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.

Complete Genome Sequence of Neisseria gonorrhoeae Multilocus Sequence Type ST7363 Isolated from Thailand.

A Neisseria gonorrhoeae multilocus sequence type (MLST) ST7363 strain was isolated from a patient at the Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand, in 2010 and completely sequenced. This strain is susceptible to ceftriaxone and cefixime. A complete circular chromosome and circular plasmids were assembled from combined Oxford Nanopore Technologies (ONT) and Illumina sequencing.

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%]).

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.

Pre-exposure Prophylaxis Use and Detected Sexually Transmitted Infections Among Men Who Have Sex With Men in the United States-National HIV Behavioral Surveillance, 5 US Cities, 2017.

BACKGROUND: Men who have sex with men (MSM) using HIV pre-exposure prophylaxis (PrEP) may be at high risk for bacterial sexually transmitted infections (STIs). We examined the prevalence of extragenital gonorrhea and chlamydia by PrEP status among a multisite sample of US MSM. METHODS: MSM aged ≥18 years were recruited through venue-based sampling to participate in the 2017 National HIV Behavioral Surveillance. In 5 cities (San Francisco, Washington DC, New York City, Miami, and Houston), participants completed a questionnaire, HIV testing, and pharyngeal and rectal STI specimen self-collection. We measured prevalence of pharyngeal and rectal gonorrhea and chlamydia among self-reported non-HIV-positive MSM who reported using or not using PrEP in the previous 12 months. RESULTS: Overall, 29.6% (481/1627) of non-HIV-positive MSM reported PrEP use in the past year. MSM who reported PrEP use were more likely to have any STI (ie, extragenital gonorrhea and/or chlamydia) than MSM not on PrEP [14.6% vs. 12.0%, adjusted prevalence ratio (aPR) = 1.5, 95% confidence interval (CI) : 1.1 to 2.0], reflecting differences in rectal chlamydia prevalence (8.7% vs. 6.0%, aPR = 1.6, 95% CI: 1.1 to 2.4). PrEP use was not associated with pharyngeal chlamydia, pharyngeal gonorrhea, or rectal gonorrhea. CONCLUSIONS: The prevalence of extragenital STI was high for both MSM on PrEP and those not on PrEP in the past year. MSM on PrEP were more likely to have rectal chlamydia but not pharyngeal STIs or rectal gonorrhea. Our findings support regular STI testing at exposed anatomic sites as recommended for sexually active MSM, including those on PrEP.

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.

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.

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).

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.

The first year of the global Enhanced Gonococcal Antimicrobial Surveillance Programme (EGASP) in Bangkok, Thailand, 2015-2016.

Antimicrobial-resistant Neisseria gonorrhoeae (NG) infection is a global public health threat, and there is a critical need to monitor patterns of resistance and risk factors. In collaboration with the World Health Organization (WHO), the U.S. Centers for Disease Control and Prevention (CDC), and the Thailand Department of Disease Control (DDC), Ministry of Public Health (MoPH) implemented the first Enhanced Gonococcal Antimicrobial Surveillance Programme (EGASP) in November 2015. Men presenting with urethritis at two clinical settings in Bangkok, Thailand (Bangrak Hospital [BH] and Silom Community Clinic @TropMed [SCC @TropMed]) provided demographic and behavioral information and had a urethral swab for Gram's stain and NG culture collected. The NG isolates were evaluated for antimicrobial susceptibility by the Epsilometer test (Etest) to determine minimum inhibitory concentrations (MICs) for cefixime (CFM), ceftriaxone (CRO), azithromycin (AZI), gentamicin (GEN), and ciprofloxacin (CIP). From November 2015 -October 2016, 1,102 specimens were collected from 1,026 symptomatic men; 861 (78.1%) specimens were from BH and 241 (21.9%) specimens were from SCC @TropMed. Among the 1,102 specimens, 582 (52.8%) had intracellular Gram-negative diplococci and 591 (53.6%) had NG growth (i.e., NG infection); antimicrobial susceptibility testing (AST) was performed on 590 (99.8%) NG isolates. Among all symptomatic men, 293 (28.6%) had sex with men only, 430 (41.9%) were ages 18-29 years, 349 (34.0%) had antibiotic use in the last 2 weeks, and 564 (55.0%) had NG infection. Among 23 men with repeat NG infection during this first year of surveillance, 20 (87.0%) were infected twice, 2 (8.7%) were infected three times, and 1 (4.3%) was infected more than four times. All NG isolates were susceptible to CFM and CRO, and had MICs below 2 µg/mL for AZI and below 16 µg/mL for GEN. Overall, 545 (92.4%) isolates were resistant to CIP. This surveillance activity assessed individual patients, and included demographic and behavioral data linked to laboratory data. The inclusion of both individual and laboratory information in EGASP could help identify possible persistent infection and NG treatment failures. Expansion of EGASP to additional global settings is critical to assess trends and risk factors for NG, and to monitor for the emergence of resistance.

