CI 0.97 to 0.99)). Immediate implant insertion was not associated with increases in any STI in subsequent visits (PR=1.09 (95% CI 0.94 to 1.27)). CONCLUSIONS: Although the prevalence of laboratory-confirmed STIs was high, the immediate initiation of a contraceptive implant was not associated with higher STI prevalence rates over 3 months. TRIAL REGISTRATION NUMBER: NCT01684358.

Population-attributable fraction of tubal factor infertility associated with chlamydia.

BACKGROUND: Chlamydia trachomatis infection is highly prevalent among young women in the United States. Prevention of long-term sequelae of infection, including tubal factor infertility, is a primary goal of chlamydia screening and treatment activities. However, the population-attributable fraction of tubal factor infertility associated with chlamydia is unclear, and optimal measures for assessing tubal factor infertility and prior chlamydia in epidemiological studies have not been established. Black women have increased rates of chlamydia and tubal factor infertility compared with White women but have been underrepresented in prior studies of the association of chlamydia and tubal factor infertility. OBJECTIVES: The objectives of the study were to estimate the population-attributable fraction of tubal factor infertility associated with Chlamydia trachomatis infection by race (Black, non-Black) and assess how different definitions of Chlamydia trachomatis seropositivity and tubal factor infertility affect population-attributable fraction estimates. STUDY DESIGN: We conducted a case-control study, enrolling infertile women attending infertility practices in Birmingham, AL, and Pittsburgh, PA, during October 2012 through June 2015. Tubal factor infertility case status was primarily defined by unilateral or bilateral fallopian tube occlusion (cases) or bilateral fallopian tube patency (controls) on hysterosalpingogram. Alternate tubal factor infertility definitions incorporated history suggestive of tubal damage or were based on laparoscopic evidence of tubal damage. We aimed to enroll all eligible women, with an expected ratio of 1 and 3 controls per case for Black and non-Black women, respectively. We assessed Chlamydia trachomatis seropositivity with a commercial assay and a more sensitive research assay; our primary measure of seropositivity was defined as positivity on either assay. We estimated Chlamydia trachomatis seropositivity and calculated Chlamydia trachomatis-tubal factor infertility odds ratios and population-attributable fraction, stratified by race. RESULTS: We enrolled 107 Black women (47 cases, 60 controls) and 620 non-Black women (140 cases, 480 controls). Chlamydia trachomatis seropositivity by either assay was 81% (95% confidence interval, 73-89%) among Black and 31% (95% confidence interval, 28-35%) among non-Black participants (P < .001). Using the primary Chlamydia trachomatis seropositivity and tubal factor infertility definitions, no significant association was detected between chlamydia and tubal factor infertility among Blacks (odds ratio, 1.22, 95% confidence interval, 0.45-3.28) or non-Blacks (odds ratio, 1.41, 95% confidence interval, 0.95-2.09), and the estimated population-attributable fraction was 15% (95% confidence interval, -97% to 68%) among Blacks and 11% (95% confidence interval, -3% to 23%) among non-Blacks. Use of alternate serological measures and tubal factor infertility definitions had an impact on the magnitude of the chlamydia-tubal factor infertility association and resulted in a significant association among non-Blacks. CONCLUSION: Low population-attributable fraction estimates suggest factors in addition to chlamydia contribute to tubal factor infertility in the study population. However, high background Chlamydia trachomatis seropositivity among controls, most striking among Black participants, could have obscured an association with tubal factor infertility and resulted in a population-attributable fraction that underestimates the true etiological role of chlamydia. Choice of chlamydia and tubal factor infertility definitions also has an impact on the odds ratio and population-attributable fraction estimates.

Development of a rectal sexually transmitted infection (STI) Model in Rhesus macaques using Chlamydia trachomatis serovars E and L2.

BACKGROUND: Rectal STI coinfection models enhance the understanding of rectal HIV transmission risk factors. MATERIALS AND METHODS: Rhesus macaques (n=9) were exposed to one of three rectal Chlamydia trachomatis (CT) challenges: C. trachomatis L2 (CT-L2 ); C. trachomatis serovar E (CT-E), followed by CT-L2 ; or CT-E, treatment/clearance, then CT-L2 . Infections were monitored by PCR. Weekly blood and rectal secretion/lavage samples were collected for cytokine analyzes and/or epithelial sloughing, occult, and overt blood determinations. RESULTS: Chlamydial infections were successfully established in each animal, with varying degrees of persistence. Mucosal IL-1beta was upregulated in animals consecutively infected with CT-E then CT-L2 (P=.05). Epithelial sloughing was also significantly increased post-infection in this group (P=.0003). CONCLUSIONS: This study demonstrates successful rectal infection of rhesus macaques with CT-E and CT-L2 and describes measures of assessing rectal inflammation and pathology. Different infection strategies yield varying inflammatory and pathologic outcomes, providing well-described models for future SIV/SHIV susceptibility studies.