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.

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.

Assessing prevalence of missed laboratory-confirmed sexually transmitted infections among women in Kingston, Jamaica: results from a secondary analysis of the Sino-Implant clinical trial.

OBJECTIVES: To assess potentially missed sexually transmitted infections (STIs), we compared clinically diagnosed STIs to laboratory-confirmed diagnoses of gonorrhoea (GC), chlamydia (CT) and trichomonas (Tvag). DESIGN: Secondary analysis of a randomised controlled trial. SETTING: We used data and specimens previously collected for the Sino-Implant Study in Kingston, Jamaica. PARTICIPANTS: The Sino-Implant Study randomised 414 women to receive a levonorgestrel implant at either baseline or 3 months post-enrolment to evaluate unprotected sex after implant initiation. This analysis used 254 available vaginal swab samples. OUTCOME MEASURES: Clinically diagnosed STIs were determined from medical records by assessing clinical impressions and prescriptions. Laboratory-confirmed STIs included GC, CT and Tvag tested by Aptima Combo 2 for CT/GC and Aptima Tvag assays (Hologic, San Diego, California, USA). Log-binomial regression models fit with generalised estimating equations were used to estimate associations of clinically diagnosed STIs with laboratory-confirmed diagnoses and demographic and behavioural characteristics. RESULTS: Overall, 195 (76.8%) women had laboratory-confirmed STI (CT, GC or Tvag) while only 65 (25.6%) women had clinically diagnosed cervicitis and/or vaginitis during the study period. Clinical diagnosis missed 79.7% of laboratory-confirmed STIs: 85% of GC (n=17/20), 78.8% of CT (n=141/179) and 80.0% of Tvag (n=180/225). Hormonal contraceptive use in the month prior to the study visit was significantly associated with clinical diagnosis at any time point (prevalence ratio (PR): 1.65, 95% CI 1.07 to 2.54). As age increased, clinically missed infections significantly decreased (PR: 0.98 per year increase, 95% CI 0.97 to 1.00). CONCLUSIONS: The prevalence of laboratory-confirmed STIs was much higher than what was captured by clinical diagnosis. GC, CT and Tvag were not accurately detected without lab confirmation. Missed diagnoses decreased with older age. Increased laboratory capacity and refinement of the syndromic approach are needed to protect the health of sexually active Jamaican women. TRIAL REGISTRATION NUMBER: NCT01684358.

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.

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.

Accuracy and reproducibility of the Etest to detect drug-resistant Neisseria gonorrhoeae to contemporary treatment.

PURPOSE: Neisseria gonorrhoeae is a sexually transmitted bacterial pathogen that continues to evolve to become resistant to known antibiotics. In preparing for potential emergence, the Centers for Disease Control and Prevention recommends that clinical laboratories maintain or develop protocols to assess antibiotic susceptibly for this organism. This study examines the intra-laboratory variability of using the Etest method to provide consistent MIC values for N. gonorrhoeae and also compared the results of the Etest to known agar dilution MIC values. METHODOLOGY: Clinical N. gonorrhoeae isolates, 100 paired duplicates, were tested by eight laboratories for antibiotic susceptibility to ceftriaxone, cefixime and azithromycin using Etest strips.Results/Key findings. Overall, >80 % of the paired Etest MIC values were within one log2 dilution of the replicate. When compared to the agar dilution reference method, the cefixime Etest MIC values were consistently underreported by one dilution (seven laboratories) or two dilutions (one laboratory). The azithromycin Etest MIC values agreed 90.7 % with the agar dilution MIC values while the agreement with ceftriaxone was 90.9 %. CONCLUSION: Overall, the Etest method yielded reproducible MIC values within each laboratory with the azithromycin and ceftriaxone MIC results consistent to the reference agar dilution method while the cefixime result tended to provide a lower MIC value.

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.

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.